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Moses, How are you? im going to ask you some question, i want to use the comp cam 252 is it possible to use the stock lifters push rod and springs? also what is the push rod height ? 9.639  is ok?, im just asking again your advice, i will follow your advice regarding to collapse the lifter first , pls. also guide  how to tighten the rocker arm and the push rod.or is there any article or video that i can follow how to do it. your recommendation  .... thanks.

 

Regards to you

 

 

Mario from the philippines.

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Hi, Mario...You cannot use the original (old) lifters, they have an established wear pattern that matches the lobes of the stock camshaft.  If the CompCams lifters are not damaged, use them.  There is no change in lifter/pushrod height between stock lifters and CompCams lifters.  The stock pushrods will also work fine if you have not machined the cylinder head or the block deck.

The stock rocker arms can be installed by simply tightening the rockers in place properly with the pushrods aligned.  If the lifters are not "pumped up" with oil, there should be no coil bind or valve-to-piston interference. 

Again, your problem was likely caused by the lifters being full of oil before installation.  This can be caused by pumping the air out of a lifter while submerging it in an oil bath or from simply soaking the lifters in oil for a period of time.  The oil feed hole will slowly fill the lifter. 

Be sure to pump all oil out of the lifters before installing them.  Put cam lube on the lifter bases and lifter sides.  When the engine starts, the lifters will fill quickly.  Once the lifters establish zero valve lash, the lifter plungers will stay at that height within the lifters.

Stock pushrod length for your engine is 9.640"-9.660".  9.639" should work just fine.  As for valve springs, the stock springs should work with the stock cylinder head (no head machining or changes in valve stem height).  As I understand, your engine was stock and had never been apart, including the cylinder head.  If so, the stock valve springs will work with the CompCams 252 grind camshaft and lifters.

Note: The CompCams 252 with stock pushrods and CompCams lifters should not cause coil bind on valve springs.  The lift is way too mild for that unless the pushrod length is too long (head milled, block decked, wrong pushrods or other reasons for incorrect valve lifter clearance).  Also, when installing lifters, do not fill or "pump up" the lifters with oil.  Lube only the lifter bases and sides of the lifter.  If you fill the lifters with oil before installation, you will get too much valve lift at first engine start-up!  This can cause valve spring coil bind, valve to piston interference and bent pushrods or valves.  Let the engine's oil system fill the lifters.  Once the engine runs, it will set the proper pushrod height and lifter clearance...I prefer the 252 grind to the 264 profile.  You could run the 264, but it would be more of a mid-range to high speed gain, not the steady, low-speed torque improvement of the CompCams 252 grind...Think about your lifter installation.  If you filled the lifters with oil (soaking or pumping them full of oil) before installing them, you could have created a problem.

This leaves only one more place for error:  Valve Timing.  Make absolutely certain that you are setting the camshaft sprockets and chain according to the factory alignment method.  You cannot be off by a single chain tooth in either direction.  Use real care here.  You will have valve interference with the pistons if the valve timing is off, and this can be mistaken for valve spring bind or other problems.  If you crank the engine with incorrect valve timing, you can bend the valves against the piston crowns!  Bent valves will cause loss of compression and misfire.  Valve interference with the pistons can damage or crack the pistons.

Moses

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Moses,

     I will follow  what ever you say... im using  an Hei aftermarket  distributor where do i start my timing as im using carburator, the 390cfm holley 4 barrel. thanks you .

 

 

Mario Bedayo

Philippines

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Mario...Be clear about the difference between valve timing and spark timing.  You will set up the camshaft valve timing at the camshaft sprockets and chain.  Once the engine's valve timing is set correctly, you can install the distributor with the #1 piston at TDC on the compression stroke (both valves closed, crankshaft pulley mark at TDC.)  Position the distributor with the rotor pointed to #1 spark lead in the distributor cap. 

 

Once you start the engine, you can final adjust the spark timing with the vacuum advance disconnected.  Use a timing light...Remember to reconnect the vacuum line, which should be hooked to the carburetor's ported vacuum pipe.

 

Do you have instructions on how to set the valve timing correctly?

 

Moses

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Hey Moses,

     Your amazing!!! Man, i dont know how to set valve timing correctly  want to learn from the Master. also what trans fluid will i use as atf +4 is very very Rare here to find what we have here is syngard valvoline what atf will i use dex 3 ? or mercon , i dont know what fluid the first owner use and what youve advice to change the filter and fluid so i want to change, need your advice about this.another thing My friend... what can you recommend for my set up, in the engine. is the comp cam 252H grind is ok or do you have another recommendation want a little faster in highway and got accelaration when to overtake in the city with lot of traffic.my car is carburated. it has still good engine . it doesnt smoke  and what octane will i use here 95 Ron is ok ? Thanks .Have a nice weekend.

 

 

 

Mario Bedayo

Philioppines

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Mario...Here is the complete factory procedure for changing the timing sprockets and chains.  Read through, there is specific information on setting the valve timing and how to check it.  Make certain that your straight edge measures through the centerline of the crankshaft and camshaft when you align the timing marks.  Follow up with the chain pin count as shown in the illustrations. 

 

Note the references to the camshaft bolt tensioner, pin and spring.  Make sure you account for these parts if your engine uses these parts.  As described, be careful when installing the camshaft:  Do not drive the camshaft plug out the back of the engine when you install the camshaft.  Do not attempt to change the camshaft bearings.  They should be fine unless you damage them removing and installing the camshaft. 

 

When removing and installing the camshaft, keep the cam on center and use extreme care not to damage the cam bearings with the lobes.  You can take a long bolt and cut the head off, smooth the end, then thread the homemade "tool" into the nose of the camshaft to help hold the cam on center during installation in the block. 

 

Here are the instructions for changing the timing sprockets and chain and setting the valve timing.  If the timing chain has much wear, change it and the sprockets.  If not much wear, leave the crankshaft sprocket in place during the camshaft change...Either way, follow the valve timing steps:

 

Jeep 4.0L Timing Chain Installation and Valve Timing.pdf

 

For transmission fluid, Valvoline makes an ATF-4 equivalent.  You can use ATF+3 as an option.  Dexron II is not recommended, it will cause clutch chatter... Here is the data, if you get Valvoline locally, this should work.  Ask the Valvoline supplier for this ATF:

 

Valvoline ATF-4 Product Information.pdf

 

The CompCams 252 is an excellent camshaft from idle to 4,500 rpm.  You will have a performance ceiling around 5,000 rpm.  The best thing about this camshaft is that it works well at the rpm you drive the vehicle.  Low end torque is very good, midrange strong, and the rpm ceiling of 5,000 rpm is realistic for a 4.0L Jeep engine. 

 

RareCJ8, a member here at the forums, has a fresh 4.6L stroker engine built by Hewes Performance.  His camshaft is the CompCams 252H.  The camshaft enables pulling a trailer behind his Jeep CJ-8 Scrambler, the whole package is over 6000 pounds when loaded.  This Jeep crawls over the Rubicon Trail at high altitudes with the trailer.  The 252H is a very realistic choice for your purposes.  You could run a CompCams 260 (or a 264 grind), but you would give up the bottom end torque of the 252H.  I prefer the 252H all around.

 

I have used the 252 CompCams on everything from Jeep inline sixes to a Ford 300 inline six and 383 stroker V-8s (Chevrolet 350 with 400 crank and 0.030" resize bore).  I first used this camshaft in the 1980s.  If you want to do the work involved, this camshaft performs well at your engine's compression ratio.  95 RON is plenty, and you're lucky to get it.

 

Moses

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You're welcome, Mario...As an additional note, make sure the pushrods are straight.  Find a flat machined surface or a piece of flat safety glass.  Roll each pushrod slowly over the surface of the glass.  Check for any signs of a bent pushrod tube...Follow the camshaft and chain directions I have provided.

 

Some time ago, I did a video vlog on how to check and set valve lifter clearance on the non-adjustable Jeep inline sixes and OHV pushrod fours.  You should not have to adjust clearance on your stock engine, but for a better understanding of valve lifter clearances and AMC/Jeep lifter settings, you may benefit from the video.  I just moved this video to the home page of the magazine, you'll find it near the top of the page:  http://www.4WDmechanix.com.  

 

Moses

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HI! Moses,

    Mario Again, May i know please the comp part number as im confuse as i look to summit and ebay im not sure . is it CL 68 200-4  252H  grind.? AS my cam was not serviceable any more as the mechanic installed  the wrong way so ill buy another one , i took about a year of service then my jeep misfire no power. when we open the engine  bent pushrod  the lobe of the cam was not an egg shape any more the lifter  l hole in the center , but its only 2 lifters and 1 lobe and cams cannot be repaired your right maybe he installed the lifter full of oil. this is a lesson i learned and will cost me money. i know your recommending a comp cam. im afraid it will happen again , but this time will follow all instruction from you. how about if i use crower cam any advice please. Thank you again.

 

 

Mario Bedayo

Philippines.

 

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HI! Moses,

    Mario Again, May i know please the comp part number as im confuse as i look to summit and ebay im not sure . is it CL 68 200-4  252H  grind? As my cam was not serviceable any more as the mechanic installed the wrong way so ill buy another one, i took about a year of service then my jeep misfire no power. when we open the engine  bent pushrod  the lobe of the cam was not an egg shape any more the lifter  l hole in the center, but its only 2 lifters and 1 lobe and cams cannot be repaired your right maybe he installed the lifter full of oil. this is a lesson i learned and will cost me money. i know your recommending a comp cam. im afraid it will happen again , but this time will follow all instruction from you. how about if i use crower cam any advice please. Thank you again.

 

 

Mario Bedayo

Philippines.

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Hi, Mario...I know that you are wary of a camshaft failure.  The CompCams 252H grind that I use is the 68-200-4: http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=8&sb=1.  The description says "not for fuel injection".   This applies to later coil-on-plug engines, and CompCams has a custom grind for the 2000-2006 4.0L inline sixes.  (I shared that information at another forum topic:   http://forums.4wdmechanix.com/topic/493-which-camshaft-for-a-2000-jeep-xj-cherokee-stroker-46l-engine-build/?hl=coil-on-plug#entry2747.)  That camshaft is not required on your 1994 4.0L engine.  You can use the 68-200-4. 

 

The CompCams 252H grind is very mild and does not bend pushrods or cause valve spring coil bind.  The 68-200-4 is often installed in 1964-up AMC and AMC/Jeep inline six-cylinder engines that have a distributor (listed as 1964-97, though this cam will work to 1999 engines with a distributor).  These are stock engines with no other modifications. 

 

I have used this 68-200-4 camshaft profile in a variety of engines, from inline sixes to V-8s.  It works well with a stock, moderate compression ratio.  It works well in stroker engines designed for low-end torque and horsepower in the mid-range rpm.

 

Note:  I have no "agenda" in recommending this camshaft.  I'm not paid by CompCams to promote its products, and they have not advertised at the magazine site or forums... This is a grind that I have used for nearly 30 years.  It is mild and safe on the rest of the valvetrain.  I have no experience with the Crower camshaft, though they do make very good products.  I also knew the late Jack Clifford, and Jack designed excellent camshafts for inline sixes...I like the mild nature of the CompCams 252H grind.  It produces optimal low-end torque and mid-range power, which a relatively stock Jeep 4.0L engine really can use!

 

Since you bent a pushrod and lost a camshaft lobe, I'm concerned about the condition of your engine.  If you are not disassembling the entire engine, I would at least flush the engine and crankcase thoroughly to remove metal debris.  Also check for leaking, bent valves where the pushrod and lifters failed.  It takes tremendous force to bend a pushrod, and the usual cause is valve-to-piston interference.  When a valve hits a piston crown, the valve will bend under that force.  This will cause poor valve seating, a sticking valve and a loss of cylinder pressure.

 

I would run a cylinder leakdown test.  If you do not have a tester, you can make one.  See my topic on cylinder leakdown testing:  http://forums.4wdmechanix.com/topic/164-how-to-make-an-inexpensive-engine-cylinder-leak-tester/?hl=%2Bleak+%2Bdown+%2Btest.  Even if you cannot read actual "leak down", a spark plug/air fitting adapter like I illustrate can allow blowing compressed air into the cylinder that had the bent pushrod.  Make sure both valve rockers are completely loose and the pushrods removed.  This will seat both valves at that cylinder.  Check whether the compressed air leaks rapidly out of the cylinder at the valves.  Air coming through the intake is a bent or leaking intake valve; air exiting through the exhaust system and tailpipe is a bent or leaking exhaust valve.  60-80 PSI air pressure from an air compressor should be plenty for this test.

 

If you do have a bent and leaking valve(s), the cylinder head must be removed.  Make sure the piston(s) are okay.  Repair the cylinder head and valves or replace the head.  Do not install a camshaft until you are certain that all 12 valves are sealing properly.

 

Moses

 

P.S.: We should have started at least two new topics...There are several subjects all under your original question, Mario.

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Moses,

 Thank you... yes  a new topic, my engine valves are  ok  so with the pistons and i see theres no oil  in the top and not damage , i talk to my mechanic about the installation of the cams , he told me that what he did the rocker arm is to tight and the lifter maybe was not collapse  , and now  i told him  you procedures, that what we are going to do. ill buy another set with that part number with the lifter and will install again following your instruction.  still i will use comp cams.i know you are not advertising, but  it serve you well, Thank you Very much.

 

 

Regards.

 

Mario Bedayo

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Good, Mario...Glad there is no valve damage.  That is always a concern with bent pushrods.  Let us know how this work turns out...

 

Buena suerte!

 

Moses

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