A whole lotta shakin' goin' on (5.0 vibration issue)

[Rox Crusher]

So I swapped in a used 5.0 EFI motor from a 98 Explorer.

Bought it off of Craigslist from a guy who got it out of a low mileage (80k) salvage rig. Course that could be total BS as it was in his garage.

Took the pan and the intake off and it was super clean inside so I decided to use it as is.

It has had a mild vibration since start up and I now want to try to resolve it.

The motor runs nice, without any miss or timing issues.

It isn't that bad at lower RPMs but when I put the RPMs up it gets dramatically worse, especially in first gear in the 4R70w.

I have ran it with the tranny and transfer case in neutral without any improvement. I have ran it with the serp belt off......again, no change.

I took the inspection cover off and checked torque converter bolts which are all tight. The flex plate was new at install and I am pretty certain I bought the correct one, but I can't find the receipt. I took the following pics of it and I am hoping some expert can confirm that is indeed the 50 oz version. Wondering if it might have been mis-boxed or made wrong.

The weight is about 4.5" long x 1" wide x 1/2" tall.

The dampner had never been off and looks to be in good shape but I suppose I will be taking it off to make sure.

Meanwhile, can anybody confirm the flex plate based on the pics and info provided ?

Any other suggestions are certainly welcome.

Thanks in advance !

 

[rguest3]

The vibration does sound like it is balance related, so you are on the right track.

Correct as well that the Flexplate and Balancer have to be 50oz. too. Have to confirm these parts though, especially the new flexplate.

I could guess as to which one you have based on the weight in the picture, but its been too long since I have compared.

 

[Viperwolf1]

Yank that balancer off the spare parts engine in your garage.

 

[BRONCO26]

Ck your harmonic balancer to see if it has slipped or cracked at the key way. I had a 94 mustang 5.0 that the key way in the bal had cracked and it slipped on the crank shaft.

 

[TwoDalesDad]

I have also spun a dampner on a hp 289. The truck. Vibrated like a 2 dollar hotel bed.

 

[DonH]

If you engine came from a unrelible source check to see if harmonic balancer is the correct one for that engine.

 

[Rox Crusher]

If you engine came from a unrelible source check to see if harmonic balancer is the correct one for that engine.

It is correct.

I have a good friend who is a Bronco parts hoarder and he has several Explorer 5.0 engines so I have compared it against them.

 

[Rox Crusher]

I have also spun a dampner on a hp 289. The truck. Vibrated like a 2 dollar hotel bed.

but at least you were saving some coin !

;D

 

[Rox Crusher]

I went to the hoarder's house and looked at one of his OEM flexplates from Explorer 5.0 and it is same as pics above.

Guess I better focus on the balancer / dampener.

 

[landshark99]

Swamp balancers with a known good uncracked one like the one on the engine stand

 

[Broncobowsher]

What accessory drive are you running? I have not seen that listed yet.

 

[Viperwolf1]

What accessory drive are you running? I have not seen that listed yet.

Explorer.

 

[Rox Crusher]

Explorer.

if your coming to the swap meet could you bring your fan wrench and puller please

 

[Viperwolf1]

if your coming to the swap meet could you bring your fan wrench and puller please

I'll put it on the list. Oh wait, I don't have a puller.

 

[Rox Crusher]

I checked the key and keyway in the crankshaft and the keyway in the balancer and it all looks good.

So I swapped on a different (used) balancer without any improvement.

Any other things I can check ?

 

[jw0747]

motor mounts...

 

[Rox Crusher]

motor mounts...

motor mounts are new and the bolts are nice and tight

same with all the transfer case mounts, etc

but, I am thinking something similar as you

This 4R70W is just a tad longer than C4 and I remember that the clearance between the transfer case and the body was almost nothing.

Tomorrow I plan to check if it happens to be touching the body and transmitting a vibration

keep the ideas comin' guys................I need all the help I can get

 

[DirtDonk]

Doesn't the EEC-IV computer have the ability to do a full-on cylinder balance test? Is it one of the standard KOEO tests by any chance?
Just wondering if it would be worth a self-test to see if anything obvious is wrong.
Internally that is.

Paul

 

[Rox Crusher]

yes, it does

we did this test shortly after start up as it had a miss

turned out one of the fuel injectors wasn't firing as the wiring in the connector had come loose

 

[crews44]

I've been having se issue with a 92 5.0 ho motor. Changed balancer and flywheel with not luck.

Interested to see if you get issue fixed.

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