ANOTHER WATER IN OIL QUESTION

[Rick Stephens]

I wonder if with blown head gaskets, causing air pushed into the cooling system and excessive heat failed the same portions of both heads around the exhaust valves. Other than bolting on a different set of heads or block off plates for the decks, I can't think of any tests to be sure the block isn't cracked instead.

 

[blando]

I wonder if with blown head gaskets, causing air pushed into the cooling system and excessive heat failed the same portions of both heads around the exhaust valves. Other than bolting on a different set of heads or block off plates for the decks, I can't think of any tests to be sure the block isn't cracked instead.

Good thought. Only one head gasket on starboard side was blown and the corresponding valves were tuliped. No obvious anomalies on the port side head or gasket. Of course that doesn't mean it didn't cause something internally in theat head.
I'm going to put plastic cling wrap over distributor and dip stick holes and poke tiny holes in them then soapy water and look for bubbles. This will confirm block cracks. I'm looking for a replacement engine now.

 

[blando]

I wonder if with blown head gaskets, causing air pushed into the cooling system and excessive heat failed the same portions of both heads around the exhaust valves. Other than bolting on a different set of heads or block off plates for the decks, I can't think of any tests to be sure the block isn't cracked instead.

ok just did pr trest with plastic over dipstick hole and distributor hole with soapy water and no bubbles..
Buuut did soapy water down all 4 oil drain holes on heads and there IS air from all of them which now makes me think the heads are cracked. idk
how would air be escaping from those oil drain holes ?. they seem to just be a tube that goes directly back to galley.

 

[tank1949]

The big question is ....

is the air coming from the head into the oil drain port ( would have to be a crack in both heads in the exact exhaust port , no?)

OR
Is the air coming from the galley( no obvious cracks visible)/ bottom end of engine meaning block is cracked?

or am I missing something or not understanding how the cooling passages run?

It has been my experience that if water (now air) is coming from blown head gasket, it will be easily identified (rust) after removal. There is always a crud trail. I also suspect that you are in for a lot of work. It is not rocket science, just lots of labor. If I had 60+K to **** away on 2 4 stroke Yamies, I would. However, once you get all the broken stuff fixed and well maintained, Gas will double in price and no one will be able to afford boating. LOL

 

[Lou C]

I had this same concern when I did mine, the block deck I cleaned up really well and looked at it with a magnifier and it looked good, so I took a gamble with reman heads and new gaskets. But unless you have a machine shop inspect the block and heads, there is always that element of the unknown.

 

[blando]

It has been my experience that if water (now air) is coming from blown head gasket, it will be easily identified (rust) after removal. There is always a crud trail. I also suspect that you are in for a lot of work. It is not rocket science, just lots of labor. If I had 60+K to **** away on 2 4 stroke Yamies, I would. However, once you get all the broken stuff fixed and well maintained, Gas will double in price and no one will be able to afford boating. LOL

The heads surfaces were milled

 

[blando]

I had this same concern when I did mine, the block deck I cleaned up really well and looked at it with a magnifier and it looked good, so I took a gamble with reman heads and new gaskets. But unless you have a machine shop inspect the block and heads, there is always that element of the unknown.

Heads were checked and serviced by machine shop. He didnt check for leaks bec he thought they were fine by inspecting visually. Im going to do a pressure check under water tis weekend .

 

[blando]

I wonder if with blown head gaskets, causing air pushed into the cooling system and excessive heat failed the same portions of both heads around the exhaust valves. Other than bolting on a different set of heads or block off plates for the decks, I can't think of any tests to be sure the block isn't cracked instead.

verry possible.

i had a thought ..the heads were milled but i didnt check the block deck for flattness, i wonder if theres a leak there or if i cracked the heads when torqueing down if the gap was big enough. i thought i heard a few pops when torqueing down. im taking off and going to inspect the block deck , and then do underwater head leak test i saw on line.

 

[Lou C]

I think he should have magnafluxed the heads and you should always check the block for flatness. Use a precision straight edge and feeler gauges should be less than .003” variation.
Also very fast important is to clean out out the cyl head bolt holes in the block with a thread chaser because they get crudded up due to raw water cooling and if the threads are not clean your torque spec will not be accurate. I would also replace the head bolts with new if any doubt about their condition. The devil is in the details

 

[tank1949]

The heads surfaces were milled

Well, something is leaking? I had one that was defective (remanufactured) from machine shop. The last water passage port near rear of motor eroded internally and allowed water leaked into chamber. Good luck!

 

[blando]

Well, something is leaking? I had one that was defective (remanufactured) from machine shop. The last water passage port near rear of motor eroded internally and allowed water leaked into chamber. Good luck!

yes something is leaking thats what this whole conversation is about.

 

[blando]

I think he should have magnafluxed the heads and you should always check the block for flatness. Use a precision straight edge and feeler gauges should be less than .003” variation.
Also very fast important is to clean out out the cyl head bolt holes in the block with a thread chaser because they get crudded up due to raw water cooling and if the threads are not clean your torque spec will not be accurate. I would also replace the head bolts with new if any doubt about their condition. The devil is in the details

Thanks for your reply.
I pushed for leak testing or magnifluxig the heads but the machinist was very confident they werent cracked ( he could have been wrong) and yes i should have checked the block, will do this weekend. I cleaned out the head bolt holes so that torque is accurate. Im leaning toward either i cracked the heads torqueing them down on an uneven block deck or if the block deck is uneven it can leak, or what Rick Stevens said "I wonder if with blown head gaskets, causing air pushed into the cooling system and excessive heat failed the same portions of both heads around the exhaust valves.Other than bolting on a different set of heads or block off plates for the decks"
I have minimal experience with this process but learning a lot. Im going to do an underwater leak test this weekend.

 

[blando]

I wonder if with blown head gaskets, causing air pushed into the cooling system and excessive heat failed the same portions of both heads around the exhaust valves. Other than bolting on a different set of heads or block off plates for the decks, I can't think of any tests to be sure the block isn't cracked instead.

I think if i can rule out the heads then ill finall know its the block..Ill check the heads if there shot then ill get new ones and if still a leak then ill know its the block. If the heads check out ill know its the block. That sound about right?

 

[Rick Stephens]

I think if i can rule out the heads then ill finall know its the block..Ill check the heads if there shot then ill get new ones and if still a leak then ill know its the block. If the heads check out ill know its the block. That sound about right?

About all you can do.

 

[blando]

About all you can do.

Digging deep and beating a dead horse but one more thing to consider i guess.
When i sprayed soapy water on the area that the most air was coming out of (the oil drain hole in head), it must have sealed the leak briefly, and it blew out one of my plugs on a manifold hose i had plugged for the test.
That seems to be another argument that its the heads or uneven block deck - A-by the minimal amount of water i put in there that caused this -and B -how quickly it blew- any thoughts?

 

[tank1949]

Thanks for your reply.
I pushed for leak testing or magnifluxig the heads but the machinist was very confident they werent cracked ( he could have been wrong) and yes i should have checked the block, will do this weekend. I cleaned out the head bolt holes so that torque is accurate. Im leaning toward either i cracked the heads torqueing them down on an uneven block deck or if the block deck is uneven it can leak, or what Rick Stevens said "I wonder if with blown head gaskets, causing air pushed into the cooling system and excessive heat failed the same portions of both heads around the exhaust valves.Other than bolting on a different set of heads or block off plates for the decks"
I have minimal experience with this process but learning a lot. Im going to do an underwater leak test this weekend.

UR learning!!!!!! I feel your pain as do most on this forum. Most of us have been THERE to one degree or another maintaining MCs. I sense that if you pull manifolds and heads and look for rust seeping through a crack or heads that you will find something. I suspect crappy heads since machinists will not flux. I have never seen anyone turning down labor fees $$$. That's troubling! I highly recommend after pulling heads to carefully examine for cracked cylinder walls or/and near lifter area. If not obvious, take heads to another machine shop and have fluxed or pressure tested. Just my 2 cents... Good luck!

 

[Lou C]

I had no problems getting my shop (SK SpeedShop in Long Island NY) to magnaflux my old heads and it clearly showed the cracks from a previous overheat. I think they charged me $40 or so to check them out. And they found another shop that sells reman heads and I was able to buy a pair of pre vortec heads for about $550. Well worth it to at least not have to guess about the heads.

 

[Rick Stephens]

UR learning!!!!!! I feel your pain as do most on this forum. Most of us have been THERE to one degree or another maintaining MCs. I sense that if you pull manifolds and heads and look for rust seeping through a crack or heads that you will find something. I suspect crappy heads since machinists will not flux. I have never seen anyone turning down labor fees $$$. That's troubling! I highly recommend after pulling heads to carefully examine for cracked cylinder walls or/and near lifter area. If not obvious, take heads to another machine shop and have fluxed or pressure tested. Just my 2 cents... Good luck!

When magnafluxing heads have to look inside ports above the valves. That's where the heat is and where the thinnest section of the water jacket is. A couple of forum users talk about how easy it is to rust right through that area on a salt water boat.

 

[Lou C]

True that's why I was leaning toward replacing the heads on mine even if they were not cracked. The machinist felt all the cooling ports were getting eroded in the heads. 15+ years of raw water cooling in salt. Who knows how close these were to rotting through. Here I have never heard of a block rotting though and even my orginal intake is very solid right under the stat housing.

 

[tank1949]

When magnafluxing heads have to look inside ports above the valves. That's where the heat is and where the thinnest section of the water jacket is. A couple of forum users talk about how easy it is to rust right through that area on a salt water boat.

I had very similar to me after buying reman heads from local shop. Shop stated heads were NOT from a boat, but they were cancer-ed from something! It cost me a motor!