VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1926 Cylinder head 4 cyl

Does anyone have a cylinder head that is not cracked for sale. I think that is my overheating problem.

i just went through the same thing on my 26 . i went through six heads before i found one that was not cracked . they usally crack inside the exhaust area where you can t see or magnaflux you have to air check . i got to where i would not buy any unless i air checked it first or a money back guarentee.most get insulted if you offer five dollars for the head but they say its has been magnafluxed look at it . i have six out in the shop that is cracked and they have been magnafluxed . one only leaks when it gets warm usally if they are off an engine there is a reason . the best one i found was used as a door stop for forty years . what im trying to say is bewhare . hope this helps

That's what worries me. I will be extremely careful.

Bob

Bobkra;
There's one for sale on EBAY. It's in the 490 section.
Item # 330433084413.
Good Luck.

The head on my 27 was cracked and I took it to an engineering shop where they welded and remachined it. No problem after that.
And what is magnaflux?

Magnaflux is a Brand name for Magnetic Particle Inspection.
It is a procedure for checking for cracks in steel and cast iron items by magnetising the part ,and then using coloured or fluorescent iron filings to highlight any cracks .

Hi Aussie Chev,

Whilst restoring my 28 engine during a engine reconditioning course at a trade school discovered a crack approx 1/2 inch long, forget actually the location as it was about 30 years ago, but it may have been around the middle 2 cyl, coming from a water hole along the head.
Anyway much to my amazement as a "green" mechanic the instructor showed me how to drill and plug the crack with a series of small threaded plugs, approx 6, after which the head was machined. Apparently the process relieves the stress that caused the crack in the first place. Anyway no problems every since, despite several boil drys in the early days from being stuck leading a parade and not being able to stop. Other wiser heads than mine might have some comments on the method of drill and plug.

Ray

Hi,
That is a very good type of repair as no heat is required which could develop more cracks.The 28 heads seemed to be far less prone to cracking.

The trouble with the single port exhaust heads is that they crack inside the exhaust port wall and it is very difficult to attempt any type of repair successfully.I now run a 28 head on my 27 motor.
A mate had the same problem.He even cut a cracked head in half to have a look at the construction and the extent of the cracks.Between himself and me there is a pile of 16 rejected cracked heads.He got lucky as I had a spare non genuine head that was in good shape.
The other 16 went for scrap.

Pushrod,
How do you "air check"? I think I have the same overheating problem with my '26 Touring. It has a '28 motor.

I think pushrod is refering to a pressure test of the head to check for cracks in the castings. A "Leak down" test can be perfomed on a head and cylinder by replacing the spart plug with an compressed airline fitted , and then observing the rate at which air is disapated from the cylinder. This can check valve sealing and piston ring sealing as well.

They quite often perform pressure tests on cylinder heads prior and during overhaul , by bolting the head on a flat plate, and then using air pressure to find leaks.
http://en.wikipedia.org/wiki/Leak-down_tester

I believe Pushrod's technique is to use a flat plate to seal the head, plugs in the bolt and water inlet/exit holes and then apply air pressure to check for leaks. Soap applied to the exhaust passages is also a good idea. Any bubbling indicates a leak. If none are found cold then heat with a torch a bit and check again.

i questioned the one for sale on e bay and he said he knew nothing about the head and it had not been checked so it is not worth the freight . no refund

Guys and Gals
1926 head call Jon at 507-202-3794, he has other 26 parts also.
Ken 45145

I recently was involved in the search for a usable head for my '24 Touring. Best I could do was find a severly cracked '27 head. I took it to Tucson Cylinder Head Service, 2114 N. Stone Ave, Tucson, AZ 85705. They are a first class shop with wonderful customer service. For $298 they magnafluxed, tanked and cleaned, installed new valve seats, reworked the guides, pressure tested, surface ground and installed new valves and springs (I provided the valves and springs). They even painted the head with the correct '24 color (I provided). It is now installed and works great. Incidentally, I got my new copper head gasket from Olson's Gaskets in Port Orchard, WA. Top quality gasket at less cost than most offered ($45).
I found it interesting that although the original head for '24 operates without a valve cover and the '27 originally had one, the '27 fits just the same and looks and operates just like the '24 i.e. without a cover.
If you would like any other info., just let me know.
Bill R. '24 Superior Touring