New 383 (Noise)
Thread Starter
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
New 383 (Noise)
Looking for help once again on this one...
I picked up my 80 two weeks ago after having the original L48 stroked to a 383. Dyno'ed very well. Internals include Keith Black forged Flattops, I-beams, Scat crank, XE274, Roller Rockers and Edelbrock RPM heads.
The shop was not able to eliminate what sounds like a "lashing noise" within the engine. Basically sounds like a deisel between 1500 and 2500 and has a low knocking noise at idle.
Is very pronounced when cold then really quites down when the engine gets to full temp.
Have checked the rockers, timing chain, lifters, etc...
Any ideas?
Ed
I picked up my 80 two weeks ago after having the original L48 stroked to a 383. Dyno'ed very well. Internals include Keith Black forged Flattops, I-beams, Scat crank, XE274, Roller Rockers and Edelbrock RPM heads.
The shop was not able to eliminate what sounds like a "lashing noise" within the engine. Basically sounds like a deisel between 1500 and 2500 and has a low knocking noise at idle.
Is very pronounced when cold then really quites down when the engine gets to full temp.
Have checked the rockers, timing chain, lifters, etc...
Any ideas?
Ed
Burning Brakes
Joined: Sep 2001
Posts: 1,166
Likes: 0
From: Tulsa Ok
Just a guess , but you might check clearance on the oil pan. I can't remember who it was that posted awhile back, but their engine builder clearanced the block but not the oil pan resulting in a knock.
Drifting
Joined: Nov 2004
Posts: 1,284
Likes: 933
From: Indiana
2024 C3 of the Year Finalist- Unmodified
WHen my 63 was new, it had a terrible piston slap when it was cold. I believe because of the forged aluminum pistons and maybe the clearances. Once warm it was just fine. The engine lasted over 185,000 miles before a cracked valve seat dropped water on top on number 8 piston.
I've been thinking about a 383 but keep reading about having to clearance the block and run the corrrect cam, so haven't done anything yet. Hopefully your engine shop did all of the correct clearancing.
A loose damaged harmonic balancer can cause a knock also.
Ol Blue
I've been thinking about a 383 but keep reading about having to clearance the block and run the corrrect cam, so haven't done anything yet. Hopefully your engine shop did all of the correct clearancing.
A loose damaged harmonic balancer can cause a knock also.
Ol Blue
Racer
Joined: Dec 2001
Posts: 328
Likes: 0
From: Dallas County Texas
Without hearing it - sounds like normal forged piston warmup
They can be noisey as a spark knock until warmup (typically a couple of minutes at idle/when the oil temp picks up a little.) Before mine developed whatever it's current problem is, mine was the quietest forged setup I had ever heard.
Don't ignore this though. You coul have a small problem now that has not done any serious damage which could change badly. If you have a warranty, have them listen to it, without suggesting the forged piston noise (don't give them an excuse.) If you don't, or they are putting you off, go to another shop and have THEM diagnose it.
Don't ignore this though. You coul have a small problem now that has not done any serious damage which could change badly. If you have a warranty, have them listen to it, without suggesting the forged piston noise (don't give them an excuse.) If you don't, or they are putting you off, go to another shop and have THEM diagnose it.
Thread Starter
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
Thanks Guys.... The shop totally disassembled the engine to attempt to find the issue but came up with nothing (so they say). I'm going to take it back later this week and drop it off and tell them not to bother calling until it's fixed.
Or I've thought about taking it to another shop and sending the original shop the bill for fixing.
Will most likely give the original shop another chance...if they give it back to me with the issue, then I'm taking it somewhere else.
Ed
Or I've thought about taking it to another shop and sending the original shop the bill for fixing.
Will most likely give the original shop another chance...if they give it back to me with the issue, then I'm taking it somewhere else.
Ed
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
with Mr. Blue.Thats the symptoms of piston slap with forged pistons. And a big reason why most stock pistons are cast (well cost is probly the decider).
Forged pistons have more strength but do have that disadvantage. Thats why the eutechtic (or however its spelled) pistons are popular. Nearly the strength of forged but the seal and cost of cast pistons.
Also some of the older block boring machines are not as accurate as the new machines. Older method was to hand hone each cylinder and measure with feeler gauge (yep 'bout 2' gauge) to fit each piston then mark for correct hole/installation. They did this with GTO block and i had very little slap on morning start-up until warmed up. Only ur machine shop knows what they used to bore and fit.
Anyways u should always allow any mtr to warm to normal op temp before u romp on it ED.
cardo0
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Thread Starter
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
Originally Posted by JonnHeather
What kind of dyno numbers did you get with that cam? Heads?
Race Director
Joined: Jun 2000
Posts: 10,046
Likes: 675
From: FL
Is this the same motor that you said the builder had wiped two cams in? If so, did they strip it bare and clean it thoroughly? Wiped cams leave a lot of metal that can trash bearings and such. Been there, done that, got the T-shirt.
Thread Starter
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
Originally Posted by SteveG75
Is this the same motor that you said the builder had wiped two cams in? If so, did they strip it bare and clean it thoroughly? Wiped cams leave a lot of metal that can trash bearings and such. Been there, done that, got the T-shirt.
Thread Starter
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
I'm returning the car to the speedship in the morning... They continue to state that they WILL FIX IT.
Hopefully not another 3 months...
Hopefully not another 3 months...
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by 80TexasC3
I'll let you know when we eliminate the noise...then dyno.
