head gasket questions

mumpsimus

mumpsimus

Member
Hi guys. I've recently installed new head gaskets, Best brand. I installed them dry, and water was leaking from the exhaust pipe immediately upon starting the motor. I then removed the gaskets, and greased them with wheel bearing grease on both sides and reinstalled. (The grease was recommended by a friend). Water is again leaking into the exhaust valves. It appears that the problems are on cylinders 1-3, based on compression tests being low on those three. Leak down test showed that they were leaking, but I was unable to determine where the air was going. My ears are not that great I guess, but it sounded like it was coming into the radiator.

The car is a 37 Woodie, with the original 21 stud flathead. I torqued the head nuts to 60-65ftlbs. Heads are not warped, and were recently milled .040" to raise compression slightly. Valves are not touching the heads at full lift. Motor is stock other than the milled heads, but it was rebuilt in the 1980s and has only done about 6000 miles in the past 30 years. I've driven it 2000 miles in the last year since I bought it.

Questions:
1. What brand of gasket do you recommend?
2. Do you recommend installing the gaskets dry, or with copper spray, or with some other treatment? Anything special around the exhaust valves like high temp silicone or something?
3. Should I do a valve job while I have the heads off?

Thanks guys! This is my first flathead, and I'm enjoying learning some new things.

Pete in San Francisco.
 
You installed new gaskets for what reason? Both the head and block surface needs to be completely flat. I use the copper seal. Do the valves when the heads are off, I don't know another way.
 
I installed new head gaskets to replace the old ones that were torn up when the heads were removed to be milled.

Heads and block were clean and flat. I went over the block with a single-edged razor blade to make sure that there was nothing left of the old gaskets.


J Franklin said:
You installed new gaskets for what reason? Both the head and block surface needs to be completely flat. I use the copper seal. Do the valves when the heads are off, I don't know another way.
Click to expand...
 
You milled .040 off did you check it without a head gasket so nothing touched?
Are the studs leaking? Have a real good look and make sure the head or block is not cracked.
Probably Best gasket copper gaskets [507?] will do as much as anything if all is flat and clean . Use some copper sealant or Hylomar spray even old timey silver spray paint. you dont need to torque beyond 50 - 55 lbs.
Did you re-torque through three heat cycles?

Valve job .. How was the vacuum reading?
 
Just checking, but did you follow the torque sequence recommended in the manual? I usually get to final torque in 3 passes following the sequence. And then torque again after a few heat and cool cycles until they quit moving following the sequence. I used the copper gaskets with copper spray sealer.

JB
 
Thanks Talkwrench. I don't know about studs leaking? Does that allow water into the ex. valves? I'll look at them tomorrow after work. What should I check?

Also, I didn't do three heat cycles. There was so much water in the exhaust pipe, and steam coming off of it, that I immediately freaked out a bit! I'll do all three when I get the new gaskets later this week though.

I'll try Best 507 and copper sealant, and stay at 50-55lbs.

I did check the valves and pistons without the gaskets for clearance. I used a method that I read about here, with little tin foil balls held in place with grease, then measured with dial calipers. It was a pretty clever way to do it.

thanks again,
Pete


Talkwrench said:
You milled .040 off did you check it without a head gasket so nothing touched?
Are the studs leaking? Have a real good look and make sure the head or block is not cracked.
Probably Best gasket copper gaskets [507?] will do as much as anything if all is flat and clean . Use some copper sealant or Hylomar spray even old timey silver spray paint. you dont need to torque beyond 50 - 55 lbs.
Did you re-torque through three heat cycles?

Valve job .. How was the vacuum reading?
Click to expand...
 
Thanks 3twinrides. I did follow the pattern for all 21 nuts, sneaking up on the torque setting in one pass, then fully tightening with the torque wrench for the second pass. But I can do it in three passes next time.

I'm used to working on motorcycles from 1915, and they have heads cast in one iron lump with the barrels, so no head gaskets! So much easier. :)

thanks again,
Pete


3twinridges said:
Just checking, but did you follow the torque sequence recommended in the manual? I usually get to final torque in 3 passes following the sequence. And then torque again after a few heat and cool cycles until they quit moving following the sequence. I used the copper gaskets with copper spray sealer.

JB
Click to expand...
 
I don't recall reading whether you have aluminum or cast iron heads. Was there any corrosion on the heads if they were aluminum? How did you determine that the used heads and block surfaces were flat? Everyone does the first torque cold. I also do the first heat cold cycle without any water in the engine. If you have aluminum heads, you torque them dead cold each time. If you have cast iron heads, you torque them hot each time always following torque sequence. I always spray the head gaskets with Coppercoat but any sealer will do. I have never had any water issues like you describe. Aluminum heads will require at least 4 heat/cold cycles and often more before they stop moving, iron heads usually are done at 3.
 
Original iron heads. The heads were milled flat, I checked the block with a straightedge. But it was tough to fit the edge around all the studs. So the block might not be perfect.

Thanks for the tip on the 3 heat cycles. I should have done that instead of pulling the head off to check it. I'll try again with a new gasket later this week.

I wouldn't mind buying aluminum heads, but will they give any additional power over the iron ones? The old 21 stud motor could always use a bit more torque when I'm hauling the whole family in the wagon!

thanks again,
Pete


deuce_roadster said:
I don't recall reading whether you have aluminum or cast iron heads. Was there any corrosion on the heads if they were aluminum? How did you determine that the used heads and block surfaces were flat? Everyone does the first torque cold. I also do the first heat cold cycle without any water in the engine. If you have aluminum heads, you torque them dead cold each time. If you have cast iron heads, you torque them hot each time always following torque sequence. I always spray the head gaskets with Coppercoat but any sealer will do. I have never had any water issues like you describe. Aluminum heads will require at least 4 heat/cold cycles and often more before they stop moving, iron heads usually are done at 3.
Click to expand...
 
I an not a 36 expert but I think the passenger cars came with aluminum heads stock, and the iron heads were either truck or replacements. Actually you probably will have less issues with the iron heads if you aren't having it judged.
 
There is no way for the head gaskets to allow water into the exhaust valves without also filling the cylinder with that same water. Be very careful you do not wreck your engine with a hydraulic lock. If the block is CLEAN and flat and the heads are flat and nothing is binding to prevent the fasteners from actually applying the correct tension the next place to look is for a cracked block. Are the threads clean and allowing the nuts to contact the heads without the use of a wrench?? Is it possible the nuts are stopping at the original location before the .040 was milled??
 
I’ll measure them again, but the stud threads appeared to be long enough. Possibly there is a crack, since the problem is only on the passenger side of the motor. I’ll look closely tonight.


QUOTE=JWL;1671174]There is no way for the head gaskets to allow water into the exhaust valves without also filling the cylinder with that same water. Be very careful you do not wreck your engine with a hydraulic lock. If the block is CLEAN and flat and the heads are flat and nothing is binding to prevent the fasteners from actually applying the correct tension the next place to look is for a cracked block. Are the threads clean and allowing the nuts to contact the heads without the use of a wrench?? Is it possible the nuts are stopping at the original location before the .040 was milled??[/QUOTE]
 
I would suggest you take out the spark plugs keeping track which Cyl. They came from and check for any differences.. Steam or water will tend to clean them usually enough to tell which cyl. could be the problem. jms kx
 
Good idea. I have the plugs labeled and will check them. The motor only ran for about one minute with the water leak, but that might be enough time for the plugs to differ.

Kerk said:
I would suggest you take out the spark plugs keeping track which Cyl. They came from and check for any differences.. Steam or water will tend to clean them usually enough to tell which cyl. could be the problem. jms kx
Click to expand...
 
I bought Best copper gaskets, sprayed with copper spray, then installed and torqued in three increments to 55inlbs. Re-torqued each time after running the motor three times. Everything seems to be working fine now. Thanks for the advice guys.
 
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