Moses Ludel

David, if you used an MLS head gasket, there would normally be no need for re-torque. In the video, I devote three full minutes to cylinder head nut torque details. Review the video from 14:00 minutes to 17:00 minutes. Actual final torque, established by tightening the four cylinder head nuts uniformly and in cross, is 49 ft-lb. Yes, it's 49 foot-pounds or approximately 67 Nm. Make a point of re-adjusting that head torque real soon to prevent coolant seepage into the cylinder or damage to the head gasket that would require removal of the head for gasket replacement. I'm very pleased and excited that you have the engine running, you're very close to a finished job at this point! If the head gasket is the tough MLS type, you likely are fine here if you re-torque the head now. (Regardless of the current torque setting, if uniform and equal, the gasket is flat and probably sealing.) This will require removal of the rocker box and, as you suggest, a fresh valve clearance check and adjustment. All of this will go quickly, you're familiar with the process! Keep us posted...and congratulations, David! Moses

Fascinating, David, the photos say it all! I haven't seen innovative welding like this since watching the BMW frame repair at Mongolia during the 'Long Way Round' movie with Ewan McGregor and Charley Boorman. Hey, ya gotta do what ya gotta do! (A great song, incidentally, recently resurrected in the movie "Blood Ties". I knew the Johnny Rivers version from my high school days, the soundtrack in the movie was Al Wilson's take.) The key to success with welding is the complete fusion of metal that underlies any weld. What you want here is enough heat to melt the base metal on each side of the weld, then the insertion of a metallurgically appropriate filler metal into the molten puddle. This technology may not warrant discussion with these weldors at Burundi. However, I never underestimate the capacity or skill of any practiced weldor. Fortunately, welding is as much a hand/eye and intuitive application as it is academic and technical. When I taught welding, we had a particular student who did well with oxy-acetylene and went directly to TIG, laying down exceptional GTAW welds. Upon graduation, he wound up performing aircraft engine impeller repairs. His training was no different than others, and some students, frankly, failed to master the craft, never grasping how much heat to apply or when to dip the filler metal into a liquid puddle. When I watch weldors, I'm absorbed in their "process" and immediately conscious of right moves and wrong. This is from practice that began with a year of welding training in high school. I was fortunate enough to experience the post-WWII methodology: start with basics and get as much hands-on time as possible. Our instructor, who doubled as the FFA (Future Farmers of America) chapter advisor, repeatedly drove home the fundamentals. As a result, we each learned to gas weld, braze and stick weld properly. I thank Mr. Gray, he paved the way for my later training and many years of professional welding around engineering plant repairs, heavy equipment repair work and automotive technology. When I can muster the time, I'd like to produce a series of welding instructional HD videos and impart that experience. Best not to grind off any metal...I'll keep my eye open for a pristine stock muffler, David. Often, owners discard the OEM system when upgrading to performance equipment...Maybe we can drum up a backup unit. Moses

Welcome to the forums, Michael! Here's the rundown on what you face with this swap... 1) If emissions are an issue, the 4.2L, especially if still carbureted, would be a retro engine and not acceptable for emission compliance in states with smog inspection. If you have a Mopar EFI conversion (preferably a second generation system with single rail FI patterned after the '97-up TJ Wrangler), you might be able to get by with an inspector willing to ignore (or ignorant of) the earlier 4.2L long block versus a 4.0L engine. This would still be an engine change from four- to six-cylinder, which requires a smog referee station in California. 2) The 2.5L bellhousing pattern is entirely different than the 4.2L. (See my article at: http://www.4wdmechanix.com/YJ-&-TJ-Jeep-Wrangler-Clutch-Replacement.html. This is a 2.5L with AX5 transmission in a 1987-90 YJ Wrangler.) You also have an AX5 manual transmission in the '97 TJ, which was only used with 4-cylinder engines. This is an issue, as the AX5 will not work with the AX15 bellhousing, so you'll be seeking an AX15 transmission and bellhousing. The flywheel for the 2.5L could work with your 4.2L crankshaft, I've used a resurfaced 2.5L flywheel on a 4.0L engine. You'd need the correct pilot bearing for the 4.2L crankshaft and use of a manual transmission. 4) The real kicker is the frame. Both the Jeep YJ Wrangler and Jeep TJ Wrangler use a different frame for the 2.5L engine versus the inline six-cylinder 4.2L or 4.0L engines. At the magazine, I show what it takes to modify the frame and install a 4.0L or 4.2L in a YJ Wrangler originally equipped with the 2.5L inline four: http://www.4wdmechanix.com/MIG-Welding.html. The same principle applies with a TJ Wrangler's 2.5L four versus 4.0L inline six-cylinder frame. Aside from the emissions legality issue, unless you have welding and fabrication skills, this could be a major project. The difference is the location of the side/front motor mounts. The 2.5L frames have the mounts permanently welded further back on the frame rails. Whether this was an engineering upgrade or for ease of production, the two-frame production method is somewhat puzzling. On CJs, the inline 4-, inline 6- and V-8 engines could be accommodated with factory bolt-in frame/engine brackets and even a cross brace bar that bolted into position. Beginning with the YJ Wrangler, AMC/Jeep adopted the four- and inline six-cylinder frame approach. Chrysler continued this approach through the Jeep TJ Wrangler era. As a point of interest, the welding and fabrication that you see in my article is overkill compared to the OE frame brackets. The basic brackets are Advance Adapters products, the additional, reinforcing steel plate is by yours truly. The vehicle is my son-in-law and daughter's, and I wanted the mounts and welding to be indestructible for off-road, hard four-wheeling. Welding process is MIG, in this case with ER70S-6 0.035" wire. Trust this helps clarify, Michael... Moses

You're welcome, Ax167...Let's make that YJ reliable! Moses

Ax161...Welcome to the forums. When the 2.5L runs right, everything is good? This sounds like the crankshaft position sensor (CPS) not getting a consistent reference signal during cranking. Whether or not you have rear main seal oil seepage, the CPS picks up oil and debris over time. Often the device is not defective, just dirty. The CPS is at the back of the engine on the converter housing or bellhousing. When you're looking forward, the CPS bolts into position around 11 o'clock. Remove the CPS without damaging the plastic wire connector. Clean the CPS with electrical contact cleaner and test the ohms-resistance, moving the wires gently to be sure there is not a wire open. The test is across the "A" and "B" terminals at the CPS connector. The test is supposed to be run with the engine hot, although this gets difficult in terms of burning yourself, so be very careful. With the CPS connector plug disconnected and your ohmmeter leads between the "A" and "B" terminals, you should get a reading of 200 +/- 75 ohms. In addition to the ohms resistance reading, you need a clean CPS probe. Try this and see if that's the fix. If not, we'll take it to the next step. Another general problem area is poor or oxidized wire grounds. In particular, the engine to body and engine to frame and battery grounds must not be oxidized or loose. This turns up a lot with the early YJ Wrangler 2.5L. Check the ground attachment screws for oxidation and resistance. Moses

The dyne results are enough to warrant the programmer tune. You have the option/settings for a mild tune, more aggressive tune and even stock. An added benefit is the ability to calibrate your speedometer for the tire diameter. All in all, the software fix is the least invasive and will serve you well over time. I'm running the full performance mode and not pushing the throttle, which is very responsive when you do—at the cost of fuel consumption. You will be impressed with the performance boost, very clearly Chrysler left a lot of power switched off. In part, this is due to the 48RE transmission, so beware. Adding power does place more load on a transmission noted for issues when stressed. I do like your pyrometer approach, wasn't aware that Edge offered that option. A standalone pyrometer kit is expensive but the best barometer for diesel preservation. When installing the pyrometer, there is a very specific way to tap into the exhaust manifold and avoid damaging the turbo. You want true engine exit exhaust temperature here. The programming will put additional power into the equation. I'm curious about the fuel efficiency gains with the oversized tires and stock axle gearing. The Cummins ISB turbo engine is not a "high speed diesel". I am a former heavy equipment operator (Local 3, Operating Engineers in the '70s) from the 1693 Cat era. In off-highway tune, those 893 cubic inch, inline six cylinder off-highway engines produced and peaked 1090 ft. lbs. torque at 1000 rpm, with a governed maximum speed around 1700 rpm. Tip in the pedal, maximum torque on tap. In off-road equipment, they pulled and dragged like a locomotive with that kind of torque. Off-highway emissions were a non-issue at the time. The basic Cummins ISB design is from the same era as these Cat engines. It behaves more like a medium duty truck engine in its Dodge Ram form. The major gain with this engine over the Powerstroke/Navistar and the Duramax is the quick torque rise. Here, an 8-speed transmission, or at least 6, would be good. If I had my choice all over again, I would have gone with the manual 6-speed on this chassis. Were it not for the considerable effort involved, I'd consider a changeover. This is also my rationale about the Gear Vendors split shifting, although that gets busy and, as you note, would take some time to cost amortize. My personally imposed rpm ceiling is 2400 rpm, though there have been times when I've pushed this engine to 2900-3000. Higher rpm is possible but not rational. Note: Discussing mileage, I have a friend with an '04 Ram 2500 Cummins. Shifting at 2,400 rpm per gear (manual transmission) like a gasoline engine, he never saw better than 18 mpg with this truck. I suggested the Hypertech programmer to make better power and efficiency at a higher rpm. I am very interested in the results you get with your programmer pick. Before the Hypertech, I was resistant to the idea, since the install, I'm very much in favor of a tune improvement here. Let us know your programmer choice and the results! I'm most curious to see whether the 3.73 gears and oversized tire diameter will work together. Re-calibrating the speedo will help put the package into perspective. Moses

Wastintime...You do have a good bump in tire diameter, much like my '05 3500, which now has 34.6" diameter tires. I really lost fuel mileage with these tires and 3.73 gearing. That was also before the chip change, though. The later programming/tuning change was a major performance gain. In discussions, Hypertech believed that fuel mileage would go up considerably with the tune, but since I installed the program after the change to 4.56:1 gearing, I cannot confirm a significant gain. What I do know is how hypersensitive the Cummins ISB 5.9L engines can be to rpm and load. If you go to Cummins PowerSpec, commercial vehicles (to 50K GVCW) use lower gearing like 4.10:1 with our original size tires. The chart would have 4.56 for tire diameters beyond this. (Cummins thinks the ISB engines should spin 2150-2400 rpm at the highway cruise speed. That would take our fuel mileage into the dirt, but we're not lugging the commercial loads of a medium duty truck.) That was my motivation for the 4.56:1 change, as Cummins does know these engines. I'm not, however, constantly pulling a nine horse trailer that would rival commercial use. So, if the oversized tires are important, a direct restoration in gearing would be 4.10 in your case. If you plan to tow regularly and accept that towing does create a different fuel mileage dynamic, then 4.30:1 (if available) might be a good choice. In any case, after careful monitoring and experience, I do accept that my truck will never see 24 mpg consistently again. This is due to the increase in curb weight, the lift and aerodynamics losses, and the friction of the tires, which you hint about when questioning tread patterns. Ironic that you mention the California towing scenario. My first inkling that the 3.73:1 gears would not work with the oversized tires was a trip from the Reno Area to King of the Hammers (Johnson Valley) with a Vortex toy hauler in tow. I thought that my truck, with its historic track record for fuel efficiency plus the "overdriving effect" of the big tires, would get better mileage than earlier tows. Years prior, on a trip to Moab with a virtually stock, non-accessorized truck and the XJ Cherokee on our car hauling flatbed trailer, we towed 70 mph with the cruise set, including 6% grades, and netted 17 mpg. To my great disappointment, the Johnson Valley trip with big tires and 3.73:1 gearing netted a whopping 12-13 mpg at best! We're bucking physics: There are trade-offs for every change made to our trucks. Lift kits and oversized tires, add-on accessories, removing the air dam up front, take your pick, each takes a toll. Realistically, the only way you'll win here is apples for apples. I believe the engine programming change was very worthwhile if for no other reason than pushing the increased torque peak up the rpm scale to a realistic 2,000-2,100 rpm range. For your cruise speeds and towing habits, this could help. I would suggest the use of the Hypertech Max Energy program. Try it first with your current tires and gearing. (I'd really like to know your results!) One of the best inducements for the Hypertech Max Energy program was its promised "tow friendly" tuning. Although I would still like to add a pyrometer to confirm load and heat with this program, I've experienced no negative issues to date. Note that I am very engine and transmission protective while towing and watch my engine coolant temp gauge for any indication of extra loads. I am always driving for fuel efficiency, engine protection and to take a load off the 48RE transmission. This latter concern is important. The lower 4.56:1 gearing substantially reduced load on the 48RE. Oversized tires with 3.73 stock gearing has the opposite effect. BFG and other tire producers do rate tires for friction and economy. As a rule, mud tire treads are not the best pick for economy and rolling resistance. On your point #2, you currently are getting an "overdrive" effect with the big tires. If anything, the wrong tuner/programmer might move the torque peak in the wrong direction! This is not the case for the Hypertech Max Energy tune, however. The torque at 1,600 rpm (stock torque peak rpm) is as good with the Max Energy program as with the stock programming. (See the dynamometer run charts at my article on the Hypertech product: http://www.4wdmechan...ge-Cummins.html.) I'm without bias when it comes to helping owners get the best mileage possible. There are several variables involved. Let's work through this for your driving and towing situation. Moses

The gas welding (oxygen-acetylene) process is optimal for this fix, David. The amount of oxidation rules out TIG, it would be near impossible to descale the parts sufficiently for that process. MIG (GMAW) is an option, a talented stick (SMAW) weldor might be able to do the repair, too. (Maybe a pipeline trained Burundi welding expert?) Thinner gauge, older metal like this, I really like oxy-acetylene. Check out the magazine video examples, you'll understand my enthusiasm for gas welding in these cases. When you have the piece repaired, make certain the weldor positions the two shell parts as they were originally. Given the bends and twists in the muffler assembly, off-setting even slightly would have dire consequences when trying to reinstall the muffler! Should turn out well, this is resourceful and saves considerable cost. There are several aftermarket mufflers for performance gains (FMF and others). You've likely racked up enough startup costs for now! Moses

wastintime...Welcome to the forums, glad the information on steering linkage and the box helped. First off on the tire size change: Did you calibrate the speedometer to match the new tire size? Are we talking about an accurate 20 mpg at 70-75 and 12 when pulling? When I ran the 265/70s with 3.73 gearing and empty, the typical best mileage was 24 at 65-69 mph. When I went to a steady 75, mileage would drop to around 22. Here is my calibration video: http://www.4wdmechanix.com/How-to-Dodge-Ram-Speedometer-Calibration.html. Here's how to check error quickly: http://www.4wdmechanix.com/How-to-Measuring-Speedometer-Error.html. What is the rated diameter of the 295/75/17 tires with your wheel width? The 265s should have been around 31.9" if OEM type tires. Your 295/75s are likely in the neighborhood of 34.5". This is a fairly large bump if you have 4.10 gears and a manual transmission. I did the reprogram with Hypertech and would readily acknowledge the performance gain. Fuel efficiency gains were marginal, although it did not get worse. The tune gives me peak torque by 2100 rpm instead of the rated 1600 stock. Here're my findings: http://www.4wdmechanix.com/Hypertech-Max-Energy-Power-Programmers-for-Jeep-4.0L-and-Dodge-Cummins.html. The only thing that will assuredly get your mileage back is a gearing change. I have the 48RE automatic, and the closest correction for my 34.6" diameter tires would be 4.10 gears. I opted for 4.56:1. (4.30:1 was not available from AAM at the time, I understand that it is now.) My tires are 34.6" (rated as a 35") diameter. I went a bit far with the gearing—intentionally. The plan is more trailer pulling and a 65 mph cruise speed peak when I can keep a lid on it. The fuel mileage penalty is linear beyond 65 mph with these gears. 4.10s would have sufficed were it not for the hefty accessories, winch bumper and auxiliary fuel tank, etc. I'm guessing curb weight "empty" (auxiliary fuel tank and fuel included) is around 8800-8900 pounds. I need to weigh the truck and confirm...Had the 4.30:1 gears been available, I would have picked them. I'm currently planning a true 36" diameter tire change. That would provide a compromise between the 4.10 and 4.56 ratios with the current 4.56:1 ring-and-pinions. I'm geared a bit lower than I need, and like in your case, we're running empty a lot more than trailering. With that moderate change (1.4" diameter), I would expect a true 21-23 mpg at 70 mph on a flat road. If you decide to do the 11.5" and 9.25" AAM ring-and-pinion gear change out yourself, my video coverage at Vimeo on Demand would be useful: http://www.vimeo.com/ondemand/aamaxlerebuild. If you're referring to the link to Cummins PowerSpec, try this: http://cumminsengines.com/powerspec. Trust this is helpful, pleased to take the discussion further... Moses

David...In the video, you can see me lubing the camshaft bearings and sprocket/chain with LubeGuard. The auto-decompressor mechanism could gain from a light lube in that process. This is a busy mechanism with a one-way, spring loaded clutch. It can get sticky. On my XR650R, pre-rebuild, the motorcycle had set for a long period in storage (previous owner). I attempted to kick over the engine and had the auto-decompressor jam several times with increased kicking effort and even a lock up of the kick starter, which did free itself without damaging parts, fortunately. This was another incentive for my opting out of the auto-decompressor and installing the Hot Cams Stage 1 camshaft to eliminate the stock auto-decompressor. Again, there is nothing intrinsically wrong with the auto-decompressor or stock camshaft, many racers liked the feature. In "Dust to Glory", it appears that the engines use an auto-decompressor with Stage 2 level camshafts, as the riders are kicking repeatedly and in rapid succession during restarts at the pits. This is not possible with the manual decompressor, as it takes a few seconds to "find" TDC and tip over slightly before kicking the starter through. Though this may sound time consuming, I can start a high compression thumper with just the hand lever decompressor in about the same time or less than an auto-decompressor. For high compression XR thumpers, Honda capitulated early on and added the auto-decompressor for kick starting. My XR350R and XR500R each have cable actuated decompressor mechanisms. The kick starter mechanism actuates an exhaust valve unseating lever via an external cable to the rocker box. The auto de-compressor became incorporated with the camshaft on the XR600R, a feature that the XR650R inherited. Note: Some members are having difficulty adding photos or illustrations to posts. Simply click on "More Reply Options" next to the "Post" button. Drop to the bottom of the full editor box, and you'll find the "Attach Files" button at the left. That will open up your computer file browser, where you can pick the photo file or any other file (several at one time if you like), then add it/them to the attachments. You'll see the photo(s) or file load. Now place the curser at the point in the edit box where you want the photo to appear. Click on the "Add" button next to the loaded file. The bracketed file description will appear in the edit box. When you "Post", the photo (thumb) or file (like the PDFs I like to toss out for folks) will appear in position at your post! Moses

Thanks for your interest in the CJ rebuilder's book, it will provide considerable guidance as you delve into this problem with the Dana 300, Kevin. I'm sorry the fix isn't simple, but we do depend upon the transfer case in the middle of nowhere, and at least you're not sending a cell phone distress message from the backcountry. The Dana 300, with its helically cut gears, is the best "stock" transfer case Jeep ever offered in a light utility 4x4 model. Iron cased and gear drive, you're light years ahead once you rebuild this unit. Let's cross fingers that the needed parts will not stack up. If the unit was not terribly noisy, and if the gear clash did not cause added damage, you may find that most hard parts are reusable. The springs, detents and poppets are the interlocking mechanism between the shift rails. They help hold or "detent" each gear position and also prevent grabbing two gears at one time as the shifter moves. Between my book and Forman's contribution at the forum, you should have bases covered. We're here for any additional questions or as sounding boards! Moses

Thanks, Tim...I'll keep in mind your suggestions when I do the video. By habit, I lay pieces out in order of disassembly and am oriented before parts cleaning. Others may lose track, though, and you make a good point. Keep us posted on how this works out for the XJ Cherokee project. Also where you find the snap rings you need. Keep in mind that they are selective fit thicknesses. Moses

Kevin, there are a few "smaller" repairs that can create better gear hold-in on a Dana 300. However, simpler cures like carpet or boot interference are unlikely, since 2H is not at the top or bottom of the shift pattern. Before plunging into a rebuild, I would suggest a quick check of the shift rails and linkage around the shift lever. There are times when either loose parts or binding prevent full shifts or detent action in a given gear. That's the external fix. Shift rail springs and poppets can cause trouble, but these parts usually last between rebuilds. Our fellow forum member, Forman, did a thorough rebuild on a CJ-7 Dana 300 and posted with detailed photo illustrations. Here is that post and follow-up: http://forums.4wdmechanix.com/topic/260-rebuilding-a-jeep-cj-7-dana-300-transfer-case/ I perform a detailed step-by-step rebuild of the Dana 300 in my book, the Jeep CJ Rebuilder's Manual: 1972-86 (Bentley Publishers). If you plan to do your own rebuilding of sub-assemblies on your Jeep CJ, this book has served many owners well. It is available through Advance Adapters and several of the 4WD/Jeep parts suppliers. Moses

Marc...Could be time for a cylinder leak down test. You shared earlier that the shop did a compression test, and this is not the same thing. Do you have an air compressor at home? A wonderful tool for pinpoint diagnostics of engine seal is the leakdown tester. I share details on leakdown testing and vacuum tests at these forum discussions, including tips on DIY work: http://forums.4wdmechanix.com/topic/164-how-to-make-an-inexpensive-engine-cylinder-leak-tester/ http://forums.4wdmechanix.com/topic/165-vacuum-tests-for-quickly-pinpointing-engine-trouble/ http://forums.4wdmechanix.com/topic/174-quick-test-for-engine-timing-chain-wear/ The first two tests are definitely useful. The third as well, though I doubt you have an issue with timing chain wear yet. Your engine has a camshaft position sensor and crankshaft position sensor. If the PCM is doing its job, you will get a MIL if these two measurements are out of spec. Out of sync camshaft and crankshaft positions indicate severe timing chain wear. A manifold vacuum gauge test is quick and can reveal valves not seating properly...Let's hold to the immediate codes and issues. We can advance from there if necessary. Moses

You're making very good progress, David! Yes, the camshaft bearing set pin should be in place before installing the camshaft and sprocket. This is shown in the video, but I'll add a footnote. Will also emphasize the importance of seating the oil plunger circlip in its groove. If the valve clearance and valve timing are correct, the resistance that you're feeling without the spark plug in place should be the tension from the valve springs. Exhaust valve unseating is part of the auto-decompression system. When adjusting the valves, you must bring the rockers and valves into position without passing TDC on the compression stroke. If you do pass TDC, continue rotating the crankshaft two more turns to bring the piston once again to TDC on the compression stroke. If you do go too far, the auto-decompressor will unseat the exhaust valve to relieve compression. This is what you're experiencing, making you want to loosen the adjuster. The gap closure and valve opening is actually the auto-decompressor working. Try just bringing the piston to TDC on the compression stroke while rotating the crankshaft in its normal direction of rotation. Review the valve adjustment section of the video. See 25:41-minutes. You'll recall that the intake rocker arms open together, but the exhaust valve rockers are separated. One exhaust valve rocker works with the auto-decompressor on the camshaft. The other exhaust rocker works with the hand lever decompressor. Note: As a precaution, check or adjust the hand lever decompressor free-play to make sure there is no interference when adjusting valves. As for your break-in oil, the zinc additive will help. Do not use the synthetic oil yet. You want enough friction at the piston rings to seat the rings. Your synthetic oil offers exceptional lubricity, which can prevent normal ring seating. At your first oil change, you will remove the non-synthetic oil and zinc additive. Now you can refill with your synthetic oil if the rings are seated. I would go to 400 kilometers before this first oil change. That way, the rings will surely be seated. As a footnote, I installed a new oil filter after the first 50 miles and topped off the oil. This gets rid of initial flushing and wear-in particles that may accumulate in the oil filter. Check the oil level immediately after shut-off, before the oil drains downward into the sump and engine. Run the engine, idle down, shut off and immediately check the oil level. If you wait, a false reading will lead to overfilling and possible damage to seals and crankcase sealing. Moses

Marc, I want you to review the information at the engine-codes.com site. Pay close attention to the overview/generic diagram on the P0455 system. The problem can be as simple as a poor sealing gas cap or as complex as an LDP Pump or even the PCM. I'd certainly try for the gas cap fix first: P0455 Jeep Code - Missing or loose fuel cap - Incorrect fuel filler cap used - Fuel filler cap remains open or fails to close - Foreign matter caught in fuel filler cap - EVAP canister or fuel tank leaks - EVAP system hose leaking - Fuel tank leaking http://engine-codes.com/p0455.html P1486 Jeep Code - Leak Detection Pump (LDP) pressure hose obstructed - Faulty Leak Detection Pump (LDP) - Obstructed hose - EVAP canister obstructed http://engine-codes.com/p1486_jeep.html As for the noise you describe, it could be ping or lean fuel mix. There could be a vacuum or intake manifold leak that's causing a lean mixture. With the engine at an idle, try misting a lower-volatility spray (WD-40 or similar penetrant) along the intake manifold to cylinder head seam. To prevent a fire, avoid spraying directly on the header/exhaust. If engine speed changes, you've got a leak. Cool the engine down and try tightening the manifold bolts. Test again. If still leaking, considering a gasket change. (This could be the on and off #6 misfire code, too.) I'd resolve the code throwing issues before plunging deeper. We can ride this through to a solution! How many miles does the Jeep have on it? Moses

Pleased that this worked out well, Ron! These issues also pop up when installing an exhaust header that takes up space needed for wire clearance. Wires end up melted on the exhaust header...Routing is important. Glad you nailed this, others will benefit from our exchange! Moses

David...I like your can rattle metaphor! Had a special moment at Baja, Mexico this week. We were inland 60 miles from Ensenada, middle of nowhere, storm clouds brewing, stopped for a driver change in our Ford Raptor pickups and racing buggies. The setting would be homelike for Burundi, I'm sure, the humidity spiked up, thick clouds threatening rain, puddles dotting the dirt road, obviously from overnight cloudbursts. Suddenly, I hear a familiar note, the staccato of Honda XR motorcycles. Swarming into a group, just up the road, were a bunch of hardcore dirt motorcyclists. They were tackling our route and obviously hitting the higher gears. While we chatted about race vehicles and the new BFG All-Terrain KO2 tires, I watched 10 bikes launch down the road at 150 yard gaps, just enough to quell the dust. Yep, the distinctive exhaust notes were nearly all Honda XR650Rs, there was a lone XR400R also clipping through the gears! The exhaust notes rapped out, and you knew they were having a good time! Two engines will catch my ear: the Honda XR650R and a P51 Mustang's supercharged Rolls-Royce Merlin. We now live near Reno and were at Yerington, Nevada for the 15 previous years. The Reno Air Races (this weekend at the old Stead Air Base) feature P51s, and the pilots often test in the skies over our area. I've been to the races and spent as much time in the pit area as the grandstands. These modified V-12 engines are formidable, and the huge props have a distinct pitch in flight. An approaching XR650R or P51 will spin me on my heels. In still air, you can hear a P51 from miles away. I have some welding how-to videos at the magazine site if you have the equipment. The steel in the muffler should be easy to gas weld if you do not have a MIG or stick welder. You'll have more control and uniform cool down with oxy-acetylene welding. (Better not to braze here.) If the inner parts are the same material as the outer canister, I'd use ER70-S2 filler rod, commonly available. (A "coat hanger" weld would likely work at remote Baja!) Make sure there are no gasoline fumes in the muffler before welding! Type the word "oxy-acetylene" (without quotes) into the magazine's search box at www.4WDmechanix.com. You'll return a list of links for my gas welding instructional. Enjoy! Moses

The No Pinch tire tool must be accompanied by some tire levers for dismounting the tire; fortunately, they take up little space. We can envision wrestling the tire off a rim with levers, on the ground (with a tarp underneath) or perched between two rocks. The installation is usually the bigger challenge, and this is where the No Pinch tool takes over. I can see why plastic epoxy would not work on your speedo housing. On my drive housing, there was a stress crack, which did respond (for the moment!) to the epoxy repair. I'll likely get a new speedometer drive at some point, the mail-order price was around $55 (U.S.) when I hunted for one. One thing that does help with the epoxy is to wire brush or course sand the mating surfaces to get a rough contact edge. Epoxy does not adhere or bond well to smooth surfaces. If you have the time/ambition to access the steering head bearings, there will be numbers on the cups and cones. They will not be the exotic (internal use) Honda O.E. numbers but rather the standard bearing code numbers that you can either use directly or cross over to other bearing manufacturers. This will make it easier to find bearings, even at Burundi. When you study a bearing catalog, it becomes clear that bearings are typically "standard" and replaceable without difficulty. There are occasions when a bearing is truly proprietary or used in very few applications. From the steering head parts illustrations, I would expect these bearings to be standard fare and available through bearing supply channels. As a footnote on your WD-40 cleanout before greasing the head bearings, if you did not remove all of the WD-40 before packing grease into the bearing(s), WD-40 will likely dissolve or dilute the bearing grease. From what you described, you likely were trying to see if loosening the bearings would solve the stiff steering issue. The plan was to install new, properly packed bearings soon. Moses

shovel guy...You can easily get by with the stock Dana 30 front and AMC 20 or Dana 44 stock rear axle and 33" tires. I would consider the one-piece axle shaft conversion for the AMC 20 rear axle, if that is what your '86 has. Looking forward to hearing more about your project and how you bring the CJ-7 up to speed! Moses

Clutch linkage can be an issue. Decades ago, I did a magazine still photo shoot at Arizona involving a radically built Jeep CJ-7. The owner insisted on "jumping" with the truck and orchestrated a launch from a berm edge. When the Jeep landed, the stock CJ mechanical clutch linkage fell apart. We spent an hour in the field patching it back together. There are factory and aftermarket hydraulic (external slave, please!) clutch linkage systems and the time-honored Advance Adapters chain linkage, popular for vintage Jeep models with through the floor pedals. I like your resourcefulness and use of McMaster-Carr! We're located near the western distribution warehouse for MSC, and their catalog is a great resource, too! Some have built their own air compressor systems, using a rugged York A/C compressor. (The heavy duty York design uses a bona fide crankcase to provide lubrication.) It can be done and saves a bundle. As for boosting your engine power, if you do have a rebuild planned, the 4.6L stroker upgrade is my choice. This is the hybrid 4.2L/4.0L that makes the biggest bang for the dollar. It will work with the Mopar EFI and an injector change, and I currently cover this very thoroughly at the magazine site. I plan to make this information available in HD video rental form soon, everything you need to know for building and tuning a 4.6L inline six for a Jeep CJ, YJ, TJ, XJ, ZJ or WJ! See the magazine site and use 4.6L as a keyword. Hard brake pedal can be the booster but also suggests poor brake system condition. Your '86 CJ Jeep has decent disc brake capacity at the front and adequate drum rear brakes. Both work well when in top condition, and this means true running rotors and drums, lining and pads that are not glazed or damaged, and hydraulic cylinders in good condition. A common error is to assume the pedal needs more "boost" pressure for the vehicle to stop. If the vehicle weight and brake sizing are a good match, boost should only enhance the pedal pressure. A brake system in good condition should stop well—even without boost. Many CJs from your era do not have boosters and still can stop well without pedal assist. So, make sure your front and rear wheel brake systems are working well. You may find that the rotors or drums are glazed, the lining is glazed, or the hydraulic cylinders have wear or piston binding. Moses

Marc, your 4.0L does not have an EGR valve system, or I would suggest checking that area, too. For older model Jeep engines, EGR can create issues and symptoms like you describe. For anyone interested in how Mopar got around the need for EGR on the MPI 4.0L engines, here are the parts schematics for an '02 Jeep TJ Wrangler 4.0L exhaust system, very busy by any standard. These parts cost a pretty penny when they exceed their duty cycle. Older EGR systems were cheaper by comparison: 2002 TJ Wrangler Exhaust and Manifold.pdf Back to 2002. Do check the PCM connectors and contacts. Any resistance or opens in these circuits can wreak havoc. We'll go from there, Marc. Let's solve this riddle and get your Jeep running reliably and without the MIL displays. You have considerable time and parts expenditures, the aim is to get some ROI! Please update on the vacuum circuit checks, MAP test and PCM connector findings... Moses

socom51...Welcome to the forums and thanks much for posting the photo. Please furnish more pics at the forums "Garage", you have a tastefully done, racing prototype, "badass" XR650R! I just got back from Baja, Mexico, the launch of the BFG All-Terrain KO2 tires. (More on that at the forums shortly.) If you want to get a bunch of motorheads into a lively discussion about the Baja 1000 and motorcycles, just mention your Honda XR650R! I drove a "Wide Open" race buggy for two days, my co-driver the first day was Marty Fiolka. He was involved in the production of "Dust to Glory", and we had a lively chat about the XR650R. Our last night at Mexico, I talked with a member of the Ford/Miller Motorsports driving team who just happened to be wearing a T-shirt from the Baja 1000 race. I mentioned my XR650R, and guess what: He has raced the Baja 1000 on his XR650R. We talked about tuning and starting technique, he was quite interested in how I can start the beast in one or two kicks, three kicks maximum, hot or cold...Small world? Or is there just some serious interest in the iconic Honda XR650R! I'm about to mount a big fuel tank. Is yours an Acerbis? I'm considering their 6.3 gallon tank. Looks like what I need for the Nevada desert, some stretches are over 100 miles—each way...What's your range? I'm sure David and Greg can't wait to hear more details on how you've set up your machine...I certainly want to know! Moses

JJ_Jeep refers to a traditional Positive Crankcase Ventilation valve or PCV, which the later 4.0L engine does not use. Instead, it has an orifice elbow on the valve cover, similar to what JJ_Jeep describes. JJ_Jeep offers some good strategies for the purge valve and vapor or EVAP system. Vacuum hoses can cause issues as we have discussed. Thanks, JJ_Jeep. Thanks for adding information and history, Marc. I'm actually starting to think you have a PCM problem or at least poor connectivity at the PCM plug connections. Another possibility is faulty grounds, we're working with a DC system where weak or high resistance grounds can create a voltage drop. Have the PCM plugs ever been disconnected and re-plugged? Try this and examine the contacts for "black" oxidation that can raise resistance. The PCM itself can be defective, but let's not leap to more "parts replacement". Try the plug connections first. Trace down underhood battery connections, grounds to the body from the engine, the grounds to the PCM, and frame to engine grounding. Corrosion, paint, oxidation and any other resistance can cause troubles. You are experiencing random fault codes, some asymptomatic troubles, some symptomatic troubles. Either the Jeep has high parts duty cycling or there is a universal source for the faulty behavior. At the very least, rule out the PCM. I've seen cases where the PCM has a short or intermittent open that is very hard to trace. Solid state circuitry and electronics can be difficult to address. The PCM may be incapable of identifying its own defects—despite a manufacturer's insistence that the PCM/ECU/ECM can "self-interrogate" or troubleshoot. This is not always true. When new, our '05 Dodge Ram Cummins engine acted up with cylinder misfires that roamed from cylinder to cylinder when the truck had 800 actual miles on it. The warranty tech insisted that the ECU was defective, Chrysler made him change and swap injectors, load test ground circuits, lamp load test the injector grounds and spend days of pointless work on a brand new truck. Eventually, Chrysler conceded that 25 late trucks with similar trouble in the zone must mean there was a universal problem. The dealership was "permitted" to install a Cummins Recon replacement ECU (a quick job on these engines). End of problem, the first solved in the zone, this truck has run over 130,000 miles since without a problem. Chrysler recently notified owners of a "lifetime warranty" extension on the ECU. I received a notice along with many thousands of others. Moral of story: PCMs do not always self-interrogate properly, kind of like "HAL" in 2001: A Space Odyssey. I had conversations over the last few days with John Herrick (CRAWL Magazine publisher). We both attended the BFG new tire launch of the All-Terrain KO2 at Baja, Mexico and flew out of and back to Reno, Nevada together. John has an LJ Wrangler with a 4.0L that had similar symptoms to your Jeep. Turned out to be the PCM, which had taken a hard jolt on the previous owner's watch. John replaced a laundry list of parts, trying to cancel MIL signals. Coil on plug bar, many of the items you've done. Of course, at high mileage, there are often trouble spots like the TPS, the fuel pump module and sock, the injectors and so forth. But all at one time? That can point to a global problem. Follow up on plug connections to the PCM (use care on these connectors, they are plastic and fragile!) and the ground system...Do you have any aftermarket software upgrades (a "chip") in the PCM? Wiggle the PCM bodies while you're getting a code. Cancel the code, and see if it stays off. Do the vacuum checks at the MAP, which can be tested with a vacuum hand pump...We'll move on from there. Moses

Tim, my approach with synchronizer parts is a direct match. What does not work is "mix and match" of various parts or designs. If the original brass blocking rings, sleeves and hubs are still in good condition, with the braking ridges on the inside of synchros still capable of grabbing the gear hubs securely, I would reuse these parts. Measure the synchro ring to hub gaps or movement with parts in position on the shafts. This is a clue about wear at the brass ring braking surfaces. If these specs are within tolerance and the gaps are good, you should have no issues with these parts. Correct gear lube is the other concern with synchronizer performance. The right lube will allow smooth shifts and also permit the brass rings to "brake" against the gear hubs. I am in the process of producing a narrated how-to HD video on the AX15 transmission rebuild. It will be a feature at Vimeo On Demand shortly. Watch for the release... Moses