Pressure-Sealing Blocks

[Admiral]

Does anyone know about pressure-sealing engine blocks? I ran across an article from Hot Rod magazine the other day where they interviewed Mike Herman of H&H Flatheads out in California. He says they do this to every engine they build. It sounds like pressure-sealing could be an excellent way of addressing the smaller cracks our beloved flathead blocks tend to get.

According to Herman:

"We also pressure-seal every block with a cast-iron resin that we heat to 180 degrees and pump through the water jackets at 20 pounds of pressure. It will show if there are any leaks and also coat all the water jackets. This is a must; we have been doing it for over 40 years with thousands of engines."

Other than this article, I've never heard of this process before. An internet search doesn't seem to reveal much about it. Here's a link to the article in question: https://www.hotrod.com/articles/1111...lathead-motor/

[Tim Ayers]

I'm interested as well. I've gone through 5 blocks. Latest one, I trusted the shop to magnaflux it and they did the normal spots, but never mag checked the valley. Sure as hell, this block has a 3" straight crack right behind cylinder #8.

My builder believes it's too thin to weld this spot on the block effectively. Block had been bored and ported extensively, so I would love to find a fix for this situation.

It does show up at 20 lbs while pressure testing and we don't believe this part of the water jacket would get that much pressure from the water passing through.

We've toyed with using hi-temp epoxy and running sodium silicate to "fix" it. I would really like to know if this process works.

[nickthebandit]

When I was working at a company that used quite a few aluminum, and bronze castings which could be porous We had the castings pressure sealed with a Loctite product These castings were used to build dynamometers that were subject to high pressure when testing various engines. After they were pressure sealed we did not have any leakage due to porosity.

[19Fordy]

THANK YOU Admiral for posting that info.
Seems like a great idea.
Wonder what it costs?

[deuce_roadster]

I wonder how thick this coating is and if it effects cooling like a layer of rust inside does. Sounds like it would be good to do. I have an NOS block that would be nice to know it wouldn't ever rust due to the resin keeping water away from the cast iron.

[Admiral]

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Originally Posted by 19Fordy

THANK YOU Admiral for posting that info.
Seems like a great idea.
Wonder what it costs?

Sure thing, 19Fordy! Assuming this process works, and I have no reason to doubt its efficacy since H&H has done it to thousands of blocks over decades, it could be just the thing we need to keep even less-than-perfect engines running without leaks.

Originally Posted by deuce_roadster

I wonder how thick this coating is and if it effects cooling like a layer of rust inside does. Sounds like it would be good to do. I have an NOS block that would be nice to know it wouldn't ever rust due to the resin keeping water away from the cast iron.

I'd assume the block's internal passages would need to be cleaned down to bare cast iron for the resin to properly adhere. Once applied, I wouldn't think this material would be very thick at all, certainly not enough to reduce cooling capacity. Heck, many engines would probably run cooler after receiving a thorough internal cleaning.

As for your NOS block, I think rust would NOT be an issue at all, assuming you use properly mixed modern-day antifreeze.

[ford38v8]

I would think that benefits would vary for individual situations. A block that would normally be marginal would still be marginal, and some of those would fail during the process that may otherwise have been built, and further, may not have failed otherwise. This is pure speculation on my part, as "doing the math" can selectively prove or disprove such theories. One benefit that is easy to understand is that a process like this is a good marketing tool for shops that advertise its use for "every block they build".

[JSeery]

You would think if it was that great a process other shops would be using it.

[tubman]

Originally Posted by JSeery

You would think if it was that great a process other shops would be using it.

The process is probably quite expensive and appeals to only a few that can afford to "gild the lily", so it makes sense that only the highest end shops would do it. There are a lot of things I would like to do with the engines I build (pinned heads and bronze-lined valve guides ala' "GOSFAST" and perhaps this), but they are out of my budget and too far away. I would love to have an H&H engine, but alas, it will never happen. I'll have to just get by with my old "Tub Specials", I guess.

[Mike in AZ]

Pressure seal costs $120. Per their catalog. Don’t know what prep before sealing would cost. They do acid dip, hot tank, etc. Costs in the catalog Mike

[Tim Ayers]

Originally Posted by tubman

The process is probably quite expensive and appeals to only a few that can afford to "gild the lily", so it makes sense that only the highest end shops would do it. There are a lot of things I would like to do with the engines I build (pinned heads and bronze-lined valve guides ala' "GOSFAST" and perhaps this), but they are out of my budget and too far away. I would love to have an H&H engine, but alas, it will never happen. I'll have to just get by with my old "Tub Specials", I guess.

Haha. I hear you. I never thought I'd be in the camp of can't find a good block for I THOUGHT I had two proven good ones. In reality, I had none. That was an expensive lesson to find a shop familiar with flatheads.

If $120 would help me save a block, I'd gladly pay it plus tip. Tearing down a flathead sucks. I've done four within the past two months. My garage looks like a slaughter house for old, greasy pig iron.

[flatjack9]

Originally Posted by Tim Ayers

I'm interested as well. I've gone through 5 blocks. Latest one, I trusted the shop to magnaflux it and they did the normal spots, but never mag checked the valley. Sure as hell, this block has a 3" straight crack right behind cylinder #8.

My builder believes it's too thin to weld this spot on the block effectively. Block had been bored and ported extensively, so I would love to find a fix for this situation.

It does show up at 20 lbs while pressure testing and we don't believe this part of the water jacket would get that much pressure from the water passing through.

We've toyed with using hi-temp epoxy and running sodium silicate to "fix" it. I would really like to know if this process works.

That happened to me years ago before I pressure tested blocks. I used a high temp epoxy (don't remember which one) to repair the area. That was well over 10 years ago and my friend has it in his vehicle with no problems. I'd say go for it. By the way, I test at 50 lbs.

[Tim Ayers]

Originally Posted by flatjack9

That happened to me years ago before I pressure tested blocks. I used a high temp epoxy (don't remember which one) to repair the area. That was well over 10 years ago and my friend has it in his vehicle with no problems. I'd say go for it. By the way, I test at 50 lbs.

By chance, do you remember what you used? We are thinking hi-temp JB weld, but really haven't look into yet either. That will be the last option.

This block hunting is getting old quick. I've gotten to the point where I can lift a bare block in and out the truck by myself; if need be. I guess it's a good work out if anything.

[flatheadmurre]

I have a different aproach to sealing small cracks.
After pressure testing and finding a small crack( talking hairline ) i hook the block/head up to the vacuum pump i use for testing valve sealing.
Then apply fluid weld to the crack and let the vacuum draw it into the crack.
Heat cure it.
Pressure test again.

[Tim Ayers]

Originally Posted by flatheadmurre

I have a different aproach to sealing small cracks.
After pressure testing and finding a small crack( talking hairline ) i hook the block/head up to the vacuum pump i use for testing valve sealing.
Then apply fluid weld to the crack and let the vacuum draw it into the crack.
Heat cure it.
Pressure test again.

Interesting.

[40 Deluxe]

If epoxy is going to be used, do research to find a better product than JB. Not that JB is a bad product, but it's consumer grade. There are better, more expensive epoxies that are used in industry and not sold in the average hardware store.

[ford38v8]

Originally Posted by 40 Deluxe

If epoxy is going to be used, do research to find a better product than JB. Not that JB is a bad product, but it's consumer grade. There are better, more expensive epoxies that are used in industry and not sold in the average hardware store.

More expensive products are sold to Uncle Sam in which the paper trail is actually valued more than the product itself. Traceability is of paramount importance, otherwise epoxy is epoxy, and is formulated to meet multiple specifications.

[hook00pad]

My son threw a rod through the block on a 5 HP Briggs racing kart in the 90's. Since we already had quite a bit of money in that engine, I epoxied the hole with clear J B Weld. That engine ran quite a few more races, winning some and losing some, but never leaked and never blew out the aluminum block. The engine still runs and the repair was over 20 years ago.

Al Hook

[tubman]

I have heard that there is something called "DevCon" that is like JB weld on steroids. I have never had an occasion to use it, but I think "Ol' Ron" has. Perhaps he will chime in on this.

[marko39]

yes, devcon is a great epoxy that hardens like steel. i used it to repair leak in the bottom of my old air compressor tank (rust) holds well even at 175 psi.

[tubman]

Originally Posted by marko39

yes, devcon is a great epoxy that hardens like steel. i used it to repair leak in the bottom of my old air compressor tank (rust) holds well even at 175 psi.

Yikes! I guess that proves that DevCon is probably as good as people say it is, but using it that way can be very dangerous. Have you ever seen a picture of an air compressor tank that exploded? They let go along weakened seams. The rust has probably weakened the bottom your air tank, and there is a good chance the whole thing might let go. I had the same problem with mine, and formed a piece if 1/8 steel to the entire bottom on the tank about 4" wide and stick-welded it to the bottom of the tank. That was about 20 years ago and it's still holding. I still worry about it, but with my air distribution system, I'm nowhere near it, so if it does go, it probably won't kill me.

[1952henry]

Another epoxy choice...
https://www.belzona.com/en/products/1000/1111.aspx

[40 Deluxe]

A problem with a crack in the valley is the oil that has seeped into the crack as well as soaked into the cast iron itself.

[Tim Ayers]

Originally Posted by 40 Deluxe

A problem with a crack in the valley is the oil that has seeped into the crack as well as soaked into the cast iron itself.

Yes. It would need to cleaned again before repaired.

[Ol' Ron]

Many years ago I found a crack in the valley, it was quite long (4"). The block was a miled rebuild and the customer didn't want to spend much money on it so I drilled both ends, (yes it's quite thin), ground it clean grove it with the Dreml and used JB weld over the area including the two screws I put in it.. I think it's still running.
Moroso sells a ceramic stop leak, might fix some of these.

[Karl Wolf]

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In the mid 1970's,
I worked in an automotive machine shop.
There was a fixture for doing pressure checking, made by Irontite
As an adendum, there was a provision for curculating heated Irontites "ceramic motor seal" through the head being checked.
It didn't get used a lot- I don't remember what the cost was.

Karl

[tubman]

I thought the Belzona video about repairing a crack in a block to be quite interesting.

[Tim Ayers]

Originally Posted by Ol' Ron

Many years ago I found a crack in the valley, it was quite long (4"). The block was a miled rebuild and the customer didn't want to spend much money on it so I drilled both ends, (yes it's quite thin), ground it clean grove it with the Dreml and used JB weld over the area including the two screws I put in it.. I think it's still running.
Moroso sells a ceramic stop leak, might fix some of these.

OK, thanks. It almost looks like a casting flaw that finally let go. I’ll post a picture of the area soon.

[1952henry]

Originally Posted by tubman

I thought the Belzona video about repairing a crack in a block to be quite interesting.

I have no experience with it myself. I know they used it at work for heavy equipment, including leveling a floor under the drag transmission on one of the draglines.

[51woodie]

I have used different Devcon products over the years, depending on the application. Most industrial supply stores stock it (at least in Canada), and the products are available in various sizes. Here is a link that will get you in the general direction, but a call to their tech support, is often the best way to get the stuff that will work best for what you are doing.


https://itwperformancepolymers.com/products/devcon

[philipswanson]

Originally Posted by tubman

I have heard that there is something called "DevCon" that is like JB weld on steroids. I have never had an occasion to use it, but I think "Ol' Ron" has. Perhaps he will chime in on this.

I have used Devcon extensively but never on a block. Great for repairing splines and other structural repairs. I used it on the floor of my 40 in seams.

[philipswanson]

I would be leery of putting a coating in the water jackets. Would inhibit heat transfer to the water and act as an insulation.

[Ronnieroadster]

Originally Posted by philipswanson

I would be leery of putting a coating in the water jackets. Would inhibit heat transfer to the water and act as an insulation.

Theres no way to get to the area from the water jacket the repair would be on the block surface in the lifter valley area. The years of oil into the pours of the casting can be dealt with by pulling a vacuum from the water jacket not easy but also not impossible and then spray into the flaw with a good quality cleaner to remove the oil. Like old Ron wrote that are of the block is very thin theres no material for pinning. However its possible to be tig welded with a lot of care its best to experiment welding on an old junk block first. Many years ago i repaired a similar area with leak issues with just good old JB weld and as other have seen its still holding perfectly on a non stock hot rodded flathead.
Ronnieroadster

[philipswanson]

Originally Posted by Ronnieroadster

Theres no way to get to the area from the water jacket the repair would be on the block surface in the lifter valley area. The years of oil into the pours of the casting can be dealt with by pulling a vacuum from the water jacket not easy but also not impossible and then spray into the flaw with a good quality cleaner to remove the oil. Like old Ron wrote that are of the block is very thin theres no material for pinning. However its possible to be tig welded with a lot of care its best to experiment welding on an old junk block first. Many years ago i repaired a similar area with leak issues with just good old JB weld and as other have seen its still holding perfectly on a non stock hot rodded flathead.
Ronnieroadster

I wasn't speaking of a valley repair or any repair. I was referring to the process of pressure sealing locks in general. Not for a repair process but eliminating corrosion.

[russcc]

I had a small pinhole in one cylinder just above the bottom position of the piston in a 59 block that showed up in pressure testing after boring. I called Mike Herman and asked him if he used Irontite Ceramic Motor Seal, and would it seal that pinhole. He said that Irontite was the process they use, but it will not work in the combustion chamber. I called Irontite and the engineer said the same thing, the can't guarantee a seal in the combustion chamber.
This is the product. Irontite makes the pin and kits for pinning blocks.

[Yoyodyne]

I called Irontite and the engineer said the same thing, the can't guarantee a seal in the combustion chamber.

Does that mean it won't work in your case, because the cylinder is exposed to combustion?
How did you fix your block?

[40 Deluxe]

Originally Posted by Yoyodyne

Does that mean it won't work in your case, because the cylinder is exposed to combustion?
How did you fix your block?

As long as the pinhole is below the top ring, it's not in the combustion chamber.

[Tim Ayers]

Here is a picture of the crack in the valley on the 59AB.

[cmbrucew]

Tim


That looks like one for Ole Ron's repair.


Bruce

[russcc]

The pinhole was in the combustion chamber. We bored & sleeved it. Got the NOS sleeve from Fred at SSO. Worked great. The shop used some type of sealant between the sleeve and block. Same stuff they use on valve seats.