Water in Cylinders, Blown Head Gasket

[edwardc]

This is going to be a longish post to catch up on what's happened outside the forum, so apologies in advance.

I was in the middle of a week long cruise. The engine had been running fine for the 1 hr it took to motor into the inlet where we docked. The raw-water-cooled A4 was running at 160 deg. This is a little warmer than usual, but I attributed that to the 100 degree air temp and 80+ degree bay water temp. The head and head gasket were brand new, installed in April of this year.

After two days in port, I went to start the engine, and it started a little hard. After 3 short cranks, I turned off the water inlet and continued trying. It started , and I opened the water. It began running rough, and would not idle. I went below and found water leaking from around the manifold gasket. I shut down and pulled the plugs, and cranked it, and got a geyser of water out of #3 & #4.

Now, the two most likely causes of water in the cylinders are backing water in through the exhaust, or a blown head gasket. Since the head & gasket were brand new, and installed by a reputable and experienced A4 mechanic, I discounted that possibility and concentrated on the exhaust. After discussing the matter with Don, his conclusion was that my system had an inadequate amount of riser, and this had allowed a siphon to start while I was docked, which filled the waterlift muffler and backed into the manifold and cylinders. His recommendation was to clear the water, as described elsewhere on the forum, and, until I could rebuild the exhaust, always start with the water off, and close the water before stopping.

Well, after 4 oil changes to get (most of) the water out of the oil, I did this. When I cranked it dry, it understandably took a while to start, but eventually did and smoothed out. But as soon as I opened the water, it began to buck and sputter, and was clearly running on two cylinders! Shut down, closed the water and pulled the plugs. Water again! And a lot of it! More geysers when I cranked with the plugs out. Since the water had entered with the engine running, there was no way it had backed in through the exhaust. It must be the head gasket! A quick thumb-on-the-spark-plug-hole compression check confirmed this. I cleared the water again, sprayed oil in the cyls again, and drained the oil again.

After getting the engineless boat back to home port (an adventure in itself), I put fresh oil in it and did a real compression check. Found #1=80, #2=45, #3=40, #4=35. Prior to this, all four had been in the 85 - 90 range.

At this point, I have a call in to the mechanic, but I'm at a loss to explain what happened. I watched the him install the new OEM head, and he did a a careful clean job, and used the newer black gasket (but only one). But now it's clearly blown. Is it his fault?

Or is it possible that the original water came in as Don suggested, and that cranking it with water in the cyls is what blew out the gasket? Or was the gasket the culprit, blowing out during my 1 hr run, and letting water in after I stopped?

[Dave Neptune]

Tough luck

Edward, ouch! Yes it probably blew the head gastket while starting or just as the beastie started. You should use the 2 gaskets provided from Moyer or any "REPUTABLE" A-4 supply/mechanic, they should know this!!
I wouldn't worry to much about the compression figures at this point.
Pull the head as it was just off it should be easy . While the head is off check the intake/exhaust manifold for cracks (possible & doubtful) or openings between jackets. When you get the head off dump some oil in the cylinders to soak the rings MMO would work quite well for this.
Get a gasket kit from Moyer and have at it. You will probably do a better job of torquing the head than a mechanic in a hurry!!! Many instructions on the site, it's not a bad job at all.
Important, get the head off asap so you can get the cylinders oiled as well as the valves.

Good luck!
Dave Neptune

[domenic]

Gas has Ethonol...some gas has 80% Ethonal...the A4 was not designed to take the pressure of todays fuel.

Read the thread, "How to destroy an A4."

[67c&ccorv]

Yep - two head gaskets required!

[edwardc]

The mechanic is suggesting that most head gaskets burn through, rather than blow out. On a blown out one, he expects the compression numbers to be close to 0.

[hanleyclifford]

Remember that by having only one gasket installed, the combustion chamber volume was reduced thus increasing compression. Can anyone calculate what that might mean for compression ratio?

[Baltimore Sailor]

The MMI gaskets are metal-reinforced, and according to MMI, have never had a burn-through. However, since only one of the gaskets was used, the only way to be sure is to remove the head.

[lat 64]

If I remember in the days, we used to shave off near .050" from the gasket surface of a small block chevy to get about a point of ratio. That is-ie. going from 9:1 to 10:1.

But there's too many variables to be a reliable rule of thumb. If the combustion chamber is large, then you must cut more off to make a difference. Also bore-to-stroke ratio messes with calculations.

With a large combustion chamber like the A-04, and the "square" bore-to-stroke ratio, I don't think one gasket thickness made a enough difference here to blow the head gasket.
Also, if the gasket is blown, it would have been blowing bubbles into the water and maybe sucking water back in after it got shut down for the day.

Just some ramblings, maybe one of the other hot rodders has better understanding than me.
Russ

[tenders]

Don has run the compression numbers on the 1-vs-2 head gaskets and the difference is nominal, maybe 5psi as I recall--within the sensitivity of most compression testing tools.

I don't think 1-vs-2 head gaskets are the problem. Nor is ethanol.

I agree with Neptune and Baltimore. Get the head off and find out for sure. It won't be difficult if the head was recently off. You may end up casting some ill repute on your mechanic.

I'll go out on a limb and randomly guess that you'll find a few loose studs that let the gasket blow and are allowing water to seep into the cylinders.

[Dave Neptune]

Flaatheads & compression

Due to the nature of the flathead and the length of the runners that deliver air from the valves you have a considerable volume. By reducing the height of the gasket or gaskets and even going to a copper shim (popular in the old days) you will only gain a tiny bit of compression and the down side is that you have now reduced the area restricting the air flow both in and out. It is a fine line working with flatheads to balance the intake/exhaust versus compression required for more dramatic cam timing. An overhead has the runners behind the valves reducing the volume (being compressed) considerably and the I&E can be opened for higher volumes of air.
A side note I know of a few old Ford flatheads that have replaced the small blocks that have occupied their frame rails. There have been some vast improvements for flatheads going to roller type tappets and cam profiles. There are a few 32 flatties on the street that are quite fast today.

Dave Neptune

[jhwelch]

Did you mechanic use a torque wrench to 30 ft/lbs? And after you had used the engine for
a while did you retighten the bolts? Not that this would have prevented what
happened, but since you have to go through the process again it is something
to keep in mind.

[67c&ccorv]

Westerbeke introduced a .050" thicker head gasket in 1996 (made by the Victor Gasket Co.) that was supposed to eliminate the doubling of the original head gaskets.

However, it was sold with a warning to check the cylinder pressures after installation (especially for engines which had the cylinder head resurfaced) and that pressures over 125lbs would result in blown head gaskets.

If your motor had an aftermarket cylinder head that had a smaller than spec combustion chamber that might = a blown head gasket.

I believe Don had a Florida motor some years back with an aftermarket cylinder head that produced 6.72 to 1 compression ratio - this was sufficient to blow both gaskets and the owner reported that the motor ran very strong! I am inclined to believe that the majority of blown head gaskets that occur after a rebuild by enthusiasts (like myself) are due to blow-by caused by a poorly prepared cylinder head-block mating surface.

It really does pay to have those surfaces machined by someone who has the equipment and the expertise to do the job properly.

[Don Moyer]

Just one slight correction to the previous post. It was Victor themselves who originally introduced the steel reinforced graphite gasket in common use today and it was definitely not their intent to eliminate the long standing Universal recommendation of using two head gaskets. In fact, Victor included a small note recommending two gaskets in their standard Victor packaging for many years. I had the opportunity to collaborate with Victor on the design of the gasket and to do the original testing. The reason for the two gaskets is to approximate the thickness of the old copper clad asbestos gaskets and thereby retain the original compression ratio.

Don

[67c&ccorv]

Thanks for the clarification Don.

[edwardc]

The MMI gaskets are metal-reinforced, and according to MMI, have never had a burn-through. However, since only one of the gaskets was used, the only way to be sure is to remove the head.

I have a new set of head gaskets in hand, and the head is coming off this weekend. I plan to examine the old gasket carefully.