Don Terrill’s Speed-Talk

In the past i was advised to use JB Weld to match a manifold runner to the head. When doing work on my intake I found that it detached from the alu and kind of ballooned. Luckily it didn’t come off and wind up in the motor.

So what’s best ?

No experience with it yet but I haven't heard anything bad about splash zone yet.

Belgian1979 wrote: ↑Thu Feb 15, 2018 6:34 am In the past i was advised to use JB Weld to match a manifold runner to the head. When doing work on my intake I found that it detached from the alu and kind of ballooned. Luckily it didn’t come off and wind up in the motor.

So what’s best ?

Honestly? Weld is the only thing I trust. There are epoxies out there and i have a couple on the shelf and on a drag engine people use them, but if you want to know it's right and never ever have to worry about it the weld it.

I have never seen any kind of epoxy last forever. Fuel or heat or both degrade it and eventually it starts to peel or come loose. I agree weld it and it lasts forever. Now next thing is to get a good welder who knows their stuff so head does not warp or crack after the welding process.

Splash Zone is the the easiest to use and is the least expensive. Have it in lots of heads and holds up real well. The absolute best is Belzona 111, but it is very expensive and harder to work with. But the Belzona will stand up to alcohol also.

It won't balloon as the JB Weld?

Welding is not really an option due to possible warping and having to resurface. I rather leave it alone as is if it cannot be filled.

rebelrouser wrote: ↑Thu Feb 15, 2018 12:09 pm I have never seen any kind of epoxy last forever. Fuel or heat or both degrade it and eventually it starts to peel or come loose. I agree weld it and it lasts forever. Now next thing is to get a good welder who knows their stuff so head does not warp or crack after the welding process.

Does this include splash zone and belzona ?

I wouldn't trust ANY type of epoxy or adhesive for longevity. OK to use for short periods to test port shapes etc. I have used Devcon, one of the many heat & supposedly fuel proof epoxies, but it eventually goes soft & cracks.

The severe temp differences & the hot/cold cycles that the adhesives are exposed too cannot help either, from ambient temp to 180+.

I believe the Ceramic expoxy types are the best way to go .

Just a question when I leave it as is : cut the intake gasket to fit or leave it ?

I would have thought the different thermal expansion of iron and ally compared to the epoxy might also come into determining which one is best for an application

Belgian1979 wrote: ↑Thu Feb 15, 2018 6:34 am In the past i was advised to use JB Weld to match a manifold runner to the head. When doing work on my intake I found that it detached from the alu and kind of ballooned. Luckily it didn’t come off and wind up in the motor.

So what’s best ?

Surface preparation is everything in epoxy bonding. Aluminum in particular oxidizes quickly, so you need to prepare the surface and apply the epoxy immediately after preparation completes. I have used JB Weld original without fail in both gasoline and E-85 applications. My current air cooled head has run the same epoxy on the port floor for 7 years. Even though they are more difficult to work with, I prefer the paste to the putty formulations. Most paste have better mechanical properties primarily because they include less filler. The Belzona 1111 is the only Novolac/Bisphenol epoxy blend I have found, all others are Bisphenol types. (A or F). The Novalac base is the reason it is more resistant to alcohols.

It was grinded prior to putting on the JB Weld. So unless were talking about oxidizing in a matter of seconds I don't think that was the issue. I have to admit in most places where I had to place a small layer was ok. The balloning took place where I had to make it 2 mm thick.

Belgian1979 wrote: ↑Sat Feb 17, 2018 12:02 pm It was grinded prior to putting on the JB Weld. So unless were talking about oxidizing in a matter of seconds I don't think that was the issue. I have to admit in most places where I had to place a small layer was ok. The balloning took place where I had to make it 2 mm thick.

it happens almost instantly. The oxide layer forms and seals the material below protecting it which is why it appears aluminium doesn't corrode, but the surface is oxidized so nothing will stick to it very well. You could clean it and apply a self etching epoxy primer then put the the fill material over that. Or you can put screws in from the bottom that can anchor the fill...or both.....or call around and find someplace that can weld it. If you are talking about 1/2" - 1" deep on 1 or 2 sides of the manifold and less than 1/4" thick then the whole job should be less than an hour of work...I charge $100 for something like that when it shows up here if its clear and you've clearly marked where you want weld and you never have to give it another thought.

You just need to find someone who know WTF they are doing though. Welding engine parts that have been soaking in fuel and oil is a bit different than welding clean virgin metal, you have to roll the torch a round to float up the contaminants and understand they come to the top so the top of the weld will look like sh!t. A lot of time I hit it with the torch then need to clean it again before I can think about adding fill because the surface is contaminated almost instantly....aluminum is like an oil sponge and you need to burn it out. Its easy enough to do once you know that's what you need to do but you need to find someone who knows that is what you need to do and won't try to mig it or something else dumb.