Has anyone used the high temp JB Weld on a block?? Any success?
I used it to repair burnt exhaust ports on the 18 Couplet...2 years ago and it's driven most days..
Don't try it anywhere near the exhaust ports! Good cleaning is very important. I really don't recommend it for too much if you want to do a proper and full rebuild. But it can make good repairs of non-structural damage and many freeze cracks on an engine which has good bearings and you want to avoid the heating and cleaning required for proper damage repair which usually ruins the Babbitt bearings, and sometimes warps a block enough to also require re-milling most of the it.
One of the good things about J B Weld for minor cast iron repairs, is that it seems to be mostly non-invasive. If, in the future, you do want to do the right repair? Proper heating and cleaning for that "proper repair" generally burns the epoxy out and it does not add much to the time or cost of a proper repair.
Drive carefully, and enjoy, W2
My '26 Hupp has a crack between no 5 valve and cylinder. I drilled and filled with Devcon as a short term solution while I source another block. Six months and it is still holding!
I use steel metalized Devcon instead of JB weld. It can be machined and is ideal for metal repair. I used it to repair some water jacket cracks in my 1913 roadster 49 years ago and it still doesn't leak.
I have a friend that has had very good luck with marine-tek epoxy it is a 2 part mix black in color. I dont know if its better than j-b weld but he fixes cracked blocks in boats and says it is the best
R.S. I have good results with JB Weld on Engine blocks
This is the repair I did on my '26 Hupp. Given the location of the crack I never thought would last.
JB Weld is not a miracle cure for repairing cracked engine blocks and etc BUT its the next best thing to it.
I have used it on gas tanks, engine blocks and other fixtures.
Some will surely disagree about its effectiveness, but it worked for me.
Have you run that engine for any length of time?
I've used JB Weld to hold the rear cam bushing and driveshaft bushing in place, to repair a crack in a water pump and as a glaze to seal pin holes in a pan. It works well and will hold up to the heat of engine oil. If immersed in gasoline, it will become soft like putty. Thicker applications hold up better than thin ones. I personally wouldn't use it in high heat applications.
Jb weld is some strange stuff,sometimes it will work wonders,sometimes it has left me with more trouble than I had in the first place.
I typicaly use the Liquid steel I can get at Napa. Single part in a tube.Works well.
Where I used it 1 time was in the cylinder of a kolher engine that had broke the second ring . There was a tiny scar on the cylinder that would catch oil and the engine would smoke. Ran to well to bore and all that mess. I put some in the crack then used sandpaper to get rid of 95% of the extra then honed the cylinder and it cleaned right up.Engine is still running well with no smoke.
I also used it on a hydrolic cylinder that a chain got jammed against and it cut a groove in the cylinder. This allowed oil to get by under pressure. I sanded the groove,put this stuff in, and sanded with fine paper till there was none left but what was in the groove. No leaks. Saved a 400 dollar cylinder.
The engine in my TT runs good but had a crack in the front of the block. The guy I bought it from said it had been "welded" .What he didn't say was the JB part. I found that out later when i rubbed over the spot with sand paper. But after all this time, no real issues.
Your experience with JBW and gasoline is interesting. Years ago, I bought a McCormick Deering engine that had a gas tank in it that was more JBW than steel. It worked fine with no leaks or gumminess but I replaced it anyway. I'm thinking the difference is the alcohol content of our modern gasoline.
Interesting. It could be the alcohol. I used it to repair a buggered hole in an NH carb that was constantly immersed in the fuel in the bowl. When I opened it up a year or so later, the JB Weld was gummy. It didn't give me a problem in use, but I did notice the deterioration when I sold the car and inspected the carburetor.
Thanks for all the confidence in using JB Weld. I have wire brushed the area before any application. Is there a suggestion on a cleaner that I should consider using to ensure good contact? Dick C.
I use brake parts cleaner to clean grease and oil off most everything metal. It also dries fast. PK
I bought a Troy Bilt mower in 1985 which had a defective crack in the crankcase which caused oil to leak out. I removed the motor and V'd out the crack with a dremel tool, cleaned it with lacquer thinner and put the 2 part (4:1) epoxy Aluminum Devcon putty in the V'd out crack. 30 years later, mowing several times per summer in 95 degree heat, the Devcon is still holding. I wouldn't hesitate to use it to to repair a Model T engine block.
Once mixed, Aluminum Devcon has the consistency of smooth cake icing and goes on very nicely. When it starts to set up, you can use your water dampened finger, to smooth the surface to a glass-like smoothness. JB weld, on the other hand, once mixed, has a firmer consistency and does not spread as effortlessly or smoothly and I question how well it penetrates the depths of the crack like I am confident Devcon does. As you have probably surmised, I much prefer the Aluminum Devcon Epoxy putty, over JB Weld. Jim Patrick
Another excellent product, if you can find (and afford) it is Belzona.
I work in prototype for Ford, and we use it often to repair/modify castings for transmissions. Once it's hardened, it can be machined like aluminum. I assume looking at the posts above it's comparable to the aluminum Devcon.
There are two types though, one is more 'liquid' and 'shiny' when it dries. Try to avoid that one if you want to machine it.
Oh- and as an aside- I did use JB weld once on a Chevy truck I had. The 02 sensor bung broke off on a Sunday afternoon, and I did't have gas for my MIG. So I JB welded it back on. The next weekend, I took a load of concrete to the dump, which involved going up a pretty steep hill on 5 Mile in Northville. Once I got to the top, you could REALLY smell the JB weld burning in. In fact, I got stopped at a light next to a guy who keep screaming to his driver, "WHAT IS THAT SMELL? IT'S SO AWFUL". I had to chuckle.
By the time that trip was over, there was no more smell, and it lasted the 5 more years I had that truck.
The JB quick does not hold up in some applications as well as the standard JB weld, gasoline is one of those. I still use the old standard stuff most of the time. KGB
Jerry, I am trying not to run any distance. I only did the repair as a temporary measure as the car was on a promise. Probably about two hundred miles ago now. I have no faith it will last.
JB Weld is very suitable for engine block repair. 15 years ago, I developed a line of optical mirrors that were designed for use in high-temperature environments. In short, the assemblies where bonded with JB-weld, and consisted of three bonded mirrors that had to maintain co-alignment to the order of 2 arc seconds or less. These assemblies were put to use in the smokestacks of oil refineries to measure emissions through interferometery. The mirrors and JB weld withstood extended temperature excursions of over 550 degrees F. This went on for months and was a huge success.
The worry of JB weld around exhaust ports is unfounded. If failures were experienced in those areas of the block it was because the surface wasn't prepared correctly or the glue that was used was beyond it's shelf life. Other factors could apply too, but I could mount a stout, defense that it wasn't the fault of the adhesive.
JB Weld is good, But I believe Devcon is better. It is an epoxy like JB Weld but is also impregnated with metal powder. You have a choice of steel, bronze or aluminium. It can be machined and tapped. I do not know the effects of alcohol but as I said, I fixed two water jacket cracks in my 13 roadster block over forty years ago and have had no problems since..
Glen.. that is an excellent argument for the structural properties. My note was merely in defense of the structural properties of JB Weld in a high heat environment. I am unfamiliar with the Devcon. Is it rated for high heat applications?
Latest on JB Weld, I found out that like many other great products, JB has a type for every occasion. They have a JB Weld that is made for wet areas. The high temp one I used still weeps. I will try to grind off and use the "wet" environment type.
I'm wondering if a combination of the JB Weld and then coated with POR 15 to "seal" it from gasoline might be a solution to fuel areas so the JB Weld does not get soft?
I am looking forward to reading more of your posts ....
Several years ago I had a rusted out 1910 block to repair. Here's what I did. No leaks so far.
Royce - Since this thread has "drifted" to the degree that it has, I made an observation ref the picture of the 1910 engine block that you repaired:
I noticed that the valve springs do not all appear to be a uniform sort of "oily" color that you would expect. They have one or more coils that have a lighter, sort of gray appearance. In fact, there are springs with one, or two, or three, or four coils of this lighter gray color,.....???
Probably a dumb question that I'll feel stupid for asking about, but then I'm thinking that I just might learn something for asking about it. So what's that all about Royce, or is it really just "nothing",.....??? Thanks,.....harold
That '10 that I was working on for a friend sits in a dusty warehouse adjacent to a commercial auto paint shop where there is lots of sanding and paint polishing going on. I think what you are seeing is the shiny metal reflecting the camera flash versus the areas where dust is clinging to the oily springs on most of their surfaces.
Goes cold too.
JB fixed a small refrigerator evaporator where son had poked a hole in the aluminum freezer compartment with a knife while in college.
JB, pulled vacuum, charged and runs today some twenty years later. I was lucky that one had a schrader on it.
Ken in Texas
JB weld, I tried it on the exhaust manifold on my '29 International doodlebug engine (Waukesha XA) 25 years ago. Didn't grind or clean or anything, too young to know any better.
We ran it around a bunch back then.
Went out and looked just now and finally, a hairline crack on top.
Love these stories!