Repair of Police (B) Head..

[F.M.]

I have two of them, Both cracked in the combustion chambers.. Are they worth trying to fix ? if so how ?. Been told by one shop that they have not had much luck trying on other heads..

[jw hash]

I have two of the same, and one I have over $300 in it trying to save it and they are just a conversation piece,

[Pete]

They can be torch welded.
I wouldn't trust any other method.

[J and M Machine]

Originally Posted by F.M.

I have two of them, Both cracked in the combustion chambers.. Are they worth trying to fix ? if so how ?. Been told by one shop that they have not had much luck trying on other heads..

We can metal stitch them as there is no stress to the head as we are drilling and pinning the crack rather than induce heat to repair it.
http://www.jandm-machine.com/metalStitching.html

[CarlG]

I have one as well. It's cracked in the thin water jacket (it froze with only water in the engine, no antifreeze.) It was that way when I got the pickup. Right now it's yard art!

[1928Mustang]

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Can you please send me a picture of the crack.


Thank you Brian

[dumb person]

Depending where the cracks are they can be drilled & pinned.
It's what I've done on heads anyone else would throw away.

The lock & stitch things are pretty good.

[Pete]

You said the cracks were in the combustion chamber.
Stitching has a VERY poor chance of working there.
Anywhere else on the head stitching would be ok.

[Joe K]

And given the price of stitching, or even welding - it may be more cost effective (and more certain) to simply buy an aftermarket high compression head.

I am reminded of welding an aluminum skylight frame. 1/8 section at four corners and a filler piece along the short side.

$450 was the quote locally. "I get minimum $125 an hour for welding aluminum."

Welding CAN be expensive. Maybe especially so when you're talking pre-heat, inter-pass peining, and post weld heat treatment. All possibly "chargeable time."

Even the weld materials. Eutectic brand cast iron rod runs $125 a pound - back in the 1990s.

So I bought the kit for my MIG and learned how to do it myself. But I had the luxury of time, a MIG, and could invest $100 in the conversion kit for the MIG and $125 for the full Argon bottle as a sort of gamble. Fortunately on this one I won!

Joe K

[J and M Machine]

Originally Posted by Pete

You said the cracks were in the combustion chamber.
Stitching has a VERY poor chance of working there.
Anywhere else on the head stitching would be ok.

Wow: I guess we'll have to call this customer with Pierce Arrow and tell him to throw the head away we've repaired.
Because stitching doesn't work?

Actually stitching is the best means to repair old cast iron. Example shown of somone trying to braze the crack only made it worse. We in turn cut out damaged area and made pieces fit them and then stitched them back in. This was years ago.
This head was attempted to be repaired and did more damage by adding heat to combustion chamber making areas brittle. Cut out damaged areas made pieces in the combustion chamber and car is still running without water leaks.

Yes We make a living repairing these so I may be slanted in our opinion but in our defense; stitching works and once painted only you know it's there.
Think twice regarding welding.

http://www.jandm-machine.com/metalStitching.html
P8020039.jpg

PA240056.jpg

[Pete]

Originally Posted by J and M Machine

Wow: I guess we'll have to call this customer with Pierce Arrow and tell him to throw the head away we've repaired.
Because stitching doesn't work?

> We will see how it is down the road a bit.

Actually stitching is the best means to repair old cast iron.

> That statement could get you in big trouble someday.

Example shown of someone trying to braze the crack only made it worse.

> That is generally very true. While brass will work in many cases, it is old
technology and not used too much any more.

We in turn cut out damaged area and made pieces fit them and then stitched them back in.

> I have stitched pieces 18 inches long and 10 inches wide in the side of
Caterpillar D8/D9 blocks where rods went through, and you could not tell it
had been repaired from the outside.

This was years ago.

> Likewise.

This head was attempted to be repaired and did more damage by adding heat to combustion chamber making areas brittle. Cut out damaged areas made pieces in the combustion chamber and car is still running without water leaks.
Yes We make a living repairing these so I may be slanted in our opinion but in our defense; stitching works and once painted only you know it's there.

> Many moons ago, I was the first employee of the now biggest diesel engine
repair facility in the world.
I would not paint a combustion chamber. Waste of good paint.

Think twice regarding welding.

> When a job came in I never had an opinion on it. I am qualified to look at it
and say it should be repaired a certain way.
I would have torch welded that head with cast iron rod. You couldn't tell it
had ever been repaired and no chance of any pins leaking down the road.
You are right though, if you don't know welding, you should not do it.

http://www.jandm-machine.com/metalStitching.html
Attachment 396913

Attachment 396914

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[eagle]

If you have experience gas welding and you have a piece that you would otherwise throw away, why not give this a try: First drill the crack ends. Take some old piston rings and break them in half. Put the head in a gas grill until hot, open the grill with flame still on and using a good hot torch, heat the crack until poking it with the rod (broken ring) it starts to get putty consistency. Then melt in rod, keeping it just the consistency of putty. Scrape/mix it into the crack. When done close the grill lid and slowly turn down temp over some time. Grind if rough. I've done this with amazing results. I've had people declare me an idiot over it too but it works and works well. The trick is to get the heat right so the putty consistency is there. I learned this at a booth at EAA flyin Oshkosh. The guy there would teach anyone who would listen. Was selling Acetylene torches.