JE Howells Twin V

[Harglo]

Any one that has built JE Howells twin V.
Em able to get ea cly fire on its own. Need some help how to time it. As cly one is on its power down stroke what should be taking place on cly 2? Is its the job of the fly wheel to maintain tell next power stroke of cly 2?
Harvey

 

[geo]

Mine will fire on both but won’t run I think rubbish machining on my cam gears are the problem will I redo them probably not.
have a look at how a v twin Ducati fires that should help you

 

[Nerd1000]

Shouldn't No. 2 fire 450 degrees after No. 1?

 

[tractor162003]

If # 1 is on the left then 450 degrees after No. 1 or it could be 90 degrees after No. 1 but I don't think so.
If # 1 is on the right then 270 degrees after No. 1

 

[Harglo]

Mine will fire on both but won’t run I think rubbish machining on my cam gears are the problem will I redo them probably not.
have a look at how a v twin Ducati fires that should help you

Yes that may be some of my problem also. There difficult to make per the drawings the flanks are so tiny. Em confused as to what should be happing in cly 2 after cly 1 firers.
Harvey

 

[cwelkie]

Harvey - I'll give it a go with the following configuration/starting point/assumptions:

1. Viewing engine from the rear (i.e., the ignition rotor side)
2. Engine rotating clockwise
3. Ignition rotor turning counter-clockwise (2:1 gear driven from crank tailshaft)
4. Ignition rotor fabricated as per page 39 in drawings (135 degrees between magnets)
5. Setup to fire at Top Dead Center (TDC) to make description easier
6. #1 cylinder on the left

With #1 firing at TDC, #2 cylinder is half through its exhaust stroke (90 degrees of rotation due to the shared crank pin). #2 cylinder finishes the exhaust stroke and completes the intake and compression strokes (another 360 degrees) before firing on TDC. That provides a total of 450 degrees crankshaft rotation between #1 and #2 firing. The ignition/oil pump shaft reduction provides 225 degrees of ignition rotor rotation (in the opposite direction).

Once #2 cylinder fires, #1 cylinder only has to do 1 1/2 strokes (270 degrees) to finish its intake and compete the compression stroke to be back at TDC for the plug to fire.

Perhaps reviewing drawing on page 40 of the ignition system while puzzling through the above description will help. If not, perhaps someone else will give it a go now that I've "put my foot in it".
Charlie

 

[ultralight1]

You might want to talk to a Harley Davidson mechanic. The Harley twin uses the same single throw crank. That's what gives it's unique sound. Dave

 

[Harglo]

You might want to talk to a Harley Davidson mechanic. The Harley twin uses the same single throw crank. That's what gives it's unique sound. Dave

Thanks Dave
At one point was kina thinking the same so will check into it a let ya no.
Harvey

 

[cwelkie]

You'll find that Harley Davidson V-Twins have 45 degrees between cylinders. The Howell is a "90 degree twin". If you want to closely compare the Howell design to a motorcycle engine you'll have to look at Ducati, Moto Guzzi, etc.

The HD configuration does provide what is considered that unique sound due to uneven firing but also provides a host of challenges in managing vibration and with keeping the bike from shaking apart. A 90 degree twin is much less vibration prone and (as a biased and dedicated Ducati rider ) also produces a nice exhaust note.

 

[Harglo]

Harvey - I'll give it a go with the following configuration/starting point/assumptions:

1. Viewing engine from the rear (i.e., the ignition rotor side)
2. Engine rotating clockwise
3. Ignition rotor turning counter-clockwise (2:1 gear driven from crank tailshaft)
4. Ignition rotor fabricated as per page 39 in drawings (135 degrees between magnets)
5. Setup to fire at Top Dead Center (TDC) to make description easier
6. #1 cylinder on the left

With #1 firing at TDC, #2 cylinder is half through its exhaust stroke (90 degrees of rotation due to the shared crank pin). #2 cylinder finishes the exhaust stroke and completes the intake and compression strokes (another 360 degrees) firing on TDC. That provides a total of 450 degrees crankshaft rotation between #1 and #2 firing. The ignition/oil pump shaft reduction provides 225 degrees of ignition rotor rotation (in the opposite direction).

Once #2 cylinder fires, #1 cylinder only has to do 1 1/2 strokes (270 degrees) to finish its intake and compete the compression stroke to be back at TDC for the plug to fire.

Perhaps reviewing drawing on page 40 of the ignition system while puzzling through the above description will help. If not, perhaps someone else will give it a go now that I've "put my foot in it".
Charlie

Hello Charlie
Ive tryed some of your info above but to no avail yet. So now I have cly 2'coming up on compression as cly one is going through its power down stroke. But still a no go it seems the fly wheel has to carry the crank a long ways/time before the next firing event. I must add this I do not have the Hall sensors in the plastic cup. I have them on plates so can adjust the timing for near TDC. So the 135 degree may not be there. Em using a start motor with a one way bearing which spins the fly about 2-3 hundred which should be enough for the engine to kick in on its own or <>?
Harvey

 

[cwelkie]

Hi Harvey
it sounds like your cam timing is not quite right. When #1 is half way through its power stroke, #2 will be just starting its intake stroke.
for what it’s worth I’d suggest starting at the beginning and confirming events one at a time. For example:
1. Focus on #1 cylinder to get valve timing events correct in relation to crankshaft rotation.
2. Set the ignition timing for #1.
3. Set the ignition timing for #2 cylinder to be 225 (rotor) degrees from #1 (counter clockwise looking from the rear).
4. Now you can confirm crankshaft position when #2 in position to fire (I.e. close to TDC on compression).
5. Finally confirm and/or set #2 cylinder valve timing events to match what you now know from step 4 above.

Good luck - you can get this sorted!

ps
A visual aid might be made by finding a 6 foot length of 1x4 or something similar. Mark out 72 marks at every inch to represent 10 degree intervals. You can then mark out valve a timing events for one cylinder to start with and then add the second cylinder’s events alongside but out of phase.

 

[Harglo]

Hi Harvey
it sounds like your cam timing is not quite right. When #1 is half way through its power stroke, #2 will be just starting its intake stroke.
for what it’s worth I’d suggest starting at the beginning and confirming events one at a time. For example:
1. Focus on #1 cylinder to get valve timing events correct in relation to crankshaft rotation.
2. Set the ignition timing for #1.
3. Set the ignition timing for #2 cylinder to be 225 (rotor) degrees from #1 (counter clockwise looking from the rear).
4. Now you can confirm crankshaft position when #2 in position to fire (I.e. close to TDC on compression).
5. Finally confirm and/or set #2 cylinder valve timing events to match what you now know from step 4 above.

Good luck - you can get this sorted!

ps
A visual aid might be made by finding a 6 foot length of 1x4 or something similar. Mark out 72 marks at every inch to represent 10 degree intervals. You can then mark out valve a timing events for one cylinder to start with and then add the second cylinder’s events alongside but out of phase.

Yes I will start from scratch as not sure even if cly one is correct. Please stay tuned. Im new at using this form.
Cheers
Harvey

 

[geo]

The drawing of the engine on the first page shows the correct rotation from the flywheel side anti clockwise number 1 cylinder is on the right.On the back of sheet 44 it showsthe correct set up for your gear train used a degree wheel and a dial indicator directly on the cam to set the valve timing to the provided info.there is a good explanation on another machinists website practically points you in the right direction