For repairing aluminum, this is the ****. Bonds super well, can be machined, drilled and tapped. Fixed some 250R case saver mounting bolt holes. Holding up great!

 

I use Moroso A/B epoxy. Its very easy and formable to use, as well as tough enought to withstand an exhaust port repair on V8 Drag engines. You can find it through Summit Racing and other hotrod type shops or online.

 

When I was looking around about this on the net both of those names seemed to come up alot. Great to hear guys, I would love to try them when I get the chance. Are either of them sold at your average retail store? I would think not...I know Devcon is essentially a Loctite brand, but that is a less common product....

Just to add I recently tried a product called PC Fahrenheit, just to see how it would do, and I can say that it will NOT form a suitable bond for use with an engine.

So far, I am going to have to say that the standard JB Weld is the only "average" product that I would even consider.

Has anyone tried the Z-Spar Splash Zone epoxy? I hear it is top notch stuff, but it is pricey.

 

We have and that is what most porters use! we have an extra package if you need! Bought 2 complete units (A&B) and goes way too far for small ports when you have 2 gallon!

 

Moroso A and B will crack over time with oxy fuel. Devcon and Z Spar are a little pricey to be filling ports and then cutting back out. The Devcon IMO is a little more for case repair etc and not so much a port filler. If you mix a little water into the Z Spar it will push into areas much easier, its really thick after you knead the two together.

I use JB Industrial. Self levels, cuts well and stays in. Prep work is key with all epoxies.

 

Moroso A and B will crack over time with oxy fuel.

Thanks for the input. I have never encountered any cracking from it, but most of the engines I did were 1500+ HP assisted engines, and they werent allowed to run oxy fuel.

Also, I would mix a bit of red loctite in the mix as well.

 

Awesome information!

Dyno, I appreciate it, and how much?

Is there any difference between the JB weld, industrial, and marine? Specs are the same or similar...perhaps the application environment alone is what distinguishes them?

With regards to porting specifically, I've been trying to groove my floors a fair amount to help with securing. Is this preferred? And also, the edges seem to be the weak points, which is where the epoxy is usually thinnest, and this seems inevitable. Are there any sealers that help to secure points like this?

Thanks again for the replies, guys

 

some people clear the ports with automotive paint clear coat to seal it.

 

I have heard a little bit about that. I was wondering if they were using standard clear, or a high temp clear? Granted, standard automotive clear seems to hold up well on our vehicles, even on hot, sunny days, and I would bet the surfaces reach 150-200 degrees F.

 

i would use high temp. ive never done it but higher would have to be better for this application

 

I used JB Industrial. We'll see how it holds up. Application was a breeze. It self leveled and when you prop the head at the correct angle, only a small amount of blending is needed along with some surface abrasion to break up the boundary layer.

As far as the grooving goes, I took my square ended carbide rotary file and dug the corner down into the port floor about and 1/8" or so, and also finished the factory port floor with a 40 grit roll. Those two things should give it a fair amount of bite to hold the epoxy in.

Before application, the port surface was cleaned with Berrymans B-12 and then denatured alcohol, then heated briefly with my torch to dry them all the way out and drive the condensation out of the aluminum. I am a welder by trade and it is always a good idea to remove the water from all metals before attempting to bond them, either by fusion/welding, brazing, or chemically. With most adhesives, water is an impurity and will weaken the bond to the metal. The water microscopically forms a layer on and just below the metals surface, thereby limiting the cohesion of the two. It may feel dry to the touch, but trust me, all metals absorb water, even the atmospheric humidity, aspecially at colder temperatures. CA or Cyano-Acrylic glues and urethane ( Super Glue and Loctite are most common) need water as the molecular catalyst to harden. Thats why its a good idea to wet the surfaces if you are using superglue or loctite for something.

Don't believe me? Take any cool piece of metal and run a torch over it for a couple seconds and watch the water sweat out of the metal then evaporate. This is critical to good adhesion. Like he said, its all in the prep. The intake tract of the head is a very low stress area that has no impact or torsion forces, the only force it has acting against it is the pressure from the airflow. Most shelf epoxies are strong enough for this. Most of the time, the problem lies with the adhesion to the metal because of impurities on the metal. Thats when the epoxy comes apart.

mho - juice

 

I hope it works well for you! The head I have sitting here has gone through almost the exact same treatment, except I used standard JB Weld and a heat gun rather than a torch. I hope it was adequate...

 

What's the purpose of the loctite?

 

Thats a tip I got from Kenny Dutweiler once when I was at Comp Cams. He claims it make this particular epoxy a bit softer once set....possibly to keep it from cracking. He did a bunch of rockwell harndness tests on it mixed with different type stuff such as loctite. I took his word, and Ive done it since, after all he does his homework.

 

kenny dutweiler knows his stuff.

 

Thanks Torque, very interesting stuff! I would have never thought to use something like that.

Just as an update, after playing around with the idea of sealing and speaking with a few companies, I am gonna have to say it is probably better off alone. Aside from making it much more difficult to get a stong bond while still preserving the natural "texture" necessary for the port to maintain proper mixture, it seems like these companies are not confident in prolonged exposure to gasoline. So if you are gonna do epoxy work, take all the necessary prep procedures, and I feel like the bond with "itself" is enough to preserve the structure of the epoxy in the spots where bonding is a tad more difficult.