1990 vs 1992 4.3 block swap

[Chris51280]

chevymaher. I believe you've done a few rebuilds yourself. Whats your take on the head gasket situation? Can I use the standard felpro set?

 

[chevymaher]

My van has a Mercruiser 4.3 I bought from a marine supplier. It came with Fel Pro truck gaskets. Fel Pro is the best available.

Marine sets just have things like the exhaust gaskets which are different.

 

[Lou C]

Looks like there was no oil film at all. Looks very dry.
Is there anybody that restored the block with oversize parts?

the oil at that point was milky due to the water so I wiped a lot of it out. But normally on this engine the oil looks very clear, not dark at all. Your block cleaned up nicely! Make sure you don't lose that fuel pump adapter and the pushrod, they are hard to find....on these 4.3s the fuel pump mounts upside down compared with the V8s.

I used Fel Pro marine gaskets for the heads and intake. Salt water use though. I also replaced all the cyl head bolts with ARP bolts due to corrosion.

 

[Chris51280]

would regular gaskets work with the .060 over bored pistons? I have been told they may work

 

[Lou C]

might want to take a look at grumpy's garage forums and ask the question there, or find a local auto machine shop and ask them.

 

[Lou C]

Also Fel Pro has a forum on their website, they will answer questions if you post up there.

 

[Bondo]

would regular gaskets work with the .060 over bored pistons? I have been told they may work

Ayuh,...... Odds are the fire ring will overhang the bore, exposin' it directly to combustion, 'n it won't be supported by the block,.......
Failure will be guaranteed,....

Do the math,......
The fire ring needs to sit at the edge of the cylinder/ combustion chamber,......

Marine sets just have things like the exhaust gaskets which are different.

Ayuh,.... Gotta be 1 piece,.... 'n possibly the t-stat housin', 'n carb gaskets,.....

 

[Scott Danforth]

would regular gaskets work with the .060 over bored pistons? I have been told they may work

get MARINE head gaskets for the larger bore.

 

[Chris51280]

How do I know the Marine gaskets have the larger bore. I will see if I can get some answers from Felpro

 

[Chris51280]

So one exhaust riser looks like this. The other side is ok. This is and was a freshwater boat. If i do a leak test and its ok, would you still use this one or replace? It didn't give me any problems So far.
the reason for the engine replacement is this repair. There were no problems and the oil was not contaminated.

 

[achris]

That damage on the exhaust manifold and the engine block looks suspiciously like freeze damage.

Pressure test the manifold, and if it's holding pressure, I'd keep using it. Same with the block, holding pressure, it's ok.

Chris.........

 

[Chris51280]

thanks chris. I already have the donor motor torn down for a rebuild. Will start harvesting the auxiliary parts from the old engine. I will get the marine gaskets even though they will see fresh water only. They are roughly twice the price than a regular rebuild kit at summit. The motor will get new rings, bearings, oil pump, valve seals. I will lap the valves and deglaze the bores. Getting a speedy sleeve over the damper so all rotating components stay together. The pistons should clean up nice since not alot of miles were on it. I could see the markings on top of the pistons. That should last another 10 years at least.

 

[Chris51280]

So I got a response from felpro. The 17211 and 17210 are ok for over size bores. The difference is in the cover gasket design. Vortec vs non vortec. Looking at the pictures, the vortec seem to be a different design in the cover with additional gaskets for the bolts. Its just hard to believe the older style cost double.

 

[achris]

Not unusual to find cost of old parts goes up.. as engines get older the demand for rebuild kit goes up. Manufacturer cashing in on demand.

 

[Scott Danforth]

How do I know the Marine gaskets have the larger bore. I will see if I can get some answers from Felpro

you order it by bore.

since your bore is over 4.0, your next head gasket is a 4.125" fire ring

https://www.summitracing.com/parts/fel-17010

 

[Chris51280]

This is what i got as a response for the 17210 set. Which includes intake and exhaust marine gaskets.

"Both sets contain the same head gasket that will work with a .060” over bore engine. The only difference is the valve cover gaskets between a balance shaft engine and non-balance shaft engine."

So the 17010 is just one head gasket.

I believe felpro ob the set and will order the rebuild kits

 

[Lou C]

Nice to see how fast they got back to you. I used their gaskets on my top end overhaul. Fit well and no leaks. I replaced the head bolts because they were all pretty rusty due to the raw water cooling. Get a thread chaser to clean out the bolt hole threads in the block.

I think it makes sense to use marine gaskets even in fresh water. Keep in mind the standard gaskets assume you are using antifreeze with corrosion inhibitors. And even some freshwater can be pretty corrosive.

 

[Chris51280]

So the timing chain was definitely stretched and had at least 1/2 movement. Other than the link style chain, have you used others? I haven't opened the mercruiser engine yet to see if they used a roller chain. I assume not! Is it worth to go to a roller chain? Summit has alot of different ones which alot say they are not compatible. So the direct replacement is the older link style chain. I think that the older style will be fine with the rebuild.

 

[Scott Danforth]

stock is fine

 

[Chris51280]

I looked at the current head gasket and it measures 4.09" on the diameter. Cleaned the piston today. They are not prefectly clean from carbon put they don't have to be. One of them has some scuff marks on the top ring.