hey 454, which 294 comp cam are you running? hydraulic, hrdraulic roller, flat tappet or solid roller? running springs that are matched to the cam? Do you know what the valve/piston clearance was on assembly? I`ve got competition cam books on every cam they have made or are making now. 9.9 times out of 10, evidence is present to determine just what caused the failure. I did once have a 468 to do the same exact thing. After intense inspection and thought, i never found the cause. I had a new seat and valve installed, fixed the piston and pit it back together. (bad valve?) That was 6 years ago and its still running strong. I still dont know what the cause was but i still say 9.9 times out of 10.
Check your piston to valve clearance before condemning the valve. And look at the other pistons to see if any light contact there.
Next to last picture....looks like the valve was bent..before it broke.
And I am wondering about these super clean pistons with no color...yet I see another piston with color. And you know water does an excellent job of removing carbon in a cylinder.....
Bob, you were right!!! All of his intake valves were kissing the pistons
Cheap parts that only lasts 9hrs maybe!..You don't hear that stuff until it goes crunch or kaboom!..
Art, those are mabley valves.....
hey 454, which 294 comp cam are you running? hydraulic, hrdraulic roller, flat tappet or solid roller? running springs that are matched to the cam? Do you know what the valve/piston clearance was on assembly? I`ve got competition cam books on every cam they have made or are making now. 9.9 times out of 10, evidence is present to determine just what caused the failure. I did once have a 468 to do the same exact thing. After intense inspection and thought, i never found the cause. I had a new seat and valve installed, fixed the piston and pit it back together. (bad valve?) That was 6 years ago and its still running strong. I still dont know what the cause was but i still say 9.9 times out of 10.
The hydraulc with matching springs. We found the problem today. The valves are hitting the pistons. He didnt check piston to valve clearance but I will do it tomorrow for him.
Also check where the cam is phased at. Advanced tightens the p/v clearance on the intake. Rule of thumb is .007 per degree.
Also check those other valves are not slightly bent.
Posting Permissions
Reply With Quote