PTS Flowbench Forum

what is the best epoxy to use for reshaping or repairing ports? both intake and exhaust. i have seen epoxy used alot but have read some conflicting reports on its ability to work. i need some for reshaping the intake runners on some harley heads. has any one used the A B type that moroso or manley sells?

Intake manifold/ ports, cast or alu, z-spar is what i us.(It's original intention was for repairing bottom of boats, will set up in or out of water. 2 part epoxy.
It's kinda expensive but you can fill many a ports with it.
had mine for 2 years now, still works good!

There's and epoxy out there some wheres that's used for the exh side, i think.......probably be cheaper to have the exh side welded, i think.

ok i have read about that. were could i purchase som from? do you know of any retailers so that i would not have to order it online.

I knew you were going to ask me that.......lets see if i can find it..............
OK, this is the only place i know that you can by it by the 2 Q instead of 5 gal.

There's many names for it. Z-spar, Splash Zone, and a couple others i can't remembered.
as long as it said A-788 on the can somewhere, it's what i us.
here you go!

http://www.marinenutz.com/products/Z%25 ... ller*.html

look like it on sale too

From the Z-spar site;

A-788 is also solvent and chemical resistant when cured. It has been used as a grout and to patch perforated steel in tanks and pipelines holding mineral spirits, xylol (xylene), gasoline, acids, alkalis, hot water solutions (up to 160 deg F).

Z-spar seems to be the bench mark but I know of a shop that uses Devcon exclusively. Plastic Steel and/or the Titanium Putty depending on the application.

Z-spar can be tough to work with and there are a lot of tricks people have figured out over the years.

Although it comes highly recommended by many, I worry about the low temp range of Z-Spar - particularly if used on air cooled engines.

I wonder if someone originally used it for a repair after breaking through into a waterway and others have just taken it a step further using it for general port filling.

Like many fillers and adhesives a lot of it is about good surface prep too.

Like many fillers and adhesives a lot of it is about good surface prep too.

I will 2nt that!

As far as the cold, i will be giving that a good test. although my car never is run below 50*(no choke, no intake heat,) it does have to survive vary cold winters.

I have seen it in the -30's F told of the -40'sf. my garage has seen -10 many many times.

If i ever get these heads done and on my car, we will see. personalty i don't thing there will be a problem.

Just a tidbit off the subject but.

I was taking to guy on the internet that, as a kid, would hang around a local head porting/machine shop, that work on a lot of small block Mopars.

He told of a lot of experiments, most that failed. Like bring the 18* chry head valve angle up to 20 then angle milling the deck surface to bring the valve angle back to 18........and it failed.

He said that they like to polish the roof and bowl area but tried to keep the flloor as ruff as possible.
They us a lot of epoxy trying to get a better shape for the port. The thing he said next kind a shocked me but made me go Hmmmm.
He said that they would mix the cast iron grinding back in the the epoxy before laying it on the floor/ssr, gave it a good texture and he said it was hard to even tell it was epoxy there.

Sounds like a NO EPOXY rule class trick to me
But for the texture reasons, when i get a port shape that i'm happy with, I just might try it!!!

Flash wrote:Just a tidbit off the subject but.
He said that they would mix the cast iron grinding back in the the epoxy before laying it on the floor/ssr, gave it a good texture and he said it was hard to even tell it was epoxy there.

Sounds like a NO EPOXY rule class trick to me

Brings back memory's from the early 90's of my Saugus Speedway days. Sometimes it's not what the rule book said you couldn't do but what it didn't say you couldn't do.

the air cooled heads that i am working with run at a temperature anywere from 250 - 300 degrees. so i dont know if a 160 degree rating is high enough. i have looked at an epoxy that a few manufacturers have and they have one style for intake and one for the exhaust. the intake is two bars of putty you mix. i spoke with a rep from one company he said it was just for filling holes not changing the shape. i dont understand why that would be. i will try to post alink