I did a couple of practice port jobs on a couple of my bad intermediate housings till I felt confident that I could do a good job on the good plates, So yesterday I started my port job which is a large street port, well the port looks damn good accept that I started to see a little bigger than a pin hole as I was using the stone to smooth the grinding, so I stoped right there,sure enoughI went into the water jacket , so I cleaned the surface and I applied JB Weld to both sides of the port on the coolant side as well as the port side, I read many fourms and mant rotary builders use the same stuff cause they purposely overport for a larger port than fill the coolant jacket hole in the port, tonight I am gonna sand the port and polish it to finish it, and feed back would be greatly appreciated,
Thanks

 

Try and use a bars stop leak too, that make circulate through your coolant and grap onto that hole and block it. But dont use too much cause it can clog your whole cooling system.

 

Don't use any "stop leak" products.

JB Weld is fine as long as the area where it was applied was PERFECTLY CLEAN. You can also weld it shut if you have the appropriate equipment (preheat, use a wire/rod designed for cast, then post heat). Brazing is likely the best approach a it won't ever crack.

 

I personally wouldnt trust it, especially given how cheap and readily available used irons are.

I've never heard of a legitimate builder filling ports with jb weld, unless it's a full bridge or p-port.

 

I think I am gonna stick with the JB weld, cause the hole is so small and people have actually used this tuff to fix cracked engine blocks, the intake ports dont even get that hot, nowhere near its temperature rating and if I sand it and polish it, it should be good to go, plus I put some inside the coolant jacket to form kind of a double layer,"I mean ****, why wouldnt it work, yes, if I wasnt pressed for time I would get a new rear iron, but I dont have anymore time, I have to build now"plus it is chemical resistant, should resist gas, anitfreeze etc, and it is waterproof. but the point is I effed up and I fell confident 99.9% that this should work without a problem, anymore feedback greatly appreciated
Thanks

 

I find it odd that many novice engine builders are willing to jb weld up porting mistakes or cracks in water jackets, yet they balk at the mere idea of reusing rotorhousings or some internal seals/springs.

But yes, it will probably work...for a while, anyway. I wouldnt like the idea that it could get hot, become brittle, break off, and go through the engine. Do you have any idea what sort of air turbulence and vibration will be encountered long-term? With fuel being sprayed directly on the repair most of the time?

 

yah, thats a pretty good point, I will look into a new rear iron. I have allready invested about a 1000.00 into my rebuild so there is no reason to go half assed now and have one little mistake trash everything, thanks for the advice

 

STUPID idea....... if you want that engine to last, do it right (get a new one, or braze it). not to mention the port walls must be extremely THIN in the areas you ported if you busted through, doesn't matter if its a pin hole, if you busted through, the entire port wall is thin now in that area.

JB Weld has its place, and its NOT in engine parts/componants.

~Mike............

 

True That

Thanks

 

Braze it.

 

what all is involved in the brazing process, how do I do it, sorry about the dumb question

 

i'm with Kevin, he just beat me to the post...


i would find another iron and try again, filling it with JB weld only works if the spot has plenty of grab onto the surface and thick enough to not break off and go into the motor and is mixed properly in one setting not 2. in other words, large port jobs they often use large amounts of the stuff and create pockets for the weld to grab onto and hold since the iron expands and contracts at different rates than the JB weld. those engines are built for short term performance use not daily driving. so if you want a long lasting engine i would advise against using it.

again, i suggest hanging it on the wall for ornamentation and finding another iron.

i've been down this road, ignored people's suggestions and learned from my own mistakes though people told me what would happen. save yourself the trouble.

 

JB Weld (or any epoxy) is not going to work well in that kinda environment.
One of the things most epoxies have a hard to resisting is heat.
Heat is typically used to SEPARATE epoxy bonds.

Metal expansion will cause separation or cracking.

Get the bitch welded at minimum.


-Ted

 

An iron is a big lump of metal, so you'll need a decently sized torch. Oxy acetelene or a large oxy propane. You will need to TOTALLY CLEAN the surrounding area. Get a die grinder with a little wire wheel and make sure it's STUPIDLY CLEAN, then clean it some more. A bronze flux-covered brazing rod that says "For cast iron" on the tube should be used.

You need to heat the area until the brazing rod melts by touching it to the area to be repaired. Don't get it too hot, or you will burn the zinc out o fthe rod and the repair will be weak. Google for "how to braze" for info.

You will likely find that you will have to preheat the entire iron in an oven to several hundred degrees.

Or do what everyone else says and get another iron. They're cheap.

 

Thanks so much everyone

 

Thread closed, I got a new rear iron, this time I am gonna make sure I dont eff up, thanks again everyone