Makes no sense. What am I missing

[squonk 41,153]

Trying to get this engine to run from my engine stand thread. The points are opening at the beginning of the intake stroke. That's when the pushrod is moving out to open them (1st pic) The [parts engine I have moves the points open on the compression stroke like its supposed to. (2nd pic). Logic says it's 180 deg off BUT how can the lobes on the cam move? The cam drives the points as well as the valves. How can it be off like that ? Both pics are when the points begin to open.  @richmondred01

 

  

Edited July 12, 2021 by squonk

[Ed Kennell 38,225]

The points should open both times the piston is at top.   On the intake and the power stroke.

[Pullstart 62,911]

Different length points push rods?  Was it running before or a recent build?  Guessing here obviously...

[squonk 41,153]

8 minutes ago, Ed Kennell said:

The points should open both times the piston is at top.   On the intake and the power stroke.

Ed the cam turns half the speed of of the crankshaft so no that isn't the case.

[squonk 41,153]

Pushrods are the same length. I bought this engine as "Rebuilt and will run" At the show the kid says I can't get it to run. I 'll never buy an engine sight unseen again! 

[ebinmaine 67,605]

I'm no Small engine expert by a long shot but maybe the cam or crank is not the right one for that application?

 

[Ed Kennell 38,225]

20 minutes ago, squonk said:

Ed the cam turns half the speed of of the crankshaft so no that isn't the case.

Sorry Mike, I didn't realize that.   But, I guess that means the crank and points cam can be out of time with the valves.

Edited July 12, 2021 by Ed Kennell

[squonk 41,153]

11 minutes ago, ebinmaine said:

I'm no Small engine expert by a long shot but maybe the cam or crank is not the right one for that application?

 

I wondering the same thing. Who knows what this kid did to put it together.

[squonk 41,153]

6 minutes ago, Ed Kennell said:

Sorry Mike, I didn't realize that.   But, I guess that means the crank and points cam can be out of time with the valves.

Ed the points are driven off the same cam as the valves. So the cam would almost have to be twisted or possibly broken and rewelded wrong for the points lobe to out of whack with the valve lobes.

Edited July 12, 2021 by squonk

[Pullstart 62,911]

Well, it’s on the stand, right?  Lettuce know when you figure out what the cam looks like...

[stevasaurus 22,764]

are these K-181-S engines??

 

[pacer 3,173]

Setting the cam timing hasnt been mentioned --- with the unknown history of the engine, I would check to see if the cam is timed to the crank, usually a dot on cam tooth and a dot to match it on the crank.....

[squonk 41,153]

14 minutes ago, pacer said:

Setting the cam timing hasnt been mentioned --- with the unknown history of the engine, I would check to see if the cam is timed to the crank, usually a dot on cam tooth and a dot to match it on the crank.....

That was my thought, but the pushrod lobe should still be in time with the valve lobes. When the points open,the valves should be closed no matter where the cam is in relation to the crankshaft.

[stevasaurus 22,764]

Actually, Mike is right...it is all about the cam shaft.  Where the piston is has nothing to do with what is going on.  Look at this picture...the lobe for the points is to the right on the cam shaft.  The other two lobes work the valves.  The points should be opening when the valves are closed.  In the K-181, the cam shaft is one piece, hard to believe it is twisted or welded.  In the K-161 the cam is 2 piece...maybe we have a 7 hsp cam in there.  Any way, got to open it up Mike.  BTW, Mike, did you check the point gap?  

 

 

credit to Pronzy for the picture.

[squonk 41,153]

I think my Brotha Dino is on to something.I got the impression that these kids had a bunch of engines laying around. Found 8HP written on the inside of the sheet metal. I wouldn't be surprised to find a 2 piece cam in there. Forgot all about that BS.

 

And yes sTEve, I have had the points on and off. It does this no matter where I set the gap.

[stevasaurus 22,764]

I knew it wouldn't make any difference Mike...just another piece of the kids doing things puzzle.  

[JCM 9,177]

As Arte Johnson would say, Verrry Interesting, but stupid.

[stevasaurus 22,764]

Remember, there should be a brass washer on the cam shaft on the PTO side...easy to lose.  

[squonk 41,153]

Looks like I'll be tearing down 2 to make 1

[Snoopy11 5,714]

1 hour ago, pacer said:

Setting the cam timing hasnt been mentioned --- with the unknown history of the engine, I would check to see if the cam is timed to the crank, usually a dot on cam tooth and a dot to match it on the crank.....

True, but usually if it is off time, the cam will hit the rod...  dunno how much clearance is there, but this is usually the case if timing is off.

 

Might be that the cam is off timing, but it would be by quite a few teeth...

 

Tracking down this issue is going to take measurement, I think. Perhaps wrong length cam followers or pushrods...

 

If I am missing something here, feel free to ignore me... LOL

 

Don

 

 

[stevasaurus 22,764]

Not necessarily, if you just need another cam shaft, Shynon or Pronzy might have a spare.

[squonk 41,153]

 

@stevasaurus does this look like a 2 piece cam? Good thing I took it apart. Hole in the rod cap is on the wrong side. 

Edited July 12, 2021 by stevasaurus
I think so Mike...check thread below.

[ebinmaine 67,605]

Yeeeeesh

[oldredrider 2,548]

If that engine were mine, I'd take it completely down. Metal in the gears is a bad sign.

[stevasaurus 22,764]

Mike, here is the thread I was thinking of...scroll down and look at these pictures.