TEA-20 Stuck valves - head off?

boingy · Jan 7, 2017

The plan for today was to finish fettling the petrol tank and related stuff, then take the opportunity to have a quick poke around under the rocker cover before the tank goes back on. It was not quite as perfect as I had hoped.

We've got three stuck valves. One exhaust stuck closed and one of each stuck open. Unless anyone has a magic method of freeing them I guess the head needs to come off.

So, the questions:

1. Any way to free up the valves?

2. Will it be most likely be rust on the stems?

3. When the head comes off, what happens to the water pump? I though it was bolted to the head but it gets no mention in the manual.

This is a tractor that we're told has not been started for around 35 years. What we don't know is why it was mothballed or whether any one has *tried* to start it since then....

cdmn · Jan 7, 2017

After that long, it should be looked at. Who knows what the wild critters
have hidden inside.

A little heat, with an electric heat gun, for example combined with some high quality gun lubricant, and light tapping might get them free, but the seats may be corroded.

I've had engines start on a few cylinders, but as the water-jacket warms up, the stuck valves
begin to pop loose. Not after 35 years though.

BushogPapa · Jan 7, 2017

Rocker arms OFF, fill the cylinders with ATF and Patiently nurse those stuck valves with a SMALL brass hammer and plenty Penetrating oil..

With enough patience you hay get them to get loose..

DO NOT Hurry it or drive them down...just tap to encourage the Penetrant to flow...

Sure, Head off IS an option...

Steve@Advance · Jan 7, 2017

That the engine will turn is a good sign that there probably hasn't been liquid water sitting in the cylinders.

Yes, the valves are stuck from rust. Valves sticking open is a common problem, but a valve stuck closed indicates some serious rust!

What gave up when it turned through? A bent push rod? Broken rocker?

You have nothing to loose but some time trying to get them loose. Remove the rocker shaft assy. Get some penetrating oil started going down the stems, start pecking at them with a soft hammer...

Some oil in the cylinders will help too, get the rings freed up while working on the valves.

Good luck!

boingy · Jan 8, 2017

Thanks folks.

We're in no rush so we'll certainly try a bit of releasing oil for a week or so. (Current favourite recipe is 50/50 ATF and acetone).

Steve, I had not considered the implications of the one that is stuck closed so we'll have a good look at the related bits today.

I have a feeling we'll end up taking off the head in the end but, like I say, no rush and the water pump thing is still bothering me. Everything I've seen in print and in videos shows the pump staying behind when the head is removed but on ours it looks for all the world like it is bolted directly to the end of the head.

504 · Jan 8, 2017

I soak the stems and try to get some spray in the cylinders on the valves. Tap the stems with a hammer ,I like a good rubber mallet or brass one. If you have one stick down feed a length of 3/8 nylon rope in the spark plug hole, rotate the engine and rock it to bring the valve back up. Too hard and you will bend the valve take your time tap it down and then push it up with the piston and rope. The last one I did took two days to get the valves free,it ran fine after I freed them up.

TEA-20 Stuck valves - head off?

boingy

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cdmn

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BushogPapa

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Steve@Advance

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boingy

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504

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