Bellhousing shaft issue mating to a new GM Vortec 4.3

[Radon17]

Hi,

My old engine was a 90s Volvo Penta, that bellhousing shaft went through the flywheel damper with no bushing behind the flywheel. I have a new 4.3 GM that I'm trying to mate to a 290 bellhousing, but have some issues..

1. The bellhousing shaft is long enough for the splines to go through the flywheel damper, BUT! The bushing on the end of the shaft is not seated in the cup of the main engine crank. I'm assuming that the bushing keeps the shaft from getting out of balance if the dampner is out of balance.

2. The bushing is too big to fit in the cup even if the shaft was longer.

Looking for any help, last hurdle of this repower.

Thanks in advance.
A.V.

 

[Don S]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Remove the flex plate and post a picture of the end of the crankshaft.

 

[billbayliner]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Randon, it sounds as though you have also changed to a later style flywheel cover with the single bearing PDS and pilot nose. This would not be a 290 flywheel cover, but perhaps the later charcoal gray fywheel cover.
This single bearing PDS requires the crankshaft bushing to hold and maintain PDS center. If a bushing is not available for this crankshaft, you may need to have a custom bushing fabricated.

Also, in the future this single bearing PDS can be removed from the rear [for bearing replacement] without removing the engine. Quite an improvement over the double bearing PDS.

 

[Radon17]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3



The bellhousing is identical to the coversion bellhousing- http://www.michiganmotorz.com/volvo-penta-bell-housing-conversion-p-770.html

it's almost as if I'm missing a part that should slide into the center. Like I mentioned above, even if the bushing fit the inner hole, the bellhousing shaft is not long enough to push it in. The inner cup is slightly smaller in diameter than the bushing.

 

[Don S]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Get the dimension across the crankshaft opening, and the diameter of the hole in the bushing. Then head to your local ball bearing supplier and find one that you can press into the end of the crankshaft.
Your local volvo dealer can also look up in the dealer info for installing the newer style engines to older drives. Their info will have the Volvo PN for the bearing, or they might even have a special bushing. But I would bet a bearing.
Wouldn't surprise me if you found an auto parts store that showed a truck with the newer engine and a pilot bearing for a manual transmission.

 

[billbayliner]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Since it's a single bearing PDS, the front portion of the PDS needs a crankshaft centering bushing, just as an old school car or truck standard transmission does.
Also, Borg Warner is Borg Warner. The dimensions regarding the PDS and the Borg Warner drive coupler and distance to the engine rear flange and to the flywheel are industry standard.
I can't explain why the pilot nose length is not right as per what you are saying.
Like said, you can have a custom bushing machined since this does not spin like a std car/truck transmission when the clutch is disengaged. So there is no need for this to be a ball bearing.
It's only job is to hold center of the PDS pilot nose since the drive coupler is not intended for this.

The flywheel cover that Michiganmotors is selling is the later style, not a typical 290 style.
We don't usually see these until the 5.7GLPMDA, 5.7GIPMDA, 5.7GIPMDACE models.
Volvo lists a p/n for this bushing for the 5.7L engine.
Bushing, primary shaft to crankshaft 3860697
I'm not sure if this would be the same bushing for your Vortec 4.3L.

 

[Radon17]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Thanks Don and Bill,

The part I have is 3860697. I was ASSuming that this would be the easiest part of my repower ;-)

 

[Don S]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

So there is no need for this to be a ball bearing.

I agree it doesn't have to be a ball bearing, but for a few bucks you can get a ball bearing of the correct size to fill the gap. Remember the old rubberband engines all had ball bearings, and not bushings.

 

[billbayliner]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

I agree Don. It could be a ball bearing or a bushing. If a ball bearing is easier to find, then that's the way to go.
I think that the ball bearing in the rubber band engine was a carryover from the auto engine and std transmission.

Randon, I'm thinking that it's obvious that that bushing is wrong. It just looks too small for the crankshaft. The bearing or bushing fits the rear and largest bore in the crank, not the smaller forward one.

I also noticed that the drive coupler did not leave grease marks very far onto the PDS splines.
Note how long the Borg Warner PDS splines are. I think that the PDS should have slide further into the coupler.

So my first question is, are you saying that the pilot nose is not going into the crankshaft deep enough to engage into a bearing or bushing [even though there is no bushing right now]?

Michiganmotors sells these flywheel covers un-assembled from what I can see. When you got this, was the PDS installed or not installed?
If you installed PDS, did you install it completely into the flywheel cover bore before any snap rings went in?

If you put a straight edge across the front of the flywheel cover, the pilot nose shoud sit proud by 3/8" or so.

 

[Radon17]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

The bushing (3860697) has an OD 1.094in and ID of 0.591in. The forward bore that would hold the bearing has an ID of 1.01in. The bigger bore has an ID of 1.70in.

With straight edge across the pilot nose sits at about 3/8"

It's interesting that you say the bushing should fit the largest bore because with my calculations, only about 1/2 inch of the pilot will be in the bushing when the housing is bolted on, that is assuming the bushing fits in the smaller forward bore. Is that 1/2 inch enough to keep the shaft steady?

Do they make a bushing that will fit the bigger bore with the same inside diameter as the bushing?

 

[Don S]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Like I said up in reply #5, find a ball bearing. They are inexpensive and a bearing supplier can find one to fit your dimensions.

1.70 OD X .95 ID. if accurate should work fine in place of the bushing. It won't turn, and it's a damn site cheaper than having a special bushing made if you don't happen have a machine shop in your back pocket.

The OD of the bearing should be a tight fit in the crankshaft.

 

[Radon17]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Ok, thanks again. I'll let you know how it goes.

 

[Radon17]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Don - Just out of curiosity, why a bearing and not a bushing for this application other than cost? As I understand it, in an automotive application the shaft would spin in the bearing/bushing when the clutch is engaged. In this application, the shaft will only move the distance of the flexplate springs, never complete revolutions.

 

[Don S]

Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

It was an option if you can't find a bushing. I don't personally care if you use a bearing or bushing. But I doubt you find a bushing that size but it's very possible you could find a bearing that size. If you want to pay to have a bushing made, go for it.
Like I said earlier, a Volvo dealer has lists of what new parts are needed to use newer engines on older drives, and it may have a number for a bushing or bearing for that application.

 

[Radon17]

Problem solved! Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Problem solved! Re: Bellhousing shaft issue mating to a new GM Vortec 4.3

Hi

I found two solutions to the problem that worked with the bellhousing issue:

1. Bushing - http://www.summitracing.com/parts/MCL-8617/ - $40
2. GM Roller Pilot Bearing part no: 12557583 - $20

I ended up going the bushing route because the shaft does not spin inside of the bushing. Seemed like a more reliable option. With the bushing, the tip of the shaft is about 3/4 of an inch inside the bushing.

Thanks for eveyone's help!
A.V.