Cylinder pitting and part interchange question

[soulhawaii]

The project I'm working on had compression issues, and i opened up the top of the engine to find that there was some rust in the intake manifold, and one of the cylinders has pitting on the side where it looks like water got in the engine and sat. My question is has anyone dealth with this, if it's minor can it be bored out and does the whole engine need to get bored and done, if other sides if they have no pitting?

My other question is, I know gaskets and some other parts should be bought marine engine only, but can pistons / rings be interchanged with the chevy 4.3l? I only ask because I'm on an island and shipping anything bigger here tends to be impossible or very expensive, but there are auto parts stores that can get me those things.

I added a picture of the cylinder if it helps in my questions. Thank you!

 

[Scott Danforth]

pictures are not uploading (current forum issue)

however your motors rotating assembly is exactly the same as the same year TRUCK motor

you dont say what year you are working on.

however generally best to do a bore and hone on all cylinders

for a 4.3, I would find a running similar year motor, pull the long-block and swap over the marine water pump, brass core plugs, marine head gaskets and all the marine accessories.

here is some reading.

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

 

[Bt Doctur]

the motor dosent know what its going into ,some parts are marine specific Depending on the pitting a .020 or a .030 rebore is possible

 

[soulhawaii]

I just realized I never mentioned the year, I believe it's a 1999, sn is M619800. I see a lot of listings for balance shaft, which I know my motor has, but also 1 piece or 2 piece main seal, so do I need to look for this specific long block?

 

[Scott06]

Yours will be 1 piece rear seal with a balance shaft. Any 4.3 96 or later will have that block with vortec heads which you will want to keep. Some castings like the 090M have metric threads for side motor mounts and Flywheel cover.its about $20of bolts to swap from one to the other if you run into this.otherwise everything else fits up perfectly.

Id tear it down and take it to a machinist if you can assemble it I can’t see you spending more than like $1200 for machining and parts unless the rods and crank are toast too.

 

[soulhawaii]

Okay thank you for the response, I'll take it to a place here and see what they say, I've done car engine rebuilds before but on platforms I'm familiar with (Mitsubishi and Honda) and some of the Marine stuff makes me nervus, like aligning the bearing once the drive is off, and also getting the timing on the engine right. Going to read the manual again and hopefully it'll start making sense soon!

 

[soulhawaii]

I foind this engine on CL, do you guys think it would be better to pick it up and have it worked on instead of mine, considering the rust pitting and so on?

https://honolulu.craigslist.org/oah/pts/d/kailua-gm-43l-v6-vortex-engine-used/7118804666.html

 

[Rick Stephens]

I'd have no hesitation taking yours to a machine shop for a quote.

I bought a 'donor' boat back a few years that had a newly rebuilt, apparently pristine 4.3L with Vortec heads and a nice shape Gen2 drive. I figured to swap it into my boat. When I pulled the motor and started looking it over, I pulled the plugs to find a lot of water and rust. The previous owner left the motor in the boat with a tarp over it while working on the trashed hull, but left the spark arrestor off the open topped carburetor. It was full of water. I fired it up, since it wouldn't hurt anything any longer, but decided to tear it down. One of the cylinders needed 20 thousandths to get rid of the pitting. Machinist wouldn't even consider just doing the one hole - we talked about it just from the standpoint of wondering why - he said one hole makes it impossible to work on later.. So zero mile pistons and rings got swapped out and I bored to 40 over. That motor has been a serious runner for me ever since. No cooling issues or any other problems with having gone to 40 over. The pistons and ring sets we bought were for a 350 Chevy, cheaper by far than a set of six of the exact same stuff.

 

[Scott06]

Okay thank you for the response, I'll take it to a place here and see what they say, I've done car engine rebuilds before but on platforms I'm familiar with (Mitsubishi and Honda) and some of the Marine stuff makes me nervus, like aligning the bearing once the drive is off, and also getting the timing on the engine right. Going to read the manual again and hopefully it'll start making sense soon!

if you have successfully done car engine rebuilds don’t over think it. A marine engine is a kin to a truck or industrial engine. Get the right mercruiser manual.
achris
can give u a link to his gimbal bearing alignment video on u tube.

in the end what you will find is as long as there isn’t too much boat around the engine, they are easier to work on than most cars these days.

 

[Scott Danforth]

I just realized I never mentioned the year, I believe it's a 1999, sn is M619800. I see a lot of listings for balance shaft, which I know my motor has, but also 1 piece or 2 piece main seal, so do I need to look for this specific long block?

as the other Scott mentioned, any 4.3 1996 and later will work.

so any 1996-2004 S-10 and S-10 blazer motors or even a 1996-2015 Chevy Silverado 1500 or GMC Sierra 1500 with a 4.3 can give its long block.

or take your existing motor to your local machine shop.

to pull the motor you need to pull the drive first.

 

[achris]

...achris
can give u a link to his gimbal bearing alignment video on u tube.....

Link (My Videos) at the bottom of my signature...

Chris.....