Jeep Strokers

I think one bearing manufacture use to have one. However, I can't recall which one.

After taking the crank out he redacted his remarks as to being able to use a oversize thrust and resurfacing the thrust area. Looks like I'm getting a new crankshaft.

OK so I finally got her torn apart and here is what I found, other than the Number 3 main (thrust side) being destroyed and taking the crank with it.

The cam checked good.
Lifters "look" fine (not completely sure on how to check if one is collapsed or not).
Rod bearings are ok...there was one that looks borderline, but new crank and bearings and a R&R check on the rods should rectify that.
Pushrods are all straight.

So, what would cause that pushrod to jump like that? Also, on a side note...how far down should the "burn marks" be inside the cylinder? I feel like what I'm looking at in my motor seems a bit excessive, maybe I can take another .010 off the block? Maybe that would also solve the pushrod issue, assuming they are a bit shorter than they should be...

I may be changing the cam and lifters...any suggestions on one that builds more torque down lower than the 231-4 I have now?

Suggestions? Hints? Solutions?

Thanks

Collapsed lifter, worn cam lobe, bent pushrod, sticking valve, rocker arm not center (bent bridge). What is the preload on the push rod that came unseated? Did you verify the pushrod is still straight?

Check the lifter that that push rod cam off of. You should feel resistance when you push down on it unless it has bled down. Take it apart and make all the parts are there. I had a comp cams lifter missing the spring once.

So I've determined why my crankshaft got destroyed...wrong pilot bearing. Apparently I overlooked it when I assembled the engine. Oh well...learning experience for me...now if I could just figure out why that pushrod jumped.

SilverXJ wrote:Collapsed lifter, worn cam lobe, bent pushrod, sticking valve, rocker arm not center (bent bridge). What is the preload on the push rod that came unseated? Did you verify the pushrod is still straight?

Check the lifter that that push rod cam off of. You should feel resistance when you push down on it unless it has bled down. Take it apart and make all the parts are there. I had a comp cams lifter missing the spring once.

You have asked the same question here multiple times in this thread, and SilverXJ has given you the same response. The only recommendations I see that you have checked are bent push rods and a visual check of the cam lobes from underneath. You need inspect the lifter, make sure the rocker is centered on the valve stem, then pull the spring off the valve that spit the pushrod and make sure that valve moves freely in the valve guide. I have had 2 engines over the years with this problem, and both times it was a binding valve guide.

x2 valve. been there, bent that !

Sorry if it seems redundant. I have done everything you have suggested. I completely dismantled the valve train and lifter alongside my machinist and there is absolutely nothing out of the ordinary. Everything is free and non binding, that's what is so confusing. There is nothing visible or otherwise that points to a problem. I guess the only thing left to do is get it running again and see if it happens again. It is really a wierd thing.