bearing clearance issues...

Go down

bearing clearance issues...

Post  Lazarustorino on March 31st 2016, 6:32 pm

I was checking the clearance on my main and rod bearings last night and everything is too tight. On the mains I have between .002 and .0025 clearance, and the rods are pretty solid at .002 of clearance. I'm gonna check the main bores and the rods later to see how the measure up to factory spec to see if they can be honed out a bit, but I would really prefer undersized bearings if anyone knows of a place that sells them. The crank has been ground and polished down to .020 undersized on the mains and rod journals, and checks in pretty dead on with less than half a thou variation. It would be far easier to put in bearings that are .019 then to have the mains and rods honed. Anyone know of a company that sells bearings like that for a 460?
avatar
Lazarustorino

Posts : 18
Join date : 2015-10-23

View user profile

Back to top Go down

Re: bearing clearance issues...

Post  Lazarustorino on March 31st 2016, 6:40 pm

or if anyone knows of a different way to get the clearance I need. It would take two days for the line hone and rod hone at the shop I use, two weeks to get the crank redone for the .001 I need... but doing the crank would be about half the cost of doing the mains and rods. I'm at a loss at the moment and the bore gage and mic's are making me cross eyed, lol.
avatar
Lazarustorino

Posts : 18
Join date : 2015-10-23

View user profile

Back to top Go down

Re: bearing clearance issues...

Post  69F100 on March 31st 2016, 7:48 pm

If I couldn't find the bearing I needed I would op for the crankshaft
avatar
69F100
BBF CONTRIBUTOR
BBF CONTRIBUTOR

Posts : 5103
Join date : 2009-01-04
Age : 51
Location : Irwinville Ga.

View user profile

Back to top Go down

Re: bearing clearance issues...

Post  rmcomprandy on March 31st 2016, 7:48 pm

Lazarustorino wrote:I was checking the clearance on my main and rod bearings last night and everything is too tight.  On the mains I have between .002 and .0025 clearance, and the rods are pretty solid at .002 of clearance.  I'm gonna check the main bores and the rods later to see how the measure up to factory spec to see if they can be honed out a bit, but I would really prefer undersized bearings if anyone knows of a place that sells them.  The crank has been ground and polished down to .020 undersized on the mains and rod journals, and checks in pretty dead on with less than half a thou variation.  It would be far easier to put in bearings that are .019 then to have the mains and rods honed.  Anyone know of a company that sells bearings like that for a 460?

That amount of clearance is absolutely fine unless you are using thick oil and making over 800 horsepower.

rmcomprandy

Posts : 4985
Join date : 2008-12-02
Location : Roseville, Michigan

View user profile http://www.rmcompetition.com

Back to top Go down

Re: bearing clearance issues...

Post  Lazarustorino on March 31st 2016, 10:58 pm

checked them again... the rods are as low as .0014 clearance on a couple. The engine builder I use told me between .003 and .004 on the mains, and .0028 to .0032 on the rods. I just got done making a detailed list of all the measurements and what I need them to be, gonna take the crank back in tomorrow and see if they can polish/grind it down to what I need. The guy I use is awesome, same shop built the engine that was in Brian "chucky" Davis' car if you watch street outlaws you know he was the dude that wrecked the crow, lol. This experience has left me wanting digital micrometers though, I hate reading the "tenth" graduation marks on standard ones.
avatar
Lazarustorino

Posts : 18
Join date : 2015-10-23

View user profile

Back to top Go down

Re: bearing clearance issues...

Post  Dave De on April 1st 2016, 7:20 am

Be careful here.
Are your gages calibrated? It sounds like you are using a transfer gage method. Good shops use dial bore gages for this and they have ring standards to zero out the bore gage. If you are using telescoping gages and mics to transfer a better practice might be to use plasti-gage.
avatar
Dave De

Posts : 525
Join date : 2011-05-27
Location : Utica, MI

View user profile

Back to top Go down

Re: bearing clearance issues...

Post  Lazarustorino on April 1st 2016, 3:55 pm

I'm setting a dial bore gage to the micrometers that are set to the size of the journal on the crank... I realize there is a bit of room for error here, and I've been stressing it a lot. I also used plastigage as well, but got pretty consistent results there too. I'm going to ask my machine shop to verify the measurements for me I think. I don't want to risk screwing it up. I'm just trying to avoid the 500 dollar charge for short block assembly is all, and I like doing the work myself.
avatar
Lazarustorino

Posts : 18
Join date : 2015-10-23

View user profile

Back to top Go down

Back to top


 
Permissions in this forum:
You cannot reply to topics in this forum