Ok, Here is the skinny. I sent my housings out to have ported. When I got them back the otherday, I was checking them over. I noticed that the place that did the porting went a liitle to far and had to use JB Weld/epoxy to seal the coolant passage from behind. The front plate coolant passage is completely sealed with epoxy above the intake port and the rear plate is partially sealed by epoxy where it was pushed down into the coolant passage.



My question is this. How bad is this? Ihave read that some people do this to get as much port as possible. I just don't think it is right to pay money for something that is now hacked up. The one passage is completely sealed off on the front. Will this stuff come out? Does it just mean that I now have a pretty agressive port or did I get f*cked.



Mike



I have not had the chance to speak to him yet so no names are being given out.

 

ya that blows, you should get some new irons and find a new port shop. by the way who did the porting?

 

I do not want to say until I have the chance to talk to them. Lets just say that the housings went in for other work and they said that the ports could stand to be a bit larger. They seemed to have a good handle on different port styles and sizers so I trusted that they would do a good job enlarging my ports. I was told I had a mild street port and that there was 20% more that could be gained.



Now I am not only out the money I spent on the porting but the money I spent on the housings. This is a double whammy.



Mike

 

As long as the surface was properly prepped for the epoxy it should be fine

 

Well, that is what porting IS. You're hacking up the housings.



Sometimes the port shape extends beyond the casting, so you have to epoxy or weld as needed. Welding cast iron being fairly tricky, epoxy is generally used.

 

what about the fact that the coolant passage on the front iron is completely sealed.



I understand that porting is taking metal away, but how many good porters need to use epoxy to fill a hole they created when porting?



If it boils down to I now have a nice big port that flows well at the expense of having some epoxy to fill a hole that won't ever cause a problem then fine. But if this is a sign of bad things to come then that is what I want to know.



Mike

 

Well you gotta understand that even though Mazda tries... All plates are not cast the same. This will happen sometimes. As long as the surface is clean JB weld or good industrial epoxy will hold up.



Just make sure that you can reach and seal it from both sides to give the stuff a better anchor.



Good luck.

 

As far as plugging the coolant passages: The one on my P-Port housings are completey filled. IT is a relatively low heat area so I'm NOT worried about it. And filling the passage ensures the epoxy cant break free.



If you want to, go ahead and drill a small coolant passage thru the epoxy

 

I have one of my ports epoxied on the back side using a product called Resin Lab. Used to be known as plastic mastic and it's the only thing recommended by the top shops for filling holes. I know Judge Ito uses the same stuff. He actually puts it in BEFORE porting and then ports as needed. My engine ran without leaking for well over a year. When I had the engine rebuilt by CLR, they found a crack in one of my dowel pin holes so the iron was replaced. It would have gone on forever realistically...it's great stuff.

 

afaik Ito uses JB Weld.

he just mentioned that someone (Rob / Pineapple?) suggested Plastic Mastic. or not?