Gauging Tappet Clearance without positive indication of TDC

[Cave_Dog]

As you all may know, I've got no compression in any of my cylinders, and I believe it is due to stuck valves. I've removed the pump and carb and taken the picture shown below:



Each one of these is an INTAKE and an EXHAUST valve for each of the four cylinders, correct? The valves should move freely up and down. Can I try breaking them free from this position or do I need to remove the head and try tapping them with a hammer? All of the adjusting nuts move up and down freely as I turn the engine with the handcrank. Without knowing positively which position is TDC for each cylinder, how do I measure the tappet clearance with the feeler gauges?

Thanks
Cave Dog

[hanleyclifford]

Cave Dog - Until you have the valves free you cannot even think about adjusting the clearance. Your valve chamber shows evidence of substantial water intrusion. Now that you have access to the valve springs you may try snapping the valves down with a screwdriver inserted into the spring just above the valve spring retainer. Keep shooting MM oil into the cylinders and also thru the springs just where they exit the valve guides. You need to work oil into those guides - I believe there is just enough rust in there to stick the valves. Also, inspect each spring carefully to see if any are broken. If this does not work you will have to pull the head.

[sastanley]

Cave Dog...i am no expert but those 4 "floating valves" are stuck..The P.O. of my boat pulled the head many times due to stuck valves..when I acquired the boat I was warned of a sticky valve or two...I have chosen not to pull the head myself (yet) , and repeated MMO treatments thru the spark plug holes have freed up my sticky #4 exhaust valve..which is the cylinder where I had reduced compression numbers.

As always, YMMV. I'd try MMO treatments any time you can steal an afternoon to the boat..spin it over with the starter or a hand crank, and repeat...maybe they'll break free...

To answer your other question - to get TDC, the best way is to observe the roll pin in the front of the flywheel coming up to 12:00 when you observe both valves closed (compression stroke) on #1 cylinder...usually the "thumb over the spark plug hole" and feeling pressure confirms this.

[Laker]

Off with it's "ead !!!

Based on my recent experience with some very stubborn stuck exhaust valves , I'd get it over with and the pull the head. Then you can visually determine which of the two valves in a given cylinder is stuck , lube it from above , rotate the crankshaft until the other valve is open (assuring that the cam is free of the stuck valve) , and work the stuck valve down. A short section of softwood dowel set atop the offending valve , tapping on the dowel with a hammer , worked for me. If it sticks on the next rotation (mine did) , lube and repeat.

Pulling the head will set you , and your valves , free!

Laker

[hanleyclifford]

aye, and a curious aside

Are we looking at blue paint in the valve chamber?

[Dave Neptune]

Getting loose!

Cave Dog, good to see progress. You can also move the valves in an upward motion to break them loose if you are careful. Once they have been loosened you can worry them back and forth until they are free.
Once again have your starter button at the ready so you can crank the engine. When you are ready you can use a stack of "feeler gages" or something "flat" and insert between the valve and the lifter and crank the motor, the lifter will push straight up and and get them to start moving a bit.

First use about .025 to .030 with the gages and turn the engine by hand. You will see which lifter is coming up so you will know which one to put the feeler gage in. Once you have gotten the offending valves to move try a bit of downward pressure then repeat, now you can use the stater button. Now you can increase the stack of gages a bit ( I wouldn't go more than .060/.80) to increase the movement. Do this a little at a time being careful not to completely colapse the spring on itself. Once they are starting to move even if it is just a bit keep working at it and they will steadily move more and more until they are ready to go.

DO NOT ADJUST THE VALVES UNTIL YOU HAVE STARTED THE MOTOR AND IT HAS RUN FOR A BIT. The KRAP under the seats wil not allow for proper adjustment until it has been run to clear the KRAP.

You can put the cover on or even leave it off to start the engine. not much oil flying around in the chamber when running. You can actually adjust while running if you are practiced in an ancient art of adjusting while running which is the most accurate way.

Dave Neptune

[hanleyclifford]

Ah, the Ancient Art - now we are dating ourselves. Dave, I bet you were one of those guys who adjusted between trial runs.

[Cave_Dog]

The worst news ever

FINALLY, CAVE DOG HAS COME THROUGH THE FOR THE WIN!!!!
THE HEAD HAS BEEN REMOVED, and below you will find pictures! More questions have been raised and what I believe to be a huge tragedy.
I've got valves stuck from here to tim-buck-too.

#4 intake & exhause valve work perfectly, both closed with the cylinder at the top

#3 cylinder refuses to move at all as I turn the handcrank, the 1 & 4 move, but the 2 & 3 don't. this cyliner was filled up with water/MMO/WD40 other stuff when I got off the head off so I wiped it out but can't get it to move

#2 cylinder moves up and down freely, but I can't remember what problems I had with the two valves, the cylinder was perfect

#1 cylinder moves up and down freely but one of the valves (can't remember which) instead of going down on the next stroke, goes further in the opposite way, but then will go down if I tap it with a screwdriver.

Hopefully these pictures help and you guys can tell me how screwed I am about the #3 cylinder not moving at ALL. I'm hoping I'm not totally screwed






Cave Dog

[ndutton]

Cave,

The bottom end has to come apart to fully assess #3 piston. Look for a missing rod cap, broken rod, broken wrist pin or piston wall at the wrist pin. The fact that #4 moves means the crank is intact. Time to remove the engine from the boat.

Don't throw in the towel yet, there's still more info to be gleaned.

[hanleyclifford]

Cave Dog - If the engine turns over and all 4 pistons are going up and down and you don't see any real bad scoring on the cylinder walls then the situation probably looks a lot worse than it actually is. This is the juncture well call "valve job time". Before you take any thing else apart make yourself a wooden block with holes or some kind of a rack so you can be sure to get each valve and tappet back into the hole it is going to come out of. Next put something in the oil drain holes in the valve chamber so you don't lose something into the oil pan. Then start taking out the valves using the appropriate spring compressing tool. Take note of how each valve seat appears and test each valve for straightness. You are probably going to replace a few valves, no big deal. This engine has had a major water hit - it needs a good cleaning and oil treatment. Take pictures again of the valve seats once you have all the valves out. Keep talking to us. Good work on disassembly, Hanley

[Laker]

C. Dog ,

To clarify your statements , are you saying that the # 3 PISTON is not moving up and down when you rotate the crank ?

In your tappet picture I see two valves stuck in the same cylinder. Do you mean valves , or piston?

[hanleyclifford]

Laker - Good catch. Seems like Neil and I got different understandings from the same post.

[ndutton]

#3 cylinder refuses to move at all as I turn the handcrank,

Yeah, I took it literally. If the piston's moving and not the valves, ignore my previous post.

[roadnsky]

#4 intake & exhause valve work perfectly, both closed with the cylinder at the top

#1 cylinder moves up and down freely but one of the valves (can't remember which) instead of going down on the next stroke, goes further in the opposite way, but then will go down if I tap it with a screwdriver.

I think he differentiates between PISTON (cylinder) and VALVES in his #4 and #1 discussion.
But, I'm sure he'll tell us...

[Cave_Dog]

It's Piston #3, I will take pictures later today. I did in fact mean that the PISTON (cylinder) does not move at all, but as I RECALL the valves both work, although out of sync. But, as was mentioned, the #4 PISTON is moving freely and those valves work perfectly. Everything else is chaos. So what was the next step, removing the valves and checking them out, figuring out a way to get BENEATH my cylinder, etc?

UPDATE: To be more specific, I had to slightly turn the sticking valve on the #1 cylinder and it would slide into its seat. After doing this several times, it actually started to work itself. This means my only two problem cylinders are #2 & #3.

SPECIAL THANKS for the kind notes, it took me literally forever to do this because it was my first time removing the head.
Thanks to all
Cave Dog