Powerplus or Bust, Eh?

[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.

[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.

[painterdale]

Very cool, Kevin!

Dale

[Shaky Jake]

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










We're having fun now!




Kevin

.

[Tom Lovejoy]

very interesting, looking forward to hearing your results

[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


.

[T. Cotten]

Just promise you will do it, Kevin!

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

...Cotten

[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(?).

[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


.

[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


.

[T. Cotten]

Yes they are. That is not the problem in this case, but I do have a story about that. On the second or third day of the Cannonball, my #2 spark plug looked good, my #1 spark plug was all sooted up. At the time I was still focused on getting my automatic oiler adjusted correctly, and the engine was still over oiling and smoking a lot. I assumed the fouled plug was due to excessive oil consumption, but I couldn't understand why it only affected one spark plug. I was discussing this with Iron Dinosaur Dave in the motel parking lot and he asked me if I've been adjusting my carb on the fly. I said yes. He said something like "I think you have a vacuum leak on one cylinder. You've richened your carb to the point that the cylinder with the leak is running right, which means the cylinder without the leak is way rich." Sure enough, I walked over to the bike, put my hand on the manifold nuts, and the one on the #2 cylinder was loose enough to turn by hand. After I tightened it I no longer had spark plug problems. I didn't have equipment for a bubble test with me, but I tested it with starting fluid. I checked the manifold nuts every day after that.

Kevin.

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

[TechNoir]

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

[Shaky Jake]

Even if you found something other than the manifold, Kevin,...

I'd bubble-test it anyway.

PP manifolds are evil.

....Cotten

Yes they are. That is not the problem in this case, but I do have a story about that. On the second or third day of the Cannonball, my #2 spark plug looked good, my #1 spark plug was all sooted up. At the time I was still focused on getting my automatic oiler adjusted correctly, and the engine was still over oiling and smoking a lot. I assumed the fouled plug was due to excessive oil consumption, but I couldn't understand why it only affected one spark plug. I was discussing this with Iron Dinosaur Dave in the motel parking lot and he asked me if I've been adjusting my carb on the fly. I said yes. He said something like "I think you have a vacuum leak on one cylinder. You've richened your carb to the point that the cylinder with the leak is running right, which means the cylinder without the leak is way rich." Sure enough, I walked over to the bike, put my hand on the manifold nuts, and the one on the #2 cylinder was loose enough to turn by hand. After I tightened it I no longer had spark plug problems. I didn't have equipment for a bubble test with me, but I tested it with starting fluid. I checked the manifold nuts every day after that.




Kevin


.

[Shaky Jake]

OK, I'll give you some more information. Here are the valve timing design specs as published in Construction and Maintenance of Indian Motocycles 1916 & 1917 Military Models, ppg. 20-22, paragraph 18-21 and pg. 18

Inlet Opens 0 DEGREES (TDC)
Inlet Closes 52 DEGREES AFTER BDC
Exhaust Opens 58.5 DEGREES BEFORE BDC
Exhaust Closes 29.5 DEGREES AFTER TDC
I have not found any published design values for total lift on PowerPlus engines.



Here are my actual results, at the valves:

#1 cylinder:
Inlet Opens 31 DEGREES ATDC (31 degrees later than design)
Inlet Closes 21 DEGREES AFTER BDC (31 degrees early)
Inlet Total Lift .111 inches
Exhaust Opens 47 DEGREES BEFORE BDC (11.5 degrees late)
Exhaust Closes 35 DEGREES AFTER TDC (5.5 degrees late)
Exhaust Total Lift .264 inches


#2 cylinder:
Inlet Opens 25 DEGREES AFTER TDC (25 degrees late)
Inlet Closes 17 DEGREES AFTER BDC (35 degrees early)
Inlet Total Lift .128 inches
Exhaust Opens 44 DEGREES BEFORE BDC (14.5 degrees late)
Exhaust Closes 28 DEGREES AFTER TDC (1.5 degrees early)
Exhaust Total Lift .250 inches




In summary, at the exhaust valves there is some shortage of duration ranging from 6 degrees on #1 to 16 degrees on #2. The exhaust action is also shifted a bit in the late direction by about 8 degrees. Note that the timing mark on the cam was correctly oriented.

The biggest problems though, are at the Intake valves, which are short 60 to 62 degrees of total duration. That's a little over a quarter of the design duration. In other words, the Intake valves are only open 3/4 as long as they should be. On top of that, the Intake valves are only opening half as far as the exhaust valves. I don't know what the design values are for valve lift, but if I had to guess, I'd say they may have used 1/4 inch for both Intake and exhaust. If that's the case, they are only opening half as far as they should.

It's pretty clear that the Intake valves are my choke point, causing the symptoms that I described. I have a pretty good idea what is causing this, and I've already started working on the solution. Any guesses? I love it when you guys participate in the discussion...




Kevin


.

[T. Cotten]

Even if you found something other than the manifold, Kevin,...

I'd bubble-test it anyway.

PP manifolds are evil.

....Cotten