1929 Head Gasket Rep[lacement/bubbles in radiator

R

rmonty1

Junior Member
A friend has a 1929 model A Tudor that she wants to get running and reliable. We determined quickly that it was overheating due to a bad radiator. We replaced the radiator and after replacing the radiator, I noticed bubbles being made in the radiator while it is running. I have never worked on a Model A before, but I figured it was a head gasket. We removed the head and didn't find the narrow places on the gasket between the cylinders blown out like I expected. Can someone walk me through how to inspect what I am looking at/for to make sure I don't have valve problems, etc. I know the bubbles in the radiator aren't good, I just want to make sure I do everything needed while the head is off.

Thanks for any input!
 
You have to look very carefully at the head gasket for signs of water tracking from one or more of the water holes to the combustion chamber. Sometimes, this is just a dark stain. It sounds like the gasket may not have been properly sealed when installed or the head was not properly torqued or it is just old.

There are some good threads here on the Barn relating to installing a new head gasket.

My opinion.

Chris W.
 
Check the deck and head for flatness. Install the new gasket. Create an adapter that goes from the spark plug hole to an air fitting. Apply air and check for air in radiator using each plug hole.
 
When Minerva leaked between #3 & 4, the gasket "LOOKED OK", but at the top of the cylinder walls, there were little "etching" marks, left from water bubbles clinging there. My first warning of a leak was a dead miss on those 2 cylinders, for 3 or 4 seconds, on a cold start up, and some loss of water.
Surfaced the head & a "modern" gasket fixed it.
Bill W.
 
The head is at the machine shop now being checked for cracks, etc. It will be resurfaced if needed.

What, if anything, should I do to the valves while I have this thing apart? The edges of the valves don't appear to be burned, however, there are a couple of them that seem to have some wobble in them when they are extended (springs compressed). I would think this would indicate valve guide wear. I have search for lapping the valves in the forums, and haven't really found much on that.

I am not a professional mechanic by any stretch of the imagination, but I am aware that doing "too much" to an older engine like this can lead to other problems. Things like getting valves to seal properly could lead to blow by in the cylinders etc.

Thanks for any opinions and comments!
 
I don't see why doing some minor valve work would be an issue... If the valves wobble, defiantly have the guides replaced.

After you replace the guides, and before you reassemble the rest of the valve train, defiantly lap the valves. Go to your local auto parts store and purchase valve lapping compound and a valve lapping tool. Apply the lapping compound along the sides of the valve (where the valve comes into contact with the seat) and attach the lapping tool to the top of the valve. Roll your hands on the sides of the tool so that the valve is rotating on the seat in an alternating clockwise and counter-clockwise fashion. Continue to do this until you've removed minor pitting and created a shiny surface on the seat and valve.
 
Besides needing a good cleaning, does anyone see anything catastrophic- looking in these pictures? Not really sure what to look for. :o

I am thinking the rust on top of the exhaust valves probably isn't a good thing? :confused:
 

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Monty,
IF IT WERE MINE, I'd do this:
1 Scrape & clean the block & top of the valves & look for cracks. (By the way, that's NOT rust on the valves, just normal deposits.)
2 Open each valve & brush under them with a hand wire brush.
3 Re-surface the head, put it together & do multiple re-torqueings of the head, @ 55 Ft Lbs, COLD. Do the first re-torqueing warm, after first running it for 20 minutes, or so. (From the looks of #4 intake valve, you were leaking into #4 cylinder.)
Bill W.
 
I would scrape out deposits that have collected in the water jacket while you have the head pulled. Preventative maintenance is always a good thing!
 
It appears to me that you were not getting good sealing in the areas adjacent to the valves, especially on #4 cylinder. Be sure the block is absolutely clean where the gasket seals before installing the head.

I see where you have all the studs removed. If the engine does not already have good quality heat treated head studs, I would install them.

Original studs are soft and will stretch when torqued. Good quality heat treated studs will not stretch and you will have less problems keeping the head tight and the gasket sealed.

My opinion.

Chris W
 
https://www.youtube.com/watch?v=TCI2JFTUiZE

Here is John Karal showing how to check for cracks.

https://oldcarroadtrip.wordpress.com/2014/10/07/56789-tow-no-i-meant-ten-dang/

The above link Al Clarke at Go Devil Garage is helping me check the head/block for cracks with an engine in the car.

https://oldcarroadtrip.wordpress.com/2015/02/17/the-gulbankian-brothers/

This link is J&M Machine working on the engine and also checking for cracks. There is also video of them decking the block, installing valves, etc.
 
Bill Williamson - Thanks for the input. I like that plan and had pretty much decided that would be the course of action. The head wasn't cracked (just heard back from the machine shop) and they did resurface it. Going to head that way and pick it up shortly.

DJ S - I think at this point, I am going to forego the valve cleanup. I think I am going to just clean her up, put her back together and see how she runs. At some point in the future, I hope to convince the owner to rebuild the engine completely. The car is in original condition, and she wants to enter it in some local shows as totally original as it can be. I have rebuilt a couple of old willys jeep motors several years ago, and just enjoy the simplicity of these old 4 cylinder flat heads.

CWPASADENA - I think the gasket was leaking all over the place. I know the exhaust/intake manifolds were leaking. There was a lot of carbon buildup on the exhaust stud/nut on #4 cylinder, and when I removed the manifolds, there were no gland rings. I ordered all new head and exhaust studs and nuts from Mac's and they are out for delivery to me today. Also ordered copper intake/exhaust gaskets and gland rings.

Wish me luck! Excited about putting this all together and see how it turns out!
 
Monty,
Model A engines are quite forgiving, and as some can attest, they don't have to be ABOLUTELY PERFECT, to give some quite dependable service.
Bill W.
 
I also would suggest you spend some time getting the water jacket cleaned out while the head is off especially behind #4.
Pull the inlet casting to access the chamber around the cylinders.
You will want to back flush the block before you hook it up to the backflushed radiator.
Scale and rust flakes will come loose now that the head has been pulled in my opinion.
Bob
 
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