Don Terrill’s Speed-Talk

The head porter at SAM said they won it.

If you want the top ring to break in by chemical polishing, use a high ZDDP oil with no detergent to hinder its attachment to parts.

If you want the top ring to wear in through metal to metal contact, use something else.

[quote="MadBill]

...but guys found they needed enough more oil ring tension with them that the overall drag was less with a really light Napier 2nd ring and a lighter oil ring...[/quote]

That's the way I see it also.

Still not to sure how sllckness could cause cracks in cams. Galling and possibly scoring from skidding rollers, but not cracks. The hypothesis from the manufacturer was that the lifter was skidding on the lobe. They recommended bead blasting the lobes to roughen them up and aid traction. I'm dumb a...

No Sir, the black ones I'm referring to were steel, I don't know what type. They weren't cast though. They would only fail with synthetic oil. If something like Kendall was used they were fine.

The title to the thread made me curious. I've never heard of oil traction before.

I saw induction hardened (black cores) solid roller cams that when run with synthetic oil would develop small cracks and pieces of lobe on the opening ramp would chip out. The flame hardened cores (gold ) wouldn't do it.

I'm not a cam guy so excuse my terminology.

Add to that list wet flow, exhaust port quality(didn't say flow), low lift reverse flow on the intake port, seat runout, guide length, on and on......

Well it isn't. There's a lot more to it than intake port flow (which is crucial BTW).

I would have the headers ground flat and use red silicone.

I never got away from the LSx builds. I don't publicize my projects much. When a customer decides to post about it is the only time it'll come up.

The way John's heads are done doesn't lend well to digitizing. I use a sonic checker and *push* the sweet spots in the head as far as I can safely.

The heads on this engine received a LOT of time. John was patient, and he got something good.

I have no doubt the car will run a good number at the track. This is the same port I've used on other cars that perform well.

Thanks John for the opportunity.

The only way you can coil bind a spring that has .050-.060 clearance in a running engine is if the valve is lofted off the nose. If thats the case, and it is entirely possible, then he has big spring issues. But if this is a STOCK engine as he posted, I doubt that is the problem unless he is runnin...

All I see is the support rail and the expander, no oil scraper rings.

Runs fantastic with a few gallons of Aviation fuel added and 34 degrees total timing all in at 3000 RPM. I'd experiment with delaying full advance until later in the rpm curve. Full advance at 3000 may be too much too soon. Engines usually want less timing at peak torque than they do at peak hp.

I would replace all of the seats in that head. OEM seats usually do not have enough interference fit to start with, and you'll be distorting some of the seat pockets by welding the head. Bore nice new round seat pockets and put new seats in with about .007" interference fit. Make sure to have a...