JB Weld and Hidden Repair

Larry Evans lfevans@pacbell.net posted

Nearly 15 years ago my brother and I repaired some damage to the cylinder bore of a 3 hp. Fairbanks Morse Z. Before we got the engine the wrist pin had worked loose and gouged two sets of deep parallel grooves the full length of the stroke. We didn't want to go to the expense of boring and sleeving so decided to try the wonder product called J-B Weld that we had heard about. We cleaned the area and ground the grooves out a little deeper for better adhesion and applied the epoxy per the instructions. After it set up we carefully sanded down the high spots and then honed the cylinder. All of a sudden the engine now had some decent compression.

The engine has now run many hundreds of hours since the repair. Even though the engine has maintained it's high compression we decided to pull the piston and check on the condition of the J-B WELD. Much to our delight the four grooves still were filled with the material and no high or low spots could be felt. I tried to take some pictures but just couldn't get my camera inside the cylinder.

Regards,
Larry Evans
Arcadia, Southern California, USA
mailto:lfevans@pacbell.net
http://www.oldengine.org/members/levans/

John Culp johnculp@chartertn.net responded

I patched a rough spot in the side of my IHC M's hopper, filling it a bit above flush intending to grind it smooth. Big mistake! Cast iron grinds off with an abrasive wheel more easily than J-B Weld. Took a lot of careful work to get it smooth.

I had to remove a previously botched J-B Weld repair from the bore of my Coldwell Cub. Got it out by heating it intensely with a propane torch, but I had to get it so hot I was worried about the bore getting overstressed and cracking. It finally turned chalky and could be scraped out. I replaced it with fresh J-B Weld and smoothed it perfectly flush with the bore by pushing a lightly oiled ring through the bore with the piston crown while the J-B Weld was still soft.

John

Joe Betz jlb94@juno.com unexpectedly said

I have purchased engines -
later to find that many repairs are done with J-B Weld.
It IS pretty remarkable stuff, and has it's place.

However - I am very much against making repairs with the quick
and E-Z, J-B Weld method.
Unless YOU are the only one to ever own that engine.

My only concern is this - - -
When you sell that engine - -
Will you tell the purchaser what he's getting ???

Just my opinion.


Joe Betz said that.
Library, PA
jlb94@juno.com

Joe......

At first I was going to let this pass without comment but I began to wonder why you would take such a stand. I respect the fact that you stated it is just your opinion but as I thought about it I had to assume that what you did not like was the fact that J-B WELD is a product of relatively new technology and not available when the engine was built. The fact is that J-B WELD has been around at least 30 years and I'm sure that there are members of this list that own and show engines that were in use even more recently than that. If my assumption is correct then I guess that it would also be inappropriate to lubricate the old engines with modern lubricants, paint them with modern paints, use a little carefully trimmed Teflon tape for fuel and water line joints, synthetic rubber hose for fuel lines, etc., etc.

To carry the concept a little further I guess I should not use any of my electric hand or shop tools when working on my engines since many of the farms of that era had no electricity. I suppose I'd better get rid of the fluorescent lights in my shop also. I'm sure the list could go on and on but this is enough for starters.

I'll probably also have to forget all information that I've picked up on this and all other Internet sources since computers, digital imaging, web sites, etc. are relatively new. The post office and telephone will have to suffice for communication but licking the new stamps doesn't make them stick any better and I can't find the crank or dial on my phone.

Also I don't recall stating that this was a quick and easy repair. It probably would have been quicker and I am sure it would have been much easier to take the block to a good machine shop and ask them to bore and sleeve it back to the original diameter. I doubt that I could have gotten away with just boring the cylinder and then having the piston enlarged with metal spraying as that technique probably was not available in the early 1920's. In the original post I didn't bother to mention that it took several hours of very careful work to contour the newly applied J-B WELD back to the exact shape of the cylinder without damaging the original cast iron.

As far as telling a potential purchaser about the repair, of course I would and offer to pull the piston and let them inspect it. I have nothing to hide and I am sure they would be delighted that the cylinder bore was one part of the engine that they would not have to worry about.

Regards,

Larry Evans
Arcadia, Southern California, USA
mailto:lfevans@pacbell.net
http://www.oldengine.org/members/levans/