oil hole

[69vette427]

Going to start putting the engine back together. Been apart for quite some time. Read in a few articles about drilling a hole in one of the oil plugs in the front of the engine to help oil the timing chain. Is this really agood idea , what size hole do you drill and does it matter what plug you drill.

[Torchred73]

69vette427,

According to the book "Rebuilding the Small-Block Chevy", a 0.030" hole is drilled in ONE of the oil gallery holes to lube the chain. It shows a hole of the same size drilled in the upper sprocket thrust face of the block for use in racing engines with "high seat pressures".

I personally have not done this, but someone who has may chime in.

Hope this helps,
Torchred73

[6880 Mike]

Originally Posted by 69vette427

...Read in a few articles about drilling a hole in one of the oil plugs in the front of the engine to help oil the timing chain. Is this really agood idea...

Not necessary.

[D_B]

Originally Posted by 6880 Mike

Not necessary.

Agreed. GM made a lot of changes to the Gen1 and Gen2 all the way up to the Vortec and never added that oil port. I think the chain gets plenty from the ports to the oil galley.

[smokem2020]

I drilled a small hole in my BBC gally plug for a gear drive I was using. I'm not sure what size it was but it was the smallest one I had. Now the Oil runs out the timing chain cover gasket. I'd not do it again unless I was sure of the drill size.