1985 OMC stringer 800 with a 4.3 possible cracked engine block

[cup of Joe]

I had a Topic on can you repace engine without pulling the out drive.
Thank you for the replies.

Now may not have to pull engine,
I gave the cooling system a leak test of 23 lbs of air, the results was no leakage.
The puzzling thing is the oil is milky. I changed the oil and filter twice.
The engine runs great, but how is the water get in the oil??
The only cracks I found was each exhaust manifolds has a crack along the bottom about 3-4 " long.
Any body have any input on this??
I was going to do a Compression test to check each cylinder for PSI but got snowed out.
I let the cooling system with 23 lbs of PSI for one hour, no loss if PSI.
Thank you

 

[Tnstratofam]

I wonder if the engine block has a crack in a water jacket that only leaks at operating temperature. Or a head gasket that is damaged that is also only leaking when the engine is hot?

Pressure testing the cooling system might not show a leak like that.

Just a thought.

 

[cup of Joe]

If the Water can only come from the cooling system , Wouldn't pressurizing the system show if there is a leak?
operating temperature might show a leak.
I'll try doing another pressure test with a higher PSI may be 50 PSI might show something different
Those two Exhaust manifolds cracks on the bottom shouldn't cause water to get in the oil,Right.

 

[Scott Danforth]

50 psi will blow the core plugs out.

Your manifolds are cracked, the most likely were leaking water into the exhaust ports, and into the cylinders which in turn leaks into the oil

Change your manifolds, the change oil and run it.

 

[cup of Joe]

thank you Scott, I will have to wait till this snow storm passes, I'm going to check the plugs , and perform a compression test .
The Engine runs great,
for the exhaust manifolds I'm going to drill holes along the crack . grind a grove and around the crack and put two layers of J B WELD

I put J B WELD above a spark plug Head crack on a PCM engine, It lasted for 4 years. never leaked

 

[cup of Joe]

I guess I would not be able to patch the exhaust manifold inside.
Will a 1987 Cobra OMC work, I can get two for 189.00

 

[Scott Danforth]

thank you Scott, I will have to wait till this snow storm passes, I'm going to check the plugs , and perform a compression test .
The Engine runs great,
for the exhaust manifolds I'm going to drill holes along the crack . grind a grove and around the crack and put two layers of J B WELD

I put J B WELD above a spark plug Head crack on a PCM engine, It lasted for 4 years. never leaked

you cant JB weld the inside, so why waste your time. buy new manifolds

 

[Scott Danforth]

I guess I would not be able to patch the exhaust manifold inside.
Will a 1987 Cobra OMC work, I can get two for 189.00

skip those, they would be the factory bat-wing manifolds that were known to fail internally.

 

[cup of Joe]

If I do not use factory bat-wing manifolds, then what exhaust manifold would work better.
Year? Type?

 

[Scott Danforth]

the replacement for the batwings.... see post #3 of this https://forums.iboats.com/forum/eng...ines-outdrives/10539977-so-i-ve-been-thinking

however I do not believe that they match the stringer. however I believe the exhaust manfolds for the 3.8 are the same ones on your 4.3 as the 4.3 is a slightly larger bore'd V6 than the 3.8 chevy it was replacing.

BTW, if your 1985 motor is toast, the 1985 is a one-year-wonder as they changed the crank in 1986 and the new crank wont work with the stringer drive button. you can take the ford drive button and have it re-machined.

 

[cup of Joe]

I do not think I have bat wings in the 1985 engine , It is a one piece manifold. lie the manifold in the photo
this photo is looks like the one in my 1985
I can get this set for $600. they say 1985-1990

 

[Scott Danforth]

that is a batwing manifold. they were notorious for cracking internally from poor castings and taking out the motors. there is a reason they do not make that style anymore.

 

[cup of Joe]

Thank you, The search is on For a three piece Exhaust.
Do you know would fit my 1986.
the boat is a 1986, with a 1985 engine i guess.
Is there a way to check my engine year from the serial tag?
On the tag near number one cylinder ,just below the head on the block is 225079

on the rear of the engine behind the coil is 14071177 with 26G1 next to it.

 

[Scott Danforth]

Look at the link I posted in post #10

if you have a 4.3 and a stringer, that combination was only made in 1985. In 1986, the cobra drives were out, having been delayed a year ( they were supposed to be a 1985 release)

Your boat may be titled and registered as an 86, however most likely made in 1985. My 2002 SeaRay was build in 2001 and was a hold-over as well. Happens a lot in the boating world

 

[cup of Joe]

thanks Scott, the 1985 -1986 thing is nuts, but ill deal with it
On one hand I want to sell it and on the other hand I want to fix it.
My boat is outside and it snowed , so this are harder to deal with.
I got the exhaust manifolds out ready to pressure test.
the engine PSI dropped 10 PSI 6 hours holding at 10 psi.
So i'm thinking the block and heads are ok.
I can get the OMC 4.3L V6 Exhaust Manifold Riser/Elbow Conversion Kit 984221/984222-- GLM-58994 for $700
or the stock bat wings 984221/984222 for $500

 

[Scott Danforth]

if you think the 85/86 think is nuts, you should try to follow along with all the 4.3 changes

here is some reading on the 4.3 https://forums.iboats.com/forum/engi...asting-numbers

 

[Howard Sterndrive]

GLM-58994 won't work as manifold castings will not clear your Selectrim engine mounts. You'll have to stay with batwings or the 3.8 2 piece manifolds. Both tough to find.

 

[cup of Joe]

Thank you all for your help.
Finally after 3 days of snow I got to uncover the project.
I found out Where the water got into my 1985 4.3 OMC STRINGER.
I found the fuel pump gasket upside down causing the engine to let water into the engine when I steam cleaned
the bulge area and engine.
Engine cylinders PSI 160 in all except one it was 155 PSI
Cooling System PSI check was 20 PSI for 6 hrs, three days later still holding 5 PSI.
Got new used Batwings, old ones were cracked on the out side.
She Runs great,
I changed the milky oil and filter 3 times,
I wonder how many times more I will have to change the oil and filter to clear up the milky oil?

Here is the set up I used to check for cracked block,heads.cooling system.

 

[Scott Danforth]

if the oil continues to be milky, your probably still leaking water into the engine. a single oil change should get rid of the milky oil and the trace amount of water left would evaporate when the motor is run at temperature.

however 3 oil changes would mean the water is still coming in somewhere.

 

[cup of Joe]

Thanks Scott,
Each time I changed the oil and filter, it was less milky.
I did steam clean the engine and bilge area pretty good and i have new used batwings that are not cracked.
Time will tell.
thanks again