Water showed up in oil today!

[66miles]

Brian. Was the pre 49 Merc 239ci (3-3/16 bore n 3-3/4 stroke) with the pre 49 Ford 3-1/16 bore for a 221ci. Then post 49 Ford went 3-3/16 bore for 239ci while Merc went 3-3/16 bore with 4" stroke to give 255ci? I think it went something like this. Just tryin to work out what motor this is.

[scooder]

All Mercs from 38-48 were 3 3/16 x 3 3/4. As I said earlier, some blocks have the bumps but no plugs, I have one here.
Any chance of a pic of the gaskets? Do you have a bore that's cleaner than the rest, piston crown, valves and combustion chamber? This would indicate water getting in.
Martin.

[scooder]

Ford engined were 3 1/16 till the war, after the war Ford's went to 3 3/16 same as Merc. Next change was 49 when Merc got the 4" crank.
Martin.

[66miles]

Thanks for the numbers Martin. Pretty much tells me this is a canadian pre-48 Merc motor. Sorry but I'm still getting things sorted so I can post pics. You're right about the clean pot. The one that I suspect may have been seeing a bit of water has staining on the bore with piston crown being clear of carbon and brownish in colour. Exhaust valve has quite a thick concrete build-up on it with a sort of flow-pattern to it. Rest of bores are shiny clean, piston crowns have a bit of carbon build-up, and exhaust valves only have a very thin cream-coloured coating.

[Snouts out]

Blown gasket.I blew a RH side on a 50 in the hot summer of 1973.Limped in to Raliegh NC,pulled into gas station,and thank god the old owner knew flatheads and where to get parts.He showed me how to fix it. It got me home to Cincinnati,no problems after that.Don't over analyze ,and fix that water pump(that's another story).

[66miles]

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Hey snouts. I'm hoping you're right and it is just a gasket. Easy fix! Kinda struck me as strange how she went from clean oil to choc milkshake in maybe 2 days, maybe less. Can a gasket blow that quick and let that much water in?

[Paul Dobbin]

If the heads are fine, my vote goes to the freeze plugs. Happened to me the same way with one of my V8's

[66miles]

Paul. Freeze plugs (if there are any) would suit me fine! At least it's not a death sentence for the motor. Some have suggested that these early Canadian mercs often had no freeze plugs installed. Only way to tell of course is to drop the oil pan which I haven't gotten round to yet as I'm under doctor's orders to stay out from under that car for a week (pinched a nerve in my neck n now only one arm works). On that subject though, if one of the plugs is leaking it must be a tiny tiny leak cos I filled both sides of the block with water 2 days ago now, and neither side has lost any water.

[66miles]

Just a little side note to this story... While cleaning off the top of the block something caught my eye sitting down in the bottom of one of the intake ports. Fished it out with a bit of wire. Carburettor float needle valve! Who knows how long that thing's been bouncin around in there, could've been years!

[Andy]

You can see if you actually have freeze plugs by looking at the pan rails. The blocks with the plugs have prominate bulges tapering up into the sides of the block. No bulges=no plugs

[66miles]

Yea. Guess that would be a pretty good place to start. One of our knowlegable Barn members, scooder, reports that he actually has a block like mine, that has the bumps on the bottom rail of the crankcase but has no plugs (no holes). Couple other guys also have said that not all of the blocks with the bumps actually had the plug holes drilled. Only way to tell is to pull the pan. Has Anyone pulled a pan on a 47-48 Merc while the motor is still in the car? I don't want to make too big a deal out of this if it's only a blown head gasket after all.

[BILL WZOREK]

I hope I am WRONG but I was taught that oil in water won't be head gasket.
Because the oil is running in the engine under more pressure then the water & the head gasket keeps compression away from the water / if a bad gasket you should have oil in water not other way around,or the gasket could be bad but leaking water outside of the engine.

::I may be wrong but I don't think that there are any oil ports from the block through the head ::

You have to look in a area that the water can get into the engine under the low pressure that the water is at.

The direction that you are taking this seams like the most possible.
Pulling the pan is the best route. then reinstall the heads and pressurize the block.
remember the cooling system is a left side & a right side that don't connect with each other till the radiator / you can take the Radiator out of the loop & plug off the lower hose. and put the pressure it top hose, that way you take out the chance of hurting the radiator with to much pressure.
Doing one side at a time you can focus on just that side while you look for the problem.

GOOD LUCK

let us know what you find.

[TomO]

Read the post by Alan, and introduce air into each cylinder though a leakdown tester or a modified spark plug. Watch for bubbles in the coolant as you do this. If any bubbles appear, you will have found the area of the leak. If you do not have any bubbles and you still have water in the oil, look for cracks in the oil pan area.

Merc engines had 239 cu in from the start in 1939. The post war engines had a large 59 cast on the bell housing. If your engine does not have that, post a couple of photos showing the timing cover area and the exhaust ports. One of the old timers will be able ti identify the block from those photos.

[66miles]

Thanks Bill n Tom. You both make good points that I will keep in mind as I go! Bill, I agree with your points on how water would most likely make it's way into the oil. Easy for this to happen on an OHV engine as oil and water passages BOTH pass from block to head past the gasket. As we all know this doesn't occur with a flathead. That said though, would it not still be possible for water to pass through a blown gasket into the combustion chamber on the induction stroke. At this time there is a vacuum in the cylinder while there is pressure in the cooling system. If the leak were bad enough, maybe not ALL the water is burned off, leaving the remainder to work it's way past the rings and into the crankcase. As I am sure you can tell, I am holding out a great deal of hope that this problem is either a blown head gasket, or a blown freeze plug (in that order). The other options aint so nice!

[37 Coupe]

It will be interesting to see what the cause of the symptoms will be. I had a similar problem about 30 years ago on an 8RT engine that was perfectly good until I about ruined it with a set of aluminum heads and copper head gaskets. The heads were brand new out of the box Edelbrock and at that time I was told the best gaskets to use were the copper ones. Never had them on long enough for any corrosion problems just couldn't get them to seal,milk shake coolant,water and oil or oil and water. Put original heads back on with new fiber original type gaskets and no problems. It may have been the heads but was probably the gaskets,probably should have tried fiber gaskets with the heads but I was done with it. You never really said what type gaskets you are using,have you? Hope it is this simple to fix.

[66miles]

37 Coupe. The new gaskets are copper sandwich type, (I just posted a thread asking how to fit them). The old gaskets were another metalic sandwich type but they didn't look copper. They were silver in colour and had made in england stamped on them.

[BILL WZOREK]

Originally Posted by 66miles

Thanks Bill n Tom. You both make good points that I will keep in mind as I go! Bill, I agree with your points on how water would most likely make it's way into the oil. Easy for this to happen on an OHV engine as oil and water passages BOTH pass from block to head past the gasket. As we all know this doesn't occur with a flathead. That said though, would it not still be possible for water to pass through a blown gasket into the combustion chamber on the induction stroke. At this time there is a vacuum in the cylinder while there is pressure in the cooling system. If the leak were bad enough, maybe not ALL the water is burned off, leaving the remainder to work it's way past the rings and into the crankcase. As I am sure you can tell, I am holding out a great deal of hope that this problem is either a blown head gasket, or a blown freeze plug (in that order). The other options aint so nice!

66miles

If that was true 2 things / 1st on the return stroke which would be compression it would be greater the water pressure putting compression in to the cooling system,pushing water out ether the cap or out the overflow.
2nd if water got to the pistons they should be washed clean of carbon & scale.

Keep going in the direction you are going,I think you will find it.

ONCE AGAIN GOOD LUCK

[RCM]

Cant help, but sure hope its an easy fix.
Keep us updated and good luck.

[66miles]

Many thanks again to you Bill and also RCM for those words of support. Bill, I'm totally done with tryin to second-guess this thing. I'm sure a lot of Barners will breath a great sigh of relief at that! I'm hoping today to be able to muster enough strength in my good arm, my chiropractor would have harsh words for me but too bad for him, cos he aint gonna know. Then I'll get those heads bolted back down, change the oil, fire her up with fingers crossed, and hope my luck is back in. If not, I'll be droppin that dirty ol' oil pan off. Comes to that, I'll pull the intake manifold off for a look too. Here's hoping!

[mfagan]

Let us know the outcome, please .