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Author Topic:   Noisy 383
Dirt Full Roller

Total posts: 43
posted January 14, 2002 09:29 AM
Are 383 Chevys noisy motors? We have built a few for race cars with open headers but don't notice it. Now he have built one for a pickup with exhaust, It sounds like a diesel
when it is idleing. Is this a common problem?

Dirt Administrator

Total posts: 5556
posted January 14, 2002 10:54 AM UIN: 16262997
Cam to Rod not ask me how I know what your talking about.


Dirt Full Roller

Total posts: 43
posted January 14, 2002 01:02 PM
Now I'll tell you the whole story.This motor was actually built twice. The first time we built it we used a .040 over block that had been ran as a 350 for awhile that was a mistake! When we got it running it made awful noises so we took the oil pan off and spent about 2 days looking at the bottom of the motor trying to figure out where the racket was coming from. We finally came to the conclusion it was the cast pistons were too loose in the bores so we tore it down and started from scratch. This time we had a block bored .040 put it back together and the noise isn't nearly as bad. So don't skimp and try to save money cause it's not worth it in the long run. I don't think it is the cam hitting the rods because the 5.7 rods bolts were ground on and it's a Comp High Energy 260H Cam probably the littlest cam ever put in a 383. I just thought it might be a common trait of these motors to be noisy, I have been told the old 327 were noisy even when new.

Dirt Forum Racer

Total posts: 98
posted January 14, 2002 05:57 PM
Stock pistons have the pens offset to stop some of the piston slap.Most aftermarkets pistons have the pen in the center to make more power.Won't notice the noise with open headers.My 355 sounds like a hay bailer when I run the IMCA mufflers.

Dirt Freak

Total posts: 467
posted January 14, 2002 06:24 PM
You said that you had another block bored . Did you use the same .040" over pistons from the other block ?? If so , perhaps you have a collapsed piston or two . If they were run too loose in the original block , then they will most likely be collapsed . How much piston to wall clearance do you have now ?? Most cast pistons will only run .0015"-.002" piston to wall clearance . Any more than that , and it will sound like your describing .

Hendren Racing Engines
Rutherfordton , NC

Dirt Full Roller

Total posts: 43
posted January 14, 2002 06:40 PM
The new motor has .002 clearance. We used the same pistons in the other motor they only ran for about half an hour, but a racer that works at auto tire and parts told us that alot of brand new pistons are collapsed when they come from the factory. It don't help to be using $120 pistons either that may be the problem.

[This message has been edited by chevyscrounger (edited January 14, 2002).]

Dirt Forum Champ
Total posts: 564
posted January 14, 2002 10:02 PM UIN: 25419780
Check your lifter holes. I had a friend who had a 400 was making some racket. He tore it apart and couldn't find anything wrong and put it all back together. He noticed a couple of lifters were real loose so he had the lifter holes bore to a bigger size and the motor never made another sound.

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