Engine vibration HELP!

[Fastbackin1970]

I have a 1972 Ford F100 that I replaced the engine with a Jasper 302 V8 about 6 months ago. It has a 3 speed manual floor mount transmission.

The truck has a vibration at 1500 RPM that shakes the entire truck.

It doesn't matter if the truck is in neutral or driving down the road as soon as it hit's 1500 RPM it shakes.

Why would RPM matter? Specifically why wouldn't it get worse at higher RPM?

When the shop I took it to replaced the engine they didn’t replace the flywheel or the clutch. (Don’t ask me why)

And it's getting progressively worse.....

Any ideas?

[craftsman]

Look above the starter and find the date code, to be sure they didn't put a newer engine in, look something like this D7AE. If the engine is 82 or newer you will have to change the flywheel, they changed ballance weight around that time. C7 would be 1967, D7 1977 E7 would be 1987 and so on. It could be something else but it would be good to know the year of engine.
This is a start on finding the problem anyway
Here ia sample of what to look for http://www.classicmustang.com/casting_numbers.htm

[Ranchero50]

It could be a dozen different things. Sounds almost like you have a 50oz imbalance motor with a 28oz flywheel and harmonic balancer but since it's getting worse, a basic mechanical checkup would be prudent. Pull the plugs to make sure they are all firing, check the compression to make sure each bore is contributing.

Does it run smooth otherwise? Start right up, no detonation or any other odd things going on?

Jamie

[Fastbackin1970]

It starts and runs perfectly, it just vibrates like crazy.

One other note and this may have something to do with the getting worse part. It now appears that the rear main seal is leaking.

[Fastbackin1970]

I have two areas of concern, first. I have read a lot about engine vibration in the last few years. This truck has had a vibration in it since the day I bought it. After the engine change the vibration was 98% better but still there. Now after about 4,000 miles it appears the vibration is back. I have always been suspicious of the transmission. I suspect while it is a three speed manual transmission, it isn’t the original three speed transmission to the truck.

One of my first red flags was when I tried to replace the speedometer cable. The end that goes into the transmission is from 57-60 three speed transmission or a 60-64 three speed transmission in all the parts catalogs. The truck originally came with a 240 six and a three speed. (Figure 2 speedo cable is the one that fits.)

According to the catalog the 1972 speedometer cable is completely different at the transmission end.

I suspect whoever changed the engine over to the V8 used the wrong flywheel and that’s why these engines are coming apart after 4-6k miles.
So I now have:

1.) A vibration at 1500 RPM.
2.) A leaking rear main seal.
3.) I suspect maybe an incorrect flywheel.
4.) A clutch that is either getting oil on it or out of balance.

I dropped the truck off at the shop who did the engine change today. They are going to drop the transmission and clutch to get to the rear main seal. I’m going to take the transmission, the flywheel, the clutch to KC Clutch here in Kansas City. I am also considering have the driveshaft harmonically balanced.

Any other suggestions?

I will take some pic tomorrow once everything is out of the truck

[fordman]

oops i edited this post because i didnt see that it was happening driving or sitting still. so it cant be the u joint or driveshaft.

[BobbyFord]

Pull the pan and get the number off of the crank throw and that will tell you which weight flywheel it is supposed to have.

[craftsman]

They may have used the 240 flywheel

[Fastbackin1970]

If it's the wrong flywheel will it damage the new engine?

[Ranchero50]

Um, yes...

[Fastbackin1970]

Pull the pan and get the number off of the crank throw and that will tell you which weight flywheel it is supposed to have.

Crankshaft is a 2MA crankshaft.

So I think it needs a 280z ext harmoic balancer and a 28 oz ext flywheel.

I think they may have put the wrong harmonic balancer on the truck.

[fordman]

so the shop didnt fix it yet?

[Fastbackin1970]

so the shop didnt fix it yet?

I honestly don't think they know how Fordman.

The stamp on the Harmonic Balancer is TF-08-07 not sure who makes it or what those numbers mean.

[fordman]

so the balancer didnt come on the engine when it was rebuilt by the crate engine people?

[BobbyFord]

Pull the pan and get the number off of the crank throw and that will tell you which weight flywheel it is supposed to have.

Crankshaft is a 2MA crankshaft.

So I think it needs a 280z ext harmoic balancer and a 28 oz ext flywheel.

I think they may have put the wrong harmonic balancer on the truck.

2MA crankshaft gets the 28 oz. goodies.