Unseen24-7

I'm currently rebuilding my 6 port 13B (due to a coolant leak) and disovered the source of my coolant leak...broken groove on the front iron (see pics). My dad took a look at it and he figured he could weld it up no-problem. The iron will probably be lapped slightly anyway so any uneveness from the weld should not be a problem.

My only real concern is that the heat from the weld will adversly affect the nitride coating on the rotor surface. Will this be a problem? Any other things I should be aware of?

Thanks,
Devan

beefhole

iTrader: (29)

The nitride coating isn't really necessary there (not in the combustion chamber). However, why get it welded then lapped? You can find tons of 6 port irons cheap, you're better off just buying a used one in good shape.

GoodfellaFD3S

iTrader: (213)

Definitely get another iron. It's already been compromised and is much more likely to have another break at a different spot...... don't use it.

Gurew

iTrader: (4)

it can be done with nickle but really this is only done on expensive irons like 20b centers etc...what year/type engine iron is this, i might have another one

arghx

iTrader: (3)

if this is a 6 port iron you shouldn't even consider repairing it, those are dirt cheap

Unseen24-7

its an '87 (made in '86) 6 port, MT. The front cover oil o-ring boss is an old style.

Why would you say that? Welding is free to me, and lapping can't cost more than a used iron can it? Wouldn't you have to lap that used iron anyway? I'm not trying to justify fixing it, I'm just asking.

How common is it for irons to break water seal grooves like this?

Gurew

iTrader: (4)

its very uncommon because there is alot of labor involved in the welding and cleaning up the weld etc..you will need to tig weld with nickel if im not mistaken. lapping is a bad idea anyways...ideally you should surface grind not lap.

arghx

iTrader: (3)

I had a major chip in my s4 4 port iron when I tore my engine down. It was very close to compromising the seal. But I had overheated the car when my fan clutch failed.

A previous owner may have overheated your engine or failed to change coolant.

Gurew

iTrader: (4)

also letting the engine sit for long periods of time between driving can cause the same thing

prof

I'd change it - it can never be as good welded - and for sure it will be corroded elsewhere and go somewhere else - better off with a good 2nd hand iron with good edge on the groove.

PvillKnight7

iTrader: (16)

You can try remaking the wall with JB weld and use silicone on the seal in that area when you re-stack the engine.

Turblown

iTrader: (12)

You can probably get a used n/a iron for $50ish.

I have welded a customer's coolant seal groove, been 12k without problems. I also tore it down near 10k miles and it looked just fine.

Gurew

iTrader: (4)

go ahead and shoot yourself in the face

Gurew

iTrader: (4)

hey hey elliot whats up, heard the twin t04 turned out nice

Unseen24-7

Pardon my ignorance, but what exactly is the difference? I always thought lapping was similar to deglazing a cylinder. What type of surface finish do you want for a good rebuild? Many of the rebuild threads online show pics of irons with a dark dull grey color, not the shiney chrome look when its first disassembled. Do you even need to do anything, can it go back together just as it is (assuming no excess wear)?

Ok I'll buy a used one(if you have one, fire me a pm), but I think I'll still let my dad have a go at mine just to see how it turns out, maybe use it on a future build or something.

PvillKnight7

iTrader: (16)

http://www.youtube.com/watch?v=NB-nAeCRKd8
http://www.youtube.com/watch?v=fXfk0DrxAYY
https://www.rx7club.com/showthread.p...nding+compound
https://www.rx7club.com/showthread.p...nding+compound
https://www.rx7club.com/showthread.p...nding+compound

PvillKnight7

iTrader: (16)

If your plate wear is less than 0.004" and you are reusing the old seals you don't need to lap the plates.

jal301

iTrader: (4)

Although most people would not recommend it, if you were attempting a budget rebuild and properly prepared the area before and after welding, then it could be done with success. Don't JB Weld it.

RotaryEvolution

iTrader: (30)

you can weld it, it is just a pita.

just because it's a non turbo iron doesn't mean they will be around and available forever, people who tell everyone to pitch parts are dumb and don't think about what is down the road 10 years from now for the rotary engine. i already can't find 7's in the wrecking yards.

stevensimon

iTrader: (11)

ive welded a few. if memory serves, the early s5 turbo irons have this issue somewhat commonly. just weld it lap it and file the groove. it will not affect it in any way. also see if you have any other thin parts of the iron seal wall and reinforce them to prevent other breaks.

the surface you want on your iron is not completely smooth. oil should bead up, not just slick off but most people dont lap so as long as that weld doesnt bother it, you should be fine without lapping the surface area.

PvillKnight7

iTrader: (16)

yea.... if you can imagine an exponential decay curve for the population of rotaries in the yards for the past 5 year...we've gone from 10 to 0.

PvillKnight7

iTrader: (16)

do not dismiss the powers of the jb weld! they are great and mystifying.

g14novak

iTrader: (1)

And turn back to liquid at 180 degrees. Definitely would not trust in such a significant part as where part of the compression stroke is.

Welding + surface grinding + lapping seems like it may be the way to go. If it doesn't work, the only thing your out on is a little bit of weld and time.

PvillKnight7

iTrader: (16)

What have you been smoking?

http://www.jbweld.net/faq.php

500F continuous

Since the coolant doesn't go above 230F JB Weld will work fine.