Water in Cylinders, Blown Head Gasket

[edwardc]

... 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.

Right after the new head & gasket were installed, I had compression readings in the 85 to 90 range on all 4 cylinders.

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

This was a brand new OEM head. (expensive!)

[edwardc]

Did you mechanic use a torque wrench to 30 ft/lbs?

Yes, and I watched him do it.

And after you had used the engine for
a while did you retighten the bolts?

No, but I did check them after things blew, and they were still tight, with no sign of water around any of the head studs.

[edwardc]

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.

I've already taken off all the head nuts in preparation for removing the head, and all of the studs were tight and stayed in the block.

[edwardc]

Update: Worst Case Scenario

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.

It's been a while since I posted on this topic, and a lot has happened, so I wanted to do an update.

The head came off easily. I used an old mechanic's trick and replaced the plugs and turned over the starter with all the head nuts removed. This "popped" the head free, and removal was then simple. The gasket showed the expected traces of rusty water in places, indicating that it was blown (see attached photo).

I scraped & cleaned the head & block, installed 2 new gaskets from Moyer, replaced the head, and torqued all the nuts to a total of 30 ft-lbs in a "center-out" pattern in three passes. After that, I re-ran a compression check. All four cylinders were now equal, but somewhat low, at 60 psi. I attributed this to a combination of dry rings and some crud left in the valves that would clear out. I also pressure-tested the water jacket in the exhaust manifold and it was fine.

Meanwhile, I had ordered new stainless steel pipe fittings from McMaster, and an anti-siphon valve from Moyer, to rebuild the exhaust stack properly. I was still assuming that this had been the original cause of my water-entry woes. Alas, I was soon to discover that this was not so!

As a final check before rebuilding the exhaust, I decided to pressure test the block's water jacket with the new head gasket installed. I put a pressure gauge on one end and hooked the other up to an air compressor set to 15 psi. But it seemed as if I had done something wrong, as I could not get the gauge to even budge. Finally, i turned off the noisy compressor, took the hose from it, and blew on it. To my utter despair, I could plainly hear all of my air whistling out the #3 spark plug hole! It seems I have a cracked block!

Since I was getting compression, I knew that the crack had to be in the valve chambers and not in the cylinder. It was just getting into the cylinder through an open valve. So I rotated the crankshaft until both valves on #3 were closed, removed the manifold, and repeated the test. Now, no air was coming out the spark plug hole. Instead, it was coming from the #3 exhaust port. I sealed that with the palm of my hand and tried again. Now, there was some resistance to my blowing, but a lesser amount of air was coming out of the sistered #3-#4 intake.

So, it seems I have a large crack in the block, spaning the #3 exhaust and the #3 & #4 intake. This explains all the symptoms I was seeing. I tried to inspect the inside of the exhaust port, using a light and a camera set to macro focus, but had no luck in seeing anything.

At this point, it looks like there's nothing left to do but start on pulling the engine and replacing it with a rebuilt one.

[rigspelt]

The head came off easily. I used an old mechanic's trick and replaced the plugs and turned over the starter with all the head nuts removed. This "popped" the head free, and removal was then simple.

Now, that's cool.

[sastanley]

Hanley, check out the nice rounded fitting at the aft end of the manifold!!! We need a source for those and what hose size that is.

+1 rigs...nice trick there Ed.

[hanleyclifford]

That actually looks like a thru hull tailpiece. Very smooth flow and come in all sizes. Cannot tell what size that is. My guess would be 1/2" for 3/4" hose.

[edwardc]

Hanley, check out the nice rounded fitting at the aft end of the manifold!!! We need a source for those and what hose size that is.

It's a 5/8" hose. Don't know the source of the fitting. It came with the boat.

[hanleyclifford]

Ed - So sorry about the cracked block - feels like a loss in the family. Perhaps you can find an engine with other deficiencies to combine with your good components. Best Regards, Hanley

[lat 64]

chin up

That's a dang shame!
If I had block I'd send it.
Well, at least you're qualified to inspect a new block if you find one.

Good luck and I hope you get to go sailing soon,

Russ

[edwardc]

Ed - So sorry about the cracked block - feels like a loss in the family. Perhaps you can find an engine with other deficiencies to combine with your good components. Best Regards, Hanley

That's a dang shame!
If I had block I'd send it.

Thanks for the kind words, guys.

At this point, I'm thinking that, in the interest of time, I'll probably buy a rebuilt short block from Don and transfer my manifold, head, alternator, starter, fuel pump, carb, and electronic ignition from the old engine. This seems to be a good balance between time & cost.

Along those lines, does anybody have dimensions for a simple benchtop engine cradle? I'm thinking along the lines of a piece of 3/4 inch ply and a couple of pieces of 2x6. I figure to build two of them and set the new engine up next to the old to simplify the transfer and buildup.

[lat 64]

Ed,
I posted a shot of my cobbled up stand for an earnest young man at the thread called 12 year olds rebuild Post # 16

http://www.moyermarine.com/forums/showpost.php?p=27349&postcount=16

Russ

[edwardc]

Ed,
I posted a shot of my cobbled up stand for an earnest young man at the thread called 12 year olds rebuild Post # 16

http://www.moyermarine.com/forums/showpost.php?p=27349&postcount=16

Russ

Thanks Russ. That's exactly the kind of thing I was thinking of. Those look like 2x8s rather than 2x6s. What's the spacing? Someone told me its 11 1/2 ". Sound right?

[hanleyclifford]

According to the diagrams I have the measurement athwartship motor mount to mount is 11 1/2" on center.

[lat 64]

Oh my goodness! You guys measure things?
I just pushed the two boards up to the oil pan rails and used bugle-head deck screws with washers through the motor mount holes.
More deck screws "toenailed" the boards to the cross pieces. I did have to use a roofing axe to chop out a little clearance for the dipstick boss.
Something else you should make room for in the shop is a big overstuffed arm chair for reading the manual and sipping something. Most of this work is done after a regular days-o-work slog.

It snowed here a little yesterday. Time for armchair sailing.
R