Chevy & GMC Vans

More unfortunate news-

Ive removed the gearbox again, and I have performed the spin test on the aluminum flywheel, and that too has a definite heavy spot, though not as pronounced as the cast iron stock flywheel. It is not a neutral balance as I had hoped.

Since installing the 617, ive driven maybe 12 miles in test drives, and I have more bad news. The imbalanced flywheel fiasco has caused what looks like a rear main seal leak around the crank that has clearly presented itself since the last time the transmission was down (2 days ago). That will have to be fixed now as well, I hope I didn't wipe any bearings also.

here is the aluminum flywheel spin test-

http://www.youtube.com/watch?v=9Lhy4va2 ... e=youtu.be

Both flywheels are now at a machinist getting the one matched to the other

Well, theres only one real true way to get it right so it runs proper I suppose eh?
I know you dont wanna have too, but looks like you might...

doyoulikeithere wrote:Well, theres only one real true way to get it right so it runs proper I suppose eh?
I know you dont wanna have too, but looks like you might...

Yup, crank has to come out.

The rear main seal clinched it. To replace that seal I have to damn near remove the crank anyway, so might as well do it right. I've come to peace with how completely the two seconds it would have taken to scribe the end of the crank and flywheel has created an ever evolving nightmare of additional work

tinworm wrote:Yup, crank has to come out. The rear main seal clinched it. To replace that seal I have to damn near remove the crank anyway, so might as well do it right. I've come to peace with how completely the two seconds it would have taken to scribe the end of the crank and flywheel has created an ever evolving nightmare of additional work

If you have the crank out, I suspect you will take it, the flywheel you wanna use, and the Harmonic balancer, all to the machine shop to get balanced as a unit
New main and rod bearings perhaps, should run like a top after that !

Just think how great it will be once you have it dialed in eh ?!?!

doyoulikeithere wrote: If you have the crank out, I suspect you will take it, the flywheel you wanna use, and the Harmonic balancer, all to the machine shop to get balanced as a unit
New main and rod bearings perhaps, should run like a top after that !

Just think how great it will be once you have it dialed in eh ?!?!

cant wait, not just for the diesel, but now I really miss the manual tranny.

been driving around my 92 replacement short van, and its very solid, but these automatic 2wd vans are awful in the snow.

Too much work for a few weeks to muck about with the diesel van, but I at least intend to get the crank dropped this week, and get the machinist working while I finish up some major projects.

I do have that nv3500 kicking around though....... The 92 might get some presents eventually

long overdue update-

pulled the 83 motor and installed an 85 motor.
83 motor is on a stand for future repair and use in some other project.
85 motor out of a 300CD was installed.

Very busy summer work season is drawing to a close, so hopefully I can get this SOB up and running. Unfortunately I replaced the van with a bigger van a while back, and dont really have a use for this anymore. (once you can lay a 4x8 sheet of drywall or plywood flat in a van, its hard to go back to the smaller version)
Dont want to let it sit and rot, so probably will get it running reliably and sell it.

some new pics. For a little spicy variety, I decided id try and install the new motor through the front of the van. This is technically possible, but I wouldn't do it again. Thought it would be a time saver, but it took almost 4 total hours to get the engine lined up with the motor mounts. and even then I may have cross thread one of them, will resolve later. Some pics of the install process-

83 engine removed-



85 engine ready for teardown-



cramming that sucker in there-





It can only be done at an angle, and just barely at that. Flywheel is off getting matched balanced and this time I MARKED the position of crank to flywheel.

I may make a modification to the front lower bracket here along the red line, if that dropped a few inches, you could fire a motor in and out of this van very fast.

Awesome work as usual Tinworm.
Thanks for the update. kinda sad news though...