Confusion about chevolet main bearing oversize markings.
jwarden
Just bought a 68 vette with a 327 ci engine. I had to replace the
rear main seal and decided to replace the main bearings while I had it
apart.
When I removed the main bearings, I found that the rear main
bearing was marked .001 oversize, the front bearing marked .0012
and all the middle bearings were marked .0006. All bearings were
stamped GM 1967, so I don't think they have ever been replaced.
Has anyone come across a situation like this? Should I just replace
all the bearings with .001 oversize, replace with identical sizes
removed or maybe replace with standard .000 size?
Thanks in advanced,
Ken Gibson
mands-v
jwarden <jwa...@flash.net> wrote:
snip:
how do the old bearings look ? do you see a copper
color ?
if it wasn't broken ? ; )
use some plastic gauge ... ( i am not a fan of the
stuff ) and only use it to double check machine shop
work.
put the bearings back in and gauge the clearance with
the above.
you might have just opened up a can of worms.
your other choice is to remove the crank and have it
ground to a single undersize: i.e. .010" for rods and
mains.
regards,
mands-v
you can get more with a kind word and a gun..
than just a kind word
Ron
My guess is that these bearings were select fit at the factory. If they
aren't showing wear, I'd just put em back in and replace the rear main
seal and be happy. Otherwise, you are going to need to either plastic
gauge or mike everything and go from there.
Have fun!
Ron
J. Forbes
>Just bought a 68 vette with a 327 ci engine. I had to replace the
>rear main seal and decided to replace the main bearings while I had it
>apart.
>When I removed the main bearings, I found that the rear main
>bearing was marked .001 oversize, the front bearing marked .0012
>and all the middle bearings were marked .0006. All bearings were
>stamped GM 1967, so I don't think they have ever been replaced.
>Has anyone come across a situation like this? Should I just replace
>all the bearings with .001 oversize, replace with identical sizes
>removed or maybe replace with standard .000 size?
I suggest you measure the crankshaft, and see if you can use standard size
bearings and still have it within specs. You might also check the clearance
with the old stock bearings, if they are within tolerance, just put them back
in.
Lots of Chevy engines back then had select fit bearings, including
the last 350 I took apart, a 2bbl 1970 car engine....there's nothing special
about your engine.
Jim
Phil Murray
No big deal. You've got a select fit engine.
Measure your crank and bearing bores, that will tell you what you need to
do.
I would not just replace with standard size bearings!
If there is any wear on the crank at all, you might be better off having
the crank turned and then you can use a set of undersize bearings off the
shelf.
--
Phil Murray
pmurray@@inx.net
Remove one of the "@" signs if contacting me via E-Mail
jwarden <jwa...@flash.net> wrote in article <3467D4...@flash.net>...
> Just bought a 68 vette with a 327 ci engine. I had to replace the
> rear main seal and decided to replace the main bearings while I had it
> apart.
>
> When I removed the main bearings, I found that the rear main
> bearing was marked .001 oversize, the front bearing marked .0012
> and all the middle bearings were marked .0006. All bearings were
> stamped GM 1967, so I don't think they have ever been replaced.
>
> Has anyone come across a situation like this? Should I just replace
> all the bearings with .001 oversize, replace with identical sizes
> removed or maybe replace with standard .000 size?
>
> Thanks in advanced,
>