Miller Trailblazer 55G further questions...stuck valve

Gunner:

This seems to have been crossposted to amc from an ongoing conversation in rcm. Try to determine that the piston is not near TDC, loosen the rocker and move it out of the way (assuming a stud mounted rocker), and just WHACK the valve stem with a plastic hammer or rawhide mallet.

The valve in in an L head engine..no rockers. The valve runs parallel ot the piston bore and is operated by a cam shaft that runs parallel to the crank.

Gunner

Gunner:

Ahh, I see. A flathead. Well don't stick a metal screw driver between the cam and the valve stem, too much chance of scoring the cam and/or valve stem. Get an 1/4" think aluminum flat plate only wide enough to fit between the cam and valve stem, disk sand a gradual taper on it and wedge it between the cam and valve stem. What's the thing in the far left cylinder? It doesn't even look like a piston?

See if you can't find some Kroil and soak the rusted areas with that. I would be surprised if you didn't have success. You will have to let it soak for several days (and keep adding more if you see it disappearing).

Gary

Have you tried heating #1 area on the head with a torch? That might loosen it up a bit. Can you get "Liquid Wrench" or some such into the valve guide? Next thing you might try is removing the camshaft and lifter completely and pressing the valve out with an arbor press or hydraulic press. That would beat pounding on the thing and chancing slipping and damaging something else.

Jim

Its about 4 ounces of Marvel Mystery oil mixed with rust, sitting on top of the piston.

There are Cam Lifters, round cylinders that have the tappet adjuster, that go between the actual cams and the valve stems. With the tappet adjustment all the way open, there is about 1/16" clearence between the top of the adjuster and the bottom of the valve stem

Its a Continental F-163 engine, pretty common in forklifts and welding machines. It sat for a long time. However..the rust is bothersome, as there is a full muffler at a right angle to the exhaust stack..and water should not have gotten in via the exhaust system. It leads me to believe that the head gasket was leaking in the area of #1 (left cylinder) and because of the design..it could ...could travel into the other cylinders. #1 cylinder walls are rusted, but its moderately easy to remove with a fine brass wire brush.

Anyways...that rusted solid valve....

Gunner

Kroil dude, once you've tried it you'll be a believer too...

Ill hunt up some.

Gunner

take your Oxy torch and heat the valve up - they are designed to tolerate some heat - heat it near the center so you are getting heat onto the stem. Bring it up to where you can just barely see a dull red glow, then use the aluminum wedge others suggested to lift it - press smootly, as it cools it should start to move - don't mess iwth the head when it's hot or you may bend it or otherwise damage it. If all else fails, arc weld a nut to the head of the valve so you can get it to move with a big puller, then once it's a little free, remove the keeper from the bottom of the valve and pull it out, inspect guide and if needed pull it too and replace.

I got 3ea of the brass brushes trimmed down to your bore and a 1/4" spindle installed. They gathered a bunch of end brushes and started assembly on some impact brushes. Should ship Mon. or Tue. I'm still playing musical doctors, that's my story and I'm sticking to it!

Heat + Kriol! IIRC, the guides are bronze. Heat the valve from the top and shock it to get the Kroil to climb better and get in from the top. Kroil burns real good, we used to have spray bottles until people used them for flame throwers.

Did they switch over to the "creamy" lubricant? That would be like Napalm! LOL

I try to discourage such things but I'm usually the main culprit.

Take the manifolds off, if haven't already. Then pour the Kroil into the port.

HEAT the valve and seat up some. Then heat up the bottom of the guide some. Let it cool down and set a couple dry ice pellets on the valve. The thermal change should be enough to free the valve. You should be able to save the valves and the rest of the parts as long as you don't break the parts.

Be careful not to break the camshaft when prying! Lots of good suggestions already given. It might help to hammer on the valve head, especially with an air hammer, even though it is already down. You might try some gentle tapping on the side of the valve stem. You can remove the valve keepers to remove some of the restraint on the valve (dont let them drop into the pan). You also might try a rotating tapping against the edge of the valve head. If you have the manifold off you might get a punch under the valve head. As I am sure you know, once you get any movement it will nearly always eventually come free. Penetrating oil, heat, and vibration eventually work for me.

Don Young

Thanks Tom

Got a mag based portable EDM capable of burning out a valve stem?

Sigh.....

Cast iron valve guides. See other post with links to carnage....