VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 Cracked heads

I am being told that the 4 cylinder heads are notorious for cracking. Assuming this is true, are the 27 heads included? I understand that there were some improvements made in the late 27 head.

I had a stack of 1927 and 1928 cylinder heads, about 10 to 12 in all. In checking each cylinder head not one was salvageable. They were all boat anchors because of the numerous cracks.

Don't know of a single port 4 cylinder head that is not likely to be found with cracks. Those are 1927 and earlier. The two port '28 heads are much less apt to crack. I have not checked all that I have but only found one that had a non-repairable crack problem when it was checked.

So are you saying that the cracked heads can be run without difficulty

That is not what I was trying to say. Rather a high percentage of pre-'28 heads are cracked and not useable. Much less '28 heads are useable. Some may have small cracks in the valve seats that are saved by installing new valve seats.

Mine is the 27 head and it was cracked in several places. I found a old guy that specialized in fixing heads and blocks that are hard to find. He cut open the top of the head, welded and brazed the crack and than floated porcelain inside the head, pressure tested it. I have not had a problem since then. Its not cheap, but if you want to keep it original its worth the money. You can find used heads but most of them are cracked. It cost me $400 to have it fixed.

Very interesting to hear of a successful repair. You do not say where or why the head was cracked. Here in OZ it is practically always heat cracking inside the exhaust port where it usually cannot be reached for repairing.
We tried oven heating heads to red hot and all manner of magic repair welding systems etc all to no avail. It seems the metal in the crack area of the port has been affected by the gasses and heat of combustion and we could not get it to take weld of any kind. External cracks were easily repairable such as those from freezing damage.
In all we collected 35 heads and not one was repairable, all cracked inside the exhaust port. But of course that is why they were lying around in the first place. The best place to get a head is off an engine, the assumption being it was still serviceable when last used.
Good used, or new heads seem to be available in the US. Here, despite the thousands of Chev Fours in service in their day, good heads are to kill for. I'm sure if it were a "F" problem a modified improved version would have been made years ago. GM milked the spare parts cow in the day and never came up with an improved version. There were even OZ made versions available outside the GM parts supply which were better but nevertheless still used to crack eventually.
Afraid I can not offer any answers other than keep looking! Be careful buying old heads because the cracks are not visible and is how we ended up with 35 of the blighters! We found the best procedure was to sand/abrasive blast inside the port only (therefore cheap) after which major cracks were easily visible. Then if the head looked OK dye testing was used to see if very fine cracking was starting and if that proved OK then the whole thing was blasted including inside the jacketing. Then the machinists for guides, seats etc had nice clean material to work with.
Reproduction heads would likely fix the problem with a bit of porting and better quality casting iron. Alas no one has seen our plight as worth the effort given that one universal head design could likely be made to fit all models up to '28.
Of course a '28 head can be made to fit your engine without too much drama, and give better performance because of different valve size, opening and breathing. But here they too are as hard to find as good single port heads, being only a one year production run and it being a common fix in the day.
Cheers,
Geoff.