Cylinder Head Deck Repair

[Vintagewrench]

49174929771_5458bd1c11_b.jpg

This vintage Volvo racing cylinder head has one issue that needs to be taken care of before proceeding forward with rebuilding it. At some time in the past when someone moved it the deck surface between two of the cylinders got scratched and there is also another mark below it as can be seen in the photo. At the widest point the scratch is about .030" and while it is hard to measure it the depth it appears to be no more than .005" to .010" deep.

The best way to get rid of it would be to mill the head to remove it, but since its all ready been milled .140" and the CR is 13:1 its thin I'd rather not mill it or fill the area with a pin. A Cometic .035" thick gasket with 3-layers and a thin black coating will be be used and will cross both of the marks.

The question is there any type of high-temp epoxy or another type of a compound that could be used to fill it and also seal against the pressure of combustion and stand up to racing use??

[strokersix]

What is wrong with filling it with a pin right at the fire ring? Seems to me that would work fine.

[Vintagewrench]

What is wrong with filling it with a pin right at the fire ring? Seems to me that would work fine.

Nothing wrong with using a pin as I mentioned before. The issue is the spots were it needs be pinned are thin which could make it difficult to peen the pins to get them seal against the threads after installation. A sealant also can be used but its better if the seal is metal-to-metal.

[Cubic_Cleveland]

What’s wrong with welding the marks up and re-surfacing?

[mag2555]

A good preheat and Spray weld is the route I would take followed by a mill which would only need to knock off another .001" from the deck.

[tenxal]

The question is there any type of high-temp epoxy or another type of a compound that could be used to fill it and also seal against the pressure of combustion and stand up to racing use??

J.B. Weld 'High Heat' is what you're looking for. Make sure there are no raised edges along the scratch. If so, lightly dress them down to the deck surface. Skim coat the product along the scratch and remove the excess with a sharp razor blade so all that's left is the filled scratch. Mineral spirits rubbed on the razor blade helps 'cut' the product so it won't 'lift' out of the scratch as you go across it. After it dries, you can lightly dress it with some wet 600 grit paper. I used it to save some very expensive and impossible to find castings years ago. They are still in service today.

Hope this helps.

[Vintagewrench]

What’s wrong with welding the marks up and re-surfacing?

First off, thanks to everyone who has responded.

Nothing, although the deck on the outside of the combustion chamber walls is thin and warpage could be an issue.

A good preheat and Spray weld is the route I would take followed by a mill which would only need to knock off another .001" from the deck.

Thats a good idea, but again I'm worried about warpage from the preheat,

The question is there any type of high-temp epoxy or another type of a compound that could be used to fill it and also seal against the pressure of combustion and stand up to racing use??

J.B. Weld 'High Heat' is what you're looking for. Make sure there are no raised edges along the scratch. If so, lightly dress them down to the deck surface. Skim coat the product along the scratch and remove the excess with a sharp razor blade so all that's left is the filled scratch. Mineral spirits rubbed on the razor blade helps 'cut' the product so it won't 'lift' out of the scratch as you go across it. After it dries, you can lightly dress it with some wet 600 grit paper. I used it to save some very expensive and impossible to find castings years ago. They are still in service today.

Hope this helps.

Interesting, never knew J.B. made this version. Have you ever used it to seal against the pressure and heat of combustion?

Anyone who has used Belzona 1511 (Super HT-Metal) with this type of a issue? https://www.belzona.com/en/products/1000/1511.aspx

[gmrocket]

has there been any grinding work on the head since it was last run? because that looks like a die grinder burr skid mark from someone being careless.

so if it ran ok since being pulled apart , i suspect that was there before, what head gasket was on it before?

[FC-Pilot]

The question is there any type of high-temp epoxy or another type of a compound that could be used to fill it and also seal against the pressure of combustion and stand up to racing use??

J.B. Weld 'High Heat' is what you're looking for. Make sure there are no raised edges along the scratch. If so, lightly dress them down to the deck surface. Skim coat the product along the scratch and remove the excess with a sharp razor blade so all that's left is the filled scratch. Mineral spirits rubbed on the razor blade helps 'cut' the product so it won't 'lift' out of the scratch as you go across it. After it dries, you can lightly dress it with some wet 600 grit paper. I used it to save some very expensive and impossible to find castings years ago. They are still in service today.

Hope this helps.

I have seen this work and have done it myself with positive results. I did it on heads that had receiver grooves for o-rings in the block, but the heads were then used on a block with no o-rings so the receiver grooves were filled with JB weld and sealed fine. I first saw it on an engine with two stages of nitrous and MLS gaskets. After seeing that I then used it twice myself on my own naturally aspirated engines. Yes, a little hokey, but worked well. I only used standard JB weld as I did not know there was high heat stuff.

Paul

[mag2555]

You only need to preheat to like 400 degrees ,but the heat up and cool down from 200 degrees up or down needs to be done slow to have no warpage take place.

[tenxal]

Interesting, never knew J.B. made this version. Have you ever used it to seal against the pressure and heat of combustion? Anyone who has used Belzona 1511 (Super HT-Metal) with this type of a issue? https://www.belzona.com/en/products/1000/1511.aspx

Yes, I've used it....worked great. I haven't used the Belzona product you referenced but it looks like it would do the job. Let us know what you end up doing and some pics.

[Vintagewrench]

has there been any grinding work on the head since it was last run? because that looks like a die grinder burr skid mark from someone being careless.

so if it ran ok since being pulled apart , i suspect that was there before, what head gasket was on it before?

The head hasn't been on an engine for over 30 years and the head gasket is long gone. It was used on a '67 Volvo F/Production 1800s that won the New England region SCCA Championship in the late-1960s so all of the clues are long gone.

[/quote]

I have seen this work and have done it myself with positive results. I did it on heads that had receiver grooves for o-rings in the block, but the heads were then used on a block with no o-rings so the receiver grooves were filled with JB weld and sealed fine. I first saw it on an engine with two stages of nitrous and MLS gaskets. After seeing that I then used it twice myself on my own naturally aspirated engines. Yes, a little hokey, but worked well. I only used standard JB weld as I did not know there was high heat stuff.
Paul
[/quote]

Thanks for sharing, that's interesting.

You only need to preheat to like 400 degrees ,but the heat up and cool down from 200 degrees up or down needs to be done slow to have no warpage take place.

Thanks for the run-down.

[/quote]
Yes, I've used it....worked great. I haven't used the Belzona product you referenced but it looks like it would do the job. Let us know what you end up doing and some pics.
[/quote]

Thanks, we will let you know how it gets repaired and the outcome.

[Dave Koehler]

The long mark between chambers looks like a grinder slip as others have said.
It is so shallow I don't see it as an issue AND it's not deep enough for the epoxy fix to get a good grip.
The other is hard to determine the depth so I have nothing to offer.

Will a .005-.007 cut really make a lot of difference in head flex?

[Vintagewrench]

Will a .005-.007 cut really make a lot of difference in head flex?

It may because the area between the the arrows (below) in the photo is only .050 thick, cut down from about .20" thick because the deck has been milled .140"

The mark inside of the circle is for the most part behind the HG fire ring.

AMark.jpg

Enlarge the photo (below) which visually shows how much has been cut off of the head. It is on top and an uncut head head is below it.
Take notice of the thickness of area where the two tabs face each other in the center of both heads.

A.jpg

[gmrocket]

The long mark between chambers looks like a grinder slip as others have said.
It is so shallow I don't see it as an issue AND it's not deep enough for the epoxy fix to get a good grip.
The other is hard to determine the depth so I have nothing to offer.

ya, i think it was there before from a grinder slip and ran like that. i think a composition style head gasket would conform to that no problem

Will a .005-.007 cut really make a lot of difference in head flex?