Questions on lifter bore correction

[Dwight Southerland]

Caution on using anyone's fixtures. I bought a BHJ for a BBC years ago and after getting blueprints from Chev, found that the BHJ was out as much as most blocks. Then you have to wrestle with the assumption that the factory design and specs are the most optimum for valve train geometry. At least you will get them consistent.

[Bill Diehl]

Originally Posted by Dwight Southerland

Caution on using anyone's fixtures. I bought a BHJ for a BBC years ago and after getting blueprints from Chev, found that the BHJ was out as much as most blocks. Then you have to wrestle with the assumption that the factory design and specs are the most optimum for valve train geometry. At least you will get them consistent.

This is a good point, In most cases the factory design is not even close to optimum, as I said earlier specifically with canted valve heads

This was not brought up in the roller cam thread but it is a big reason why some guys are chewing thru lots of valvetrain parts..... did somebody mention.... "lifters"

[Jeff Stout]

Originally Posted by SSDiv6

Jeff, if your Olds 307 block has the .921 lifter, the block is for a hydraulic roller lifter, not a conventional hydraulic/flat tappet lifter.

According to the NHRA engine specs, the legal block for your HP rating, has the standard .875 hydraulic/flat tappet lifter and not the .921 hydraulic roller.

Also, the .875 Chevy lifter is not the same as the Olds/Pontiac lifter. They have different oil band locations.

Thank you for the info. I swore they were .921. Just finishing painting 1 car and next is 307 olds motor for wagon.

[Allen Sherman]

Listen to Dwight's advice, the bhj fixtures are about as bad as just leaving the block alone, we have a CNC mill at my shop that we do this job on, can't beat a CNC machine when it comes to exacting tolerances. We only charge $450 though and seeing that others are charging $500-700 to do it on a manual mill I might need to go up on pricing...lol

[Mike Taylor 3601]

Originally Posted by Allen Sherman

Listen to Dwight's advice, the bhj fixtures are about as bad as just leaving the block alone, we have a CNC mill at my shop that we do this job on, can't beat a CNC machine when it comes to exacting tolerances. We only charge $450 though and seeing that others are charging $500-700 to do it on a manual mill I might need to go up on pricing...lol

BHJ fixtures were like hooked on phonics,worked for me.LOL
Allen,
Ten years ago when I did lifter bores w/BHJ we got $375.00 SBC $425.00 BBC including bushings, by time took and bushings was how we come up with those numbers,CNC you can walk away some,manual machine pretty much stuck there.
Mike Taylor 3601

[GallopinGhost]

Allen, Without the fixture, what do you use for a reference, and how do you choose the angle ? thanks

[Dwight Southerland]

Originally Posted by GallopinGhost

Allen, Without the fixture, what do you use for a reference, and how do you choose the angle ? thanks

Factory blueprints and a CNC is the best.

[Allen Sherman]

Sorry I'm slow responding, I don't usually get on here while I'm at the shop, but Dwight answered the question already, we have factory blueprint locations programmed into the CNC, and if needed we just make program changes if an angle or location change is required...

[GallopinGhost]

Thanks guys. Looking at some dated drawings, w/o dimensions no less, The BBM lifter looks to be 90 degrees to the deck, so at least for this block using the crank and cam centerline to swing the angle, then line up with cam centerline should work. I do dimensional inspection work for a living, so I enjoy understanding how this stuff is done.

Originally Posted by Allen Sherman

Sorry I'm slow responding, I don't usually get on here while I'm at the shop, but Dwight answered the question already, we have factory blueprint locations programmed into the CNC, and if needed we just make program changes if an angle or location change is required...

[carl hinkson]

Originally Posted by Allen Sherman

Listen to Dwight's advice, the bhj fixtures are about as bad as just leaving the block alone, we have a CNC mill at my shop that we do this job on, can't beat a CNC machine when it comes to exacting tolerances. We only charge $450 though and seeing that others are charging $500-700 to do it on a manual mill I might need to go up on pricing...lol

I do all my blocks in a HAAS CNC machine and we only charge 275.00 for machining lifter bores LOL. I guess I will have to go up.