turbodave231
Moderator
- Joined
- May 24, 2001
- Messages
- 2,287
In my humble opinion, correct bearing clearances are critical in these engines because the oiling system in not the greatest. Blueprinting the oil pump and radius grinding the oil passages helps improve the lubrication in these engines.
On the Topic of bearing clearance:
.0023 is way too much for rods. I like to see .0017-.0018 on rods.
.0018- .0020 on mains is a good number for my engine builds.
Bearing clearances this tight usually scares the crap out of any engine builder not familiar with Buick V6 engines. The typical 700 HP BBC needs lots of bearing clearance because the crank is a big, long, heavy shaft. It flexes alot! Tight clearances in these applications can lead to bearing failures. Plus they have superior oil pumps and lube systems. The big clearances can covered up with a big pump. (this also create a windage problem).
Controlling bearing clearances in these engines is critical for engine life. Too much clearance drops oil pressure. Trying to make up oil pressure with a HV pump is a band-aid. It usually ends up with spun rod bearings on 5 & 6. I've seen it numerous times!!!
I share this because I would hate to see you make those mistakes.
On the Topic of bearing clearance:
.0023 is way too much for rods. I like to see .0017-.0018 on rods.
.0018- .0020 on mains is a good number for my engine builds.
Bearing clearances this tight usually scares the crap out of any engine builder not familiar with Buick V6 engines. The typical 700 HP BBC needs lots of bearing clearance because the crank is a big, long, heavy shaft. It flexes alot! Tight clearances in these applications can lead to bearing failures. Plus they have superior oil pumps and lube systems. The big clearances can covered up with a big pump. (this also create a windage problem).
Controlling bearing clearances in these engines is critical for engine life. Too much clearance drops oil pressure. Trying to make up oil pressure with a HV pump is a band-aid. It usually ends up with spun rod bearings on 5 & 6. I've seen it numerous times!!!
I share this because I would hate to see you make those mistakes.
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