Port epoxy

[BVHOG]

With the obvious issue of the M8 heads having too large of an intake port for the 107-114 ci has anyone considered using port epoxy? I had a set of SBC heads done 30 years ago at Wegner auto in Markesan WI that had a large amount of epoxy used to raise the port floor (Aluminum Brodix) and they never gave me any issues whatsoever.  If so, what brand? where to buy?  I'd be willing to at least try it on my own test bike.

[Durwood]

With the obvious issue of the M8 heads having too large of an intake port for the 107-114 ci has anyone considered using port epoxy? I had a set of SBC heads done 30 years ago at Wegner auto in Markesan WI that had a large amount of epoxy used to raise the port floor (Aluminum Brodix) and they never gave me any issues whatsoever.  If so, what brand? where to buy?  I'd be willing to at least try it on my own test bike.

I have had the same thought Bob. A friend of mine has been running a set of Reher-Morrison built Brodix heads on a 565" BBC with epoxy in the floor of the intake ports without issue for quite some time. No idea of what formula RM uses, but it works, at least in this application.

[kd]

The M8 heads run hot. Will the temp difference and aluminum expansion rates be a problem with epoxy?

[Durwood]

A quick breeze through the car forums I see the brand name "Splash Zone" is used quite a bit. Even Darin Morgan says it's the only brand he's seen stand up to rigorous conditions.

Looks like Amazon has it.

https://www.amazon.com/Splash-Compound-pettit-A788hg-Gallon/dp/B012RWU6UM?tag=vs-auto-insert-amazon-20

[wfolarry]

They said the same thing about the 110 heads too. 
Durwood beat me to it. I use splash Zone. Works well. Long term use you might want to seal it with Devcon epoxy but for the short term it's not needed.
I don't think it's needed but that's me. Good luck. Both of you have dynos so you can test it right away.

[1FSTRK]

Goodson PRK-99 has worked well for over 15 years in heads for HD race bikes and for prototype testing. It has run well on the street for tens of thousands of miles in throttle bodies and intake manifolds. I have not seen run in the head for customer use on street bikes but I know of a few high mile test bikes that it was used on with no trouble.

With any port filler surface prep, cleanliness, and proper mixing will make or break the entire process. 

[FSG]

I've not seen the stuff so had to Google it

https://goodson.com/products/prk-99-intake-port-reshaping-kit

[1FSTRK]

If you decide to try this get a box heavy Nitrile Gloves this is sticky stuff and the cheap gloves that come with it will rip if you touch it with them. Second thing is the wooden sticks are not strong enough to mix and apply it. A good smooth plastic works best.
When prepping think porous more than rough, roughing with a carbide cutter the finish is rough but the cuts themselves are smooth. A very sharp blasted finish works and any touch up with 80 grip paper.

I would model for the flow bench with Permoplast Clay and when you have it close outline it, take a picture and remove it to prep the surface then apply the actual epoxy. It sands and polishes to a finish similar to the aluminium. Carbide burrs will work on it but it will dull them.

[Moparnut72]

Keep your gloves wet and it won't stick. I have used this for fixing the fountain in my yard. Very tough stuff. I actually use my bare hands but keep them wet.
kk

[BVHOG]

Thanks guys, planning a trip to goodson in the next week or so to set up a mini ball driver for the M8 heads and will check out their stuff then. Probably a call to Wegner would be in order as well.

[dsvracer]

I have tried the goodson epoxy and found it difficult to work with. makes a mess in the port and then to try and shape it was difficult at best.  maybe the contents of the can were old but it didn't work for me.  i have tried all kinds of epoxy and it does make it a lot easier to build up but i find welding it is just easier and you do not have to worry about it falling out.  JMO
I have welded several sets and they work just great.  dsv

[1FSTRK]

No doubt the the use of port fillers does have a learning curve but welding has it's own set of problems, the biggest being you lose the heat treat in the head. Back in the early 80's when welding was the only option there were lots of problems, as welders improved and people gained experience things got better for sure but Harleys are still Harleys and we face challenges that just do not exist in the automotive world no matter what what method is used.

[dsvracer]

yes there is a learning curve on using the epoxies but when it falls out of the port and into the motor now you have a customer who is not all that happy.  with the welding i have found that if you keep the heat down then it doesn't seem to have a negative effect on the head. been welding hd heads since the early 90's and have had no issues.  The m8 heads are a bit tricky as they do need a lot of filler but the results are worth the extra time. and i do not have to worry about it falling out of the port.

[BVHOG]

After comparing a stock head to a set of the SE version I have came to the conclusion that welding may be the best option, the area that needs to be filled is pretty accessible. 

[wfolarry]

Epoxy the port for testing. When your flowbench & dyno are both happy have the heads digitized. Weld up the heads & have them CNC'd. Repeatable results every time.

[Don D]

Again agree with larry.
My thoughts
Just because the SE heads are higher and smaller is no guarantee they are much better performance wise than a reworked,  not welded stocker. CSA needs to be measured and velocity studied. And the motor size becomes a large factor (demand). Airflow study done and mods verified by dyno testing.

[PoorUB]

Epoxy the port for testing. When your flowbench & dyno are both happy have the heads digitized. Weld up the heads & have them CNC'd. Repeatable results every time.

If you are just going to remove it after testing, why not use something easier to shape and later remove, like body filler.

[dsvracer]

i start off using JB weld and when i get the results i am looking for, i measure the port and then bring in the welder.  the jb gives me and idea on where to weld and where to stay away from.  works pretty good for me. dsv

[K4FXD]

I know not the same,

In my younger days I was porting a set of Mopar 440 heads using Direct connections port templates. I decided to open up the intake side of the head and broke through into a water passage. I mixed up some JB weld and slathered it in there. When it dried I shaped it up.

It held up till I tossed a rod through the block. Maybe 200 1/4 mile runs plus a ton a street racing.

Wish I still had the templates, they worked very well.

Not sure if it would hold up to the aluminum heat cycles.

Larry has the best idea.

[Moparnut72]

Direct Connection was the way to go. I put one of their shift kits in a 727. I used the mid-level set up. My Duster would bark the tires going into second even with mild acceleration. I've often wondered what the race setup would be like.
kk

[HD/Wrench]

Epoxy the port for testing. When your flowbench & dyno are both happy have the heads digitized. Weld up the heads & have them CNC'd. Repeatable results every time.

[1workinman]

They said the same thing about the 110 heads too. 
Durwood beat me to it. I use splash Zone. Works well. Long term use you might want to seal it with Devcon epoxy but for the short term it's not needed.
I don't think it's needed but that's me. Good luck. Both of you have dynos so you can test it right away.

Years ago I bought a set of angle plug heads that came off a g gas car that the intake port was mostly Devcon. Never gave any problems . That was a long time ago