I have a 355 with stock crank, eagle rods, ross pistons...nothing special. I take this thing to at least 7200..it would like to go higher but I just don't trust the stock crank and two bolt mains. I make peak hp at 6800ish and by 7400 it had lost 2 rwhp. Well the last run I lost oil preasure after going through the traps and hitting the limiter(7500) right at the line(131.7mph) so I pulled it out and went through everything. Rod bearings show normal wear for a motor that lived at 7000 rpms for 5 years. When we pulled the main caps I had wear on both sides(front and rear) of the bearing but normal wear in the middle. I'm guessing this is crank walk. Is there anything I can do to alleviate this problem while the motor is out? I plan on going for a 9 sec. 6 speed pass then its on to building the turbo motor but for now I want to make sure this sucka lives.

 

Part of the problem is the manual tranny, the load and unload of the clutch pushes on the crank......the way that car has been used the last five years I would call it normal wear for a stick car that someone has used properly I seem to remember a way to put some sort of needle or torrington thrust bearing in s stick car to help that...but it is a fleeding memory.


David

 

You are talking about the thrust surface of the rear main correct?

Measure the endplay and see what it is.... if it's silly high then it's clutch like David said, if it's in spec then it's just making the clearance that it wants to have and it was tight to begin with.

If your parts in the bottom end aren't too heavy then you should not have too much of a issue with the crank, but you do have a lot of time on the parts and that more than anything else will break it.

Bret

 

Open up the clearance to .003 on the rear main only for more oil and give it .008 end play.

 

thanks guys..all great information.

 

my bearings kinda has that same thing as you described

my machinest also mention that having a stick car didnt help it any....


do you main caps so any sign of walking and digging into the block a lil bit.. mine did a minor bit nothing to scare me and do a splayed cap setup

 

Just had a forged LT1 crank welded up and reground not too long ago. there was alot of material chewed off the thrust surface...