Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

[Radon17]

Hi,

I'm repowering a Volvo 4.3L V6 with a new 2011 GM Vortec 4.3 V6. The drive is a 1988 VP 290 SP.

I have some concerns about compatibility:

The old flywheel is 12-3/4 in, the new one that comes with the engine is 14in. Do I need new bellhousing or can I reuse the flywheel and vibration dampener from my old setup? Or can I use the old housing with the new flywheel. I can't image the old starter would be compatible with the 14 flywheel.

Assuming the engine blocks are the same dimension, since they are GM V6 4.3 blocks, any issues using the old engine mounts?

In order to make sure the new engine exhaust lines up correctly with the exisiting exhaust pipes, should I be ordering the same exhaust and risers components as my old engine? Again assuming the engines have the same block dimension.

Thanks in advance,
Alex

 

[Bondo]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Hi,

I'm repowering a Volvo 4.3L V6 with a new 2011 GM Vortec 4.3 V6. The drive is a 1988 VP 290 SP.

I have some concerns about compatibility:

The old flywheel is 12-3/4 in, the new one that comes with the engine is 14in. Do I need new bellhousing or can I reuse the flywheel and vibration dampener from my old setup? Or can I use the old housing with the new flywheel. I can't image the old starter would be compatible with the 14 flywheel.

Assuming the engine blocks are the same dimension, since they are GM V6 4.3 blocks, any issues using the old engine mounts?

In order to make sure the new engine exhaust lines up correctly with the exisiting exhaust pipes, should I be ordering the same exhaust and risers components as my old engine? Again assuming the engines have the same block dimension.

Thanks in advance,
Alex

Ayuh,... The block dimensions Are the same...
The old flywheel 'n coupler should bolt right on...
The exhaust will also bolt up...

The Intake manifold is the only thing that Won't...
The intake to heads interface is different,...
The new motor will have Vortec heads...

 

[Radon17]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Thanks for the reply Bond-O

The engine comes with a Edelbrock 4b carb and manifold.

Just to be sure before I place my order, with these new Vortec heads, the risers/exhaust manifolds will be the same as my old 4.3?

Why do most replacement engines come with a 14" flywheel as part of the package?

Thanks,
A.V.

 

[Bondo]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Thanks for the reply Bond-O

The engine comes with a Edelbrock 4b carb and manifold.

Just to be sure before I place my order, with these new Vortec heads, the risers/exhaust manifolds will be the same as my old 4.3?

Why do most replacement engines come with a 14" flywheel as part of the package?

Thanks,
A.V.

Yes, the exhaust is the Same....

Volvo is 'bout the Only 1s usin' the 12" flywheel,... Donno why...

 

[HorizonblueDK]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

In your current bellhousing there is not enough space for the 14 inch flywheel. Assuming that you have the old red bellhousing. I have tried to mate a 4,3 OMC engine to the red Volvo bellhousing, but the hole wasn't big enough. The coupler was also impossible to mount, since the bolt pattern had a larger diameter on the OMC flywheel. Remember that the coupler on these engines are mounted in the holes on the perimeter of the flywheel, and not the crankshaft bolt holes.

Take a look at these photos and you will notice that the opening on the red bellhousing is a little smaller.




This is guessing, but here is my idea on why Volvo used the small flywheel on the 4,3;

The red bellhousing was intruduced in the late 70's, when Volvo started to use GM small block V8s. These engines were equiped with the small flywheel, and the bellhousing was designed for that. When the 3,8 and 4,3 V6 engines were introduced, the V8 bellhousing could be used on these engines, because of the same bolt pattern. But they had to have a small flywheel. At that time, Volvo probably didn't feel that it was necessary to redesign the bellhousing so the V6 could run with the big flywheel.
But in the end, they decided to redesign the bellhousing and thats why we have the black(charcoal) bellhousing on late V6 engines mated to SP and DP drives.

As I said, pure (qualified) guessing

Anyway, you have two options:

1. Use the old bellhousing, flywheel, starter and coupler

2. Use the new flywheel and starter, purchase new bellhousing and coupler(maybe drill/tap new holes for the old coupler, to mount it on the new flywheel)

I don't know if the V6 will vibrate more with the small flywheel, compared to the large one.

 

[captmello]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Just curious, is the new block machined for a mechanical fuel pump? Or does it come with electric?

 

[Radon17]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Hi,

Yes, it comes with a new eletric fuel pump. The old one had the mechanical fuel pump, the new engine package (Silver) is from Michigan Mortorz, it's a partially complete package. I'm trying to eliminate all the headaches/surprises I can.

 

[Radon17]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Thank you everyone for the information.

 

[billbayliner]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

As HorizonblueDK says, there are two flywheels. 153 tooth [12- 3/4"] and 168 tooth [14"].
The red flywheel cover will not accept the 168.

The new electric fuel pump requires a low oil pressure interrupt, [basically a N/O pressure switch] and will need a means of powering it prior to oil pressure when starting after sitting for a while [relay from the starter solenoid circuit].

While you have the flywheel cover off and out, be sure to replace the 2 open bearings and the 2 seals.
I just grabbed this from another site.
High quality #6206 and #6007 bearings with 2 TCM or Timken 35x62x7mm seals.
Prefill with grease until it comes through the bearings before you put the seals in.
Front seal is glued in place and the rear seal lip faces rearward not forward.

 

[Radon17]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Thanks, Yes I planned to replace the bearings and seals.

 

[Radon17]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Was going to pull the trigger on a new GM Vortec V6 4.3 from michiganmotorz.com. It turns out, from 1997+ the block bolt pattern for the starter is different. I was told my 12 3/4 flywheel with my old red bellhousing won't work because of the bolt pattern change. So now I either repower with a reman (up to 96) or get a new 14" bellhousing.

So if I go with a new bellhousing, are the dimensions (deep wise) the same? Or will I have to move the motor mounts on the stringers?

pain in the butt!

 

[Don S]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

So if I go with a new bellhousing, are the dimensions (deep wise) the same? Or will I have to move the motor mounts on the stringers?

They are the same depth. Just bigger around. You will also need the internals for the larger FW housing, along with a pilot bearing in the rear of the crankshaft. If you don't install the pilot bearing, you will destroy things.

pain in the butt!

Yeah, they usually are when you do jobs like this. That 14" flywheel (along with the newer engine) didn't even exist when your original engine was designed and put in the boat.

 

[Radon17]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Thanks Don. I talked to another repower shop, he said I didn't know what I was talking about. That my 1991 12-3/4 flywheel/bellhousing/starter will work no problem on a new block.

Frustrating!

 

[Don S]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Can't say as I ever tried putting a 12" flywheel on an engine that uses a 14" flywheel. It might fit, but I have no idea if it would change the balance of the engine or not.

 

[Bondo]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Can't say as I ever tried putting a 12" flywheel on an engine that uses a 14" flywheel. It might fit, but I have no idea if it would change the balance of the engine or not.

Ayuh,... When changing flywheel sizes, the Difference to look for is the starter mounting holes in the block...

If the block has the straight across holes, the 12" flywheel is be used...
If the block has the Staggered bolt holes, the 14" is be used...
If the block has all 3 holes, it can use Either size flywheel..

As for the Balance,.... It has to be a flywheel For a 4.3l, in the right flywheel bolt pattern to match the crankshaft....
Which is 3, 1/4" for Pre-86.... 'n 3" for post-87...

 

[Glastron_V210]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

I don't know if this will help you or not, but I'm doing research in a plan to do LSx swaps for my sbc's (LQ4 6.0 specifically) in the red flywheel cover.

There are manufacturers who make starters which will fit both the small and large flywheels (2 sets of holes). These are for the LSx blocks though. But, they may be able to tell you if they have one for your app, or have heard of someone else making one.


http://www.tuffstuffperformance.com/

or

http://www.powermastermotorsports.com/

Chay

 

[Radon17]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Hi,

I've seen a few of these 14 inch bellhousings for sale. On the drive side of the bellshousing, I see some shafts that are recessed and others where the shaft sticks out almost level with the lip of the bellhousing. I see a few of these 290 to SX bellhousing conversion kits but not sure that is what I need, I'm not going from a 290 to SX. Seems like that kit would be for mating an old engine to a newer drive.

I've added links at the bottom to show you what I'm talking about.

I'm repowering a 1991 VP 4.3 mated to a 290 VP SP drive that has a 12-3/4 inch flywheel. The new engine is a GM Vortec 4.3 with a 14 inch flywheel. I want to make sure I buy the correct bellhousing/shaft combo. Also I'm hoping that the depth of the new bellhousing will be the same so I don't end up having to move the engine mounts forward of back.

Thanks in advanced for any advice,

Dazed and confused ;-)

http://www.ebay.com/itm/Volvo-Penta..._Accessories_Gear&vxp=mtr&hash=item3cc261dc25

http://www.ebay.com/itm/VOLVO-PENTA..._Accessories_Gear&vxp=mtr&hash=item3a70054a78

http://www.ebay.com/itm/Original-VO..._Accessories_Gear&vxp=mtr&hash=item5648b799c7

http://www.ebay.com/itm/VOLVO-PENTA..._Accessories_Gear&vxp=mtr&hash=item519b06675c

 

[Don S]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Any of those should work. They really only have one type shaft. Maybe that some you have seen are coming apart.
The first link doesn't look right to me, but can't place why right off. Could be nothing more than camera angle. If you do pick up a used one, install a new bearing before installing it. Also make sure there is a pilot bearing/bushing in the end of the crankshaft for the end of the shaft to fit into. If it's missing, you will be replacing the housing again, along with some other parts.

 

[Radon17]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Thanks for the comeback Don.

Yes, in the first link the shaft length looks too long. Is that what you are refering to?

The second link, they say it's for a 4 cylinder, that doesn't seem right either? Seems like that would be the one for V6 or V8? I can't find any reference to the part number (3856701 ) on that housing.

 

[HorizonblueDK]

Re: Repowering - volvo 431A (1991) with GM Vortec 2011 - compatible?

Thanks for the comeback Don.

Yes, in the first link the shaft length looks too long. Is that what you are refering to?

The second link, they say it's for a 4 cylinder, that doesn't seem right either? Seems like that would be the one for V6 or V8? I can't find any reference to the part number (3856701 ) on that housing.

Maybe Don is referring to the proportions of that bellhousing, I think it looks a bit weird. But as he mention, it's probably the camera. And yes, there is something wrong with the shaft. It shouldn't protrude that much. The seller writes that the bellhousing is rebuilt, maybe he wasn't finished with that job, when the picture was taken.

This type of bellhousing has never been used with a 4 cylinder engine, but it CAN be used with a 3.0 (4cyl) engine, since it has the V6/V8 bolt pattern. But this engine has never been mated to a Volvo Aquamatic drive (pre SX drive) from the factory. A Volvo Penta 4 cyl bellhousing for the Aquamatic drive is completly different.

I never understood why MichiganMotorz states that this is a 290-SX conversion bellhousing. The only "SX-thing" I can see about it, is the two "feet" that is used for bolting the engine onto a pallet, during transportation.

I don't think you should worry about the part number that doesn't have any reference, it's probably just replaced by another number.

BOTTOM LINE:
You can use any of the four bellhousings for your new engine with the big flywheel. So take one of the cheapest, and inspect the bearings/seals, before mounting the whole thing.