Torque value for head

Al 29Tudor

Al 29Tudor

Well-known member
Good morning, I replaced my head gasket about 300 milles ago. At that time the head was machined to flat, not for high compression. I re-torqued several times untill there was no more takeup at 55 lbs torque. I don't know if the deck has ever been machined but the pistons are .060 over and above the deck at TDC so the engine has been worked on. Lately there has been bubbling in the radiator and a little seapage on the left side of the engine. I re-torqued it to 60 lbs. and it is still bubbling. Any advice on what is going wrong and what it should be torqued to? Thanks for your advice.
Al Leach
 
55 should be fine. Did you clean the cooling chambers while the head was off?
How's the water pump seal? Lead packing rings AND grease works fine for me.
 
you may have to pull the head off and check the head again.. I would think it's warped then replace the head gasket again and do the same method of torque up to 55ftlbs.. Or the head gasket got pinched and is not doing it's job
 
Thanks for your suggestions. The water pump is new with sealed bearings. Next I'm ordering the adapter to check compression. I'm also ordering a new head gasket.
 
Hi Tom, I used the copper spray on both sides of the thick composite head gasket suggested for engines with pistons that are above the top of the block. Looks like I'll be trying it agsin. Thanks.
Al
 
Why was the head gasket replaced ?? It sounds as if the block wasn't checked and may be your problem,, it may not be flat..
I'm assuming the compression wasn't checked before the gasket replacement,, so,, let us know what it is when you can..
 
Al 29Tudor said:
Good morning, I replaced my head gasket about 300 milles ago. At that time the head was machined to flat, not for high compression. I re-torqued several times untill there was no more takeup at 55 lbs torque. I don't know if the deck has ever been machined but the pistons are .060 over and above the deck at TDC so the engine has been worked on. Lately there has been bubbling in the radiator and a little seapage on the left side of the engine. I re-torqued it to 60 lbs. and it is still bubbling. Any advice on what is going wrong and what it should be torqued to? Thanks for your advice.
Al Leach
Click to expand...

Originally the pistons protruded about 1/32" above the deck.
 
When I bought the car the head bolts were loose. It was a mechanical mess. It was overheating, missing and backfiring, hard to start and I didn't know how to set the spark. The head gasket was blown between cylinders 1 and 2 and the carburetor GAV was completely blocked. It now has an upgraded distributor; I rebuilt the carb, new alternator, some new valves and was really running nice. Now it is bubbling when I look in the radiator. That's when I torqued it 60 ft. lbs. I'm going to check the compression next. Thanks to you all for your interest and suggestions.
Al
 
Is it bubbling because of a hot spot in the engine, or the engine is running too hot, or the radiator isn't cooling well, or is it combustion gas blowing into the coolant?
 
The temperature is good. The laser temp gun indicates below 200F with even cooling across the radiator - no hot or cold spots. An earlier response questioned if the head water passages were cleaned and they were. I havn't checked the block for hot spots though. I think it is combustion gas blowing into the coolant. It also has some weeping along the left side of the engine at the head/block seam. Except for the bubbling and a 15 minute period recently of wanting to stall with back firing, it runs so sweet. Thank, Al
 
Tom Wesenberg said:
Is it bubbling because of a hot spot in the engine, or the engine is running too hot, or the radiator isn't cooling well, or is it combustion gas blowing into the coolant?
Click to expand...

Al,
If you want to test which it is, you can get a block tester kit at NAPA. You will also need their large radiator adapter. The kit consists of a suction bulb for drawing some of the air from the upper radiator tank headspace thru a blue aqueous liquid that turns yellow on exposure to combustion gases. I'm not sure but I think it's a simple pH indicator solution responding to acidification by CO2.

Others have recommended using electronic emissions test equipment but I've never succeeded in talking a shop into letting their exhaust probes anywhere near a bubbling radiator.

Steve
 
I was chasing down an issue with my Model A running hot and overheating randomly. When it would get hot, I noticed the bubbling in the radiator. I stopped up the overflow tube, put a wet piece of cloth (I used a car wash rag) over the cap and restarted the car. When I would rev it up, I could watch the rag pop up with engine RPM. When I pulled the head, I found a couple very small cracks on the head and traces on the headgasket where cylinders 2 and 3 were bleeding into the cooling passages.

I decided to make the best of a bad situation and ordered a 5.5 head...probably one of my favorite upgrades to the car.
 
When you pull the head, check the combustion chambers on the block top for cracks. Cracks under the gasket won't leak into the coolant so you only need check the open chamber areas. You will want to be especially observant of the area between the exhaust valves on #2 and #3 and the cylinder wall of each. You can also have the areas checked with a magnaflux machine and dust if you can find someone with one and take the car to them with the head removed.
 
If it is cracked like James says ! Don't despair I have had good luck having Metal Stitching repairs in that area . It's worth it to save an otherwise god block.

John Cochran
 
Thankks JJ,
I think I would do that if the head is bad and a 5.5 head looks stock. My car is stock except for a 6V alternator and upgraded distributor.
Al
 
Hi James,
I did look at the cylinders and valve areas when the valve cover was off but the magnaflux would be a way better test. There is some scoring in a couple cylinders and I can't tell much by looking.
Al
 
Al,
All good suggestions above.... Not sure of how many bubbles you're getting but I would take the fan belt off and let the engine run with the water pump not turning to make sure you're not sucking in any air through the pump ( make sure packing is tight if that type of pump. I have seen this a number of times. I agree with Tom that a good fel-pro gasket sprayed with copper coat does the job most of the time.. in some cases I've had to use the snyders composition gasket they recommend with their HC head. If bubbles still exhist pull head and carefully examine block and head for cracks.
Not a fun job but necessary!! Good luck!
Larry S
 
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