Bright ideas needed, please.
- Thread starter Hensen1954
- Start date
Willy Eckerslyke
Well-Known Member
I'd agree if you could use them to their full potential without fear of destroying the transmission.colnerov said:
Otherwise I just foresee lots of embarassing "what's the 0-60 time mister" type questions.
Still loads of fun though!
A power take off in the middle of the engine isn't a first - I seem to remember the H16 BRM F1 engine back in the late 60's did something like that. It does allow you to use noticeably lighter, ie smaller journals and webs, crankshafts though.
That's very much the situation we have here. The torque capability of the cranks in the the three engines are designed for one engines worth of torque. If an end drive is used you finish up with the third engine being presented with three engines worth. Sure to be a broken crank or destroyed main bearings if used in anger!
That's why I am attracted to taking the power output from between the second and third engines. The worst that happens then is two engines worth of torque in one crank. Combined to needing to get the power transmission axis below the chassis instead of above it, it strikes me as a no brainer.
I also agree with idea of a very simple gearbox with only two ratios, call them start and cruise! Only snag with this arrngement is how to achieve a clutch or fluid flywheel. Again, I'm certain the bus industy can supply, so I'd be spending a bit of time mooching around a bus graveyard!
Chris
That's very much the situation we have here. The torque capability of the cranks in the the three engines are designed for one engines worth of torque. If an end drive is used you finish up with the third engine being presented with three engines worth. Sure to be a broken crank or destroyed main bearings if used in anger!
That's why I am attracted to taking the power output from between the second and third engines. The worst that happens then is two engines worth of torque in one crank. Combined to needing to get the power transmission axis below the chassis instead of above it, it strikes me as a no brainer.
I also agree with idea of a very simple gearbox with only two ratios, call them start and cruise! Only snag with this arrngement is how to achieve a clutch or fluid flywheel. Again, I'm certain the bus industy can supply, so I'd be spending a bit of time mooching around a bus graveyard!
Chris
colnerov
Well-Known Member
Hi, today whilst thinking about taking the drive from between engines 2 and 3, if engine 3 was
turned round to to avoid taking the power from the nose of the crank. It would need a special
camshaft grind to enable it to run backwards and another problem would be the distributor,an
Eldis set up could be the answer to that. I then thought how would the engines be aligned in
regards to timing. Should all No1s fire at the same time to keep the V8 sound or should they be
phased 120 degrees to acheive a smoother power delivery?
Colin
turned round to to avoid taking the power from the nose of the crank. It would need a special
camshaft grind to enable it to run backwards and another problem would be the distributor,an
Eldis set up could be the answer to that. I then thought how would the engines be aligned in
regards to timing. Should all No1s fire at the same time to keep the V8 sound or should they be
phased 120 degrees to acheive a smoother power delivery?
Colin
I don't see any need to turn engine No 3 round. Engine No 2 is receiveing torque through the nose of the crank already, and I can't think of any lack of symmetry in the crank design that would make it good for one direction flow of torque only. The crank nose is no different to the rear stub flange onto which the flywheel or torque convertor is bolted - you just need a different adaptor flange to couple the outgoing prop onto. So you simply finish up with a coupling shaft between the rear of No 2 and the front of No 3 that carries a set of chain wheel sprockets to drop the drive down to the new transmission axis below the chassis.
To be fair, this does mean that you have to replace the extension shaft / front pulley with something different to couple the prop up to, because the existing set up is driven soley by the keyway, which is probably not up to the full torque of a V8! A good excuse to lose the water pump and substitute with an electric one while you're at it!
If a satisfactory means of transmitting torque through the nose of the crank proved impractical, then there's no reason why you shouldn't simply extend the principle and have a similar coupling shaft and sprocket between engines 1 and 2 and have a third sprocket in place of the flywheel on no 3. Then all that the nose of the crank is doing is to maintain the three engines in syncronicity rather than carrying serious torque. Downside is that you have a long shaft running underneath all three engines to carry the three sets of sprockets and transfer the power into the gearbox. Up side is that you can use the chain drives to drop the rpm - say 6,000 engine rpm equates to 1,500 shaft rpm, which would allow you to use a bus transmission without having to worry about the input speed.
Chris
To be fair, this does mean that you have to replace the extension shaft / front pulley with something different to couple the prop up to, because the existing set up is driven soley by the keyway, which is probably not up to the full torque of a V8! A good excuse to lose the water pump and substitute with an electric one while you're at it!
If a satisfactory means of transmitting torque through the nose of the crank proved impractical, then there's no reason why you shouldn't simply extend the principle and have a similar coupling shaft and sprocket between engines 1 and 2 and have a third sprocket in place of the flywheel on no 3. Then all that the nose of the crank is doing is to maintain the three engines in syncronicity rather than carrying serious torque. Downside is that you have a long shaft running underneath all three engines to carry the three sets of sprockets and transfer the power into the gearbox. Up side is that you can use the chain drives to drop the rpm - say 6,000 engine rpm equates to 1,500 shaft rpm, which would allow you to use a bus transmission without having to worry about the input speed.
Chris
ghce
Well-Known Member
A single mechanical pump or an electric would be common sense as you have to re-plumb all the cooling any way, but I cant help but think that there would be a shed-load of excess heat to dissipate from the overhead of 3 engines and that idle condition would be danger territory making the electric pump and an electric fan almost mandatory especially given it's mostly show rather than go purpose.
Graeme
Graeme
colnerov
Well-Known Member
Hi hensen, Sorry for the delay but here are some basic measurements for the RR/LR transfer
box. The input and output shaft centres are 9". The case that houses the gear or chain set is
5" with the front and rear output flanges projecting 6" each fore and aft from the case.
If you want anymore let me know. these T/boxes can be picked up quite cheaply.
Colin
box. The input and output shaft centres are 9". The case that houses the gear or chain set is
5" with the front and rear output flanges projecting 6" each fore and aft from the case.
If you want anymore let me know. these T/boxes can be picked up quite cheaply.
Colin