Testing Compression

[forsailbyowner]

While the head is off another good measurement would be to mic out the cylinders. If you check them for bore size, taper and out of round you will know a lot more about spending more money vs complete rebuild. If its out of the service range do you really want to even invest in a head gasket?

[Jetexas]

Originally Posted by never monday

where are you sourcing parts?

if your this far in pull the pistons, hone and rering

The rebuild kits were quoted by a place out of Michigan operating the web site www.parts-supply.com

They gave us these two quotes:

Mitsubishi K2AS
Engine Overhaul Kit $1397.00
Includes: pistons, piston rings, piston pins, piston pin retainers,
big end connecting rod bearings, main crankshaft bearings, thrust bearings, camshaft bearing, complete engine gasket and seal kit, front crankshaft seal, rear crankshaft seal

Mitsubishi K2AS
Cylinder Head Rebuild Kit $988.74
Includes: intake valves, exhaust valves, intake guides, exhaust guides, valve springs, valve spring keepers, upper engine gasket set

If we just order a head gasket, that's coming from Lakewood Yacht Service the Westerbeke dealer in Kemah, which is why it's so expensive. Just an engine gasket set from Westerbeke is $900. We're trying to avoid Westerbeke parts if at all possible.

[Sailmonkey]

If you don't take the valve out and lap the seats, removing the head will have been all for nothing.
It's easy to do, just place the head on a piece of plywood, valves down. Then compress the springs without allowing the valves to move. this will expose the collets, pull the two pieces off and release the spring. You can now remove the spring and pull the valve out of the bottom. I'll bet that if you check with some blueing you'll find that there is not a perfect ring of contact all the way around. This can be fixed in most cases (unless the seat is corroded) by a $10 tin of lapping compound and some time.

I found a few pictures

http://www.v6z24.com/howto/valvelapping

[sigmasailor]

Wow, I had no idea about those prices. Back in 'my time' we would make our own gaskets (yes from asbestos) or simply heat treat our copper seals to make them soft again.
I do not understand gaskets are that more expensive than normal (car) head gaskets.
I feel you pain.
Lapping (that's the correct word) the valve seats will cost you just some time and not a lot of money. It's quite possible that some seats have corroded a little and can be repaired by lapping. If head gaskets weren't so expensive I would say clean-up those valves and give another try. I have to agree with NM on those rings; they probably suffered. You could pop them out and use some fine abrasive paper to clean (and grooves) them if not really damaged. You don't have much to loose that way. Pistons, cylinders and rings are nothing to be afraid off. I remember one time after a valve broke off and was bounced around a cylinder for a while. We used an angle grinder to clean up the cylinder. After a month or so (750 hours) we pulled the piston again and gave it new rings and it ran just fine after that. OK, that was an engine running at 600 rpm with a 10 inch bore, but still....

[daddle]

Please forget about rebuilds kits, gaskets, lapping until you know the problem. Whatever is wrong is very serious to cause no compression, not just low, and cause puffing out the intake. By the op's statements this is not slightly worn valves or rings.

Are you sure you are not cranking it in reverse?

[Sailmonkey]

Originally Posted by daddle

Please forget about rebuilds kits, gaskets, lapping until you know the problem. Whatever is wrong is very serious to cause no compression, not just low, and cause puffing out the intake. By the op's statements this is not slightly worn valves or rings.

Are you sure you are not cranking it in reverse?

The engine is turning in the proper direction, I have no idea where you got the idea that there is no compression. The cheapest and eaisest thing at this point is to look at the valves and determine if the seats are pitted. If they are (and they could be as the engine sat for several years) the fix is to lap (or grind). If the intake valves are not sealing the engine will puff out the intake, after all if pulls air in and compresses it it has to go somewhere if the valves leak!!
Worst case is the valves are perfect and the problem is elsewhere, but this won't be known until the valves are out of the head and inspected!!

[hellosailor]

How about putting some oil or kero in each cylinder, letting it sit overnight to see if it is getting past the rings, indicating a ring & compression problem?

I also notice the "left" cylinder in the pictures of the head appears to have a mineral deposit stain around it, that extends out to other passages. Minerals from a water leak and a bad head gasket? Or just an illusion?

[daddle]

Originally Posted by Sailmonkey

The engine is turning in the proper direction, I have no idea where you got the idea that there is no compression.

You wrote it was very easy to turn over. That means no compression. I had assumed the engine was running before the problem - but maybe I misunderstood. That would indicate something basic happened with the water dousing. And would tend to discount simple wear and tear problems like rings and valves. But maybe you've never had it running?

[sigmasailor]

Hi,

Just wondering about updates.
Any?

[um saudade]

Have not been following this but a quick read got me up to date of sorts. Before you pull the valves out do this quick test: Prop the head up at a suitable angle and pour the ports full of diesel and watch. If you never see any wet coming out of the intake or exhaust valves you have no issue with the valves sealing. A little bit of seepage is not an issue as this is not a gasketed seal just metal to metal.

If they don’t leak badly then an intake valve could be sticking. You can’t easily find this out without the removal of the valves. If you pull them yourself, use a compressor and be careful you don’t send a keeper flying into the junk in the corner of the shop! You can get the valve specs and measure everything. Be careful cleaning up the valve guides. You can polish with a wooden dowel and emery. Polish the valve stems with a wire wheel grinder.
　
Be careful with valve lapping. Done judiciously you can clean them up. I didn’t see where you have talked to a machine shop as to doing a valve job but that is not all that expensive to have the valves professionally ground.

Again, I stress the don’t get the cart in front of the horse routine. If the block is trashed and you can’t put in liners, then you don’t have anything.
　
Um Saudade

[Jetexas]

We have made progress, just not as much as I hoped. Before I pulled the valves I devised a couple of tests. The first consisted of pouring carb cleaner into the intake and watching to see if it came out of the intake valves. It did.

Then I found a suction cup a little bit bigger than the valves, and I would press it over the valves. It would blow air right through the intake and exhaust valves, so we bought some lapping compound and got to it.

Now if I push the suction cup over a valve, it will stick. I'm taking that to mean a good seal.

As the cylinders look good, I think that now that the valves are sealing, that should solve our compression issues. I'm 99.9% confident it will fire when we put it back together.

However, we won't be putting it back together this weekend. The last remaining issue was dealing with the thermostat. The bolts holding on the housing on were frozen, and I'd already stripped one out. Last night we finally cut the heads off and chiseled open the housing to find this.





I've got to clean all that crud out, drill those bolts out and re-thread the holes. Then I've got re-smooth the mating surfaces of that bracket and the thermostat housing.

Maybe next weekend we can finally put it back together.

[sigmasailor]

Looking good...as far as valves are concerned. Wow, that engine sure has seen some neglect. When you get it going you may want to consider leaving a suitable scale (dis) solvent (you can start with vinegar if you want to keep it low budget) in the engine and exhausts system for some time and thoroughly flushing it out. Is your raw water pump pushing the water through the engine or sucking it out. In the latter case take care of your impeller.
I think you stand a good change of getting it started soon.

[Jetexas]

Picking up some new bolts today. I don't really want to go through the effort to repaint the head while it's off, but I know I should.

[Sailmonkey]

It's amazing what will come out of antifreeze when left to sit for years

[Jetexas]

After lapping it seemed to seal ok in my garage, but we put the head back on the motor Sunday, and no luck. It's still pushing some air out the intake and not even attempting to fire while turning over. We thought maybe the rocker arms were out of adjustment and perhaps holding the valves open a bit, but we removed them and turned it over by hand to find the valves still weren't sealing.

Guess we'll find a shop this week to do a "professional" valve job. We may need to replace the springs as well. This project seems like it's dragging on forever.