400 Crank Balance Issues
Thread Starter
Pro
Joined: Jan 2001
Posts: 681
Likes: 2
From: Newton (Wichita Area) Kansas
400 Crank Balance Issues
Does this sound strange to anybody? Read on.
Speedomotive balanced the front of my 383's crank with mallory metal because I wanted a smaller diameter balancer and there were none available for external balance. They used an aftermarket external balance 153T flywheel to balance the rear of the crank.
The engine vibrates above 3000 rpm. Before then it's very smooth. I do have some EFI issues (vacuum leak = idle issues and etc) but I'm worried that this strange balance setup is causing the problem.
What do you think?
Speedomotive balanced the front of my 383's crank with mallory metal because I wanted a smaller diameter balancer and there were none available for external balance. They used an aftermarket external balance 153T flywheel to balance the rear of the crank.
The engine vibrates above 3000 rpm. Before then it's very smooth. I do have some EFI issues (vacuum leak = idle issues and etc) but I'm worried that this strange balance setup is causing the problem.
What do you think?
Drifting
Joined: Mar 1999
Posts: 1,931
Likes: 1
From: Norcross GA
Re: 400 Crank Balance Issues (jmr302)
As long as they balanced the Assy. (flywheel, crank, and balancer) you should not be having a problem w/ the rotating parts. 3000rpm is pretty low for an engine vibration. It would have to be pretty hosed to be show up at such a low RPM. (I presume they are competent people.)
I'd suggest you take a look at your other problems first, then maybe your engine and trans mounts.
I'd suggest you take a look at your other problems first, then maybe your engine and trans mounts.
Melting Slicks
Joined: Sep 2000
Posts: 3,099
Likes: 0
From: PITTSBURGH PA
Cruise-In IV Veteran
Cruise-In V Veteran
Re: 400 Crank Balance Issues (ZylaRace)
something doesnt sound right if they put malory metal in the crank it sounds they ballanced it internally but then why did they use an external ballance fly wheel i do not think the two of those parts can be used at the same time :cheers:
Pro
Joined: Aug 2002
Posts: 702
Likes: 1
From: the corner of walk and dont walk
Re: 400 Crank Balance Issues (jmr302)
You need to contact speedomotive right away. It is impossible to internally balance only half of a crankshaft. If they did add mallory metal to the front half, go back to them and have them finish thier job! They can internally balance the crank and ose a 153 tooth flywheel from internally balanced chevy and you will be all set. Do it as soon as possible, or you will be needing more than the balance corrected! :cheers:
Melting Slicks
Joined: Mar 2001
Posts: 2,175
Likes: 56
From: Clarence N.Y.
Re: 400 Crank Balance Issues (jmr302)
I totally agree with the others,sounds very odd that they
would hang an external balance flywheel when the crank
is internally balanced. I would think that will shake itself silly.
Let us know Speedomotives answer. Good luck. :yesnod:
would hang an external balance flywheel when the crank
is internally balanced. I would think that will shake itself silly.
Let us know Speedomotives answer. Good luck. :yesnod:
Thread Starter
Pro
Joined: Jan 2001
Posts: 681
Likes: 2
From: Newton (Wichita Area) Kansas
Update
I talked to a very reputable local engine shop about Speedomotive's balance job. They said that method can work just fine if done properly. Apparently it's difficult to add mallory to the rear of the crank because there isn't much room on the rear flange or something. So it's taking the easy way out but doesn't automatically mean it's bad.
I'm done dealing with Speedomotive. They are not customer service oriented at all. The engine is 8 months old now but I've only put 500 miles on it. Either way that's probably beyond any warranty period considering they don't offer one. They also advertised this longblock as having 10:1 compression but I found out it's actually 11.2:1.
Don't do business with Speedomotive!
I'm done dealing with Speedomotive. They are not customer service oriented at all. The engine is 8 months old now but I've only put 500 miles on it. Either way that's probably beyond any warranty period considering they don't offer one. They also advertised this longblock as having 10:1 compression but I found out it's actually 11.2:1.
Don't do business with Speedomotive!
