It's all in the timing.

#11

GlennK wrote:

Quote:

On 11/2/2009 11:48 PM, clay wrote:
James Sweet wrote:
clay wrote:
James Sweet wrote:
clay wrote:
Finally got around to looking at the ignition timing after changing
the timing belt a couple weeks back. ('83 245) 12 BTD at idle, as
it should be. Then the weirdness begins. Rev it up a little and
timing retards to ~5 BTD. Rev a little more, say 3500, and it
creeps up to 15-18. Rap it and it appears to go up from there. So,
what's up with the retardedness? Can't be good for performance.
btw, I have the vacuum line on the knock generator plugged so the
motor doesn't ping all the time... and, so it will pass smog.

If I understand what you're saying, that sounds like it's working as
expected. Remember that BTDC is *before* top dead center, so a
bigger number means more advance and a smaller number is retarded
towards TDC. It takes time for the fuel burn to take place, so the
spark fires prior to the end of the compression stroke.

Right.
I understand about ignition advance curves, etc.
That's why I said that the timing retarding initially can't be good for
performance (or emissions...)
Googling around for the correct name for the 'knock generator'... the
Chrysler ignition control module, I found an explanation posted in this
group back in 2002.
Now to find the specifics of the recall to get rid of the retard,
and figure out why I'm not getting more advance with higher rpms.
Possibly because the motor has the Chrysler module but a Bosch
distributer. As I understand it, the distributer cap should be white
but it's a Bosch red one...

There was more than one Chrysler ignition system. Early K-jet cars
used the one with the white distributor cap, later LH Jet 240s used a
different system with a normal Bosch distributor. You should be able
to retrofit in a later Bosch EZK ignition system if you want,
although I haven't heard of too many problems with the stock
ignition. You can install a hotter cam and higher flowing exhaust
system to gain some power as well, although the biggest improvement
is converting to a manual transmission if the car does not already
have one. The old slushbox saps a lot of power.

I didn't know they used a Bosch distributer with the Chrysler module.
Thanks for that.
It's a slushbox. Not looking to hotrod it. It's too tired for that.
Just want to get the motor running like it's supposed to.
Off to track down that vacuum delay valve.
I can send you the service information for the delay valves if you like
just let me know where it is 15 pages
Glenn K
Volvo Certified Technician 2008
ASE Certified Technician 2008

Got it, thanks!

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It's all in the timing.

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Re: It's all in the timing. - 11-04-2009 , 11:12 PM