Piper 285 Cam And Ignition Timing / Carb Setup?

[Guest MJThewlis]

Having fitted my Piper 285 cam to my otherwise standard engine I now find that to make it anything like idle it needs a significant amount more advance on the ignition (like beyond the timing marks with a strobe???) On the original cam it ran beautifully at the 6 degree BTDC as per Haynes manual ... flashback to somebody once told me something around fixing non broken things?!?

 

I haven't as yet touched the carb as the timing was already out of sorts from replacing the timing belt but wondered if anyone can give their experiences...

 

1. Does it really idle that badly and therefore I should set the ignition back and crank up the idle stop

2. Does it need a majorly different mixture setting to run anything like

3. Have I stuffed something else up by a long way (pretty confident on cam and crank timing + valve clearances (no clatterng and there definitely was some!)

 

Woudl greatly apreciate words of wisdom or I may have to try kicking it repeatedly and that would be a shame.

 

Cheers, M.

[Peter Bell]

Hi Mat, you will need to advance the timing with that cam, start around 14° (with vac advance disconnected!) if it 'pinks' under load then back it off a little, if it doesnt then you could try a bit more till it does! The carb will need a bit of adjusting, what type have you got? tick over speed may be a little more than it was but no more than 1000 rpm.

Peter

[Guest MJThewlis]

Thanks Peter

 

I have the original Weber 30/34 DFTH carb still running the stepper motor and ESCII ignition module. Lack of an idle speed adjustment screw is throwing me momentarily but I feel much better that it's only setup and nothing more catastrophic I've done wrong!

 

Cheers, M.

[Guest MJThewlis]

Thanks Peter

 

I have the original Weber 30/34 DFTH carb still running the stepper motor and ESCII ignition module. Lack of an idle speed adjustment screw is throwing me momentarily but I feel much better that it's only setup and nothing more catastrophic I've done wrong!

 

Cheers, M.

 

Haha found it ... more fun for tomorrow then!

[Big Jim]

You also need to change the advance curve of your ignition (see Dave Andrews website - link from our website)

If you don't want to mess about with your own dizzy, then there is a guy who will refurb it, and set it for the correct advance curve, (also link from our website)

 

You will otherwise be dissapointed in the engine performance, thinking your nice new cam will give you extra dobbins, but it doesn't seem to. well not unless you get all the accompaniments correct to go with it.

[Guest salty_monk]

The 285 Cam will run better at a slightly higher idle of about 1,100. You can even run it at 1,200. They will run at 800-900 but I found it was much nicer to drive with the power from idle coming in a lot smoother when you nail it with the higher rpm.

 

I think Piper quote 1,100.

 

As Jim says a modified advance curve is nice (or even an ignition you can map). I'd be inclined to look out for a 32/36 carb or preferably a 38 DGAS to go with it. A vernier pulley is worth it too if you haven't got one, a good tuner will likely get you an extra 5-10bhp tweaking that on a rolling road.

 

Keep the Vac advance for MPG gains. Without it you'll lose at least 4-5mpg maybe more (I know this from experience).

 

Dan

[Guest MJThewlis]

Back on road - ignition set to 14 degrees as suggested and idling sweetly at 1000rpm. I haven't changed the ignition advance - running the ESCII it suggests you can't for this distributor?

 

Been out for a short spin this afternoon and no pinking to be heard and does seem to be pulling better. I'm off to Cadwell back end of March and get a better call on it then.

 

Thanks for all the advice all.

 

M.

[Guest Ian & Carole]

Hi Mat

 

What date in March are you at Cadwell ?

 

Only 1/2 an hour from mine.

 

Ian J

[Guest MJThewlis]

26th March. It's with Javelin if you are interested.

 

Cheers, M.

[Longboarder]

ESC11 is a bit limiting for the piper 285. You would be better to change to a modified inductive or aldon dizzy to release the full potential and loose the stepper and esc2 box. If you pull the plug on the stepper motor you can use the adjustable stop to control the idle.

 

Nigel