Checking Timing 8-98 & Manual Advance

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24 Jun 2016 15:04 #31295 by curtiss
curtiss created the topic: Checking Timing 8-98 & Manual Advance
While tracking down a potential heating issue I got to thinking about the ignition timing. I have two questions:

- Manual Advance - How does this work and when do I use it? I suspect it is for starting but I have not needed to use it to start the car. When the car is running and I pull it out the engine slows down a bit, is that advancing or retarding the ignition when I pull it out?

- Ignition Timing Adjustment - How do you set the timing on these cars, is there a way to do it with a timing light and if so where and how to I read timing. I have looked in all of the books I have bought so far and it is not clear.

This is the set up I have, someone has installed a Chrysler distributor with electronic ignition in this car so that is the starting point. It also has vacuum advance and I noticed it appears to be taking full manifold vacuum.


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25 Jun 2016 23:05 #31297 by Ivor
Ivor replied the topic: Re: Checking Timing 8-98 & Manual Advance
Hello Curtiss,
I have a earlier small eight(8-77) but believe it is similar to your later small eight engine. The factory distributor is the semi automatic type with manual advance and centrifugal advance and for normal driving is left on full advance. For starting and very slow driving in top gear a retarded spark can be used. For timing a timing light can easily be used, their is a peep hole not far from the starter motor, it has a threaded plug with a square head. The flywheel is marked top dead centre for each pair of pistons, find the mark 1/8 this is when number 1 piston and number eight are at top dead centre. My flywheel ring gear has 97 teeth so each tooth is pitched at 3.71 degrees. I mark each second tooth on the advance side of the flywheel a different colour up to 10 teeth which is 37 degrees. Connect your timing light to number one lead and it is easy to check the full retard and full advance with the engine at idle and with the engine revving at about 2500 rpm the total manual and centrifugal advance. I think you will need to time your modern electronic distributor with the vacuum line disconnected and plugged as you do with cars of that era.

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25 Jun 2016 23:54 #31298 by Brad Hoskins
Brad Hoskins replied the topic: Re: Checking Timing 8-98 & Manual Advance
Curt
I think Ivor summed it up nicely
As near as I can tell, The spark knob on the dash is meant to be left in the fully advanced (pushed in) position and pulled out only if one is going to hand crank the motor. The manuals make no mention of pulling out the spark knob to start the car using the starter. That makes sense with what you are describing with the engine slowing down when you pull the knob out as you are retarding the spark.
I posted on this a while back but never really got a solid answer for the 1931 set up. I think you just answered it!

<!-- l --><a class="postlink-local" href=" acdclub.org/forum/viewtopic.php?f=1&...c.php?f=1&t=7089 [/url]<!-- l -->

You might find the Motors information I posted interesting but I did have concerns about its accuracy!

Brad

31 8-98 cabriolet

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26 Jun 2016 05:06 #31300 by Brad Hoskins
Brad Hoskins replied the topic: Re: Checking Timing 8-98 &amp; Manual Advance
Curt

Sorry that link is not very good!
Here are a couple of pages from the 1927-1941 National Service Manual. Ignore the comment on distributor rotation, it should say clockwise, not counter clockwise.

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Brad

31 8-98 cabriolet
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27 Jun 2016 23:09 #31308 by curtiss
curtiss replied the topic: Re: Checking Timing 8-98 &amp; Manual Advance
OK, I think I might finally be onto something. 

I think I mentioned this has a Chrysler distributor in the car and it was so the last owner could have electronic ignition. I looked up the part number and it is out of a Dodge 318 and as I looked into it the Chrysler turns clockwise. So I started looking at the Lycoming 8-98 and the firing order has it turning counter clock wise.

This confirms it is creating a timing issue since turning backwards I am pretty sure the counter weights are not advancing the timing. Now to track down the original dual point distributor. 

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28 Jun 2016 01:16 #31309 by curtiss
curtiss replied the topic: Re: Checking Timing 8-98 &amp; Manual Advance

Brad Hoskins wrote: Curt

Sorry that link is not very good!
Here are a couple of pages from the 1927-1941 National Service Manual. Ignore the comment on distributor rotation, it should say clockwise, not counter clockwise.
Auburn Motors Generator Starter.pdf

Attachment not found



Brad


Brad,
I am pretty sure counter clockwise might be correct on the 8-98. I just looked at the firing order of 1,6,2.5,8,3,7,4 and matched it up to how my cap is wired and it appears it does turn counter clockwise. That is what is causing me pain with the non-original distributor I have :)[/color]

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