MISSING STROKER

[92tank]

i did the compresion test this afternoon and all is good. 155-160psi. the spark plugs a had the same color so i know its getting fuel to all. and i still dont know what is wrong. but im finding everthing i test is good so i will eventually find the prob

[AlexTJ]

The biggest thing to me is that it started right after you launched it. If it were an injector or indexing it would be a hell of a coincidence if something happened to either at that exact moment. I'm thinking your hard launch may have streched the old worn out timing chain even further.

EDIT: What you could do as a temporary (or not so temporary) measure is reindex the distributor based on the stretch in the chain. You would have to cut an ear off but it's easier than replacing the chain

[92tank]

thats kinda what i starting to think cause its been getting worse. and everything iv been checking has turned out to be within specs. or above like the compression the book only calls for 150psi on the high side, but thats for a stock 4.0 so

[SilverXJ]

Question, you reused the stock lifters on the stock cam keeping the lifters in their original locations?

[92tank]

yes the stock lifters and i think they are in the same spot. 2 fell out after i turned it upside down, but i couldnt get them out at first

[SilverXJ]

You think or are you sure? If you put used lifters back on the wrong lobe you will have instant cam damage.

[92tank]

all the other ones are in the right spot just not 100% one the other 2 that fell out. im not liking were you are going with this thought. are you saying i should pull the valve cover and check every thing out? would it be that noticable on top? but remember that it clears up on the higher rpms.

[SilverXJ]

I'm not liking where this could go either. What I have heard is that using used lifters on the wrong cam lobe = instant cam death in short time. I don't think you can see it top side.

What I do know is that when my comp cam 68-231-4 dies I had a hesitation off idle and near stalling off idle when the throttle was closed. I.e. when you blopped the throttle. After that it ran fine. I spent numerous hours testing sensors, diagnosing, etc. Pulled the oil pan and saw silver particles around the cam lobes.

What I experienced didn't show up in compression or lift checking or anything else.. its like it screwed up the cam lobe profile which lead to the symptoms as provided by the PCM.

[92tank]

oh crap! well that means i might have to put the stock 4.0 back in it till i can get the stroker fixed. is there any other way to check the cam without pulling the pan? probably not but just checking. thanks silverXJ for the good news

[unlimitedrubicon]

You should be able to put a dial indicator on each pushrods and verify the correct lobe lift (valve lift / 1.6) to check for a rounded cam lobe.

[92tank]

UPDATE: i think i found the problem i decided to pull the spark pulg wires while it was running to see it i could locate which cylinder was missing and i did so then i went and pulled the injector wire and still no change, so i swapped out the injector with a different one and it ran fine. except for the fuel leaks around the injectors but that was an easy fix

so now i dont have to put the stock motor back in YEAH

now i runs like its supposed to

[billy_bob]

I don't believe that you will mess up the cam by switching around lifters. Its a probably a good idea depending on how worn the lifters are, but Ive rebuilt plenty of small blocks using same cams and lifters never putting them on the same lobe. They've gone 50 to 60,000 miles now with no problems. Granted i wouldn't take the chance if it were a new cam.

[SilverXJ]

I don't believe that you will mess up the cam by switching around lifters.

Thats just really bad advice

Ive rebuilt plenty of small blocks using same cams and lifters never putting them on the same lobe. They've gone 50 to 60,000 miles now with no problems.

Rollers or flat tappets?

[billy_bob]

flat tappet. but only cuz Ive heard to many old school engine builders tell me they've done it for years with no problems. im not saying its impossible that something could go wrong especially in a really old beaten engine or in alot of these newer motors but in a motor like the jeeps or like an older small block 350 i wouldn't hesitate on my own. those are stock rebuilds i did that in for friends so there inst much power going to them, but at work i put it back where it came out of. i dont take the risk:D.