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Showing results for tags 'jeep 258'.
Found 7 results
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I have a problem with accelerator lurching at crawling speeds since I installed my MPI/EFI conversion kit to my 4.2 six. I thought I recalled seeing a remedy for this in my Ludel's CJ rebuilders manual but for the life of me I can't find it. Any suggestions? -
Many Jeep owners need how-to information on checking valve clearances and adjusting the hydraulic valve lifters on the inline 232, 258 and 4.0L six-cylinder engines and the 2.5L Jeep pushrod engine. Between the model years 1971 and 2006, Jeep used these AMC-design 232, 258 and 4.0L sixes and the 2.5L straight four-cylinder engine (1983.5-2002). The hydraulic lifter and valvetrain design has particular needs, especially the valve clearances. When these engines develop valvetrain noise, owners often think a valve adjustment will cure the problem. In each of these AMC/Jeep engines, valve clearances are set during assembly of the engine, and adjustment is not necessary between engine rebuilds. If your engine has developed valvetrain noise, or if you are in the process of rebuilding the engine and need to know more about setting valve clearances, my HD video from 4WD Mechanix Video Network at Vimeo will assist. This video was originally a Q&A Vlog at the magazine, now available for a broader viewing audience through Vimeo. Moses -
Valvetrain noise and rocker arm interference after cylinder head work can be issues on the AMC design engines. Causes can include sluggish oil flow through the hydraulic lifters, the lifters bleeding down, or possibly excess valve/lifter clearance from valvetrain wear. At 200K miles, that's a very real possibility. Another possibility, since you're certain it's not a lower end bearing noise, is a carbon buildup knock (not likely with an MPI engine) or a piston-to-wall clearance issue. Piston skirt wear is likely, too. It works like this: Pistons naturally expand from heat. There is the normal piston-to-wall clearance to accommodate expansion when new. Over time, the cylinder bore wear creates cylinder "taper" toward the top of the cylinder. The piston skirts also wear. Over time, the cylinders and pistons wear. Cold, the engine was noisy, the pistons expanded, and for a while, anyway, the engine quieted down when warm. Now, the lifters are clacking, the cylinders are worn, the pistons have worn, and you get the sound effects! Another noise can be piston pin wear, which causes a double-knock rap...You would notice this clearly as a dominant sound when the engine is unloaded and you tip the throttle in and out. Use of an automotive stethoscope, a copper tube or a piece of PVC tubing can help isolate engine noise. Be aware that these noises will be transmitted widely and very exaggerated while using these sounding probes! At 200K miles, these engines have done a heroic job tugging a Jeep around. 2.5L models with 4.10:1 axle gears, which make the piston travel extreme over this many miles, wear an engine out sooner. An engine with this kind of mileage needs a suitable burial or rebuild it completely, restoring the short block and cylinder head to OEM specifications with pushrod lengths checked (changed if necessary) for proper valve clearance/lifter preload. Some want to swap an inline 4.0L six in place of the AMC 2.5L four, and that's not easy. I'd consider a smaller V-8 swap (GM LS 5.3L makes sense) as a practical alternative. The Jeep YJ and TJ Wrangler frames are, for unfathomable reasons, designed specifically for either an inline four or a six-cylinder inline engine. (You can see photos of the motor mounts I fabricated during a 4.0L swap into a 2.5L YJ Wrangler, and frankly, it would have been just as easy to install a hybrid V-8.) Granted, the 4.0L radiator, shroud and transmission locations were straightforward, although a four-cylinder YJ/TJ model uses an AX5 transmission, which would be replaced by a 4.0L's AX15 transmission. Aside from fabricating motor mounts, there would be wiring, cooling, exhaust, the AX15 transmission, 4.0L PCM setup and other changes. Moses
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Many Jeep owners need how-to information on checking valve clearances and adjusting the hydraulic valve lifters on the inline 232, 258 and 4.0L six-cylinder engines and the 2.5L Jeep pushrod engine. Between the model years 1971 and 2006, Jeep used these AMC-design 232, 258 and 4.0L sixes and the 2.5L straight four-cylinder engine (1983.5-2002). The hydraulic lifter and valvetrain design has particular needs, especially the valve clearances. When these engines develop valvetrain noise, owners often think a valve adjustment will cure the problem. In each of these AMC/Jeep engines, valve clearances are set during assembly of the engine, and adjustment is not necessary between engine rebuilds. If your engine has developed valvetrain noise, or if you are in the process of rebuilding the engine and need to know more about setting valve clearances, my HD video from 4WD Mechanix Video Network at Vimeo will assist. This video was originally a Q&A Vlog at the magazine, now available for a broader viewing audience through Vimeo. Moses
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Thanks for the detailed and quick reply Moses, very interesting tech. I think you're right it is probably multiple worn parts making clattering together. I am looking forward to tearing down this engine one day and seeing how it looks/checking the wear. This is Mike at MCE Fenders (MCE Mike on Facebook) and this is the lime green Jeep in our photos. (Also emerald green before it was painted) I've owned this Jeep since I was 16 in 2000. You are absolutely right, this is a testimonial for this engine. I am absolutely amazed at how problem free and durable this engine is. Since it doesn't have much power, and had larger than stock tires on it since ~60,000 miles, this engine spent a lot of time at full throttle and/or high RPM. It has had 31s and 4.10s for a few years, 33s and 4.10s for about 6 months, 33s and 4.88s for a few years, and has been on 35s with 4.88s since 2008. I could also go on about all the times it spent revving high in the snow, breathing dust in the Moab and PNW silt, and it has overheated a few times due to a water pump and electric fan issue. I always just kept the oil changed. I am probably not going to do an engine swap for a while - just not enough time right now and focusing on other Jeeps and the company, but am collecting ideas on what to do. I am definitely leaning towards a small V8. I don't want a huge powerhouse, I rather have reliability of the entire Jeep rather than a HP number on paper. So was thinking a Vortec 4.8 or possibly a 5.3. From the research I have done, the Magnum 5.2 and 5.9 are the "easiest" swaps for my TJ electrically, so those are also on the drawing board. One other idea is to try 505 Performance's new 2.5L stroker kit and head. (2.7 and 2.9 options) But I am still researching this. While the sound and power of a V8 is fun, keeping the light 4 banger but adding power might also be fun. In '08 I swapped the AX-5 for an NV3550 with junkyard parts, and bolted on a NV241-J to that. So I am thinking they will be fine with either option. The front axle is a high pinion 30 out of a Cherokee. This would probably be fine for the stroker 4 cyl. option, but probably need replacing for the V8. This Jeep doesn't have a rear axle at the moment, but it will probably get a D44 when I have time to get to this project. Too many options, haha! Mike -
Im looking at building a motor for my 83 Cj7 I have options, I have a 96 4.0 parts motor with 0630 head plus a spare 7180 head. I have two 258s one is a 1990 (006CL25 / EF3235444) the other an 80 (009C09 / 3235444). The 1990 258 i could just re-ring and drop a 4.0 head on, i wouldn't even have to plug the water jacket holes in the head as the 90 block is squared of on that side like a 4.0 block, re cam with a RV unit and i'm hauling like never before. Pretty strait forward. Or; Take the crank and rods from the 1980 block and put them in the 4.0 block. With this one i would keep the 4.0 pistons, install new rings and because the 1980 crank is the last of the 8 counter weight heavy cranks i would assemble it and assume im pretty close on balance and see what it runs like. Im thinking the second one is a bit of a gamble on the balancing but i've put lighter pistons in small block chevs before and never had to rebalance, so ive been there done that. Anybody out there done a heavy crank to 4.0 swap with all stock stuff? think it could work? -
Good info, thanks. Here's an odd one I have been trying to figure out for years. I bought the Jeep at 57,000 miles ('97 TJ w/ a 2.5L), and now it has about 200,000. So I am assuming now it's worn out and am just going to swap it out. But, this is what it has done for years: First cold start of the day, it is quiet. After about 30 seconds or a minute of warming up, I can hear a valve clatter/tapping noise starting. It did this until the engine was up to temp, then would go away as long as the engine stayed running. If it sat for a while and cooled off, it would do it again until warmed up. This never impacted the engine's performance or drive ability, so I never really worried about it. But, in the last year of driving it, the noise would appear at about 30 seconds or 1 minute of run time, but would stay once the engine warmed up. It would be quieter once warm, but definitely audible. It almost sounds like a diesel. This Jeep has sat now for about a year and a half, but I am going to revive it this winter, as well as do another build on it. Also plan to swap the engine for something else, but will always be curious as to what was making this noise. When I have a chance, I am going to tear the engine down and see if that shows anything. It definitely doesn't sound like a rod knock, and is coming from the upper part of the engine. So I am assuming it is something in the valvetrain.
