Rebuilding Cylinder Head

glenmorebuckman · Dec 8, 2017

How big of a job is it to rebuild a head on a TO-30? Is this something I can do myself or should I have it done at a machine shop? My tractor smokes after being at idle for a while and when it's working when it gets in certain positions such as going downhill. It's definitely oil smoke so I'm thinking worn valve guides or oil seals.

Steve@Advance · Dec 8, 2017

Working a head is best left to the pros with the proper equipment.

What kind of smoke are you seeing? Those engines pump very little oil up to the rockers, so oil down the guides is minimal even when worn.

Any possibility you are seeing rich gas smoke? High float level?

Jerry/MT · Dec 8, 2017

On a gasser, if your valve guides are worn they will suck oil down the intake valve at idle where the manifold vacuum is a maximum and the smoke will reduce when you operate under load with more throttle because the manifold vacuum is reduced. If you are seeing the same amount of smoke regardless of the load on the engine that is usually indicative worn or stuck rings.

I agree with Steve about letting someone with the right equipment and the experience rebuild your head.

glenmorebuckman · Dec 8, 2017

It's oil smoke no doubt. If it hasnt been started in a while, it will smoke real bad on start up and will have a little bit of a miss but will slowly clear up when throttle is increased. It starts smoking bad at an idle too. I plowed 1 acre of ground last fall and it hardly ever smoked until I would get on a slight downhill grade but coming back up it never smoked a bit.

Ron(Ont) · Dec 9, 2017

Have you done a dry and wet compression test yet? If you get much increase in pressure after the oil, your problem is more rings than valves.

Tom H. · Dec 9, 2017

I've had two heads rebuilt by a local race motor mechanic and they are the best running engines I have. Another went to a machanic that builds NHRA 1000+ hp engines and that is still on the shelf waiting to be put back together. Job runs 250-400 bucks but well worth it.

glenmorebuckman · Dec 9, 2017

I'll get a compression tester and give that a try. The engine was completely rebuilt by me and my uncle about 15 years ago and used 2 seasons
in tobacco, then the water pump went bad and the tobacco crops ended so it sat in the barn for 10 years not running. I purchased it after my
uncle passed and put a new water pump on it and have been using it every since. The smoking just started last year.

PackardV8 · Dec 9, 2017

Easy things FIRST. try retorqueind the cylinder head bolts.

If engine was rebuilt not many hours ago then should not need any head refurbishing.

Check valve stem seals, especialy on intakes. Should be able to replace seals without removing head.

Bruce(OR) · Dec 9, 2017

What your describing sounds like valve seals more than anything else. A bit of smoke on start up, nothing while running at speed and if it idles for any amount of time, it smokes again a short time until you get back up to speed. If it smokes continuously, you have bad rings. Since your not continuous, you don't have bad rings and don't need a compression check. Your smoking on an angle means that end of the engine has the worst seals on the lowest side and the valve seals which have dried out and are no longer keeping the oil out of the cylinders.
So...Shut off the engine, pull the plugs. Mark the dist cap where the rotor lines up with the cylinders. 1,3,4,2. With the rotor aimed at #2 on the cap, insert rope into #1 cylinder. Rotate the engine around and that will bring the piston up and uses the rope to hold the valves closed while you replace the seals on the valves. After your done with the cylinder, rotate it around an repeat it for the next cylinder. Keep going until they are all done. Plugs back in, valve cover back on and fire it up.
Might smoke one last time.

glenmorebuckman · May 4, 2019

Good afternoon Gentlemen,
I'm just now getting around to working on the head. I pulled the valve cover off and took some of the intake valves loose using the rope method and found that the valves seem to have a lot of play in the guides. I decided to get a valve job done next week. I decided to check all the valves and seems like they are all pretty sloppy in the guides. One question though, Do the exhaust valves use a valve seal? One exhaust valve had an oil seal on the valve but none of the other exhaust valves did.I noticed in the valve kit I ordered it comes with eight seals.

Rebuilding Cylinder Head

glenmorebuckman

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Steve@Advance

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Jerry/MT

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glenmorebuckman

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Ron(Ont)

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Tom H.

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glenmorebuckman

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PackardV8

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Bruce(OR)

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glenmorebuckman

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