Clevitte 77 bearings on .30 under crankshaft

[Mentow]

Hi there,

so im doing a rebuild on my 7bolt turbo with a .30 under crankshaft. The crank will have to be hardened again. First, i got worried of using such a grinded crank, but since SBR sells Clevitte 77 .30 under, it seems everything is going to be just fine. Im willing to run only 20psi on that engine on a original turbo, not a dragster or something at all...

My question is exactly about the 77´s: is it a good option only for high performance engines (400+ hps), or every stock should have those? I was thinking: maybe the clevittes 77 wouldnt be "too hard" for my engine? Or should i get those without any doubts in my mind?

Regards!

Michel

 

[T is for TURBO]

.3? isn't that waaaaaaaay to much?

 

[Mentow]

.3? isn't that waaaaaaaay to much?

i must agree with you. But since SBR sells bearings for .30 under, maybe it isnt thaaat much heeheh.

Im not planning to run insane boosts on that engine, so i think it would be ok..

Regards!

Michel

 

[95 gsx]

I think you mean 0.030, which reads "thirty thousandths".

 

[Mentow]

0.30inches = 0.75mm

thats what im talking about, almost 1mm under!

Regards,

Michel

 

[95 gsx]

Um, No. 0.30 inches is read as "three tenths of an inch". Please look at a ruler, try to judge what three tenths of an inch would look like, then report back what you think that number is on a metric scale. 0.75mm is 0.030. You must've heard wrong. Either way, the crank should be ok to use as long as it was done properly and you have the correct size bearings. And please, plastigauge everything before final assembly.

 

[Mentow]

Um, No. 0.30 inches is read as "three tenths of an inch". Please look at a ruler, try to judge what three tenths of an inch would look like, then report back what you think that number is on a metric scale. 0.75mm is 0.030. You must've heard wrong. Either way, the crank should be ok to use as long as it was done properly and you have the correct size bearings. And please, plastigauge everything before final assembly.

oh, yes, you´re right...sorry about that!

Could you please tell me more about the "plastigauge"? I´ve never hear such thing, does it have something to do with the hardening process that i´m going to do with the crank?

Regards!

Michel

 

[95 gsx]

Plastigauge is used to check clearances before final assembly. You will lay a strip of this plastic stuff in between the crank and each bearing and then torque everything down. When you do this it should apply a given amount of pressure to the plastigauge and flatten it. Remove the crank and then measure how much the plastigauge was flattened and that should give you an idea of your tolerances. Pretty simple really. There are other ways of doing it but this method is tried and true. As for bearings, try to stick with a tri-metal type as opposed to aluminum.

http://cgi.ebay.com/ebaymotors/PLAS...005QQitemZ150060489830QQrdZ1QQsspagenameZWDVW

One thing I should probably add, using a turned crank is frowned upon...if you can just get another one I think you would be better off. Search the archive for more info on that.

Edit: Scroll down a little and look for a thread called "machining estimates?" Look at what "Defiant" says in post #2

 

[mavisky]

I'd be leary of the clevite 777's unless they've went back to their old bearing materials. I got some of the last good ones in my motor that I rigged together in my garage and I've pounded the bejesus out of it for almost 10,000 miles so far and it's held up great.

They changed their bearing material to a cheaper and weaker material though now so I'd do some checking on that first. If my memory serves me correctly, the P-code boxes were the good ones and the bad ones were Q. But as I said, double check that to make sure its correct.

 

[95blackGsTurbo]

I'd be leary of the clevite 777's unless they've went back to their old bearing materials. I got some of the last good ones in my motor that I rigged together in my garage and I've pounded the bejesus out of it for almost 10,000 miles so far and it's held up great.

They changed their bearing material to a cheaper and weaker material though now so I'd do some checking on that first. If my memory serves me correctly, the P-code boxes were the good ones and the bad ones were Q. But as I said, double check that to make sure its correct.

Correct. Make sure you get the P-code boxes. Either way I would never grind a DSM crank more than .010". Anything more and you compromise the strength of it even if you do get it hardened.

 

[Mentow]

yep, clevitte dropped the P series...confirmed by some guy at SBR. Im going with the Engine Pro/ACL bearings..

Thanks for all your posts guys, i`ll let you know when my hit the road again...

Regards,

Michel

 

[brute]

Just get a tri-metal bearing set. King, ACL, etc. Or you can go with the Clevites as long as they're the old tri-metal style ones. Check Extreme PSI's selection out. They have a boat-load of choices. They are also very good products and ship fast.

 

[GVR4592]

They only dropped the P series for rod bearings, the mains are still tri-metal. Summit racing had a huge stock of the P series rod bearings last time I ordered from them. As for turning the crankshaft, I beleive there's only a handful of shops in the U.S. that can do it correctly. It shouldn't be more than .008 removed from the crank, and the filet radius must be retained. Most shops pay no attention to the details, they just remove material until it's round again and call it good.

 

[nightspeed87]

They only dropped the P series for rod bearings, the mains are still tri-metal. Summit racing had a huge stock of the P series rod bearings last time I ordered from them. As for turning the crankshaft, I beleive there's only a handful of shops in the U.S. that can do it correctly. It shouldn't be more than .008 removed from the crank, and the filet radius must be retained. Most shops pay no attention to the details, they just remove material until it's round again and call it good.

yea see I had like .o10 removed from mines ( i think that was what was removed ) and I know this messes up the nitrating, but my crank was cryotreated before the maching was done so do you think this will restrengthen it to some point to where I can still make some good amounts of power on it in comparison with the stock cranks durability? ( Its a 6bolt crank by the way. )

 

[95blackGsTurbo]

Cranks are very strong in our cars. Rods or the weak link usually. You will be fine with .010.