Jeep Strokers

Well, some more bad news. Pulled the oil pan tonight intending to take over to my welder tomorrow. There was chunks of metal in the pan and a fine copper coat. The cam bearings are done for. Pulled one main cap and it looked fine. Pulled one rod cap and while it wasn't perfect it wasn't good either. Pulling the engine tomorrow. Wat would cause the cam bearing failure?

This isn't my pic, but this is what mine look like:

That sucks

what has 2 thumbs and has no luck?





that guy

Yeah.. no shit.. i don't know what I am doing wrong.

its like your bill murry in groung hog day

Here are some pics of the carnage:

Cam bearing #1:


#2:


#3:


If that wasn't enough lifter #1 stopped spinning at some point:


The pistons look fine. The rod bearings aren't too bad, but they will not be re used and only one crank bearing showed any form of contamination.

However, once again the rear surface of the thrust bearing was well worn. End play increased to .012". The front of the bearing looked un touched. So either the rear surface on the crank is still too rough or the transmission is some how pushing with great force on the crank.

I really don't know what caused the failure though. Bad oil pump, maybe some issue on the cam? I installed the cam exactly like I did several times before. Broke it in the same way and never had a failure of this sort.

And I still haven't found the source of the knocking noise. All the rod bearing clearances were .0015". I just don't understand how two transmissions can be doing the same exact thing.

Wow Silver, I have never seen that before. With the wear being that bad only on the bottom, the only thing I could think of that would cause that would be not enough oil pressure to support the cam, excessive valve spring pressure or valve springs bottoming out. Have you checked your pushrods to see if they are straight? I hope you find the problem. I can't EVEN imagine how frustrating it must be.

you want to try a new block?

Clevite engine bearing failure analysis guide http://www.engineparts.com/publications/CL77-3-402.pdf

My cam bearings looked like that when I tore down to fix a defective piston.
I put a new set in and shimmed the oil pump spring.....OK so far.

dwg86 wrote:Wow Silver, I have never seen that before. With the wear being that bad only on the bottom, the only thing I could think of that would cause that would be not enough oil pressure to support the cam,

I'm leaning toward a defective pump from Melling. After the Comp failed I replaced the crank and rod bearings, the oil pump, the cam and the lifters. The clearances were all in spec, with the rods all at .0015". No bearing failure of any type prior. After the break in I noticed the low oil pressure, but it was still above spec. Previously the pressure was usually 40 around idle with a regular volume pump.

excessive valve spring pressure or valve springs bottoming out.

Spring pressure is 100# seat, ~250# open on exhaust, less on intake. And I checked all the clearances when the Comp died and there was no binding or anything.

Have you checked your pushrods to see if they are straight? I hope you find the problem. I can't EVEN imagine how frustrating it must be.

I didn't check them today but I checked them when I installed the new Isky cam and they were very straight. They made new stock style rods look bad.

the_wrench116 wrote:you want to try a new block?

I don't think that would help as I had two very different failures. First time the cam just died, this time the bearings died. The cam looks good still and the lifters look fine with the exception of the #1 that wasn't spinning.

dwg86 wrote:Clevite engine bearing failure analysis guide http://www.engineparts.com/publications/CL77-3-402.pdf

I've seen that file before, but it doesn't have "Bearing being pushed out of bore". The best one that looks like what happened is Hot Short.

TurboTom wrote:My cam bearings looked like that when I tore down to fix a defective piston.
I put a new set in and shimmed the oil pump spring.....OK so far.

So, in your case it would have been low oil pressure? Makes sense on yours since your engine usually runs at WOT where the oil pump would be opening the valve and shimming it for higher pressure would help.

So, the question is what happened first? The bearings went for some other reason (cam issue perhaps?) which caused the low oil pressure or did the pressure go low which caused the cam bearings to fail. When I installed the cam it rotated freely, not notchy or any binding. Plus the wear doesn't indicate it would be bent. as it is only on he bottom of the bearings. I'm going to check the cam on V blocks do see if it is out of round or something else. Could the machining that Isky did on the cast section of the shaft have contributed to this in any way? I installed the cam exactly as have done in the past. Lubed the lobes with the moly lube provided by Isky, assembly lube on the journals and slid it in. I did the break in with Joe Gibbs BR30 break in oil and new filter. Changed the oil and filter using a Mobil1 301 and Brad Penn 10w30.

Well, I know all the bearings will be replaced, the pistons checked over better as well as the rings. I noticed excessive slack int he timing chain, but is probably from the bearings missing material. New head gasket and all other gaskets. Prior to disassemble I was talking to Lunati about the lifters and they wanted me to send them back for inspection. Probably won't find anything other than the #1 not spinning. I'm sending the rockers to Harland sharp for inspection if they got damaged in the process. ... I don't know if the cam is even still usable due to the bearing failure (journals looked fine aside some bearing material on them) and the lifter not spinning. My machine shop mentioned something about Melling refunding all rebuild costs if they find the pump to be faulty, so I will look into that and send the pump to them. I am tempted to open it but don't want to void any kind of warranty on it.

As for the knocking and thrust bearing wear it could be from excessive pressure in the transmission... but since I replaced the transmission that leaves the transmission fluid coolers. The internal one doesn't have a clog. I found that out when i got a plug stuck in the upper fitting and forced it out with compressed air. I wasn't expecting the plug to come out that easily. The hard lines are fine.. but I suppose a soft line could be failing in a similar way to how a brake hose can fail... from the inside and can clog when they get hot.

Is this the first build that used the grooved lifter bores?

gradon wrote:Is this the first build that used the grooved lifter bores?

Glad you said that, I have a feeling that this is the problem?

It is, but I don't think that is the problem as there were two different failures. Maybe the grooved bores combined with a not up to spec oil pump.

Man, it really looks like there was something that caused the cam to have abnormal stress in that direction... wouldn't low oil failures burn the bearings all the way around? (or at least, more than we see on there?