Possible Project: Dual Predator 420cc Monster

[Ibnzmonkey]

Hey Everybody!

Man it's been a while since I posted on here. I sold my kart that I built many years ago a few months back. Now the bug has bitten me again... I am wanting to build something over the top. A custom chassis with dual Predator 420cc engines and fat burris slicks.

I was thinking of using solid sprockets on the output shafts linked to a jackshaft that holds the clutch. Teeth and ratios TBD. Right now I am trying to find a clutch that can handle the torque of two 420cc engines.

Any recommendations?

 

[KevinRADshaw]

Rig up some high grade pulleys.

 

[slideways]

Lol.. pulleys.

Noram 1800 series Enforcer will handle the power. We run them on our 45hp V-twins. And they also run them on the 55-60hp version up from ours. Good idea to run a jackshaft to one clutch because they are like $220 each. Run #40 chain with that setup.

 

[Ibnzmonkey]

Lol.. pulleys.

Noram 1800 series Enforcer will handle the power. We run them on our 45hp V-twins. And they also run them on the 55-60hp version up from ours.

I was looking at the Noram Enforcer clutches and they have rave reviews in the V-Twin crowd. I just didn't know if it would be suitable with a twin engine setup.

Good idea to run a jackshaft to one clutch because they are like $220 each. Run #40 chain with that setup.

Yea, I wanted a way for the engines to turn the same RPM. So using say (for example) 13T sprockets on the output shaft, 13T on the jackshaft, and 13T on the Clutch. Boom instant linking system. As far as performance parts are concerned, I still need to research as these Predator engines are quite new still and I haven't been able to find much or anything at all...

 

[slideways]

I wouldn't be too worried about internal stuff other than ditching the governors and maybe just putting 2 ARC rods in them. Intake and a pipe should be plenty to get you to 20hp each. Think that every time you have to buy something like a cam you need 2 of them lol..

Syncing the throttles will be tricky. I'd worry mostly about that.

 

[Doc Sprocket]

If the engines are linked together with the clutch downstream, it oughta be pretty interesting starting the engines!

I wonder if it would be better to sync the cranks, phase them 180* apart, (one engine compressing while the other is exhausting) or not bother?

Sounds like it's gonna be one mother of a tire-fryer (that will have to make frequent trips to the gas station!)

 

[carter]

I have a feeling that your gonna have a neat day when you try starting the second of the two engines while the other is turning the shaft their connected to.

 

[Doc Sprocket]

I have a feeling that your gonna have a neat day when you try starting the second of the two engines while the other is turning the shaft their connected to.

Umm- that means the second (un-started) engine is already turning! My point was that it would take extra effort to get them BOTH turning at the same time...

 

[South Kart3377]

Umm- that means the second (un-started) engine is already turning! My point was that it would take extra effort to get them BOTH turning at the same time...

But, It has e-start.

 

[Doc Sprocket]

But, It has e-start.

Then you'd want to operate both starters simultaneously for fear of overloading one.

 

[South Kart3377]

Then you'd want to operate both starters simultaneously for fear of overloading one.

Or better yet overloading your arm.

 

[Doc Sprocket]

Yeah! That's one reason I think phasing the cranks 180* off each other would help. Can you imagine trying to PULL both those beasts thru the compression stroke at the same time? OUCH!

 

[porsche930dude]

why not just run a clutch on each engine as normal. you wont need to gear down with a jackshaft with that kinda power so a jackshaft isnt really needed. no sense making it overcomplicated.

 

[Doc Sprocket]

Because he wanted the engines to stay in sync at all times, and- Hi-po 1" clutches are dang pricey!

 

[Ibnzmonkey]

I beleive opposing the engines 180* and then "hard synching" them with solid sprockets would be the best method. As far as linking the throttles is concerned. Would a tubular manifold connecting both engines to 1 large carb work? I would think the tubing would be too long to effectively fuel both engines.

1" clutches are kind of expensive. I'm just in the planning phase, in the end I will more than likely give in and just get two 1" clutches, OR settle for twin 212cc's. I really want that rape torque of twin 420's though.

 

[Doc Sprocket]

I beleive opposing the engines 180* and then "hard synching" them with solid sprockets would be the best method.

Pretty much what I pictured. Although, what do you mean by "solid sprockets"? Just sprockets and chain, or gears? I think sprockets and chain would suffice.

As far as linking the throttles is concerned. Would a tubular manifold connecting both engines to 1 large carb work? I would think the tubing would be too long to effectively fuel both engines.

I think that the manifold and single carb might be overcomplicating things for your first time out. There would be quite a bit of work involved in engineering the manifold to work at peak efficiency, and selecting and tuning the right carb. I think if the throttles are synched up well enough, any slight difference in fueling will be negligible. Spend a good deal of time making both throttle cables share the same tension, stroke, idle point, and WOT point, and then connect the two to a central cable that goes to your pedal.

 

[ArachnidBrosMN]

Absolutely fabulous idea: twice the power and still use one clutch. Sweeeet!!!!

One issue: when you oppose two engines, the shafts will spin in opposite directions.... unless you meant stacking them (as in the picture below)

What you need to probably do is find a way to start each engine, and then use a clutching system to "hook them together" once they are running.

I know you're trying to use ONE clutch but hear me out:

If you direct-connected ONE engine to your jack-shaft, BUT then put a centrifugal clutch on the other engine, you could start them separately, and "disclude" one engine when they are at idle, and it would "include" the other engine once you hit the gas!

I know I know, you would really be buying a CC, AND a TC, but better than "rigging up some belts and pulleys" in my mind.

 

[ArachnidBrosMN]

EVEN COOLER!!! : You would only have to start the engine up that has the Centrifugal clutch on it, and hit the gas, and it would automatically start your other engine up (and your foot would be on the gas simultaneously) and "boost you down the road" as the other engine fired up!! ... now I want to start a project like this!!

 

[Ibnzmonkey]

Absolutely fabulous idea: twice the power and still use one clutch. Sweeeet!!!!

One issue: when you oppose two engines, the shafts will spin in opposite directions.... unless you meant stacking them (as in the picture below)

Yea, my idea was to stack them in that orientation for proper rotation.

If you direct-connected ONE engine to your jack-shaft, BUT then put a centrifugal clutch on the other engine, you could start them separately, and "disclude" one engine when they are at idle, and it would "include" the other engine once you hit the gas!

I know I know, you would really be buying a CC, AND a TC, but better than "rigging up some belts and pulleys" in my mind.

I like your idea. I could also use different engagement springs on the clutches to get the desired acceleration and power. Say, use springs that use one engine for take off and the other engine can kick in at higher speeds.

OR go the $600 route and get two Series 40 TQ converters with backplates and chain them to the axle.

Pretty much what I pictured. Although, what do you mean by "solid sprockets"? Just sprockets and chain, or gears? I think sprockets and chain would suffice.

I mean something like this.

One on each crank coupled to sprockets on the JS that houses the clutch, then chain the clutch to the axle. If the engines are 180* then starting wouldn't be very hard at all. I could also chain an automotive starter to the JS to start both engines. (Ideas)

 

[Doc Sprocket]

and get two Series 40 TQ converters with backplates

The Comet 40 does not use a backplate. And you definitely do NOT want to use two CVT's. They'd be constantly fighting each other, as it would be impossible to perfectly sync both engines' RPM at all times.

IMHO- The best idea is the original one. Two engines synched 180* off each other, connected by chain to a single jackshaft. The output of the jackshaft would have a clutch (or CVT for that matter), feeding the axle.