Holes in oil galley plugs ...

[earntaz]

It appears some GM (BBC Marine engines) have holes drilled in the two front galley plugs. There has been discussion this extra oil aids in lubing the gear drive or chain. What this mod on a 427 95% street engine? Thoughts??

Thanks -- TAZ

[KenMaisano]

I used to do that, Back in the Day.. for a couple reasons, it oiled the thrust on the block between the upper timing gear and helped bleed any air out of the hydraulic lifters. But I would drill super small holes.

Kenny

[earntaz]

Thanks Kenny -- seems like around .030 will do the trick ... TAZ

[Jim454]

Only real value is to bleed air from the oil passages. See the reply from well respected engine builder when I asked this same question http://www.chevelles.com/forums/showthread.php?t=312666&highlight=
HTH, Jim

[earntaz]

Yep -- read the same thing somewhere ... bleed seems to be the real reason ... thanks Jim.

TAZ

[novadude]

They did the same thing on a lot of the late 90s roller SBC truck engines too.

I drilled my own .030" holes in the plugs before I installed them when I put together my '69 350 block with a retro-roller conversion. Don't know if it helps anything, but I figure GM wouldn't have done it on the later roller engines if they didn't have a reason. It certainly doesn't hurt, as I still have good oil pressure with a low volume Chevy II Melling front sump oil pump.