VH4D with burned valve and stuck head

I have a VH4D in a bobcat model 600. The engine has zero compression in cylinder 4. I think this happened when a mouse made his home in the air cooling duct and restricted cooling air flow. Four of the bolts holding the head down have snapped off and I can’t get the aluminum head off now. I Dare not pound on it anymore for fear of breaking it.

Does anyone have a VH4D for sale? Any idea how to get the head off? Can a valve be lapped with the cylinder case still bolted to the block?

Leop ---

Put 3 or 4 head bolts back in ,leave about 3/8" space between bolt head and the engine head....put the spark plugs in so the good cyl. has compression....

remove the coil wire and bump crank the engine over with the starter......idea is let the compression pop the head loose....

He is removing the head because of no compression. Pull spark plug, push some rope into cylinder and bump.

That's common on those engines. Just drill the bolts out where they pass through the head p then the head will come right off. As to the lack of compression - most likely a valve stuck open - not burnt. The "D" in VH4D indicates it has Stellite exhaust valves which are pretty rugged. You probably need to pull the stuck valve out, wire-brush the stem, clean the guide, and put back together. For cleaning up the valve-seats if needed - a hand-powered carbide-cutter is usually all that is needed.
In regard to finding heads - there are easy to find. There are many junk Wisconsins laying around. You can buy used - or new. The former Teledyne Wisconsin is now Wisconsin LLC company and sells both Wisconsin and Continental engines and parts.

The "D" means distributor ignition. Without the D, the original ignition would be a magneto.

Here is a manual for that engine.
Manual

As least on this subject - you are way off. I was a mechanic for a large Wisconsin engine dealer not long after the Stellite valves and seats became an option for repairing older engines, and standard equipment on all new Wisconsin engines with a "D" at the end. "D" stands for Stellite exhaust valves - and NEVER indicated "distributor" as you state. Many older Wisconsin engines, built before the D-series -were available with magneto, battery-distributor, generator with a piggy-back distributor, etc.
A.F. Milbrath was the chief engineer and vice-president of Wisconsin Motor Company around the time they started using Stellite. I still have copies of the company's press-release and explanation of the new D-series - along with some articles written by Milbrath on the subject.

Also - just about all the older Wisconsin repair and parts manuals explain this - telling the owner what the "D" means. Look at any of the TE, TF, VE, VF, books, etc. The VH engine was a newer design and, as I recall, by the time it came out Stellite came standard. So, I don't think there ever was a VH4 - just a VH4D. The older engines came both ways - e.g. TE or TED, TF or TFD, VE or VED, AEN, or AEND, etc. &c.


"Models with a "D" at the end is the same as the basic model. It just means it has a stellite exhaust valve(s) and seat(s). Stellite exhaust valves and seats have a coating of cobalt material which is much more resistant to premature failure due to high combustion temperatures. You can tell which ones you have as stellite valves and seats are non-magnetic and the coating is applied to a stainless steel (non-magnetic) base material.
"

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First of all thank you to everyone that posted help for me. You are all very generous to take the time to help me.

Let me clarify a few things for you experts out there to make sure I am on the right track.

I noticed the loss of power directly after adding in RESTORE engine lubricant. I used it because the engine was huffing and puffing a lot of smoke and oil out of the breather tube and making a mess. I also filled the crankcase with 20W-40 oil.

My first assumption was that the RESTORE and thicker oil had caused a valve to become stuck. However when I pulled the access cover to the valve springs off, both valves appear to be moving just fine and both lifters are rotating. Does this mean the valves are not stuck? I would assume that if one was stuck that it would at least be tapping when the engine is running? None of the valves are tapping.

After the above experiment I pulled the air shroud for that cylinder head off and discovered that a mouse had made a nice little nest in there. This led me to assume that the nest had blocked enough air flow so as to overheat that side of the engine. I also noticed that both plugs where very hard to remove from that side of the engine.

I would love to have dirty valve stem as opposed to more serious damage. Given the above description do you think it’s a stuck valve or something worse? Should I try draining the restore and running something thinner through the engine to see if it frees up the valve?

Is there a way to remove and clean the valves without removing the cylinder head from the block?

As for drilling out the bolts, how do you keep the drill bit centered on the bolt so that it doesn’t drift over to the head and cut the softer aluminum instead of cutting the bolt? On a mill this would be easy but with the engine still in the tractor and the cylinder head still bolted to the engine I have to use a hand drill.

Thank you so much for all the info. Its fire season out here and I really need the unit up and working to clear before the next big fire hits us.

Sincerely,

Leo

Drilling the bolts isn't so easy with the later engines. The older Wisconsins had cast-iron heads, soft valves, and split-skirt pistons. The later ones - D series - have aluminum heads, Stellite exhaust valves with rotators, and cam-ground aluminum pistons.
Best bet with your soft heads is to use drill guide so you can drill a small hole in the center of the broken-bolt. Then, remove the guide and the hole will keep larger drill-bits centered. With the steel-alloy bolts against the aluminum head - electroylsis causes them to fuse together. So, the threaded part of the bolt in the cast-iron block may not be stuck as bad as the shank where it passes through the aluminum head.
In regard to your valves - if one was sticking partially open - you wouldn't hear any ticking. But, this sort of thing tends to happen after an engine has sat for a long time - and gotten rust on the valve-stem. It can also happen another way from overheating - but usually when that happens - the valve sticks when hot - but then frees up once the engine is cool.
Any valve work on the valve seat or face requires pulling the head. Sometimes you can free a stuck valve though - just by reaching in beneath the tappet-cover.
In regard to your oil being thick? No, if anything it's a little thin. That engine is designed to run with straight 30W in any temps over 40 degrees F. I don't even think it has a pressure-oil system - but I don't recall off-hand. Most of the Wisconsin twins and V-fours don't use pressure oil for lube - just use the oil pump to squirt oil on certain parts. But - some of newer engines were changed a bit - and a few had drilled crank-journals with oil ports.

"So, I don't think there ever was a VH4 - just a VH4D."
I did not at all dispute the type valves in the engine. My experience with this engine is limited to ownership.
VH4

Solid-state ignition is not on the earlier distributors.
VH4D

"NOTE: Some model #'s may have a ""D" suffix. This just means it has a stellite exhaust valve. E.G. Model BKN & BKND"
Found this one a parts listing on a website. Mr. Demaris is correct about the Stellite exhaust valves.

My Wisconsin dealers Master Parts Book, 6 inchs
thick, does not list any VH4, Only a VH4D.
The D suffex, is, for hardened valves and seats.
The engine was available with Magneto, or
Distributor ignation. A built in flywheel
alternator, for battery charging, was an option.

Wisconsin's do not like multi-grade oils and unless you were using 10w30 you did NOT put in a thicker oil. The first number is the only one that really matters. Any time after April mine get straight 30, july/Aug. 40. Did you compression test? With the blowing oil I'll bet on broken/collaapsed ring where the air was cut off.