Look you noob, stop spreading bullshit.

I tell you what...put together all the housings minus the e-shaft and the rotors.
Snug tension bolts but leave the dowel pins OUT.
$20 says you can twist the housings with the tensions bolts in there.

This is not a realistic example of of what forces can damage the dowel pin lands, but it gives you a good idea of the myth of what the tension bolts do.
The tensions bolts just keep the housings together, but they do NOT keep the housings from twisting relative to each other - that's the job of the dowel pins.


-Ted

 

Ted: Do you have any input in general regarding 2mm vs 3mm without the dowel pin breaking? Since this is obviously turned into a more 2mm vs 3mm debate and general topic of such, I figured I might as well ask. Though, I am quite impressed that it's not too bad of a fight yet.

 

Nice write up. Btw, car looks good in the avatar Kevin.

 

What I want to know (a question not likely to be answered by anyone with the inside knowledge required) is why the rotary was designed, and worse yet, produced, with only 4 dowel pins. I mean, I'm not a structural engineer, but if I were looking at it from a design standpoint, knowing what forces act on an engine in a performance setting (as the rotary was/is marketed as), I would have probably thought to myself that there is no way 4 pins is enough to hold this entire engine together properly. I would have went with a *at least* 8, 1 on each corner of each half of the engine. It's obvious that their 4 pin design works, but it's not like it would have been any harder for them to design in 4 more pins for double the strength. There is plenty of room in the other 2 "corners" of teh block, with open/blank castings just sitting there serving no purpose.

 

Raising hand...

2mm seals, rear iron cracked, in the same spot as your pics, except I lost the rears apex seals too...

 

So what you're saying is that an equivalent break on your 2mm motor damaged the 2mm apex seals, while the 3mm's held up?

 

Or is it possible that break occurred because of the broken 2mm peice jamming something up? More than likely not, but figured I'd ask.

 

No, both rotor and rotorhousing are softer material than the iron which broke. As commonly seen, the rotor and/or housing would give first...plus there is only 2mm of seal thickness to cause problems, while most of these breaks show several mm of play.

 

path of least resistance..the seals are new and strong..the iron is older and worn with posible stress fractures that were not visible during the rebuild...just a thought

 

Oh, we really don't want to get into that, right?

I have never been a supporter of any of the aftermarket seals (well, can't afford $1,500+ Ianetti's!).
I truly believe is the stock Mazda OEM apex seals for almost any application.
I'll just leave it at that.


-Ted

 

does RA make a 2mm seal? If they're that strong then why not use 2mm for benefits of a better seal and less friction? I thought only reason for a 3mm was for strength to protect agaisnt detonation thats gonna happen on any street car. Like mine, just built 1500 miles and one night it creeped 2 psi what it was tuned for and I chipped a stock mazda seal. wouldn't a RA 2mm seal have held up and give you the best of both worlds?

 

bump

 

Why are we bumping this?

RA makes a 2mm seal...all you had to do was look?

http://www.rotaryaviation.com/2_mm_apex_seals.htm

Look at it this way.

The 2mm ra seals are made from their special alloy, and are X amount strong. The 3mm ra seals are made from the same material, but are now 1.5x times as strong. How is that hard to understand?

 

durr it's not lol but if a 2mm ra seal is stronger than say a regular 3mm seal then wouldn't it's be strong enough to handle most everyday situations and still have all the benefits of a 2mm seal. ie less wear and friction?

 

With the reliability records rotary engines hold when modified for high output, I think most would try to go for all the strength possible.