Hi All,
I hope your season has been well. The Huron meet looked like a blast. I wish I could heve been there.
Well, I have a slight problem with my port engine. 427 power. It was running a little rough at idle all year and the old paragon was rattling. as the rpm's increased it went away but there was still a bit of a whirring noise. I thought maybe a damper plate or somthing. Unable to tune the rough idle out by a valve adjustment, timing check, carb idle screws, etc., I pulled out the compression tester. 7 cylinders were between 115-145 psi. I know not great but managable however number 3 cyl - zero psi.
OUCH! Funny thing is the engine runs ok otherwise. Starts right up and runs good. Checked the compression several times and did the #4 cyl again to make sure I wasn't going crazy.
Pulled the valve cover and checked the valve train. All looked good and the #3 valves seem to be seating ok (rockers clearance at tdc. A new oil slight seapage/leak has also shown up at the intake manifold-block gasket right over the bell housing.
I'm thinking the next step is to pull the head. Any thoughts?
Regards,
George
Bonaventure FXA 38 2034
Rye, NY

Always good hearing from you, but not a good topic to discuss.

As you may recall, I had a cylinder that registered zero, due to the improper valve adjustment of the previous owner. After proper adjustment the compression came up a tunable spec and the motors have run well for 10+ years.

Therefore, every time I hear of a zero reading on the compression gauge, I think of my experience. Zero on the gauge is indicative of a couple of things: it can be the result of a valve being held open for some reason, either sticking in the guide or held open due to improper rocker arm adjustment; it can be a burned valve; it can be a dislodged valve seat; or it can be some other issue hopefully with the cylinder head. It could be a piece of carbon holding the valve open, and if so, there may be some way to dislodge it, but this is a long shot. Before pulling the head, I would be sure the valves in that cylinder are seating all the way down, as I believe you have allready done. I would physically push the valve down, and see how it returns up, just to be darn sure it was not some sort of a burr or something on the guide that was keeping the valve in the open position.

In the end, if this is not a stuck valve guide you really have no option other than to pull the head.

Pulling the head on a 427 requires the right of passage of pulling the 80-pound iron intake manifold first. Although you and I could probably lodge ourselves into a position to do this physically, I do NOT recommend anyone put that kind of stress on their spinal column, lest they incurr damages far in excess of any sort of engine rebuild. Use a winch or a strong friend to help, no kidding, those things will fight you.

Once the head is off you should be able to tell what is wrong quickly. Hopefully it is limited to the head, all of which is probably easily fixed. 427 heads are pretty solid, easily rebuilt, and also replacable if necessary. Keep me posted, let me know if I can assist in any way.

Regards,

Paul

Paul,
Thanks for the responce. I will be checking those tings first for sure. I forgot to mention that I had the heads off on both engines back in 1990. I had them rebuilt with the new seats and guides that were compatible with the "new" unleaded gas. I will keep you all posted. The good thing about being on a mooring is I don't really have to go anywhere to be out on the boat. So we will sill enjoy.
Geo.

Well, after some poking around I think I can say I have a bad exhaust valve. After running at fast idle for about 20 minutes, the temps are at about 140deg F. If I put my hands on the risers the starbord engine and the outboard port riser are the same, warm to the touch but I can keep my hand on them. The bad head (cyl#3 inboard) riser is hotter and I can't really keep my hand on it too long. They are all new risers from Marine Manifold. So if my theory is correct the combustion stroke is going directly into the exhaust causing the slightly hotter exahust. If the intake valve were bad, I think the engine would be missing or popping. If the rings were bad there would be a sign of smoke in the exaust. Does all this make sense? Anyway I will wait until the boat is covered and winterized before I start the tear down. Besides, I have a honeydo list to complete before I turn a wrench on that project.
Here is the offending beast. Seems a shame to tear it all apart after the oil cooler and riser job last year.

I'm off to Holland for a week on business. Have a good weekend.
George

Greetings all,
Well I got the boat swrink wrapped by Thanksgiving and I started to do the teardown of my port engine. (zero compression #3 cyl.) As I said awhile back, I suspected a burned exhaust valve. Well my diognostics were right on the money. Here is a picture of the head on my workbench,

#3 valve springs

and #3 combution chamber. See the hole?

I still need to get the other (outboard) head off. I will have both rebuilt. I will try to take some pictures in the boat this week.
Stay tuned, I'm sure I will be looking for some pointers along the way.
Cheers,
George

Yup, that valve has certainly seen better days! Wonder what causes one to burn like that? Burned a nice hole too, you've been running on 7 cylinders for a while!

Good luck on the rebuild, by all means take photos!

Thanks for the update,

Paul

George:
In your first photo, what is the bulkhead material you are using? Is it a sound dampner or the like?
Jerry - at the point of the spear.

Jerry,
It is 1" Vinyl/Foam with the 1lb/ft vinyl sound barrier laminated in the middle. Metalized reinforced mylar facing. I purchased it from Soundown. www.soundown.com
I installed it last winter. The seam tape does a nice job. I also taped all the edges in order to keep the mylar from peeling back over time.

Jerry, stay safe. When is your tour over?
George

George:
Thanks for the tip. I called the company up and found three good items I could use on the boat. The sound barrier at the bulkhead, a ceiling sound dampner, and a roll out sound barrier for on top of the deck. I would lay teak and holly on top of that. Did the material at the bulkhead make a difference when considering the price?

My tour is supposed to be over in July or so. I have volunteered for a second tour because I am getting to work with the Special Forces and like what they are doing. I am planning on attending the Lake Huron show in August so I can meet all the liars, I mean, ahhh, boat owners and fishermen from the forum here. I also want to steal all the good ideas these gentlemen have come up with and look at real craftsmanship. If Chris Wade pulls both engines, I may have to take turns at the oars, with him, while we row the Feelgood over to the show.

Things are getting kinda exciting here before the elections. The 50 civilians, of whom we knew 3, were killed by an Al Queda bomb in Kirkuk the other day. We will see what happens next.
Jerry at the point of the spear. (Move over, Chris. Its my turn to row!)