I have been contemplating an idea and wanted to throw it out to the community for feedback.

I have a coolant seal failure on my 1990 RX7 that I just bought. I have been reading the various quick fix posts and am leaning towards trying Alumaseal because it sounds like people haven't seen negative results as far as if/when they tear open the engine, there isn't a bunch of crap built up on places that aren't good. So this leads me to thinking about how the 12A motors are much more successful with this fix because the coolant is being pulled into the combustion chamber, hence the white smoke. But mine, being a 13B motor, has the typical issue where the coolant system is overly pressurized, driving the coolant into the overflow tank. So I had this cross my mind:

What if I put the alumaseal into the radiator and leave the cap off. Then start the car and get it to running temperature.Shut car off at this time. Then putting my coolant pressure tester onto the radiator and pump it up to say 20psi, maybe more. My thought process is this would force the alumaseal into the combustion chamber, similar to how the 12A seal repair goes, maybe making it more likely to work. I could cycle to running temperature, then shut down, cool down, then restart, and so on and so forth. So I am curious what you guys think of this.

One thing I will have to look at is can I run the car without the radiator cap on and not have it spit the coolant out because of the seal failure. And I also would like to hear if you guys/girls think I should pull the thermostat out, or should I leave it in, and drill a couple of holes in it to relieve the pressure buildup that is created when the engine is running. so it doesnt spit out all the coolant from the radiator. The whole premise of my plan again is to try getting the alumaseal and coolant to travel into the combustion chamber like the 12A failure does while hot.

I guess another possible way to do this would be to put my coolant pressure tester on the radiator right away with the thermostat either in with holes drilled, or take it out completely, then pressurize the system right away....and run it. But I think this would create more pressure into the cooling system from the combustion chamber pressure, and max out the pressure tester, possibly making the issue much worse.

Ok, I hope to get some feedback ASAP. I want to give this a shot one way or another by tomorrow to see if it will work..

 

I think you should be the guinea pig. Do it and report back!

 

If you're going to use the product, why not follow their directions?

 

I'm guessing you haven't looked at what the product is used for....radiators and heater cores. Not RX7 coolant seals. I see you have thousands of posts on here so I may be preaching to the choir, but if you search through all the posts with keyword "alumaseal" you will see that even though the product isn't for RX7's coolant seals, it has worked about 90% of the time in the 12A vs 30% for the 13B. This is most likely due to how the failure occurs, as I explained in the original post. So I am trying to make the 13B coolant run in the same direction as in the 12A during this failure. The problem with making that happen is the amount of pressure that is forced out of the 13B while running. So I decided I am going to give my plan a try. I am on my way to the shop now.

 

been there and done that on personal cars.

a) don't bother with alumaseal, i have had **** for luck with them on FC engines.
b) don't pressurize the system before starting the car, simply crimping the overflow hose does the same thing. but stand back and prepared for the possibility of things exploding... this is why it's not recommended because i have seen hoses blow up like balloons under some cases.
c) Bar's leak copper headgasket sealant works best but it leaves a fiberglass like material in the water jackets, usually not enough to really worry about but the radiator core may need to be rodded out.


it's nothing groundbreaking, the copper block sealant works temporarily and isn't quite as bad as some people claim it to be to clean up. but it's just buying you time if it works, don't think you will get away with it for long. it will in the long run cost you more money to clean up though, but alumaseal itself i really wouldn't even bother with it because in many cases FC coolant seals have failed due to a broken iron wall, not a minor seal leak like FD and FB engines.

 

Well I am afraid you are right. Alumaseal 1, me 0. I ran the car for about 5 minute intervals, then put 15-20PSI to the radiator for about 10 minute intervals, rinse and repeated for an hour and a half. Didn't even seem to slow down the ubbles and champagne bubbles. I would think this thing would be smoking or run like crap. But no, it runs perfect. Bummer. So I guess I will pull the motor tomorrow and learn me some rotary engine building techniques. lol. Anyone in Colorado want to show me how it's done?? Does anyone just replace the coolant seals or is it almost mandatory to do other stuff while in there? I suppose maybe porting should be considered at the least?

 

I actually had success with it in my S4 NA-powered FB. My engine was consuming about a quart of coolant a week, was starting on one rotor, and had occasional white smoke and backfiring on startup. Didn't have any champagne bubbles though. A half bottle in the morning and a 5 mi trip to Denny's and all my problems have disappeared.

 

not just soft seals, apex seals are the most costly single part of a rebuild and the OEM 3 piece seals in your motor belong in a garbage can. seal springs will be worn and need to be replaced for proper tension, keep reading..

the side seals will also be at or beyond the .015mm spec once beyond 50k miles, second most costly part of a rebuild, corner seal wire springs also belong in the garbage, corner seal plugs and oil seals need to be trashed also, so.... hence why i keep saying plan a budget of at LEAST $500 even if you rebuild it yourself, this doesn't include parts necessary to reinstall it back into the car and be reliable.

sure you can possibly get away with slobbering some silicone and adding in some oil seals but when those 3 piece apex seals let go, so will your rotor(s) and housings(s), even a single pair is more costly to replace than a set of apex seals not including going through the whole hassle again. then there is rotor housing step wear to contend with... more wear, less compression and performance.

 

Thanks for the advice. I have started looking at where to get the soft seals and I see guys are ordering from McMaster Carr. But so far I only found a part # for the inner seals. I believe I will go with Viton. Does anyone have a master part # list for the 13B soft seals? I would be mighty appreciative if someone listed all the soft seal stuff I need. Then I can start looking for the other stuff.

I would be interested in buying a good kit from somewhere, but I am kinda broke right now. So trying to do this on the cheap.

 

there is no metric equivalent that i have found for the outer seal(or even imperial for that matter, it is a huge o-ring). they have to be commissioned or put together by hand.

Mcmaster carr has the inner silicone FEP seals, they work but don't last as long as OEM or viton inners(because it in fact uses teflon to seal the engine together, the teflon chafes over time). the FEPs are great for race engines but not good if you want another 200k/25 years from your engine, they are highly reusable for the short term.

you can simply just get an aftermarket master gasket kit from atkins for $125-145 which has most everything you need minus rotor oil seals and front+rear main seals. hard seals and springs have to be ordered induvidually in kits. it's really not a bad deal considering you will need all those gaskets anyways for the install. i used to use them on all rebuilds until i built up a rediculous amount of stock and only needed the engine soft seals and began putting together my own kits for that purpose.

i use viton for just about everything now, saying it is a great material is an understatement. the viton seals will hold together even a cooking motor up to 300F, but at that point the rotor housings have since compressed and warped.

 

McMaster Carr is 9319 K239 for silicone, but they also offer Viton, part # 93445 k516. They are $15.80 each. So you say for outers I may as well get them from Mazda if I don't just go with a kit?

 

forget the mcmaster carr seals and just get the master gasket kit from atkins, it has OEM inner/outer seals, dowel seals, tension bolt seals, stat gear seal, front cover seal and all misc gaskets for the engine assembly long block.

but for clarification, the FEP seals are totally encapsulated by teflon, the material the inner o-ring is made out of basically just determines the tension the seal will give. viton will have slightly higher yield than the high temp silicone floroelastomer. the inner o-ring NEVER touches the sealing surfaces, only the teflon. so long as it doesn't melt, all is fine, so viton may be better but i have yet to see that high temp silicone liquify but have seen OEM seals turn to jello and run into coolant passages at 300F.

 

https://www.rx7club.com/rotary-car-p...-626610/page4/

read this ... i do viton off the roll often ( customer depending ) ,, with better results than even mazda seals

PS
for those with s4/5/6 plates wanting to get temporary relief for a couple of months ,, bars stop leak and another called iron- tite are best for the iron water groove engines

not recommended as it doesnt fix a broken away water seal groove,
,, common in these engines , making it a 50/50 guess if you have a cooked seal,, or ruined water jacket ,, with the result un-predicatble if you try the stop leak

relief will only be temporary,, 3 - 6 months at best , depends on your problem

 

i'd recommend not dousing yourself with gasoline just yet, start a first rebuild with known good working parts before building parts for your engine from scratch. the OEM seals aren't great but they do work just fine, just not reusable or on the cheap.

 

If combustion gasses are over pressurizing the coolant system, there is nothing that will help short of an engine overhaul. If coolant is getting into the combustion chamber you have a chance, and alumiseal seems to have the best results in those situations.

Case in point: https://www.rx7club.com/2nd-generati...-990170/page2/