Powerplus or Bust, Eh?

[Shaky Jake]

Ha, i was going to guess duration but then thought that was too obvious so didn't bother.

As for a solution. What i would do is go back to basics. You have published data for timing so i would get it as close to thst as i could first. Then see how it rides. Then see if any published tuning data makes a difference, testing small timing changes one at a time. (All assuming that you are 100% happy with ignition timing). Then, if you think lift might be an issue i would use a spare set of cams and make small changes and test incrementally. Being a side valve at least you dont need to worry about valve/piston clashes.

John

Good discussion John. Obviously, you can't change duration just by adjusting Cam timing. You can set the valve events later or sooner, but open and close will both change in the same direction, so duration won't be affected. So, as you alluded to, the Cam would have to be reground, ...or some other physical change made. My cam is in good original shape, so I'm focusing on the components that were not in good shape... something that could affect both timing and lift...

Does that bring anything to mind? I know this question probably isn't fair, because it would require detail knowledge of Indian PowerPlus motors specifically. Still, we're having fun here, right?



Kevin


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[Shaky Jake]

As you surely know, Kevin,...

Tight nuts mean nothing to a vacuum leak.
Especially with the evil pinch slots at the bottom of the manifold.

And spraying stuff while running only shows big leaks, not the little leaks waiting to bite you, or rob you of performance.
Bubbles don't let anything get by..

Never does only one thing go wrong at a time.

....Cotten

Agreed; a bubble test is the best way to find vacuum leaks.




Kevin


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[BoschZEV]

My cam is in good original shape, so I'm focusing on the components that were not in good shape... something that could affect both timing and lift...

this question probably isn't fair, because it would require detail knowledge of Indian PowerPlus motors specifically.

I don't have even superficial, let alone detailed, knowledge of any Indian motor. But the shape of cam followers definitely affects timing (although, not lift...)... Oh, wait, yours is a flathead engine so there are no followers. Or are there? If the valve stems ride directly on the cam like in a "normal" flathead engine my guess makes no sense.

p.s. motivated by your offer of a $100 prize (you did offer a $100 prize, didn't you?...) I googled Powerplus engines. All I could find were low resolution images but there is something that looks suspiciously like a rocker arm under the inlet valve. I can't tell what it really is, or how it works, but if there is a rocker arm of sorts between the cam and the valve stem that could explain both the incorrect duration as well as wrong lift. But, maybe what looks like a rocker arm is just a valve lifter(?).

[T. Cotten]

Just promise you will do it, Kevin!

Was there really no seals between the spigots and the cylinder nipples?

...Cotten

[Shaky Jake]

I don't have even superficial, let alone detailed, knowledge of any Indian motor. But the shape of cam followers definitely affects timing (although, not lift...)... Oh, wait, yours is a flathead engine so there are no followers. Or are there?

Ding ding ding ding! I'm going to call that a win, even though you almost talked your way out of it at the end. Sorry, no cash prize. And, of course, I am assuming that I am correct about the cause of the problem, which still remains to be proven. But yes, the Powerplus cam followers can affect valve timing and lift.

The Indian PowerPlus does indeed have a kinematically complicated system of Cam Followers and valve lifters, especially on the Intake side. They all rotate on pins, and there are various arcs and planes that interact with each other by pushing and sliding contact. They do, of course, wear, and they are all old. So in order to use them reliably, you have to recondition them in some way. When you recondition them, you remove a small amount of material, which affects the way in which they interact with each other, by changing their position with respect to each other. In the end this affects angles and ratios and the like. I've spent much time watching them move, and I am convinced that this is the source of my problem. I'll post some pictures later.

So, I spent two weeks teaching myself CAD, and I began reverse engineering the Cam Followers and valve lifts. I have finished my Intake Cam Follower design, which is intended to duplicate an original part. I have given it to a machinist who has a full on CNC machining center in the machine shed behind his farm house (you gotta love Nebraska). For this first run, I asked him to just make me one Follower out of a soft steel so I can test the geometry and make adjustments as needed. I have had some original ones hardness tested, and the final parts will be made from a suitable hardenable steel that can be heat treated to the same hardness as the originals.

I got a call from my machinist earlier today, and I'm going to meet with him this afternoon to get the first test Follower.


Details to follow.




Kevin


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[Tom Lovejoy]

very interesting, looking forward to hearing your results

[Shaky Jake]

Original Intake Cam Follower on the left, first prototype on the right:










We're having fun now!




Kevin

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[painterdale]

Very cool, Kevin!

Dale

[exeric]

Now I can see how the geometry would be critical on that follower/rocker (or jumper as Merkel called it). I can also see how it wouldn't take much wear to have an effect on performance.

[Steve Swan]

what i find amazing is how those engines ran so many miles with a solid chunk of steel held by a solid pin at one end and being forced up and down on the other with no roller or anything else to cushion the hammering except geometry and trigonometry. a real testimony to the active young minds designing their machines in those times.

[Shaky Jake]

You may have noticed that there is a round rod pressed in perpendicular to the wear face that rides on the cam, and pinned in place. It's not a roller. I originally assumed it would be harder than the rest of the part, but it is not. The rod and the body of the follower are the same hardness, and they are the same hardness as cam lobes and lifters in a modern airplane engine. Here are some pictures:










So, at this point, it is not clear to me what the purpose of that rod is. If anyone knows, or has a good theory, please share.






Kevin


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[Shaky Jake]

With much sadness, I feel it important to announce in this forum that Lonnie Isam, Jr., founder of the world's most difficult vintage motorcycle event, the Motorcycle Cannonball Endurance Rally, succumbed to cancer yesterday after a three year battle. Once again, Lonnie leads us to our destination. Lonnie made his mark on the world and on very many people's lives, including my own. I will remember him as a quite and fun loving man who was not afraid to follow his vision. I would be appropriate to raise a glass or observe a moment of silence in his honor.




Kevin


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[Steve Swan]

my thoughts and condolences are with the Isam family.

they've helped bring alot of J's and JD's back to life, i couldn't have finished mine without their help.

[panthersteve]

So, at this point, it is not clear to me what the purpose of that rod is. If anyone knows, or has a good theory, please share.

Kevin

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I know it is a bit different but the '15 parts list has part number A5291 Intake valve lift hardened point, is it possible that the Powerplus had something similar and the bit you are questioning is that?

Cheers
Steve

[panthersteve]

Being on the other side of the world I did not know Lonnie but have heard his name many times, it is always sad to hear of the loss of a member of this fraternity. RIP