While putting my motor back together, I plastiguaged the main and rod bearings and came up with .002 to .0035 thousands. The book lists a maximum of .0026. Is this extra thousand going to be enough to cause low oil pressure or knocking? or do you guys think it will be ok? I have a high volume oil pump also. The motor is a 93 300.

Thanks,
Andy

 

I would try and get it back to around 2 max, 3.5 is a bit more than I would want.

 

Hey andy, where'd you get the Hi-vol oil pump? I've been looking and have found nothing.

 

yea get it back in spec, mine was out by 2 thousand when i put a set of oversized bearings in and it still had a slight knock only when cold and would loose oil pressure at less than 600rpm when warm.

 

I got the hi vol pump from Napa auto parts. They were the only one in my area that could get it.

74F250: When oyu say "out by 2 thousands" do you mean 2 thousands clearance or 2 thousands over the maximum recomended?

I think I will check one with the old bearings to see what it was before. All of the bearings had copper showing and it had little to no psi at idle when warm and would knock when I let off of the gas to shift gears or when the motor was at higher RPM with not much load. I wish I wouldn't have already bought all of the bearings, Live and learn I guess.

Thanks,
Andy

 

Look at the back of the old inserts and if they are undersized it should be marked.
Today it is pretty common practice for manufactures to use a standard insert combined with a one under insert on the same journal to arrive at desired clearances. I would guess that a good supplier would exchange the inserts should you need to do so and if they were not installed.

 

I Think Spec is up to .003" My buddy is at .003" And holds about 30psi 25Minimum i think Get a good oil pressure gauge and see what happens. Not sure what the extra .0005" will do, But hey Its A 300 Six It can run through any conditions, Right!!

 

Try this I know you already spent a lot of time to whishing that you have the right oil clearence. Just take your crank to and have it turnered then buy the oversized inserts. I did this to my 1970 300 and every thing was with in specs.