PA .65 Timing

Does anyone know the port and shaft timings of the PA .65? If so could you let me in on it? While on this engine, is it specifically timed for pipe use, or will it run right on a muffler as well?

It will run fine pipe or muffler. You don't need to change timing on the enbgine to go to a pipe.

The exhaust timing is set at 135 degrees. That will affect the pipe setting if you are going that way. If you need to know the rest, why don't you just check with Randy for the rest of the timing details?

Thanks Len,

I'll give that a try, didn't know if he'd do that, guess I just should have tried.

>It will run fine pipe or muffler. You don't need to change
>timing on the enbgine to go to a pipe.

Well, not necessarily, anyway.

In the case of the PA, certainly not.

While the crank timing mod does change the run somewhat, it doesn't appear mandatory, and it seems like you can replicate the effects with other adjustments. It also looks like it makes less difference than the difference from engine to engine. My PA61 runs just fine and it has a stock crank (and in fact, stock guts in every respect). I put in one .008 head gasket in 1998, and at this point I'm about half scared to even try to change it, since the bolts are probably seized due to disuse

In fact, unless you really know what you're doing, even making adjustments aside from prop pitch to get the speed right is probably a bad idea. Don't forget, if you can adjust it, you can adjust it wrong! Set it up per the instructions, and you will get solid and reliable runs. As you gain experience, then and only then start experimenting with small changes one at a time. I might also note that the pipe length is only one of many adjustments, and the pipe length is the LAST place to look if you have a problem. All piped engine issues are not related to the pipe!

>The exhaust timing is set at 135 degrees. That will affect
>the pipe setting if you are going that way. If you need to
>know the rest, why don't you just check with Randy for the
>rest of the timing details?

That's idea's just crazy enough to work!

Thanks Brett,

Not really dealing with and engine problem, just doing some timing comparisons. Good input anyway, always usefull.

LAST EDITED ON Jan-26-04 AT 01:03 PM (CDT)
 
Mr. Smith has graciously supplied me with the requested info.

What was it?

Exhaust 136 degrees ATDC
Blowdown 12 degrees
Shaft opens 45 dgrees ABDC 180 degrees duration

Are you sure? Or is it really 136 degrees of exhaust timing which would require exhaust opening at 112 degrees?
Don

These numbers are from the horse's mouth.

136 degrees exhaust ...is total duration, has nothing to do with ATDC

LAST EDITED ON Jan-26-04 AT 07:03 PM (CDT)
 
Thanks for clearing that up Randy, obviously I misunderstood.
I'm a valve train designer we refer to all timing events in relationship to TDC,BDC or in crank angle (720 degrees). Sometimes I leap before I look. 136 degrees ATDC would only make for 88 degrees duration. I should have noticed that. This is where I blush!

HI Randy

There is really No problem, it is typical to talk about 2 stroke sleeve timing in terms of "total duration" instead of timing before and after TDC.

Have fun

Regards