looking for the right flywheel 99 volvo 4.3 vortec w/counterbalance shaft,

stang32

Chief Petty Officer
Joined
Jul 16, 2004
Messages
513
it has a 1 piece rear main seal & plastic timing cover

so i bought this boat with a blown motor, the motor had the piston blow out the side of the block, i found that it had an old flywheel installed, the ones that are designed for non vortec motors. i think thats why the motor blew.
so i am now looking for a replacement flywheel. the only ones i have found based on part # 3853958 are over 700 dollars. i cant afford that. there has to be some other compatable flywheel out there. i see companies that make aftermarket flywheels for gm vehicles with manual transmissions and they are under 100 bucks but i cant find any cross reference.
can anyone help?
 
Last edited:

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
51,207
Here is some reading

http://forums.iboats.com/forum/engi...history-of-the-4-3-liter-with-casting-numbers

remember, your motor and flywheel came from GM and NOT volvo penta. so get a GM flywheel.

its a 1992 and later GM 4.3 flywheel with 168 teeth - for 11" clutch. (they are all the same from late 1992 - today). The flywheel did not change when they went to the vortec heads in 1996

what makes you think its the wrong flywheel and it caused your motor to blow. highly unlikely in both cases.
 

stang32

Chief Petty Officer
Joined
Jul 16, 2004
Messages
513
when i look up the part # 14103283n i get listings for pre vortec engines the part # i found for my application 3853958 fits vortec motors. the flywheel that came of thie boat weighs a ton { not literally}compared to another older flywheel i have, part #14091599n. if the flywheel is made with balance weight and the engine is already balanced with the counterbalance shaft, the engine will shake itself apart. that is mu concern.
i will check out the link you posted,
 

stang32

Chief Petty Officer
Joined
Jul 16, 2004
Messages
513
something i forgot to mention in the 1st post, is that the previous owner changed out the motor & the blown motor was only 1 year old, this is why i felt the motor/flywheel combo is incorrect .

Scott, i read your post { very informing** but it says

" All of the engines with the one-piece seal were externally balanced with specific flywheels and dampers, but the cranks were also balanced according to the weight of the pistons and rods that were installed in the engine; it?s important to use the right combination of parts. Unfortunately, there?s no sure way to tell a light crank from a heavy one short of knowing where it came from and marking it at teardown or spinning it on a balancer. There are a couple of clues that can help, though"
:

you say they are all the same up above & i have read several places that the vortec motors were internally balanced.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
51,207
nope, all 1-piece seal motors (4.3, 5.0, and 5.7) switched to external balance in 1986 from GM. they lost the big-arse flange on the flywheel which was part of the balance weight.....so the motors switched from neutral balance (internal balance) to external. the balance shaft was added to the 4.3 to calm down some of the harmonics because the firing order caused the motor to shake like a dog passing a peach pit.

if you want internal balance on a 4.3, 5.0, 5.7, 6.2, 7.4, 8.1, or 8.2..... you are going to have to take it to a machine shop and pay to have it balanced and it may be cheaper start with a custom forged crank that is designed for neutral balance.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,288
it has a 2 piece rear main seal & plastic timing cover

Ayuh,.... This is hard to believe too, as the 2 pc seals went away back in '86,....

Donno what killed the 1st motor, but if the problem was caused by something other than the motor,...
It's My guess that the same problem caused the 2nd motor to blow,....
'n My 1st guess on that is the base cause was detonation from a lean condition,....
In other words, Crap in the fuel tank,....
 

stang32

Chief Petty Officer
Joined
Jul 16, 2004
Messages
513
nope, all 1-piece seal motors (4.3, 5.0, and 5.7) switched to external balance in 1986 from GM. they lost the big-arse flange on the flywheel which was part of the balance weight.....so the motors switched from neutral balance (internal balance) to external. the balance shaft was added to the 4.3 to calm down some of the harmonics because the firing order caused the motor to shake like a dog passing a peach pit.if you want internal balance on a 4.3, 5.0, 5.7, 6.2, 7.4, 8.1, or 8.2..... you are going to have to take it to a machine shop and pay to have it balanced and it may be cheaper start with a custom forged crank that is designed for neutral balance

.


ok, if its externally balanced, how if not by the flywheel and balancer?
im confused because the balancer does not have any added weight in any particular location, it is fully round and flat on all 4 sides( hope that makes sense)

my question is how is it balanced?

as for your post bondo, i believe that when the p/o replaced the 1st motor he went up to a newer block and kept the original components, the part # on this flywheel p/n 14103283n corresponds to older engines and like i said earlier, weighs a freaking ton compared to my other flywheels
granted the boat is a 97 all the parts should be ok for any vortec motor, it doesnt make sense that this flywheel is on the engine, unless it was swapped out earlier


just so i have this listed right, i realized i typed 2 piece rear main seal on the orignal post, is should read 1 piece, i edited it to fix error
 
Last edited:
Top