Hey guys, I think I need to replace my rear seal, does anyone know if it is a 1 or 2 piece? The block # is 3970014 4 bot main from 1970. The engine was rebuilt driven about 3000 miles and sat for almost 20 years, I rebuilt the top, heads intake and carb. New push rods, rockers and got it all back together. Now I have a leak lots of oil. It seems to be dripping around the transmission shroud.
any suggestions Please. Also have oil in drivers side exhaust. When I had the heads off the cylinder walls were perfect. Help.

 

I cant remember exactly, but I think you can get them either 1 or 2 piece. I vaguely remember something about gm going to 1 piece to replace the 2 piece - or it was an after market sompany that offers them in 1 piece. something like that. I could be wrong.

 

On the smallblock the seal is dependant on the block design long story short its a 2 piece design in the 70s pull off cover block car slide under and look where it it leaking. You can also check the oil galley plugs in the back of the block by the cam and more unlikely the oil pressure fitting at the back top of the block. Oil in the exhaust could be?? poor ring seal check compression to the other cylinders.... Valve guides and or seals... inspect seals check guide clearance, cracks or head gasket (this is very unlikely)..

 

Thanks guys, I think I will investigate alittle further. But I think a stroker build is on its way. You know this sucks after all the hard work to now have to go a tear it up again.
Crap if I'm going to do it might has well go all the way.

 

old blocks are two-piece. lots of people pinch the valve cover gaskets in the back and get leaks like you speak of and think it's their rear main seal, and after the work you just mentioned, I would think it might be a safe bet

 

1969 ss, Thanks for the tip, I will install a new set of gaskets and check it out. I have a spare set floatingaround in the garage. If it works you just saved me alot of time and work.
I will let you know.
Thanks.

 

Okay I change valve cover gaskets retimed it and took it out for a spin and looks good so far. I dont think its leaking any more but its dark out and late I will check it out tommorrow and let you know.
Wow I hope my week end plans have changed. Didnt really want to pull it yet.

 

I think that might have taken care of the big leak. Thanks, now I need to do the oil pan with a 1 piece. Should be an adventure on that one.

 

If it is a stock oil pan the front seal on the early 70s used a thinner seal if you use the thicker one the pan will not bolt down tight. What happened to the oil in the exhaust?

 

still have black spatter, dont know if its carbon or oil? When I had the heads off the cylinder walls looked brand new.
dirver side is still stronger preassure than the passenger side. Dont think that is normal.