The Ford Barn

Mike1291 · 09-22-2024, 06:08 AM

I finally was able to take the head off my car and found that it had a head gasket leak between the #1 cylinder and water neck. I'm not sure what type of head I have. Should I do or check anything else while I have the head off?

The engine was bored .30 on its last rebuild. I estimate that the engine has 10,000 miles on it since then. There is no obvious wear on first inspection. It overheated badly once (the head gasket was already leaking at that time) and doesn't low idle well anymore.

nkaminar · 09-22-2024, 06:47 AM

Carefully remove the remaining studs. Clean everything up by scraping, final wipe with acetone. Do not use a rotating wire brush or abrasive wheel. Fill any pits in head or block with JB Weld and sand flat using medium grit wet and dry paper wrapped around a flat file. Clean up threads in block. Install new studs, finger tight and set head on block with Plastigauge at various places. Bolt down block at 25 foot-pounds and then remove head. Plastigauge should indicate that gap between head and block is 0.001 or less. A little larger gap is probably OK if you use the gasket as below, but if very large gaps consider having the head and block surfaced.

Test the valves by putting a little kerosene on top of them when closed and see if it leaks down into the block. If the valves are leaky, lap them.

Use the Best brand graphite head gasket and the spray copper gasket adhesive. Follow the instructions for torquing down the head but bring it up to 55 foot-pounds in increments of 10 foot-pounds starting at 25 foot-pounds.

Fill radiator with plain water and start engine to warm it up, about 20 minutes. Shut it down and let it cool overnight. Re torque. Then retorque on cold engine after 100 and 1000 miles and every year thereafter. If no leaks, replace water in radiator with 50/50 antifreeze and water. If the water is hard where you live, buy the premixed antifreeze.

JayJay · 09-22-2024, 06:49 AM

Mike - that looks like a standard Model A 4.2:1 cylinder head to me.

When I replace a head gasket I try to make sure the sealing surfaces are clean and flat. Cleaning the block carefully with a carbide scraper is the best way. Use a vacuum cleaner to remove the crud you scrape off. Be careful around the valves that you don’t scratch them. I clean off the bulk with the valve closed, then rotate the engine so the valve is open and carefully clean close. I have some old dental scrapers I use for that. Don’t use whizzy wheel or sandpaper, you can gouge the surface. I also like to replace head studs with new, it makes cleaning the surface easier. Be careful, if the stud is stuck and you break it off you will have a whole bunch of additional troubles. If you elect to “chase” the holes use only a special retreading tap, not a conventional tap, and STOP when you get near the bottom of the hole so you don’t punch through into the water jacket.

On the head, same deal. Once you get it clean take a good straightedge and lay it every direction you can along and across the surface. Measure any gaps with feeler gauge, I use 0.002” as my trigger. Any gaps greater than 0.002” and you should have the head decked (resurfaced) by a machine shop. You might want to do this anyhow just so you know.

After you get your head back from decking, set it on the block with no gasket and rotate the engine by hand. Check that you don’t have any valve interference lifting the head up.

When you reinstall the head be careful that you set it down gently. If it slips you can bend an open valve. Don’t ask how I know that.

Torque sequence - check Les Andrews Red Book for the sequence. I start with a round at 25 ft-lb, then add 5 ft-lb in steps until i get to 55. Add coolant after you get to full torque. Run the engine until it reaches operating temp (with coolant, of course), checking for leaks, then let it sit overnight. Repeat a round of 55 ft-lb and then you’re ready to drive. Repeat the head torque at 50 miles, then 100, 500 and annually.

My way isn’t the only way, but it works for me. NK (above) has a lot of good suggestions as well. I’ve had the best luck with the Best 509G graphite gasket with copper spray sealant.

nkaminar · 09-22-2024, 06:57 AM

It looks like you have the stock head. Consider replacing it with a higher compression head.

nkaminar · 09-22-2024, 06:59 AM

Jay Jay and I have basically the same instructions. Just a little difference in when to retorque the head. More frequently is probably better and won't hurt anything.

JayJay · 09-22-2024, 07:02 AM

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Quote:

Originally Posted by nkaminar

It looks like you have the stock head. Consider replacing it with a higher compression head.

Now there is a thought! Most folks recommend having a machine shop deck even a new head.

Kurt in NJ · 09-22-2024, 07:09 AM

The coloring of #3 intake valve would have me looking closely at how it is seating— it looks like it was getting hot.

Mike1291 · 09-22-2024, 02:42 PM

Thanks for the advice! I plan on replacing the studs and cleaning everything up. I'll also check to see if all the valves are sealing using kerosene.

09-22-2024, 06:47 AM	#2
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,863	Re: Replacing Head Gasket. Should I Do Anything Else? Carefully remove the remaining studs. Clean everything up by scraping, final wipe with acetone. Do not use a rotating wire brush or abrasive wheel. Fill any pits in head or block with JB Weld and sand flat using medium grit wet and dry paper wrapped around a flat file. Clean up threads in block. Install new studs, finger tight and set head on block with Plastigauge at various places. Bolt down block at 25 foot-pounds and then remove head. Plastigauge should indicate that gap between head and block is 0.001 or less. A little larger gap is probably OK if you use the gasket as below, but if very large gaps consider having the head and block surfaced. Test the valves by putting a little kerosene on top of them when closed and see if it leaks down into the block. If the valves are leaky, lap them. Use the Best brand graphite head gasket and the spray copper gasket adhesive. Follow the instructions for torquing down the head but bring it up to 55 foot-pounds in increments of 10 foot-pounds starting at 25 foot-pounds. Fill radiator with plain water and start engine to warm it up, about 20 minutes. Shut it down and let it cool overnight. Re torque. Then retorque on cold engine after 100 and 1000 miles and every year thereafter. If no leaks, replace water in radiator with 50/50 antifreeze and water. If the water is hard where you live, buy the premixed antifreeze. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 09-22-2024 at 06:54 AM.

09-22-2024, 06:57 AM	#4
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,863	Re: Replacing Head Gasket. Should I Do Anything Else? It looks like you have the stock head. Consider replacing it with a higher compression head. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

09-22-2024, 06:59 AM	#5
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,863	Re: Replacing Head Gasket. Should I Do Anything Else? Jay Jay and I have basically the same instructions. Just a little difference in when to retorque the head. More frequently is probably better and won't hurt anything. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

09-22-2024, 07:09 AM	#7
Kurt in NJ Senior Member Join Date: May 2010 Location: on the Littlefield Posts: 6,555	Re: Replacing Head Gasket. Should I Do Anything Else? The coloring of #3 intake valve would have me looking closely at how it is seating— it looks like it was getting hot.

09-22-2024, 02:42 PM	#8
Mike1291 Senior Member Join Date: Dec 2023 Location: Rhode Island Posts: 188	Re: Replacing Head Gasket. Should I Do Anything Else? Thanks for the advice! I plan on replacing the studs and cleaning everything up. I'll also check to see if all the valves are sealing using kerosene. __________________ Feb '31 Standard Coupe Member of the Little Rhody Model A Club & MARC

09-22-2024, 06:49 AM	#3
JayJay Senior Member Join Date: Jan 2020 Location: SF Bay Area Posts: 2,109	Re: Replacing Head Gasket. Should I Do Anything Else? Mike - that looks like a standard Model A 4.2:1 cylinder head to me. When I replace a head gasket I try to make sure the sealing surfaces are clean and flat. Cleaning the block carefully with a carbide scraper is the best way. Use a vacuum cleaner to remove the crud you scrape off. Be careful around the valves that you don’t scratch them. I clean off the bulk with the valve closed, then rotate the engine so the valve is open and carefully clean close. I have some old dental scrapers I use for that. Don’t use whizzy wheel or sandpaper, you can gouge the surface. I also like to replace head studs with new, it makes cleaning the surface easier. Be careful, if the stud is stuck and you break it off you will have a whole bunch of additional troubles. If you elect to “chase” the holes use only a special retreading tap, not a conventional tap, and STOP when you get near the bottom of the hole so you don’t punch through into the water jacket. On the head, same deal. Once you get it clean take a good straightedge and lay it every direction you can along and across the surface. Measure any gaps with feeler gauge, I use 0.002” as my trigger. Any gaps greater than 0.002” and you should have the head decked (resurfaced) by a machine shop. You might want to do this anyhow just so you know. After you get your head back from decking, set it on the block with no gasket and rotate the engine by hand. Check that you don’t have any valve interference lifting the head up. When you reinstall the head be careful that you set it down gently. If it slips you can bend an open valve. Don’t ask how I know that. Torque sequence - check Les Andrews Red Book for the sequence. I start with a round at 25 ft-lb, then add 5 ft-lb in steps until i get to 55. Add coolant after you get to full torque. Run the engine until it reaches operating temp (with coolant, of course), checking for leaks, then let it sit overnight. Repeat a round of 55 ft-lb and then you’re ready to drive. Repeat the head torque at 50 miles, then 100, 500 and annually. My way isn’t the only way, but it works for me. NK (above) has a lot of good suggestions as well. I’ve had the best luck with the Best 509G graphite gasket with copper spray sealant. __________________ JayJay San Francisco Bay Area ------------------------ 1930 Murray Town Sedan 1931 Briggs S/W Town Sedan It isn't a defect, it's a feature!