Making your own apex seals?
 

Okay, as far as I can tell, the major cost of rebuilding a rotary engine is the apex seals. I'm wondering if it's possible to make your own apex seals if you have a CNC machine or general shop tools? What all parts are necessary when doing a base rebuild of an engine? I don't doubt that I could do the work myself, but I was quoted like $950 for a rebuild kit, which seemed really really expensive to me. What can I do?

Can you (or do you want to) make your own piston rings on a piston engine?

To make apex seals they require the same know how, and metallurgy.

Re: Making your own apex seals?
 

:) For 950$, you can get whole j-spec, with turbo, shipped to your door! :)

The gasket set is ~135$ from the dealer.. Hurley apex seals are 150$ for a "set" (I'm not sure if a set == one rotor, or two... prolly one..) Springs, add in 20$ for the set.. Depending on what else you really need, you may be able to scrounge by with just that. I hear side seals don't often go bad--but don't quote me on that.


http://www.hurley-engineering.ltd.uk..._Tip_Seals.htm

I'm VERY much considering just going with the J-Spec turbo swap, only problem is I can't find a place selling one for $950, course I haven't looked too much, I'll look up some places now.

Can you recommend any places to me? I want one with good compression, enough to last me about two years at least, after about that time I'm going to be dumping $3500+ into a full rebuild and re-working of the whole engine (oil flow, porting, etc). So, what places can you recommend that are GOOD?

where can I find J-spec motors for this price (and in good condition)?

yeah swap for a turbo motor! Just don't forget to pick up a good engine management system.

henry--

A few places.. www.corksport.com has them.. I hear fc3s.org is/is going to sell them.. Someone I was talking to on AIM got one cheaper than corksport....can't remember where tho.. If i find him, i'll ask..

-Tesla

So what's the deal with buying a J-spec Motors? Do you buy them because they're cheaper? Or do you buy them because they're "J-Spec"

From working on both American and Japanese FC's, I see little to no difference in the engine's themselves(that means internals). I have seen one difference though, and that is that the catalytic converter's over here are different than the ones in the States, but other than that...no real difference.

All the corner/apex/side sealsand springs are genuine mazda, rotor housing, front/intermediate/rear housing appear to be the same, eccentric shaft with rotors are made of the same material....but it seems that a lot of people make a big deal about having a "J-Spec" Motor. What gives?

Please someone enlighten me!!!

Actually Jspec rotarys are just engines out of wrecked cars from Japan. Unlike some Jpecs (like some Toyota and Honda) The only advantage over a rebuilt is only price, there is no power difference. Although occasionally you get some extras, like upgraded/performance clutches or larger turbos since all the accessories are often attached.

You should note that most Jspec engines have at least 20k miles on them, and average between 30k miles and 40k miles. However the last one I opened last spring had at least 60K miles on it or they didn't change the oil often enough.

So the advantage is instead of paying $2000 or so for a rebuilt, you can get a motor for about $1000, that should last another 40k miles.

I am shopping for one right now, that I will rebuild first to new specs this winter and then put into my project Vert.

So that's where all the junked FC engine's are going!!!:D

You guys are making it crazy hard for me to get spare engine's here in Japan!!!

But hey, it saves you money.

So then my question is this...how much do junked fc motors in the states cost?

about $1000, actually the '88 and earlier go for like $850, the newer ones go for like $950.

Hurley seals.
Well, i think they are just made from soft cast iron.
Only reason they are better than mazda is they are a little cheaper for us to buy.

If they were that good why wouldn't mazda use them?
Mazda (Japan) isn't stupid.

I'm going to get one tested.

Anyone want to know what i find out?


Glen

The reason why azda doesn't use them is because THEY make their own. Why would they buy from someone else when they make their own for probably under a dollar. Also Mazda wants to sell their product. The last reason is that hurley has not been around since 1969 to make them for them. Thats like asking why doesn't Ford use Chevy's Piston rings just because they say they are so good. Thats just what I think. I am very interested in the hurly's though, has any one tryed them? Is the $150 for 3 or 6 seals?

CJG

do you think mazda would produce masses of engines with 'stock' 2 mm 3 piece apex seals if there was a 'better' option?

2mm 3 piece seals are the best seals you can get.

if you cant tune or dont trust whoever that does your tuning, there is some room for 'error' in 3mm seals, however, 3mm seals have been known to break from one ping just like 2mm seals can do.

Hey dont you aggree though that mazda makes their seals for very cheap? I mean once they have the machining proces down then all they have to do is buy the material and pay some japanise worker $3 an hour to sit their and make them. they are cast right? or are they milled. I am not super knowledgable on how they make them. Any ways I suppose you could make your own. I do think I heard though that the certain metal that mazda uses to make theirs is almost or is impossible to get. And thats after you pay to have a metalurgest do all the test to find out exactly what it is. I do aggree with you thuogh that mazda probably did do their homework and what they use is pretty much the best.

Man,you guys are choked about 150$for seals? Try743$ per rotor for Ianetti ceramic seals?They live forever but man 2 sets per race season adds up. trust me if I could make them I would but ,for what it costs to buy the equipment to do it ,it's cheaper to buy them even at 743 per rotor!:bigeyes: if you want to see a hint of the eng. that go's into this find the book The WANKEL engine by Jan P. Norbye printed by chilton book company in 1972 I may have the only copy on the face of the planet:eek:

Re: Making your own apex seals?
 

Apex seals = $300-400 for the set

Com[;ete rotor kit (includes apex & ALL other rotor seals) = $700-800
Rotor housings = $400-600 EACH
Side housings = $200-400 EACH
Gasket kit = $90-450

Apex seals not major cost of rebuild.

That's the only reason to use them... do a search for Hurley in the forum, there was a big discussion/debate/argument/pissing match a few months back, basically what turned out is that Hurleys are housing-friendly when they go bad, and they build more low-RPM compression than even Mazda seals, however they ARE weaker (the wedge corner of the long half likes to break off because that supports most of the weight of the seal as it passes the exhaust port) and over time they leave a black crud residue on the housings.

I could see using them as an alternative to carbon-apex seals for a 3mm seal engine because they'd last longer and could still go over 8500rpm, but I don't see the point for a 2mm seal engine - the factory stuff can't be beaten. (Note that I'm talking N/A engines here... for a turbo engine the choice is Mazda factory stuff)

notice how only mazda has the milling technology and process's to make 3 piece seals while everyone esle can only make 2 piece seals without the small corner piece?

I have two copies of that book !

One is as New condition, like it was just delivered to a book store, I payed $10AUS for it in a second hand book store :)

The other copy I gave to a friend of mine...I am a nice guy sometimes ?

You must be a nice guy! that book is worth it's weight in gold! He must have let you date his sister in trade.:evilgrin:

as long as we're discussing J-specs... if we were going to build a real FC project car, and start with a core from a j-spec, which would be the best core to use? (obviously the 20B, but in the 13B size area). Working with an aftermarket single turbo, and a fuel management systemm would the 13BT-REW just bolt in otherwise? Any other signifcant changes? I know the J-Spec Cosmo 13B would require custom engine mounts like the 20 b would. Anything else?
Or would it just be better to stay S5 13BT?

Im new to all this rotary engine stuff. And im a bit confused.

But, I have a few questions. Apex seals seem to be the weak point of the rotary engine correct?

If money was not an issue, what would be the way to go? Is there an "Indestructable" Apex seal? Or are all of them pretty much the same.

I have read many different opinions on this. Some say that 2mm are sufficient some say 3mm are the best. 2 piece tend to be weak, 3 piece is the way to go. But no aftermarket Apex seal comes in 3 piece. Do they just not have the machinery or know how to make 3 piece Apex seals yet?

What do the high HP rotary cars use? Drag rotary cars?

Is their an alternative to Apex seals, kind of like O-Ring for a piston engine?

Now, what causes an Apex seal to fail? I don't remember exactly but I read somewhere it had to do with improper tuning. This meaning what?

Why can't this be corrected? Or how can this be corrected? Guess im done. Thanks!!