26b Project 4 Banger!
03-06-2008 | 09:34 AM
#21
Senior Member
Joined: Jun 2004
Posts: 524
The more I think about it, the more I think the Granny's Speed Shop one-off was the best way to do it.
It had a two rotor times two firing order, with one and three simultaneous and two and four simultaneous. The minor downsides of that allowed them to use relatively stock parts, standard balancing, and no counterweights in the middle. The rear rotor of the front engine acted as the front rotor's counterweight and vice-versa. Minimal rotating inertia.
The problem with a splined connection is that the small amount of freeplay would rapidly fret away with normal torsional vibration.
For oiling, I'd just throw in the towel and go dry-sump. For cooling, personally I would try sticking a Chevy leg-type water pump above the front engine and route each outlet to a single engine, and use restrictors for each engine's outlet.
But I'm sitting in a desk chair right now, not standing in front of the Bridgeport, and plans have a habit of changing when faced with the actual work.
It had a two rotor times two firing order, with one and three simultaneous and two and four simultaneous. The minor downsides of that allowed them to use relatively stock parts, standard balancing, and no counterweights in the middle. The rear rotor of the front engine acted as the front rotor's counterweight and vice-versa. Minimal rotating inertia.
The problem with a splined connection is that the small amount of freeplay would rapidly fret away with normal torsional vibration.
For oiling, I'd just throw in the towel and go dry-sump. For cooling, personally I would try sticking a Chevy leg-type water pump above the front engine and route each outlet to a single engine, and use restrictors for each engine's outlet.
But I'm sitting in a desk chair right now, not standing in front of the Bridgeport, and plans have a habit of changing when faced with the actual work.
03-14-2008 | 12:23 PM
#23
Senior Member
Joined: Nov 2001
Posts: 2,284
My friend and I are doing two very different 4 rotor engines. One is a Jeff Bruce 23A and the other is kinda like the granny's kit except the two 13Bs are joined by a coupler from the rear counterweight of one engine to the front shaft of the other. The firing order of both will be 1,3,2,4. The 23A is fairly practical and fits in the engine bay of a GSL-SE (just barely) while the dual 13B thing will require the car to be built up around it.
03-14-2008 | 03:39 PM
#24
Senior Member
Joined: May 2005
Posts: 628
From: San Francisco, CA
Just passing through... but based on this vid:
http://youtube.com/watch?v=i9VN9gvrnRU
The scoot 23A also has a firing order of 1-3-2-4
http://youtube.com/watch?v=i9VN9gvrnRU
The scoot 23A also has a firing order of 1-3-2-4
03-25-2008 | 01:12 PM
#25
Thread Starter
Junior Member
Joined: Feb 2008
Posts: 13
I have looked at the Granny's Speed shop page and think its a great way to go about building one of these...with the exception of drilling out the e shafts.
Ok heres a radical idea...probibly wont work but just bare with me for a second.
what if instead of having a two piece e shaft you had two part housings...as long as the entire combustion area was a single piece...the parting line shouldnt be much of a problem. Then two stock e shafts could be joined perm and the middle houseings could be bolted on and then the end housings still be installed normally.
it would need a different style bearing but...maybe
What do you guys think?
Ok heres a radical idea...probibly wont work but just bare with me for a second.
what if instead of having a two piece e shaft you had two part housings...as long as the entire combustion area was a single piece...the parting line shouldnt be much of a problem. Then two stock e shafts could be joined perm and the middle houseings could be bolted on and then the end housings still be installed normally.
it would need a different style bearing but...maybe
What do you guys think?
03-25-2008 | 01:21 PM
#26
Thread Starter
Junior Member
Joined: Feb 2008
Posts: 13
Originally Posted by braddubya' post='897188' date='Mar 25 2008, 12:12 PM
I have looked at the Granny's Speed shop page and think its a great way to go about building one of these...with the exception of drilling out the e shafts.
Ok heres a radical idea...probibly wont work but just bare with me for a second.
what if instead of having a two piece e shaft you had two part housings...as long as the entire combustion area was a single piece...the parting line shouldnt be much of a problem. Then two stock e shafts could be joined perm and the middle houseings could be bolted on and then the end housings still be installed normally.
it would need a different style bearing but...maybe
What do you guys think?
Ok heres a radical idea...probibly wont work but just bare with me for a second.
what if instead of having a two piece e shaft you had two part housings...as long as the entire combustion area was a single piece...the parting line shouldnt be much of a problem. Then two stock e shafts could be joined perm and the middle houseings could be bolted on and then the end housings still be installed normally.
it would need a different style bearing but...maybe
What do you guys think?
ok so NEVER MIND...I was apparently having an IDOIT streak. Please ignore my last post...wasnt even thinking about the rotors. My bad, it wont let me edit so just forget that post ever existed ha ha ha
03-25-2008 | 01:29 PM
#27
Thread Starter
Junior Member
Joined: Feb 2008
Posts: 13
Originally Posted by heretic' post='895983' date='Mar 6 2008, 09:34 AM
The more I think about it, the more I think the Granny's Speed Shop one-off was the best way to do it.
It had a two rotor times two firing order, with one and three simultaneous and two and four simultaneous. The minor downsides of that allowed them to use relatively stock parts, standard balancing, and no counterweights in the middle. The rear rotor of the front engine acted as the front rotor's counterweight and vice-versa. Minimal rotating inertia.
The problem with a splined connection is that the small amount of freeplay would rapidly fret away with normal torsional vibration.
For oiling, I'd just throw in the towel and go dry-sump. For cooling, personally I would try sticking a Chevy leg-type water pump above the front engine and route each outlet to a single engine, and use restrictors for each engine's outlet.
But I'm sitting in a desk chair right now, not standing in front of the Bridgeport, and plans have a habit of changing when faced with the actual work.
It had a two rotor times two firing order, with one and three simultaneous and two and four simultaneous. The minor downsides of that allowed them to use relatively stock parts, standard balancing, and no counterweights in the middle. The rear rotor of the front engine acted as the front rotor's counterweight and vice-versa. Minimal rotating inertia.
The problem with a splined connection is that the small amount of freeplay would rapidly fret away with normal torsional vibration.
For oiling, I'd just throw in the towel and go dry-sump. For cooling, personally I would try sticking a Chevy leg-type water pump above the front engine and route each outlet to a single engine, and use restrictors for each engine's outlet.
But I'm sitting in a desk chair right now, not standing in front of the Bridgeport, and plans have a habit of changing when faced with the actual work.
Should this same concept apply to Granny's Speed shop version? Theres worked out fine...or am I not understanding what you mean?
03-25-2008 | 09:41 PM
#29
Senior Member
Joined: Jun 2004
Posts: 524
Originally Posted by braddubya' post='897194' date='Mar 25 2008, 10:29 AM
Should this same concept apply to Granny's Speed shop version? Theres worked out fine...or am I not understanding what you mean?
Looking at the drawings and the description, the Granny's method was just two tapered seats, with both shafts held together with a drawbolt. Radially they were located by a collection of precisely located dowel pins. Then, for belts and braces, they Loctited the mess.
Proof that the system was solid was that the engine was difficult to dissassemble, the shaft joining still be very securely pressed/stuck together.
A simple splined connection has freeplay in it by its very nature and design. That freeplay will open up, just as surely as loose flexplate bolts will result in ovalled/cracked apart boltholes, or a loose crank pulley bolt will result in demolished keyways. And those are connections on the END of the shaft, not in the middle where the torsional forces are REALLY trying to tear things apart.
Alternatively you can deliberately induce some "give" but then you'd really want to have separate ignition systems for each half of the engine. May as well lay the engines side by side and run a chaindrive from one to the other. Neat trick if you can find the room for it.