blown4now

Story goes as follows...
95 Vette LT1
installed CC304 cam
Comp R lifters
Stage 2 heads with crane dual springs
Comp 7.200 pushrods
Bowtie Guide Plates
Comp non self aligning rocker arms

After adjusting the rocker arms a bit, the car sounded quite as could be at idle, and was idling great. Give it a bit of throttle, and you get the terrible rapping noise. I talked to a few buddies who said I may need different length pushrod cause the base circle on the 304 cam is smaller than stock. I took a peak at the roller tip, and where it sits on the valve stem while on a lobe...and it appears it's barely touching, it hangs over so far. I would think this means using a shorter pushrod, but by how much?? Anyone with this setup, or similar, or just knows their LT1/SBC stuff chime in please! I do LS1's on a regular basis (daily) but this is really the first LT1 I've tooled around with setting this stuff up. I need this car to leave the shop today!!! Thanks!

Jake

shoebox

Not sure I follow your description of where the rocker is sitting, but I have read that the Comp R lifters only need ~1/4 turn of preload and no more. Could this have something to do with your noise? Also I have never heard anyone ever say anything about having issues with or the lobe being different on a CC304.

blown4now

I set the preload between 1/8 and 1/4 of a turn. Buddy of mine set his preload to 1/2 turn on his 95 vette....but it's a 398 stroker with a D1SC on it. He came up today, and he seems to think it may actually be a lower noise than valve train, like a valve contacting the piston, or the piston pin making noise. I pulled the injector clips while it was running, one cylinder at a time, but the noise really didn't change any. I don't what could have caused that problem, if it is lower end....we didn't change anything in the lower end. This car has been nothing but a hassle, but for privacy reasons, I won't post the other problems we've encountered that weren't our fault. I guess I'll let the owner make the decision when he hears it. If it is lower end...buddy with the 398 still has his old 4340 383 stroker crank, and brand new 6" h-beam forged rods that he'll sell me real cheap, if this guys decides to go that route.

BUBBA

If your lifters are pumped up and your geometry boogered, you may want to use an adjustable PR to see how long the Rod should be. JMHO

blown4now

It was a rod bearing. Pulled off the oil pan just a minute ago, #1 had tons of play in it, so I pulled it off, the bearing was spun and toast, crank was grooved, it was nasty. But it got worse...I pulled off #2 for inspection as well, bearing was pretty chopped up, but it gets better....there is about a .050" groove in the journal, between #1 and #2 where the #1 bearing had been chewing away at the crank!! I've actually never seen that before! This has apparently been going on for a while now...gonna have the owner do a bit more research into this vette.

Jake