does volvo penta 4.3gl and merc 4.3 use same block

[steele3boyz]

i have been working on a volvo motor that had frost plugs pushed out.. put them back and got it running.. seems to be running good, but i see some white in new oil change. Is it possible to swap out with a merc motor or use the block . i been reading that both use the GM block. I am going to try doing another oil change to see if it was some crud that i didnt get all out when i did first change. thanks

 

[Lou C]

They are all GM/Chevrolet engines….
I’d remove the intake manifold to see if the block is cracked in the cam valley before spending any money on it…

 

[Scott Danforth]

some light reading on the 4.3. https://forums.iboats.com/threads/complete-history-of-the-4-3-liter-with-casting-numbers.693935/

to make things easiest and cheapest. find a running motor of the same vintage from a u-pull-it salvage yard out of a truck and use the short block and heads.

 

[steele3boyz]

thanks so much for the info!!!! we are now in the process of getting small block 4.3 ... so i just need to use the heads from the volvo penta motor?

 

[Lou C]

If the block was cracked the cyl heads are probably also. You need a GM/Chevrolet 4.3 of about the same time frame as that marine 4.3. As far as the engine itself it’s all GM. Only the added accessories to make it work in a boat are Merc or Volvo.
What year is the boat it came out of? The only way to tell which variation of GM 4.3 you have is to find the engine casting #. It will be on the bell housing area if the block. There’s that and also an engine serial # on the front of the block near the starboard side cyl head. The cyl heads themselves also have # stamped on them. When I had to do a top end overhaul on mine I got remanufactured cyl heads that matched the casting #s on the originals.

 

[Scott Danforth]

thanks so much for the info!!!! we are now in the process of getting small block 4.3 ... so i just need to use the heads from the volvo penta motor?

not sure what year your motor is, you get the same year block and head from the salvage yard.

both mercruiser and Volvo Penta used GM 4.3's out of the Tonawanda engine plant (makes truck motors and industrial motors)

very highly recommended for you to get the same vintage replacement as you have, because there are so many changes to the 4.3 over the years. while you can mix-n-match parts if you know what you are doing, you can get into a situation where things do not bolt together if you do not know what you are doing with the 4.3

 

[steele3boyz]

the boat is a 1996 four winns. so i believe that motor is a 1996. I plan on getting the serial # as we start to do more investigating. we are still in process of pulling the intake. thanks for working with us.

 

[Scott Danforth]

the boat is a 1996 four winns. so i believe that motor is a 1996. I plan on getting the serial # as we start to do more investigating. we are still in process of pulling the intake. thanks for working with us.

count the intake bolts. if you have 12 bolts at an angle, the motor is a 1993-1995 vintage

if you have 8 bolts vertically, then the motor is a 1996-2003 vintage.

 

[Lou C]

If you take a look at engine remanufacture websites you can see the engines they sell grouped by what variation they are of the series. The 4.3 went through many variations and the major ones were:
1985…2 piece main rear seal, flat tappet cam
1986…1 piece main real seal
1987-88 same as above but added the roller cam & lifters
1993 eliminated mechanical fuel pump mount added balance shaft
1996 added Vortec cyl heads
Later variations included switching over to metric fasteners, some used a mix of US & Metric fasteners.
Some of the years above may be off a bit because changes in marine engines didn’t always follow what happened with automotive….

 

[steele3boyz]

ok thanks for the info. so i just hopped in there and i have 12 bolts so it looks like it is 1993 to 1995 vintage... sons first boat.... so when he gets home we will remove seats and start removing the intake to get a good look and also the serial off the block. we appreciate all the help . this site has been one of the best i have used for any projects we get into.

 

[steele3boyz]

ok .. so intake is off and it does seem the block is cracked..... two spots arent smooth below the head. when i use finger nail it gets caught on a little line. the block # is 10227196 near the bell housing ... can anyone tell me what 4.3 block i need to ask for a parts yard? or does anyone have a motor for sale ? I have never pulled out a motor from a boat. I have from cars and trucks. thanks

 

[Scott Danforth]

Pulling from a boat is easier. Pull drive first

1993-1995 S-10 would be a good source to match your motor.

If it froze, you will also need a new intake, exhaust manifolds as well as long block

I shop on car-part.com for blocks

 

[steele3boyz]

thank you

 

[jimsteele]

ok .. so another question about 4.3L I have found a OMC cobra motor that is in a sunbird they think early 90's .. the volvo penta also has OMC markings and from what i read that were similar or same makes? would this motor and out drive work .. boat is a mess but thought they looked similar and he is asking only $500?

 

[Lou C]

Post up some pix. OMC Cobras from 1986-1993 were the dog clutch model and then in 1994 they (OMC) were bought out by Volvo and the design was changed to what is essentially the same as a Volvo SX. Which is what that boat you have likely has. If it’s the older OMC drive I wouldn’t change what you have for that but the engine most likely you can use IF and that’s a big IF it isn’t cracked & it wasn’t left with water in the oil. Be very careful & post up pix…