The Ford Barn

29touring · 05-15-2023, 03:17 PM

Okay, been working on my dad's 1930 Tudor. We recently replaced the exhaust manifold, new gaskets, studs, nuts, etc. Did a compression check today and #3 and #4 were under 50 psi. Compression check was from loss of power when accelerating in 3rd gear. Pulled the manifolds and the stud between number 3 and 4 came out, along with a steady stream of water. Would a cracked water jacket here cause the compression to be low? And, would rtv on the end of the stud, or jb weld in the bottom of the stud hole fix this, or do I need to pull the engine? Thanks in advance.

Phil Brown · 05-15-2023, 03:38 PM

Most of the time (not always though) low compression in two adjacent cylinders indicates a bad head gasket.

As bad as that sounds much better than a crack in the block

nkaminar · 05-15-2023, 03:49 PM

Having a manifold stud connect to the water jacket is fairly common. It does not necessarily indicate a cracked block. Use a good sealant when re installing the stud and a sealant that will allow the stud to be removed at some later date. Do not glue it in as it will make it very hard to remove later and the stud may break off.

29touring · 05-15-2023, 05:21 PM

I replaced the head gasket a few weeks ago, in time for the membership meet in Bay City. We had water leaking between block and head. Found out I put the copper gasket on upside down. A great head slapping duh moment for me. Carefully removed head and gasket, cleaned and sprayed with copper sealant. That took care of the water seepage there. I was thinking it might also be a manifold leak causing the compression problem.

Synchro909 · 05-15-2023, 05:21 PM

Any radiator stop leak product will stop the leak at the stud and you won't need much of it so no worries about clogging the radiator.

Bob C · 05-15-2023, 06:43 PM

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You could do a cylinder leak down test to see where your compression is doing.

1crosscut · 05-15-2023, 07:11 PM

After doing the head gasket the last time did you retorque the head gasket a few more times after the initial installation?
Torque needs to be checked several times while heat cycling the engine. (Bring it up to temp and torque, let it cool, torque... repeat until it settles in rock solid at 55 lbs. ea.) If you didn't I would suspect the gasket may have failed between cylinders.

Clean the manifold stud hole well and seal the stud with Right Stuff RTV sealant or similar.

29touring · 05-15-2023, 09:15 PM

I did re-torque but only once after heating the motor up. I will get some sealant for the stud tomorrow and also check the manifolds for trueness. Thank you for the replies. I thought I could use sealant, but wanted some more opinions. Again, thank you all.

Bob Bidonde · 05-16-2023, 06:38 AM

These slides may help you. I have encountered the cracks shown on a few engines.

05-15-2023, 03:17 PM	#1
29touring Junior Member Join Date: Apr 2020 Location: Mid-Michigan Posts: 22	Water out of manifold stud hole Okay, been working on my dad's 1930 Tudor. We recently replaced the exhaust manifold, new gaskets, studs, nuts, etc. Did a compression check today and #3 and #4 were under 50 psi. Compression check was from loss of power when accelerating in 3rd gear. Pulled the manifolds and the stud between number 3 and 4 came out, along with a steady stream of water. Would a cracked water jacket here cause the compression to be low? And, would rtv on the end of the stud, or jb weld in the bottom of the stud hole fix this, or do I need to pull the engine? Thanks in advance.

05-15-2023, 03:38 PM	#2
Phil Brown Senior Member Join Date: May 2010 Location: Santee Calif. Posts: 506	Re: Water out of manifold stud hole Most of the time (not always though) low compression in two adjacent cylinders indicates a bad head gasket. As bad as that sounds much better than a crack in the block

05-15-2023, 05:21 PM	#5
Synchro909 Senior Member Join Date: Jun 2014 Location: Melbourne, Australia Posts: 7,496	Re: Water out of manifold stud hole Any radiator stop leak product will stop the leak at the stud and you won't need much of it so no worries about clogging the radiator. __________________ I'm part of the only ever generation with an analogue childhood and a digital adulthood.

05-15-2023, 07:11 PM	#7
1crosscut Senior Member Join Date: Feb 2011 Location: Lincoln, Nebraska Posts: 1,907	Re: Water out of manifold stud hole After doing the head gasket the last time did you retorque the head gasket a few more times after the initial installation? Torque needs to be checked several times while heat cycling the engine. (Bring it up to temp and torque, let it cool, torque... repeat until it settles in rock solid at 55 lbs. ea.) If you didn't I would suspect the gasket may have failed between cylinders. Clean the manifold stud hole well and seal the stud with Right Stuff RTV sealant or similar. __________________ Dave / Lincoln Nebraska

05-15-2023, 09:15 PM	#8
29touring Junior Member Join Date: Apr 2020 Location: Mid-Michigan Posts: 22	Re: Water out of manifold stud hole I did re-torque but only once after heating the motor up. I will get some sealant for the stud tomorrow and also check the manifolds for trueness. Thank you for the replies. I thought I could use sealant, but wanted some more opinions. Again, thank you all.

05-15-2023, 03:49 PM	#3
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,898	Re: Water out of manifold stud hole Having a manifold stud connect to the water jacket is fairly common. It does not necessarily indicate a cracked block. Use a good sealant when re installing the stud and a sealant that will allow the stud to be removed at some later date. Do not glue it in as it will make it very hard to remove later and the stud may break off. __________________ 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.