383 Mopar "Developed a vibration"? Ideas?

[Brad54]

My son and I are looking at a 4x4 truck (I know, not a B-Body... ) and it's got a 383/727 combo in it.
On the way home from the swap meet, the guy says "It developed a vibration. It didn't have it before, but it started on the way home. It does it whether it's driving on the road, or in Park in the driveway. Nothing is knocking or banging around, it's just shaking."

He said he thought it could be a cracked flexplate, or maybe the harmonic balancer is coming apart.
I'm thinking it could also be engine or trans mounts.

Is there anything INTERNAL that would cause this, without making noise?

The guy said he heard that 383 flexplates have a tendency to crack and that can cause the vibration. Any truth to this?

-Brad

 

[RustyRatRod]

Sure a cracked flex plate can do it. So can a bad converter, bad front pump bushing, front pump going out, slipped harmonic balancer, something broken on the reciprocating assembly, grounded exhaust, grounded motor mount, grounded transmission mount and I am sure I have left out something.

 

[Meep-Meep]

Assuming no missfires or anything like that my vote is the converter.

 

[Garys1969RR]

Maybe one of the flex plate to converter bolts is missing? Also the wrong Harmonic Bal will cause that problem.

 

[Brad54]

It's something that CHANGED while he was driving home... It was fine, and then it wasn't.
I don't know why I didn't think of a spark plug or misfire... if he burned through a spark plug wire, that'd certainly do it.

But without noise--knocking, grinding, etc., it's not the crank, rods or pistons.
Converter or flexplate is a pretty easy fix, as is the balancer...

I'll find out tonight I guess, when we go look at the truck.

-Brad

 

[RustyRatRod]

Brad I just noticed you're in Georgia. If yall have trouble with it, give me a PM. I run the office at a transmission shop in Milledgeville and the owners are both big Mopar guys. I'm sure we can help.

 

[Brad54]

Brad I just noticed you're in Georgia. If yall have trouble with it, give me a PM. I run the office at a transmission shop in Milledgeville and the owners are both big Mopar guys. I'm sure we can help.

Excellent! I appreciate that.

My son and I have been looking for a 4x4 for a while, and this one rolled into the swap meet and it was exactly what both of us are looking for. We talked it over, called the guy last night and he said it developed a vibration on the way home.

If you've ever been to the NE Georgia Swap Meet, that's the show I'm talking about.

-Brad

 

[RustyRatRod]

Ok, so you're the Brad that's always postin about the shows at Commerce? Been a couple of times. When's the next one? I'm bout ready to do sumffin when the weather warms up.

Excellent! I appreciate that.

My son and I have been looking for a 4x4 for a while, and this one rolled into the swap meet and it was exactly what both of us are looking for. We talked it over, called the guy last night and he said it developed a vibration on the way home.

If you've ever been to the NE Georgia Swap Meet, that's the show I'm talking about.

-Brad

 

[Brad54]

Yeah, that's me.
Next show is April 6.
The one this last weekend was pretty good--over 75 vendors, and nearly 800 spectators... pretty good considering the weathermen were telling us for a week that we'd need to wear snowshoes while we were building our Ark!
If you want, shoot me your email address, and I'll put you on our email reminder list. (I wont' sell that list or use it for anything or anyone else...)

-Brad

 

[RustyRatRod]

Ok Brad. Will do. Are you usually there? Would be good to meet you. The owners here are members of The Southern Slingshot Association. Maybe we'll get a chance to race this year. We couldn't afford it last year. We have a 440 Mopar powered front engine dragster and a 455 Buick powered front engine dragster. Charles says one way or the other we're doin some racin this year. lol

 

[Brad54]

Man, you guys have GOT to come to my Gear Jam vintage drags in May! Those are EXACTLY the kinds of cars I'm building that event for!!!

And yeah, I'm always there... my son and I put it on (the wife was there too, but she just pulled the 'chute and is heading for the turn-off road).

I'd love to get a Mopar event started, and I would love to have a featured Mopar day at the swap meet this year--Mopar enthusiasts that are part of a Mopar club or registered users of any of the Mopar sites (for at least a year) would get in free.

Any help with organizing that would be greatly appreciated.

-Brad

 

[RustyRatRod]

Yeah I think Charles says he was actually invited to that. Here he is drivin Ancient Orange at Bristol. That's our other owner, Rodney helpin him set up.

http://www.moparmax.com/features/2009/iv_7-funny-4.html

That was when it had the stock bore and stroke 383. It's got a 440 in it now.

 

[Brad54]

sooooo cool. I'd love to do one like that.
BBM would be the perfect way to go, too.
With a clutch-flite backing it.

-Brad

 

[RustyRatRod]

Here's Charles racin Black Widow. It's a Buick 455 powered dragster.

http://www.youtube.com/watch?v=w0fg3j_xP1E

 

[Brad54]

so perfect... exactly the kind of cars I want at The Gear Jam... I like the blown early Hemis, of course, but I want guys to come with the lower-buck, backyard builds, have them pair up against someone who runs the same times, and have fun making passes.

-Brad

 

[RustyRatRod]

We gotta 354 sittin out here on a roll cart. Rodney has already cooked up a recipie for a 402 kyoob early Hemi to go on Ancient Orange. With a blower of course. Hopefully, if business picks on up we can do it.

Plus, Charles just put a 392 in his 29 Model A rat rod and I am working on a 331 for my rat truck.

 

[Brad54]

I've got a '57 Chevy 150 2dr post station wagon I'm building into a gasser (The Widow Wagon), and it's got a 8 3/4 rear on a leaf-link suspension, and a slick-shift Hemi 4spd in a Direct Connection aluminum case... I'd LOVE to build a blown 354 for it.

-Brad

 

[RustyRatRod]

Here is Charles' two rat rods. His 29 Model A (which now has a 392 Hemi instead of the 403 Olds), and Jeepers Creepers which has a dual quad 383. Charles built them both from the ground up. They are somethin else.