View Full Version : so I spun a bearing


SportGoldSS
04-24-2012, 01:24 AM
Had a pretty bad knock after taking my car to 6800 RPM while tuning. Finally got it pulled out and tore down and found a pretty bad spun rod bearing. Motor has an MS4 cam with the double valve springs and hardened pushrods. I also have an 85mm intake and throttle body. 2001 block.

My question is, what else should I do while I am in there and have the engine completely tore down. I am going to see if I can have the crank turned and have everything else checked out.

mark21742
04-24-2012, 05:12 AM
Stock rods I take it? The one rod that spun the bearing is probably trashed, so I'd get a set of forged rods and pistons, and hopefully your crank can be turned down .010". Are you still running your stock oil pump and heads? I'd upgrade the pump and if you have the space (replace the pistons with ones that had valve reliefs) you can mill some off your heads and maybe do a little port work and valve job.

gMAG
04-24-2012, 10:31 PM
I spun two rod bearings...one of them so bad, that between the spun bearing & lack of oil, #7 crank journal was eaten up beyond repair. But virtually nothing happened to the rod.
Inspect the rod(s) and verify that they need replacing or not. They may just need a light machining, or smoothing.

Whiteaw57
04-25-2012, 01:17 AM
I definitely like the valve relieved pistons so that you can mill the heads some more idea. More compression would really be welcome with that MS4

SportGoldSS
04-25-2012, 02:07 AM
I'm thinking about this route. Have my crank checked and (optimistically) turned. As far as the rod goes, honestly there is no sign of a spun bearing, visually cannot tell or feel a difference in it from the other rods. If need be I'll get stock length forged rods. But instead of shaving a bit off the heads, what if I go with the wiseco +4 cc dome pistons, or will they have clearance issues with my valves with the MS4?

SportGoldSS
04-25-2012, 02:08 AM
Oh and I'm definitely going to change the oil pump out while I'm in there.

TransAmcoupe98
04-25-2012, 04:39 AM
How are your cylinder heads? When I spun a bearing in my old f-body, the piston kissed the heads a good bit. Also, check that your walls aren't gnarled as you might have to get the cylinders honed out to clean the walls up. Spinning a bearing sucks as it really has the potential to screw EVERYTHING up, as any catastrophic failure would. The question is, how much coin do you have? That would open the doors for more suggestions and opinions as what to do.

SportGoldSS
04-25-2012, 06:13 AM
The heads appear to be in good shape as does the top of the piston. The cylinder walls are smooth as can be but will end up getting honed anyway.

TransAmcoupe98
04-25-2012, 06:33 AM
Don't hone them if you dont have to. That 900 bucks worth of machine work dude.

black00ssFL
04-25-2012, 08:03 AM
Don't hone them if you dont have to. That 900 bucks worth of machine work dude.

umm.....they need to be honed when putting new rings in. There's no way he's doing this small rebuild and not replacing rings.

b_evans06
04-25-2012, 08:07 AM
$900 for a hone job? My local machinist charged me $240 for honing, cam Bearing install, and assembled the short block. I spun a bearing and my cam bearings got scratched from the metal shavings. I'd replace them as well and another good upgrade I had done was better rod bolts.

dodson55
04-25-2012, 08:09 AM
Don't hone them if you dont have to. That 900 bucks worth of machine work dude.

900 bucks to have a blocked honed you need a new machine shop

el33tprodigy
04-25-2012, 10:15 AM
Yea last time i had a block honed costs me 150 LOL... Time for you to shop around and quit letting your machine shop rip you off!

TransAmcoupe98
04-25-2012, 10:58 AM
I digress, I had a rotation assembly balance and some work on an intake in addition. I apologize lol. Only number that stuck out at the time. I still got raped by the prices Im seeing on here for machine work. 150 bucks to hone out every cylinder? Thats pretty damn good.

mark21742
04-25-2012, 11:58 AM
I'm thinking about this route. Have my crank checked and (optimistically) turned. As far as the rod goes, honestly there is no sign of a spun bearing, visually cannot tell or feel a difference in it from the other rods. If need be I'll get stock length forged rods. But instead of shaving a bit off the heads, what if I go with the wiseco +4 cc dome pistons, or will they have clearance issues with my valves with the MS4?

Dome pistons will do two BAD things for you.....drop your ptv clearance, and push the majority of the combustion pressure out to the ring land area on the edge of the pistons.....that's why I suggested milling and valve reliefs....maybe even a slight dish

SportGoldSS
04-25-2012, 04:40 PM
Understandable, I think I will hold off on doing any head work for now as I feel like any money in LS1 heads is a waste. I plan on doing heads but what little money I had for that is now going in the bottom end for this.