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02-15-2018, 09:38 PM | #1 |
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Groove In BBC Lifter Bore
What are your thoughts on cutting a vertical groove in a BBC lifter bore for flat tappet cam lifters?
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02-15-2018, 10:41 PM | #2 |
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Re: Groove In BBC Lifter Bore
Bushings would be better.
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02-15-2018, 11:30 PM | #3 |
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Re: Groove In BBC Lifter Bore
lifterboretools.com has reamers and bushings.
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02-16-2018, 08:50 AM | #4 |
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Re: Groove In BBC Lifter Bore
Oil pressure?
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02-16-2018, 09:09 AM | #5 |
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Re: Groove In BBC Lifter Bore
If you are not using a new CNC'd block (GMPP. Dart, etc.), there are multiple advantages of bushing the lifter bores. 1) Blocks from the 1960s are notoriously out of register. Having the lifter bores correctly aligned will eliminate potential vale train problems. 2) The bushings allow for tighter clearances, thus more accurate movement. 3) Less wear 4) You can restrict the amount of oil to the top end easily, thus allowing more oiling to the camshaft bearings.
If you are concerned about oiling the camshaft-lifter surface, you could have a vertical groove from the galley hole to the bottom of the bore.
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02-16-2018, 10:35 AM | #6 |
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Re: Groove In BBC Lifter Bore
I thought once on a BBC I had the builder ground a small flat on side of lifter from groove down to base of lifter, thus making a cavity for oil to run down lifter to cam
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02-16-2018, 11:27 AM | #7 | |
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Re: Groove In BBC Lifter Bore
Quote:
On flat tappet cams the lifter bores could be off .010 plus and not effect seat timing events as the cam is riding on a flat surface so to speak. If the lifter bore was off say .012 and you moved it in the opposite direction .024 which would be .012 off center on the opposite direction its not going the seat timing events at all. That being said on roller lifters being off .012 plus it does change seat timing events which causes an intake and exhaust imbalance plus compression from cylinder to cylinder would not be the same. |
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02-16-2018, 01:46 PM | #8 | |
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Re: Groove In BBC Lifter Bore
Quote:
Not wanting to start a p***ing match here, but that is not exactly true. First, it is not a flat surface, and it does effect valve timing events. Secondly, I did not refer to valve timing events, but rather to valve train problems that are caused by harmonics. Thirdly, I agree with you 100% about lifter bore clearances and oil bleed off. Grooves are not necessary if everything else is kosher.
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02-16-2018, 11:20 AM | #9 | |
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Re: Groove In BBC Lifter Bore
Quote:
If you have .0015 to .002 oil clearance there is plenty of oil coming out from around the bottom of lifter bore getting to the cam lobe. Dumping more oil on the crank only creates windage problems along with horse power loss. I am a big advocate on lifter bore clearance and oil bleed off. If your using a solid flat tappet go to tool steel lifter and a good cam core plus good high zinc oil and break in springs will help. Last edited by carl hinkson; 02-16-2018 at 11:30 AM. |
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02-18-2018, 06:54 PM | #10 |
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Re: Groove In BBC Lifter Bore
I never do it. I consider it a crutch, at best, which does not actuallysolve any problem, at best it might mask a symptom.
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