4BT Vibration

[DogDiesel]

On my 93 Chevy Cummins conversion, when I added an electric fuel pump, I found less vibration, smoother power, more torque and less last minute turbo wrap -up. When that electric pump stops working, I still run, but can definitly tell the difference.



I can un-plug the lift pump on my Chevy conversion and see more vibration.



Now, the question. My 4BT has a bladder style lift pump, and it vibrates the flimsy Bronco fender panels to the tune of every RPM. Has anyone used an electric fuel aid lift pump on a 4BT and what are your results?



Wayne



68 Bronco with 4BT, TH-400 3:50 gears and 35" tires = 2:80 gears and @77 MPH at max govenor.

 

[CKnoop]

I work on bread trucks with 4bts in them some of the trucks have both electric pumps and mechanical. electric pump is in rear by fuil tank can't tell any diff. running wise in a bread truck usually when the electric pump fails we eliminate it

 

[BJMarshall]

Sounds like a nice Bronco

It doesn't look like the one in my pictures does it?

 

[DogDiesel]

Yes,

Same vibration issues you described Barry.

Added brackets to fender panels and it stopped the RPM tune. But the vibrations are like on my Chevy conversion when you unplug the electric pump.

I guess there is just enough mass and bulk on the bread trucks to absorb vibration, plus better engine mounts. I also suspect less noticeable change in performance on the 4BT than the 6BT, but the injector pumps work the same. It makes massive change on the 6BT smoothness.



I'm going the electric fuel pump route.



Wayne

 

[BJMarshall]

Post some pictures when you get a chance. I'd like to see how it's looking. The electric fuel pump should be fine. Not sure why it smooths it out though. You may want to try adjusting the timing a little and see if that helps some. So far all of them that I have worked on just had a rough idle.