Billet cams and lifter supply

[Stan Weiss]

Originally Posted by Rory McNeil

Totally different situation. The OHC engines with buckets have no rocker arms, lifters or pushrods, so the valve springs are generally much less tension, since the weight of the valve train is so much lighter. Even more so with a 4 valve head, since the valves are considerably smaller, as are the spring diameters and retainers. Also, the buckets do not need to rotate like a flat tappet cam, and the cam lobes are not ground on a taper, to promote rotation.

Let leave 4v DOHC out of this and just look at 2v Single OHC. While there is no rocker arm or pushrod the bucket replaces the lifter and is traveling at valve velocity / acceleration while the lifter would be traveling slower.


Stan

[Mike Taylor 3601]

Originally Posted by John Duzac

Looking at the photograph of damage to the cam lobe makes me ask one question. What brand/type of oil was used in this engine?

The reason why I ask is my new 350 engine had about 30 runs on it and began to run slower and slower. I checked the leak down and one hole had 40%. I sent the engine back to my engine builder. It was discovered that all 8 pistons were ruined, along with the tool steel lifters. I always used Joe Gibbs oil and never had any problems. Gibbs oil was sold and manufactured under the name of DRIVEN oil. Samples of the used oil were sent in for testing. The results have not been received yet. Has anyone had issues using DRIVEN oil?

I started to use Gibbs break- in oil once... warehouse gave me a case to try..I was assembling my own engine,grabbed a quart....oiled up mains and installed crank(had already checked bearing clearance) crank wouldn't turn... pulled it back out... the oil did'nt have any slickness at all... cleaned off bearings and crank... lubed it up with Brad-penn or lucas break-in oil... set crank back in and torqued down... spun just like it should... I dumped that quart I opened and the other eleven in the used oil barrel...
looking back,I should have sent back to be checked...

[Frank Castros]

I'd like to hear more from Glenn Briglio on this subject.

[mnmaxwedge]

Originally Posted by Mike Taylor 3601

I started to use Gibbs break- in oil once... warehouse gave me a case to try..I was assembling my own engine,grabbed a quart....oiled up mains and installed crank(had already checked bearing clearance) crank wouldn't turn... pulled it back out... the oil did'nt have any slickness at all... cleaned off bearings and crank... lubed it up with Brad-penn or lucas break-in oil... set crank back in and torqued down... spun just like it should... I dumped that quart I opened and the other eleven in the used oil barrel...
looking back,I should have sent back to be checked...

Are you running a steel cam core or cast iron? If iron, it needs to be nitrided. If stee,l make sure you request the cam manufacturer to micro polish the cam lobes. Also you must run DLC coated tool steel lifters (the old Shubecks will work in a pinch). I work for a distributor that sells Driven Break In oil and we go through several pallets every couple weeks without any problems. On the contrary I have heard negative things about the new Penn Grade break in oil. It's not the same formula as the original Brad Penn. I have a couple of customers that have Rockwell testers. It seems that the "good" traditional flat tappet non tool steel lifters will have a hardness rating of about 60c. Lifters also need to be checked for crown. I received a tray of lifters from Sealed Power that were Chinese. They had sufficient hardness but no crown to speak of. Because of that they wouldn't rotate enough to prevent the lifter from dishing and ruining the cam lobe.