Issues With My 383 - Need Help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mrein3 · 06-01-2008, 08:19 PM

A couple of years ago I built a 383. I used an OEM 400 crankshaft, OEM 350 rods, and aftermarket pistons with a higher wrist pin to accomodate the longer throw of the 400 crank. Cheap way to go for a stroker.

Or so I thought.

Thursday night I had a bass fishing club tournament. I used the truck to pull the boat. The front of the engine seemed to be rattling around so I made a note to check it out. This morning I pulled a sloppy harmonic balancer off and this is what I found (see photos below).

The balancer is junk. It is cracked. The key is junk. Both of these items are replaceable for cheap. I was just about to go to the auto parts store when I thought I better look at the crank itself. It is all wore out. Is this usable? Or am I tearing down the engine and putting a new crank shaft in it?

Can a guy "get by" for a while with a new balancer and key?

Help!

Gulf Rat · 06-01-2008, 08:45 PM

Sorry, but that needs to be replaced. Did you have the crank balanced for this setup. I always give them my flywheel and balancer just to make sure I have no problems. Looks like just bad luck.

Gulf Rat

mrein3 · 06-01-2008, 09:15 PM

Quote:

Originally Posted by Gulf Rat

Sorry, but that needs to be replaced. Did you have the crank balanced for this setup. I always give them my flywheel and balancer just to make sure I have no problems. Looks like just bad luck.

Gulf Rat

Yes I had it all balanced when it was at the machine shop.

I just went and ordered a new balancer because I figured I need one no matter what the outcome. The guy there said the machine shop guy will be in on Tuesday but he (not machine shop guy) thought a new balancer, a new key, and some JB weld and I'd be good to go.

Gulf Rat · 06-01-2008, 09:53 PM

Quote:

Originally Posted by mrein3

Yes I had it all balanced when it was at the machine shop.

I just went and ordered a new balancer because I figured I need one no matter what the outcome. The guy there said the machine shop guy will be in on Tuesday but he (not machine shop guy) thought a new balancer, a new key, and some JB weld and I'd be good to go.

NO, not JB weld...but if that what you have to do. Would not be my choice.
Hell weld the key on if you have a welder. lol

Gulf Rat

stllookn · 06-01-2008, 10:00 PM

Just curious...did you use the large, 8", diameter external balancer when you built your 383 using the 400 crank?

PanelDeland · 06-01-2008, 10:08 PM

You might be able to get by for a while "if" you haven't worn it too wide.Ask the machinist if he can cut you a wider keyway and a custom key to fit the wider keyway and new balancer.Still means dissassembling the engine but would probably last way longer than JB."If" the machinist can that will give you time to build a new engine.

mrein3 · 06-02-2008, 01:23 AM

Quote:

Originally Posted by stllookn

Just curious...did you use the large, 8", diameter external balancer when you built your 383 using the 400 crank?

Yes. I used an OEM 400 small block (externally balanced) harmonic balancer. The guy that balanced everything had that, the interals, and the ring gear.

stllookn · 06-02-2008, 05:23 AM

Too bad you don't live next door...I have a 400 crank, rods and pistons sitting here that I have been trying to give away!

Gulf Rat · 06-02-2008, 06:27 AM

Quote:

Originally Posted by stllookn

Too bad you don't live next door...I have a 400 crank, rods and pistons sitting here that I have been trying to give away!

Hmmm, send them to me...going to be building a 383. PM me if you want to.

Gulf Rat

mrein3 · 06-02-2008, 07:28 AM

Quote:

Originally Posted by stllookn

Too bad you don't live next door...I have a 400 crank, rods and pistons sitting here that I have been trying to give away!

I may be interested in that crank shaft if you are willing to box it up and ship it. I'm going to call my engine guy - the guy that did the machine work on the block and the crank - and ask his opinion.

06-01-2008, 08:19 PM	#1
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,253	Issues With My 383 - Need Help A couple of years ago I built a 383. I used an OEM 400 crankshaft, OEM 350 rods, and aftermarket pistons with a higher wrist pin to accomodate the longer throw of the 400 crank. Cheap way to go for a stroker. Or so I thought. Thursday night I had a bass fishing club tournament. I used the truck to pull the boat. The front of the engine seemed to be rattling around so I made a note to check it out. This morning I pulled a sloppy harmonic balancer off and this is what I found (see photos below). The balancer is junk. It is cracked. The key is junk. Both of these items are replaceable for cheap. I was just about to go to the auto parts store when I thought I better look at the crank itself. It is all wore out. Is this usable? Or am I tearing down the engine and putting a new crank shaft in it? Can a guy "get by" for a while with a new balancer and key? Help! Attached Images __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

06-01-2008, 08:45 PM	#2
Gulf Rat Registered User Join Date: Feb 2008 Location: Gulfport, MS Posts: 99	Re: Issues With My 383 - Need Help Sorry, but that needs to be replaced. Did you have the crank balanced for this setup. I always give them my flywheel and balancer just to make sure I have no problems. Looks like just bad luck. Gulf Rat

06-01-2008, 10:00 PM	#5
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	Re: Issues With My 383 - Need Help Just curious...did you use the large, 8", diameter external balancer when you built your 383 using the 400 crank? __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary)

06-01-2008, 10:08 PM	#6
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,993	Re: Issues With My 383 - Need Help You might be able to get by for a while "if" you haven't worn it too wide.Ask the machinist if he can cut you a wider keyway and a custom key to fit the wider keyway and new balancer.Still means dissassembling the engine but would probably last way longer than JB."If" the machinist can that will give you time to build a new engine. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil" Last edited by PanelDeland; 06-01-2008 at 10:09 PM.

06-02-2008, 05:23 AM	#8
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	Re: Issues With My 383 - Need Help Too bad you don't live next door...I have a 400 crank, rods and pistons sitting here that I have been trying to give away! __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary)



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