white85transam

iTrader: (2)

I started a t56 swap today and was working on changing the pilot bushing and I'm not sure if banging on the crank cause the issue at hand or not but I need some advice as to what I should do from here. I have a traditional sbc that's been stroked to a 383 and was running a t5. When I removed the t5 I noticed input shafts had up and down movement which I'm actually not surprised. They are weak anyway hence the t56 swap. Now here's the bad part. I noticed I have front to back movement in the crank and found .022 of movement but didn't notice any up and down movement. I know this is out of spec but engines been running fine. Although I hardly drive it. Is there anyway to fix this while still in the car? If not am I better off just building a new motor?

MSgt Luttrell

That is excessive for a stock or naturally aspired engine, but a lot of turbo, nitrous engines will run them that loose because of the heat expansion they can create. If the the engine was already out of the car I'd probably go in and address it, but in all honesty it probably won't cause you any grief as it is.

Croz

Although I dont recommend "banging" on the crank, it did not cause this issue. Not sure what the spec is but ....crank end play is controlled by the rear main bearing, also called the thrust bearing. Used engines in front of a manual tranny will always have more end play then an automatic. Everytime you press that clutch down, you shove that whole crank assembly forward. When you release the clutch, the crank returns to its normal position. Glad to hear there is no vertical movement. End play should not effect oil press. I think end play should be around .006", .012" is the max I would allow in an engine that was already in service.

If you can pull the pan with the engine in the vehicle, you can remove the rear main cap, loosen the next 2 caps, and rotate the upper bearing shell out. I have done several complete main bearing replacements with the engine in the vehicle. The big thing is can you get the pan out. You may also try putting the new tranny in, then pulling the motor mounts and raising the engine in you need extra clearance to slide the pan out. I am sure there are thread on here as to whether the pan can come out in the vehicle or not

Croz

Sorry i missed your last line....if the engine is strong there is no need to rebuild the entire engine. All you have to do to change to correct the end play is the thrust bearing. All of the vehicles i have looked at with excessive crank end play or failed input shaft pilot bearings are always attributed to the person that waits at long red lights with foot on the clutch, tranny in gear. The entire time you are waiting, that crank is turning against the thrust bearing side. It is doing its job, it only has so much life in it. I know it is safer to "be prepared" in case you need to get moving quickly, but it does takes its tole on moving parts.

white85transam

iTrader: (2)

I'm kind of feel stuck between a rock and a hard place....I can either address this issue which painfully needs to be corrected or get a new rotating assembly that's fully forged for a future pro charger. I have a 010 020 block that's supposed to be stronger than some of the other castings I almost feel pushed to go that route if I have to pull the motor anyways. I just wasn't ready for this when I pulled the trans out

Croz

its a "pay me now, or pay me later" situation. It needs to be corrected eventually, how long will it last is anyone's guess. If you didnt pull the tranny you never would have found this. How much you want to fix / upgrade while your in there is all up to you.