Titanium 26b E-shaft

PaulC · 11-19-03, 04:54 PM

OK my best friends brother just bought a machine shop in which we were drafted to help clean up. Its an old place and there was lots of crap that had collected over the years. Well Ronnie said that any of the scrap we could have if we needed something made in exchange for helping him clean up and make the shop a decent place to work in. Enough back ground. I found in the junk a 44"x6"diameter titanum dowel. Ronnie agreed that he could and would help me make an ecentric shaft. Now I just need a schematic or a way of designing my own shaft. And it being made of 3032 titanium it shouldnt flex under the torque. I think the Eshaft has been the killer on all the other 26b ideas that have floated around.

Ive been contemplating this since saturday and am still torn. I know having each rotor fire independantly would make for a much smoother reving engine. But didnt the LeMans car fire 2 rotors at a time? I probably should have done a search for more info but I need to run to work in a little bit. I was thinking of running 2 20b center sections and probably hand fabricating intakes and exhaust using standard exhaust piping.

Any advice would be great. good, bad, or indiferent. This could become another pipe dream but I'm hoping not at this point.

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Jeff20B · 11-19-03, 05:42 PM

Imagine two 13Bs with their E shafts 90º apart. That's how the 26B is supposed to run. This allows one leading spark every 90º. I'm not sure about the firing order though.

j9fd3s · 11-19-03, 05:45 PM

1-2-3-4 or 1-3-4-2?

Evil Aviator · 11-19-03, 08:28 PM

http://www.mymazdarotary.com/mazda_r...paper_html.htm

http://ccn.aitai.ne.jp/~engineer/profil1.htm

PaulC · 11-19-03, 10:26 PM

Thanks

Ya'll have given me someplace to start.

j9fd3s · 11-19-03, 11:59 PM

that second site is neato

the water pump is a factory mazda race peice, zr03-15-010.

looks like a 1,4-2,3 firing order, 4801 dizzy, 76-80 housings neat neat neat

Evil Aviator · 11-20-03, 12:13 AM

Quote:

Originally posted by j9fd3s
looks like a 1,4-2,3 firing order, 4801 dizzy, 76-80 housings neat neat neat

Babelfish surfing rules!

Node · 11-22-03, 02:19 AM

what about titanium having a tendency to eat the shit out of things when its metal/metal contact when friction is concerned.
would you just have special bearings? I'd assume you could do it the same as ti conrods for cars as far as the bearing.
what about the ends too, what about the other metal/metal contacts?

PaulC · 11-22-03, 02:35 AM

Well the metal on metal contact shouldnt be any worse than normal provided all the tolerances are kept. As far as friction how are the bearings already lubricated? and since titanium has a lower coefficient of friction than the stock steel eshaft that shouldnt be a concern.

Node · 11-23-03, 04:57 AM

but i have seen a few times people say that titanium is very bad in metal/metal contact, itll chew stuff up
thats why titanium apex seals chewed up that one guys motor.
if you could get around that, awesome

would be cool to see someone on the forum make a 4 rotor, let alone his own e-shaft.

PaulC · 11-23-03, 05:02 PM

Well Titanium used in apex seals would tear up the rotor housings as the seals are pressed in and out of the rotor. All rotor housings are worn by the apex seals so I would assume that titanium ones would just be that much worse. Personally teflon would seem to me to be an awsome material to make apex seals out of if it could handle the heat and have the strength to make the compression.

However an E-shaft spins in a preset well defined set of parameters. I cant see how that would tear anything up. Besides jet engines use a mirade of parts including titanium with little or no ill effects.

j9fd3s · 11-24-03, 02:04 AM

i think titanium could work its a matter of getting the clearance right.

mike

PaulC · 11-24-03, 04:05 PM

The Titanium should work with the right clearances. Should also be stronger than the standard steel so handling what ever amount of torque coming out shouldnt be a problem.

Bitchn7 · 11-24-03, 08:22 PM

why doesnt someone make a shaft out of the sma ematerial the top fuelers use for their cranks? if they can handle 5000+HP I am sure they wouldnt flex etc when used in 4 rotor or 3 rotor form

PaulC · 11-25-03, 12:05 AM

Im sure someone would for the right price. this price happens to be free

if patience can be called free.

CCarlisi · 11-25-03, 12:30 AM

I believe steel E-shaft flex becames an issue at around 9,000rpms. This leads me to believe an e-shaft made out of softer material might be problematic at more sane engine speeds.

Do you know what grade titanium the block is?

3/2.5 ti flexes more than steel. Commercial pure titanium, the cheapest and easiest to acquire (usually from russian suppliers) is even more flexible. 6/4 is the stiffest, but a pita to cut. I used to do suspension development for mountain bike company that worked exclusively with titanium. The 6/4 alloy was the material of choice, but was so hard it dulled conventional cutting tools at an alarming rate. They used to cut it with some kind of water jet.

PaulC · 11-25-03, 02:08 PM

I thought it was 3032 but Ronnie said its somethign much tougher since its used as a coupler of some sort mating drill bits to the shafts. He said if that if a small displacement engine(under 1000lbs/ft) breaks it, it has an internal flaw. So there is a semi offical statement as to the material.

Still havent found a nlue print for the Eshaft

might need to develop one from scratch ...... that will kinda suck. My drafting skills arnt what they used to be. And I havent done machined parts inspection work in years.

Steel · 11-25-03, 07:56 PM

but the problem with titanium is that it galls, much like stainless steel. A splinter can flake off and jam the eshaft lobe against the inner rotor bearing. I'd stick with a really high grade steel.

tmiked · 11-25-03, 08:08 PM

Titanium is gall city, so if there is M2M contact, you are up a creek.
Also the expansion is greater than steel so clearances will have to be larger reducing oil pressure a lower temps.
Titanium is twice as flexible as steel, so for the same size shaft, it will flex twice as much.

Bottom line :
Its a poor choice for an e-shaft. Maybe you could make some halfshafts .....

IrishDawg · 11-26-03, 12:00 AM

just as a note, scoot's 4rotor fires each rotor by itself, though i don't remember the order.

Node · 11-28-03, 12:31 AM

gall, thats the word!

DaedelGT · 11-30-03, 09:57 PM

Just a note. You can actually get stainless steal harder than 6-4 Titanium.

17-7PH, if prepared right (50% Bainite soln.) is about 20% harder than 6/4, even when cryo treated.

btsnook · 12-06-03, 07:13 PM

hey...if youre still interested in making the 4 rotor, try www.grannysspeedshop.com, strangely enough the guy making a lot of v8 conversion kits built a 4-rotor using 2 13b's and he made some kind of coupling to connect the 2 13b e-shafts. he faced the e-shafts 180 degrees from each other and removed the counterweights, as the 2 engines would then balance each other. he used an aluminum plate to join them together, its pretty interesting...he said he got about 500 hp out of it N/A with low compression and shitty pump gas. it would be a fun project if i had 2 working 13b's and a whole lot of money to blow.

PaulC · 12-07-03, 12:31 AM

theres a thought to counter my using 2 senter sections from a 20b.

EricM · 12-07-03, 10:44 AM

Quote:

Well Ronnie said that any of the scrap we could have if we needed something made in exchange for helping him clean up and make the shop a decent place to work in. Enough back ground. I found in the junk a 44"x6"diameter titanum dowel

Hehehe... I'm surprised nobody caught this before. 44"x6" titanium scrap ? Wow... you've just found a treasure my friend. That thing is worth at least 5G's there. I'm an engineer and I know the however few 18"x4"(or thereabouts) titanium piece that we bought from MSC costs at least one large.
You must have helped your buddy remodel his shop.