'77 Bronco 4bt Conversion

[High Pressure]

i want to ride in that. you built one sweet ride. :beer:

If you enjoy riding on "wash board" roads this is the ride for you! Been working to improve a major "SHAKE" issue that the 4bts are famous for...

The whole project is a one of a kind.. others have installed 4bts into Broncos but all motor mounts, transmissions, exhaust are different. The major "SHAKE" issue happens when I place the C4 in Reverse or 1st gear at idle with the brakes applied. As soon, as the brakes are released and the accelerator is pressed the shake is decreased significantly but other resonance types occur at various speeds that are amplified through the exhaust.

Here's what I have done so far...

~Idle~
Adjusted idle speed up/down numerous times... but I'm flying blind since I don't have a tach connected yet... received a Tach this week and hope to have it hooked up in a few days.

~Exhaust~
I believe that I'm on my 3rd exhaust hanger installation configurtion... each change has improved the sitution significantly....no banging at this time...just various speed related resonance types. Next step - install a 3" dia x 8" length of braided flex exhaust in the down pipe from the turbo. Hope this will decouple some of the resonance issues.

~Fuel Pump Timing Advance~
I've been thinking about this one for some time.. and after I discussed the problem with Chuck last Sunday (yes... the "Head Potentate" does know his diesels) I got of my butt and made the special wrench to advance the fuel pump timing. Most people adjust the timing a 1/16 of an inch above the timing mark to help with the issue. I found my fuel pump timing to be about a 1/32 below the timing mark!!! So, I adjusted it about 1/32 above the mark for a total change of 1/16 advance.. This made a signifcant improvement.. it has almost removed the difference in vibration from idle Park and idle 1st gear..

~Adjusted Revese/Low C4 Band~
I intitially thought this had some effect to improving the issue but not sure now...

Other than the vibration issue.. I'm pleased with the torque and highway speed.. but really need to get some fuel mileage readings.. especially at $4.50 per gallon for diesel!!!