Pressure Testing a Block

[Ken/Alabama]

I’ve got a block I want to pressure test. So what is the preferred method? Apply air pressure and spray soap and look for bubbles or fill the block with water and apply how much air pressure to it??

[Pete]

Originally Posted by Ken/Alabama

I’ve got a block I want to pressure test. So what is the preferred method? Apply air pressure and spray soap and look for bubbles or fill the block with water and apply how much air pressure to it??

Either way works ok.
You can also submerge the whole block, pressurize it and look for bubbles.

I use 25 to 30 lb. pressure.

[flatjack9]

I fill with water and use 50 psi. air pressure.

[Bored&Stroked]

I fill with air and spray a foamy soap solution all over the thing - making dang sure to spray inside the exhaust ports (top to bottom).

[Ken/Alabama]

Originally Posted by Bored&Stroked

I fill with air and spray a foamy soap solution all over the thing - making dang sure to spray inside the exhaust ports (top to bottom).

I’ve got an 8BA block that has cracks in the intake and exhaust valve seat on the same cylinder. The crack in the exhaust is very short and runs up to the seat . The crack in the intake runs under the seat an over to the cylinder. I removed both seats and pinned the cracks . If it passes a pressure test I’ll install new seats and sleeve that one cylinder .

[Bored&Stroked]

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Hey Ken, when you put the pins in, did you coat them with any sort of sealer - like locktite stud and bearing mount? This tends to help them not leak/weep a bit.

I've found that sometimes the pins will weep just a bit - so I always start the engine and use a water-glass ceramic seal product from Moroso for the initial break in. Sometimes I do it twice just for good measure. This stuff will seal up the IronTite pins if they are weeping.

Hopefully you can save the block!

[rockfla]

I fill mine with air and have a pressure gauge on my water pump plate with an on/off valve and let it sit with 50psi of air and see IF it will hold 50 psi check it in the morning. IF its down, then re pressure the block and start with the water & soap spray bottle. IF still at 50 in the morning a shout of joy and a Fess Parker skippitdy do!!!

[Pete]

I forget the brand of pins we used to use but they were NOT IronTite.They were USA made and the instructions said to use K&W Sleeve Seal for sealer.

[flatford8]

Originally Posted by rockfla

I fill mine with air and have a pressure gauge on my water pump plate with an on/off valve and let it sit with 50psi of air and see IF it will hold 50 psi check it in the morning. IF its down, then re pressure the block and start with the water & soap spray bottle. IF still at 50 in the morning a shout of joy and a Fess Parker skippitdy do!!!

I do this same procedure, but I only wait a couple hours before I start my happy dance........Mark

[GB SISSON]

I would be a bit wary with 50 lbs in a fairly thin walled cast iron block. When I blew out that 12 ply 'roller' tire at 30 lbs, the explosion was extremely violent and caused a most unfortunate permanent hearing loss that I live with today. That's way more pressure, and I would imagine schrapnel could be involved. (Never thought I'd be one of those safety guys).

[Ken/Alabama]

Originally Posted by Bored&Stroked

Hey Ken, when you put the pins in, did you coat them with any sort of sealer - like locktite stud and bearing mount? This tends to help them not leak/weep a bit.

I've found that sometimes the pins will weep just a bit - so I always start the engine and use a water-glass ceramic seal product from Moroso for the initial break in. Sometimes I do it twice just for good measure. This stuff will seal up the IronTite pins if they are weeping.

Hopefully you can save the block!

Yes I did use a sealer on the pins. I used a Lock n stitch kit and it has a ceramic sealer for the pins. I’m a little afraid of 50 lbs . The cracks were in the valve seat area. The intake ran over into the cylinder . The exhaust had a very short crack that ran under the valve seat but stopped there. If it checks good I’ll sleeve that one cylinder.

[GB SISSON]

I had a freshly pinned and sleeved cylinder in a new rebuild that I bought. It leaked on startup. I used Kand N block seal and the instructions said to pull the plug on the affected cylinder before the run. It seemed like a good idea as the sealing wasn't working against compression. I have wondered if it might be a good idea to pressurize the block with the K W in it to drive it deep into any potential leak zones. Just a thought. Oh, and the sealer worked very well for me.

[petehoovie]

Originally Posted by Ken/Alabama

Yes I did use a sealer on the pins. I used a Lock n stitch kit and it has a ceramic sealer for the pins. I’m a little afraid of 50 lbs . The cracks were in the valve seat area. The intake ran over into the cylinder . The exhaust had a very short crack that ran under the valve seat but stopped there. If it checks good I’ll sleeve that one cylinder.

[KiWinUS]

Originally Posted by Bored&Stroked

Hey Ken, when you put the pins in, did you coat them with any sort of sealer - like locktite stud and bearing mount? This tends to help them not leak/weep a bit.

I've found that sometimes the pins will weep just a bit - so I always start the engine and use a water-glass ceramic seal product from Moroso for the initial break in. Sometimes I do it twice just for good measure. This stuff will seal up the IronTite pins if they are weeping.

Hopefully you can save the block!

Dale do you put the water glass in with the radiator you are going to keep with engine? We found with race cars it would ruin radiator if not rinsed out immediately after draining. The would not remove/ dissipate heat near as good

[flatjack9]

Originally Posted by GB SISSON

I would be a bit wary with 50 lbs in a fairly thin walled cast iron block. When I blew out that 12 ply 'roller' tire at 30 lbs, the explosion was extremely violent and caused a most unfortunate permanent hearing loss that I live with today. That's way more pressure, and I would imagine schrapnel could be involved. (Never thought I'd be one of those safety guys).

The engine encounters much higher pressures during when running.

[Tim Ayers]

Originally Posted by flatjack9

The engine encounters much higher pressures during when running.

Interesting, Jack. Never thought of it that way. How much pressure do think a motor sees while running?

[rockfla]

Originally Posted by Tim Ayers

Interesting, Jack. Never thought of it that way. How much pressure do think a motor sees while running?

Tim



My good friend and Flathead (and A & B motors) specialist re-builder here in town runs his up well over 100. I believe he goes to 130psi.

[GB SISSON]

Are we talking pressure in the cooling system here? Don't most radiator caps have something like a 15 lb cap? I woulda thought that was 15 PSI, but maybe the terminology is different. If we are driving around with 100 psi in our radiators, no wonder it's such a ****show when we pull the cap before it cools down.

[flatford8]

I think he’s talking a 100# to pressure test the block Bud.....radiator is not involved....I’d be interested in Jacks answer........Mark

[rockfla]

All my post are "block" pressure testing only