May have ruined engine!
Thread Starter
6th Gear
Joined: Aug 2004
Posts: 6
Likes: 0
May have ruined engine!
1978 Vette 350, .030 over, roller cam, roller tappets, RR's, Proform Dist, Edel. Performer intake, 650 elec. choke carb, the rest is stock
So here's the story: Car overheated big time on the interstate a while back. Cracked the radiator and pissed me off royally. Now there is a clicking noise coming from under the intake. Its not the RR's, and all the crossbars on the roller tappets are good. What could cause the clicking? Rounded lobe on camshaft? Main bearing? Cam bearing?
thanks for the help,
-John
So here's the story: Car overheated big time on the interstate a while back. Cracked the radiator and pissed me off royally. Now there is a clicking noise coming from under the intake. Its not the RR's, and all the crossbars on the roller tappets are good. What could cause the clicking? Rounded lobe on camshaft? Main bearing? Cam bearing?
thanks for the help,
-John
Navigator
Joined: Jul 2004
Posts: 9
Likes: 0
From: Williamsburg Virginia
Had the exact same thing happen to my 80 a year or so ago...turns out it was a stuck (compressed) lifter. Gave me an excuse to upgrade my cam. When you described the noise I could just hear it...drives me crazy even thinking about it. 
Thread Starter
6th Gear
Joined: Aug 2004
Posts: 6
Likes: 0
How do you mean stuck? Like siezed up in the hole and rounded the cam off? When we took the stock motor out one of the lifters had done that. Could it have screwed up the block that time and now come back to get this set of lifters too? I hope not, but if so i guess it will be long-block time,
thanks
-Johno
thanks
-Johno
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Thread Starter
6th Gear
Joined: Aug 2004
Posts: 6
Likes: 0
^I hope to god not, i won't rebuild this engine again! I took out all the lifters pushrods and rockers, they all are fine, no scratches or flat spots. Could the oil have gotten so hot that it is not lubricating good and causing knock? i reset the rockers like 3 times trying to stop the knock, and it really sounds like a tappet to me but they are all fine. I don't understand, but hopefully someone will think of something small that might be the problem
thanks
-Johno
thanks
-Johno
Easy stuff first 
Racer
Joined: Aug 2004
Posts: 399
Likes: 0
From: Chambersburg PA
DUDE CHANGE THE OIL !!!!!!!!!!!! 
I agree dont you remember the old mobil one commercial...I had a hole in the radiator in my jeep and it overheated.....That was all i could think about. A clicking sounds like a lifter...a rod is a hollow knocking sound Trust me I have heard them both . Clicking is usually in the valve train. If that is all good dont over look the accessory bearings/pullys. Hate to tear apart and enginge fo a bad alternator bushing.
I agree dont you remember the old mobil one commercial...I had a hole in the radiator in my jeep and it overheated.....That was all i could think about. A clicking sounds like a lifter...a rod is a hollow knocking sound Trust me I have heard them both . Clicking is usually in the valve train. If that is all good dont over look the accessory bearings/pullys. Hate to tear apart and enginge fo a bad alternator bushing.
Instructor
Joined: Aug 2000
Posts: 107
Likes: 0
From: Houston Texas
Had a similar problem with a new roller lifter
When we first fired my new 383 there was a tapping noise from under the intake. Further inspection revealed a lifter that was collapsing. This was a brand new Comp Cams roller lifter. We removed it and installed a new one, problem solved. The machine shop found it by loosening the rocker of the suspect lifter then priming the oiling system with a drill. The lifter would pump up, then when the pressure was removed it would collapse pretty quickly, while the others stayed pumped up.
Just a thought, but I would change the oil first.
Jeff
Just a thought, but I would change the oil first.
Jeff
