I have commishioned a local machine shop to look into pinning our latest engine project. There is a 1 time $600 tooling fee to make the base and cnc program. Which I will most likely be eating. And it is $400 for one engine. However, If I can get more engines to be pinned at the same time both prices go down. The idea is that it takes quite a bit of time to get everything setup.



This is GURU style pinning only it uses a bolt instead of a stud with a nut on the back of the engine. You can do all the bolts or just the combustion side.



Each bolt hole will be reamed out to a tight tolerance fit for the new bolts. The bolt becomes a pin as well as a bolt.



Anyways, Im calling out local folks and others are welcome to get the price a little lower.



Its prolly going to be another couple of weeks before we have the materials (bolts) fully tested so if anyone is interested in getting in on this pm me for details.



Also, these guys really know what they are doing. They are the r&d engine machine shop for a local snomobile manufacuture. Last time I was in they showed me a cyl head with removable combustion chambers they had made. Talk about a quick way to change your comp ratio. https://www.nopistons.com/forums/pub...1047683473.gif



Thanks



GregW

What about remachining for the Aussie-Style Studs?

isn't a stud better than a bolt? Because as your tighten the nut down on a stud, the resistance (tightness) is not divided between stretching the bolt, fighting the friction of the threads and the friction of the seat. Where as on a nut, you are only really fighting the small number of threads and the small area for the seat of the nut that is against it's mounting surface.



Btw where are these super strong bolt obtained? are they cut on on a lathe from stock? Because cut threads are substanially weaker than rolled threads on a commercial bolt/stud.

[quote name='banzaitoyota' date='Apr 7 2005, 10:16 AM']What about remachining for the Aussie-Style Studs?


[/quote]





Not quite following ya here. We are using new bolts taht are thicker than stock. They are cut to length and threaded on a lathe. Threads in front plate stay stock.



We could do studs or bolts I guess, I just like the bolt idea better.

The stock torque is 32lbs. Which isnt ****. You DONT need a super strong bolt to hold 32lbs of torque. Yes, thes are quite long. However, You could easily lift a 1/2 ton truck with one of these bolts. Nuff said.

GMON: I HIGHLY recommend you go read Carol Smiths triest on cutting threads in CRITICAL fasteners! A CUT THREAD IS NOT AS STRONG AS A ROLLED THREAD!. I admire the work you have put into this project, but all the fancy CNC MAchining is for Naught with the use of a sub-par fastener!

[quote name='banzaitoyota' date='Apr 7 2005, 10:30 AM']GMON: I HIGHLY recommend you go read Carol Smiths triest on cutting threads in CRITICAL fasteners! A CUT THREAD IS NOT AS STRONG AS A ROLLED THREAD!. I admire the work you have put into this project, but all the fancy CNC MAchining is for Naught with the use of a sub-par fastener!


[/quote]



banzai, I totally agree with you. That has been taken into consideration. I have been assured that the threads will rip off the cast before they will rip off the cut threads. Keep in mind this starts happening WAY above the envelope for the 29 ftlbs of torque required.



This was one of the first issues we discussed. We have a meeting set up for late next week and I will print this off so we can rehash this issue once again.



Maybe a test is in order for these cut threads on a junk housing. That should put any question to this issue at rest.



Another thing you need to remember, anyone that is doing this mod does not expect their engine to be one that goes 100k. It would be nice but above 400hp you as well as I know rotarys dont last long(relative). Im not saying we are doing anyting half assed. Im just saying the cost should mirror the benifit.



Thanks for all the input, keep it comming.



GregW

Update: These are the studs being used.



http://www.xtremerotaries.com/main2/stud.htm



Again, we still need to nail down "exact" pricing. We are just looking for others to help lower per engine cost.





Thanks



GregW

I am in with GMON on this project, the guys doign this are incredible, the owner took a snowmobile engine, cut it in half and put it on a go cart.... i was impressed. We have a meeting for next friday and will be bringing my motor up there but would really liek to lower this price.

Update: These are the studs being used.



http://www.xtremerotaries.com/main2/stud.htm



Again, we still need to nail down "exact" pricing. We are just looking for others to help lower per engine cost.



For 1 engine and 4 of the above style studs its $400 + bolt price. We are currently looking into the exact price of producing studs with these specs 4140 Chrome Moly, 180.000 psi tensile strength, all heat treated and black oxided.



Yes we are copying Guru, sorry, Aussieland is way too far for me to send my engine. And I dont see a patent anywhere https://www.nopistons.com/forums/pub...#>/biggrin.png





Thanks



GregW

Sorry for a bit OT but who's doing the work if ya don't mind revealing your source. Only reason I ask is that I'm familiar with quite a few shops up in that area from my two-stroke days. Owned several of those heads with interchangeable domes. That's common place. The really trick stuff is the actively variable chambered head. Sweet stuff!

[quote name='GMON' date='Apr 7 2005, 12:58 PM']Update: These are the studs being used.



http://www.xtremerotaries.com/main2/stud.htm



Again, we still need to nail down "exact" pricing. We are just looking for others to help lower per engine cost.



For 1 engine and 4 of the above style studs its $400 + bolt price. We are currently looking into the exact price of producing studs with these specs 4140 Chrome Moly, 180.000 psi tensile strength, all heat treated and black oxided.



Yes we are copying Guru, sorry, Aussieland is way too far for me to send my engine. And I dont see a patent anywhere https://www.nopistons.com/forums/pub...#>/biggrin.png

Thanks



GregW


[/quote]

Hey I was wondering if any of you guys have seen,heard,or tried this lighten E-shaft it sound great but if its not worth it then forget it. Someone help me out

here is the siteGURU

[quote name='86base' date='Apr 9 2005, 02:03 AM']Hey I was wondering if any of you guys have seen,heard,or tried this lighten E-shaft it sound great but if its not worth it then forget it. Someone help me out

here is the siteGURU


[/quote]



I personally would never use a needle bearing for that application. If you going to go that far what would be so hard about taking a step further and running a tube down that access hole by the dip stick and using a oil bearing?



I think its a start of a great idea.

[quote name='C. Ludwig' date='Apr 9 2005, 01:31 AM']Sorry for a bit OT but who's doing the work if ya don't mind revealing your source. Only reason I ask is that I'm familiar with quite a few shops up in that area from my two-stroke days. Owned several of those heads with interchangeable domes. That's common place. The really trick stuff is the actively variable chambered head. Sweet stuff!


[/quote]



Eckvall Engineering

[quote name='GMON' date='Apr 11 2005, 06:44 AM']I personally would never use a needle bearing for that application. If you going to go that far what would be so hard about taking a step further and running a tube down that access hole by the dip stick and using a oil bearing?



I think its a start of a great idea.


[/quote]



Whats wrong with a oil-fed roller bearing in this use? I think its far superior to an oil-film bearing for this purpose.

Thats a great price and shipping wont be killer. Definitly keep us updated. Thought about doing lightened rotors? And it would be great to have a lightened/ 2 piece e-shaft source in the states.

[quote name='scathcart' date='Apr 11 2005, 11:05 PM']Whats wrong with a oil-fed roller bearing in this use? I think its far superior to an oil-film bearing for this purpose.


[/quote]





They tend to chatter and slip instead of rolling at higher speeds. For load carrying ability its pretty hard to beat a hydrodynamic bearing.



I have a Norton rotary in bits and it has some nasty marks on the eshaft from the bearings (needle rollers) in the rotors.



With these studs or bolts that are being discussed have you taken into consideration the difference in axial stiffness of the thicker studs compared to the standard bolts, Im guessing that the cross sectional area will be two or more times that of the standard bolts. The increase in stiffness may be enough to start plasticly deforming the housings as the engine heats up.

[quote name='scathcart' date='Apr 11 2005, 11:05 PM']Whats wrong with a oil-fed roller bearing in this use? I think its far superior to an oil-film bearing for this purpose.


[/quote]



They suck in so many ways when compared to a hydro bearing. (My opinion)



If you have 100psi of oil pressure your e shaft is spinning on a 100 lb per square inch coushin of oil all arround it. Hydro pressure has some amazing propertys as well.



GregW

[quote name='Cheesy' date='Apr 12 2005, 01:54 PM']With these studs or bolts that are being discussed have you taken into consideration the difference in axial stiffness of the thicker studs compared to the standard bolts, Im guessing that the cross sectional area will be two or more times that of the standard bolts. The increase in stiffness may be enough to start plasticly deforming the housings as the engine heats up.


[/quote]



Yeah, Im back to wanting regular pins. The bolts are $400 for an engine. Thats before the machineing is done. We meet the guys on friday so hopefully we at least get going on something. Lots of pics to follow.



GregW

I've been thinking a about this a bit more, another solution may be to get gome 4340 or 4140 or whatever tube instead of rod/studes and tap the ends. This way the increase in cross sectional area will not be as large but there is still the benifit of the added torsional rigidity.



Totaly agree with the bearing thing if youve got oil pressure you cant beat a hydrodynamic bearing for simplicity, load carrying, reliability and cost



Dave

I have been setup to do this for awhile I guess I should try and get on here more.

[quote name='Zero R' date='Apr 16 2005, 05:13 PM']I have been setup to do this for awhile I guess I should try and get on here more.


[/quote]





Little more info please. Like what part of the country do you live in?

Update



Ideas have come and gone and here is where we are at. These pics are just testing the limits.

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Greg,

i stay impressed with your perseverance and attention to details. i'd love to come in on this with you, but sadly, i'm way out of pocket until i finish school.



Jason

Just got a call from CletusFD3s. They said his engine is done....Now he just needs to pay for the thing and Ill post some pics.



His cost $500 for 6 pins. Also, they said the FD block had WAY more room for the pins than did the s4 block I gave them for testing..... Should be effing bulletpoof once we get the tune spot on..... https://www.nopistons.com/forums/pub...1047683473.gif





Now, got to figure out what the next project for them will be. Thinking light rotors or a two peice e-shaft with a hydro bearing in the middle. https://www.nopistons.com/forums/pub...1047683561.gif



Anyways Im pretty stoked.





GregW

Like we chatted about on AIM Greg, I'd like to know the difference in engine knock chamber pressures vs. that of a very high horsepower engine producing high chamber pressures. It seems to me that for anything under several hundred horsepower, this might not be useful. From what I understand, the necessity for pinning an engine in this manner is to prevent rotor housing to iron housing deflection. Anybody happen to have any experience with 500+hp setpus that produced actual deflection not from engine knock?



The cars 've tuned so far haven't ever exhibited this but I have seen busted dowel lands as low as ~300's rwhp due to engine knock.



B

Someone wanna sell me a cheap RX7 so I can get in on this. Oh yea and what exactly is pinning??

[quote name='BDC' date='Jun 2 2005, 11:59 AM']Like we chatted about on AIM Greg, I'd like to know the difference in engine knock chamber pressures vs. that of a very high horsepower engine producing high chamber pressures. It seems to me that for anything under several hundred horsepower, this might not be useful. From what I understand, the necessity for pinning an engine in this manner is to prevent rotor housing to iron housing deflection. Anybody happen to have any experience with 500+hp setpus that produced actual deflection not from engine knock?



The cars 've tuned so far haven't ever exhibited this but I have seen busted dowel lands as low as ~300's rwhp due to engine knock.



B


[/quote]



http://avstop.com/AC/FlightTraingHan...etonation.html



detonation is in the neighborhood of 4000psi, normal combustion is 250-350psi. this is why i keep saying that it doesnt matter what you do to make the motor stronger, if it detonates its still gonna break.



normal combustion is a burn, detonation is an explosion

Hey thought this was gone, sorry I am located in Chicago, we have it all set up on CNC for both 20B and 13B's used to use a drill plate and a HUGE radial drill. I'm not a too big a fan of dowelling but the studs I like.

What Class of Fit are you using

[quote name='banzaitoyota' date='Jun 8 2005, 05:48 AM']What Class of Fit are you using


[/quote]





Define Class of fit



Clearences are same as stock for the dowels, no smaller than 1.5 mm for the wall of the pocket the dowel lands in.

[quote name='GMON' date='Jun 8 2005, 12:11 PM']Define Class of fit



Clearences are same as stock for the dowels, no smaller than 1.5 mm for the wall of the pocket the dowel lands in.


[/quote]





Class of Fit: Standard provided for eight classes of fit ranging from loose to heavy force or shrink fits



Also: See MAchinery's handbook page 605 (version 24)

https://www.nopistons.com/forums/pub...1047683621.gif



Whooooo!!! GMON where abouts are you in Minnesota?? I'm in Brooklyn Park, i barly ever see a Rx7 around here

[quote name='rootbeerdragon' date='Jun 11 2005, 09:49 PM']https://www.nopistons.com/forums/pub...1047683621.gif



Whooooo!!! GMON where abouts are you in Minnesota?? I'm in Brooklyn Park, i barly ever see a Rx7 around here


[/quote]



In uptown by lake Calhoon. Shoot me a pm sometime.

We got pics!!!!!



https://i5.photobucket.com/albums/y1...S/Mvc-078f.jpg



Attachment 21567



Attachment 21568



Attachment 21569

Specs for the CNC





Attachment 21570

Rotor housing drawn out with specs for the CNC

Attachment 21566



Trial and error.