Looking for advice on an Atomic 4 repair / replacement

[infy]

If the head is warped it has to be machined or replaced because it won't hold compression when reinstalled. You use a feeler gauge and a straight edge in a cross corner to corner to check if clearance is in spec.

[infy]

Doing some initial cleaning on the block deck... the valve seats don't look great. I would bet the underside of the valve heads are cooked.

I'm going to try a new spring compressor to pop them off... I may just get the one from MM

[ndutton]

The head has nothing to do with the valves sticking. I am not sure I get the connection

I have to agree, this is hard to follow. We just jumped from valve keepers to head surfacing and it's not the first time. It seems we don't finish anything before jumping to something else.

This started as a zero compression issue with the general consensus of the forum membership that sticky valves were the likely cause. We talked about how to turn the engine to find TDC in a Catalina 30 and I don't recall any resolution to that discussion. We talked about using a feeler gauge to measure for stuck valves, no resolution to that either and then the valves are on their way out of the block without a diagnostic measurement. Now the head is going to a shop for possible facing/milling? What happened to the stuck valve hypothesis? We don't even know for sure if that was the problem and it doesn't look like we ever will.

Sorry . . . .

[infy]

I have to agree, this is hard to follow. We just jumped from valve keepers to head surfacing and it's not the first time. It seems we don't finish anything before jumping to something else.

This started as a zero compression issue with the general consensus of the forum membership that sticky valves were the likely cause. We talked about how to turn the engine to find TDC in a Catalina 30 and I don't recall any resolution to that discussion. We talked about using a feeler gauge to measure for stuck valves, no resolution to that either and then the valves are on their way out of the block without a diagnostic measurement. Now the head is going to a shop for possible facing/milling? What happened to the stuck valve hypothesis? We don't even know for sure if that was the problem and it doesn't look like we ever will.

Sorry . . . .

Guys, there's more to an engine than valve clearance. Screw the valve clearance. You need good valves and seats before you can worry about that.

Check out the photo above. The valve seats are cooked. Destroyed. No valve clearance adjustment is going to make this engine run again.

Valve clearance is one of the last steps to a top end rebuild. You don't do that until after checking to make sure the valve seats, valves, springs, and etc are in good order...

As for manually turning over the engine.. there were 2 resolutions:

1. Yes you can put it in to gear and rotate the prop shaft.

2. You can cut an access hole to the flywheel and modify a socket to adapt. Or buy the official tool from MM.

[joe_db]

All true, but an A4 does not have a "top end" like a car, the valve seats are in the block. If you have the head off anyway by all means have it checked for being warped, but that is a totally different issue.

[infy]

Here's another valve seat. They all look to be damaged. I showed the photos to a friend who works at a machine shop.. he's not optimistic on having the block machined at all.

I'm going to try and see if I can find anyone willing to quote the work just to see the bottom line.

[infy]

Thought I'd give anyone following a bit of an update. I called around to 5 or 6 machine shops. Almost nobody has the equipment to machine valve seats on a flat head engine anymore. Everyone has moved on to machining valves on heads. I did get referrals to shops who could potentially do it, but they all refused the work.

They said that from their past experiences, they are highly likely to strike water due to water jacket and other corrosion.

But yes, this block can in theory be machined by drilling out and installing new valve seats.

[lat 64]

Wow, I stand corrected on the valve seats. What a weird bit of corrosion. It looks like rust, but wrong color. Was there any acidic rust stabilizer used in cleaning this?

Its disappointing that you can't get a machine shop to help. The equipment for grinding seats on side-valve engines is the same as overhead valves. The A-4 is particularly easy to do, just lift it up on the bench and have at.

[infy]

Wow, I stand corrected on the valve seats. What a weird bit of corrosion. It looks like rust, but wrong color. Was there any acidic rust stabilizer used in cleaning this?

Its disappointing that you can't get a machine shop to help. The equipment for grinding seats on side-valve engines is the same as overhead valves. The A-4 is particularly easy to do, just lift it up on the bench and have at.

Nothing corrosive. A blade and brass brush. Same marks on the head.

Best guess is this engine was probably run for a long time on bad/wrong spark plugs or with carbon deposits. Damaged by detonation/pinging.

Change your spark plugs people make sure they're to spec.