Internal/External Balance

[HJR1]

Hey all, glad to find your site here. I have a question about the 2.8 used in the s-10/S-15s. I have a '87 S-15 with a bad 2.8 in it and today I bought a used 2.8 from an '88 S-10. Now the write up here on the family tree says that in '87 it was hit and miss on whether it's internally balanced or not. My question is how do I tell on the manual transmission engines? I've read on the automatics all you have to do is check for the weights on the flex plate, but I have the 5 speed so how do I know if the flywheel is for the internal or external? My '88 engine is out of an automatic so I need to use the flywheel from the '87 if it's the correct one.
TIA!
-HJR

[geoffinbc]

Your 87 Will have a large lump cast into the back if it is external balance. You cannot miss it. Internal balance flywheels are smooth with a few holes drilled around the outside for balancing. Other checks include a reluctor ring on the crankshaft. It is a big cast disc in the center of the crank that may or may not have notches machined in it. If you have the disc it is internal balance. A one piece rear main seal also denotes internal balance.

[HJR1]

Hey, thanks for the quick reply, BTY, I see that large lump cast on the back of the flywheel so I have the wrong one for the '88. My luck. Can I just have that lump machined off? Or would it need to be balanced afterwards as well? It may just be cheaper to get the correct flywheel. Figures my donor engine was out of an automatic truck.

[geoffinbc]

Yea you can have it machined but then it does need to be neutral balanced. It may be cheaper to get a new one. If you get a used one remember it needs to be machined as well so factor in that cost.