2011 Route 66 Fun Run

[RedSnake351]

Originally Posted by Bob Broberg SPF667 460BB

Flat tappet cams have a tentancy to round out/wear down lobes especially at break in. Ask Jeff about that. Ralphie, you made a smart move to hydraulic. No more valve lash adjusting and tappet noise. Did you put the NOS back on?

AZ Bob

Yes, DWRAT, I did switch to Mobil 1 about a thousand miles prior to the breakdown, but had been running Royal Purple for about 3 years before the last switch to Mobil 1.

Bob, the engine has just over 21000 miles on it and had not solid but Hydraulic flat tappets, so it was not a break-in problem.
Did not replace the NOS since the new RPM Airgap intake is slightly taller and did not have enough hood clearance to keep the 1/2 inch nitrous plate.
Ralph

[Car Nut]

Originally Posted by RedSnake351

Yes, DWRAT, I did switch to Mobil 1 about a thousand miles prior to the breakdown, but had been running Royal Purple for about 3 years before the last switch to Mobil 1.

Bob, the engine has just over 21000 miles on it and had not solid but Hydraulic flat tappets, so it was not a break-in problem.
Did not replace the NOS since the new RPM Airgap intake is slightly taller and did not have enough hood clearance to keep the 1/2 inch nitrous plate.
Ralph

Flat tappets are flat tappets, whether they be solid or hydralic. Roller lifters can be either solid or hydralic too. I think your problem is exactly that, the Mobil One. My guess is the Royal Purple you used had the appropriate additives. They started taking the good stuff out of oil a couple of years ago by EPA decree but some racing oils kept it in (off highway use). Royal Purple may have been one to keep it HOWEVER, check any proposed oil or additive for the proper amount and type of additive. Check the manufacturer's web site.

Now that you are running a roller cam, you shouldn't have to worry about it.

Just wanted to clear up for other readers.