4.3 Merc Timing cover Help

[Rick Stephens]

I think the hump on top of the timing cover is for the balance shaft. The balance shaft came out starting in '92. I don't think that hump has anything to do with Vortec or non-Vortec.

 

[rderenzy]

I think the hump on top of the timing cover is for the balance shaft. The balance shaft came out starting in '92. I don't think that hump has anything to do with Vortec or non-Vortec.

Right. which mine has, so i need that bump. which is what worries me in buying just the rock auto cover that does NOT have the "bump"

 

[Rick Stephens]

Right. which mine has, so i need that bump. which is what worries me in buying just the rock auto cover that does NOT have the "bump"

Me thinks you are correct. I have not located a balance shaft steel timing cover. No balance shaft steel cover a dime a dozen.

 

[rderenzy]

RIGHT! which is what i'm trying to explain but i'm told to not over think it
i've had a certified mechanic go through 4 covers already, hoping this last one he just found solves it - i'll be sure to post w/ numbers and the outcome

 

[nola mike]

Me thinks you are correct. I have not located a balance shaft steel timing cover. No balance shaft steel cover a dime a dozen.

See, the weird thing is that the part number is the same for a '94 S10, which would definitely be balance shaft as for an '89.

 

[rderenzy]

See, the weird thing is that the part number is the same for a '94 S10, which would definitely be balance shaft as for an '89.

HAHA see that confuses the hell out of me even more! haha

 

[Rick Stephens]

See, the weird thing is that the part number is the same for a '94 S10, which would definitely be balance shaft as for an '89.

I get it. Also, no telling what Merc was buying from Chevy since they pretty much always trailed new motor improvements by at least a year or two. My engine is not balance shaft, but has the blocked off mechanical fuel pump mount. It is also, supposedly, a ;93 or '94 block. Definitely not a Merc sourced block though. A frankenMerc.

 

[rderenzy]

i'm still trying to figure out why my boat (a 1997) has a 1993 motor
but i dont know the history, i've only had it for 4 years

 

[Scott Danforth]

I get it. Also, no telling what Merc was buying from Chevy since they pretty much always trailed new motor improvements by at least a year or two. My engine is not balance shaft, but has the blocked off mechanical fuel pump mount. It is also, supposedly, a ;93 or '94 block. Definitely not a Merc sourced block though. A frankenMerc.

remember, the marine motors are a division of GM's industrial motors. the stamped 4.3 balance shaft timing cover may be from the natural gas gen set motor

i'm still trying to figure out why my boat (a 1997) has a 1993 motor
but i dont know the history, i've only had it for 4 years

could be a left over motor from a large purchase in 94 or 95 with your boat being built in late 96 or it could have been replaced.

when the economy went to hell in 2008, Both Merc and Volvo had an entire warehouses of 8.1 motors that were used in Mercruiser powered boats until 2011 and Volvo powered boats up until 2014 (GM quit production of the 8.1 in 2008)

 

[nola mike]

remember, the marine motors are a division of GM's industrial motors. the stamped 4.3 balance shaft timing cover may be from the natural gas gen set motor

Yeah, but I don't see what would be different from the the balance shaft pre vortec GMs that would need a different cover. What isn't fitting? Very curious about this, and surprised nobody has the answer. Can't be that uncommon. I can't remember off the top of my head how the intake relates to the timing cover. That would be the only potential difference that I can see.

 

[nola mike]

OP, buy the damn $30 part and do your part for science.

 

[Rick Stephens]

Yeah, but I don't see what would be different from the the balance shaft pre vortec GMs that would need a different cover. What isn't fitting? Very curious about this, and surprised nobody has the answer. Can't be that uncommon. I can't remember off the top of my head how the intake relates to the timing cover. That would be the only potential difference that I can see.

The balance shaft adds to the height. The non-balance shaft cover goes right around the cam gear. The balance shaft motor has an additional gear driven shaft. You can see it in the pic below.

 

[achris]

Ok, the original GM part number was 12523080, which was discontinued in Feb 2006. The replacement for that is 12509865. As yet, I can't find a source.

Chris...

 

[achris]

The link and part number Rick posted are the right one.

 

[nola mike]

achris which link, the rock auto?

You're right about the unobtanium GM part I think. The GM sites list different part numbers for balance/non-balance shaft engines. I'm thinking that whatever database these third party retailers (rockauto, napa, autozone,etc) is using is wrong, and listing the same part for all engines even though it won't fit the balance shaft engines. So the GM and merc blocks are the same and both need the same cover. Odd and sucks that it's discontinued without an aftermarket.

 

[nola mike]

But it looks like the gasket and crank seal are still available?
14090906
10108435

 

[Yegboats]

Here is the NLA list a place just listed they had one last month. I can't help with the automotive, all I can say is have them order the gm one from a local auto parts store, compare it to existing one.Return if it's different.

855400 FNLA COVER-TIMING Number Status Description
1 GREENE MARINE REPR WILMINGTON NC UNITED STATES 910-395-2074 02/12/2020 1 A-ROCK PROPELLER SALT LAKE CTY UT UNITED STATES 801-281-8288 06/19/2020 Qty Dealership City State Country Name Phone Number Last Updated

 

[rderenzy]

Yeah, but I don't see what would be different from the the balance shaft pre vortec GMs that would need a different cover. What isn't fitting? Very curious about this, and surprised nobody has the answer. Can't be that uncommon. I can't remember off the top of my head how the intake relates to the timing cover. That would be the only potential difference that I can see.

Thats a good question - i guess this 93-94 is a "special motor" a frankenstien i guess and have been told several times by certified shop that the auto parts will NOT fit this - they've put 4 covers on this damn thing and it leaks on each side, about 75% of the way up on the cover, where it tends to "dip out" (or not dip out) and there is a slight gap in coverage/seal

hopefuly they got the right part this time and i'll report out the facts!

 

[rderenzy]

OP, buy the damn $30 part and do your part for science.

haha, i actually was going to do this and drop it off to him, but before i could buy he said he found the part

 

[rderenzy]

The balance shaft adds to the height. The non-balance shaft cover goes right around the cam gear. The balance shaft motor has an additional gear driven shaft. You can see it in the pic below.

BOOOOOOM! this is EXCATLY IT and why its not "over thinking"
as i mentioned in the pics i posted - the auto ones are round at the top, this is more EGG shape which is exactly whati need

GREAT find, thank you