main bearings

[Jeff in Oh]

Does anybody know if the main journals are all the same on 9s 2s
and 8s? I bought a used block to replace my badly cracked one in
my 9. My crank is in very good shape and had .10 bearings so I
purchased new .10 ( they mic the same as the old ones).I put the
crank in today and can't even snug the nuts on the caps, the crank
will not turn, way to tight.I mic'd the journals on the old block and
the new one and they seem to be the same. Any suggestions.

 

[Dunk]

This may be a stupid question, but do the caps have any numbers stamped on them?

 

[Dunk]

I don't mean only numbers, I mean notches or any other kind of markings.

 

[Jeff in Oh]

Thanks for the quick reply Dunk , I'll run out to the shop and check
.I'll be back In a couple of minutes

 

[Jeff in Oh]

OK I'm back. The front cap says 9n6607( I think 07,stamped really
faint). The middle cap, CS, and the front cap 6 CS.

 

[John (TR)]

Its possible someone ground down the caps and old bearings to tighten up an old motor.
You may need to take the block and caps to the machine shop and have it line bored. I did on mine when I switched out oil pump bodies. They take a little off the caps, bolt them on, the re bore the whole thing to the correct size and they all line up again. The top half of the bore remains the same so the crank/cam spacing stays good. The caps donate the material.

 

[Hobo,NC]

as John (TR) says enny thing is possible,,, my bet would b the caps or a cap is from another block,,, I have 2 engines tore down at this time,,, all the caps are in one box,,, I know the engine they go to but no one else would,,, I best b marking them so when i am dead and gone they will B matched to the right engine

 

[Hobo,NC]

sorta would b hard to install the cap in the wrong place on a N,,, front cap has the oil pump in it,,, #2 has the thrust bearing,,, #3 just a plane old cap,,, it would b possible to install 2 and 3 in the wrong place or have'em installed backerds,,, me and you know the notch to notch deal but some don't

 

[Jeff in Oh]

Thanks for all the advice. I guess I'll have to take it to machine shop and have it line bored.The guy said they were the caps that came with it , but who knows.

 

[TheOldHokie]

(quoted from post at 18:00:19 05/04/08) Does anybody know if the main journals are all the same on 9s 2s
and 8s? I bought a used block to replace my badly cracked one in
my 9. My crank is in very good shape and had .10 bearings so I
purchased new .10 ( they mic the same as the old ones).I put the
crank in today and can't even snug the nuts on the caps, the crank
will not turn, way to tight.I mic'd the journals on the old block and
the new one and they seem to be the same. Any suggestions.

1) Mic the mains on your crank and report the numbers. Mic each main twice at 90 degree angles to each other. The journals should be 2.238-2.239 if it's .010 under.

2) Bolt the caps up without bearings and crank. Inspect the parting lines inside each bore to verify they are dead flush using your "finger mic". If you can feel any unevennness they are mismatched. If they feel OK mic the bores the same way you did on the main journals taking the measurements at 45 degrees to the parting line. Both measurements in each bore should be exactly the same.

3) If that all checks out bolt the shells into the mains without the crankshaft. Mic the bores just as you did in #2. That measurement should be .002/.004 larger than the main measurements you got in #1.

If 1-3 all check out consult a pro.

TOH