Re: Dial back timing light question
[Re: frank]
#180805
01/01/09 07:51 PM
01/01/09 07:51 PM
|
Joined: Mar 2007
Posts: 3,285 West Coast, USA
jbc426
master
|
master
Joined: Mar 2007
Posts: 3,285
West Coast, USA
|
You are correct. I would check the total timing with the rpm higher up. You may have some stiff springs in the old dizzy. Do you have a small block or a big block, because your total timing seems a little high?
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's 1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
|
|
|
Re: Dial back timing light question
[Re: frank]
#180807
01/01/09 08:33 PM
01/01/09 08:33 PM
|
Joined: Jan 2003
Posts: 25,200 Upper Midwest
MoparforLife
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 25,200
Upper Midwest
|
38 total seems to work good on many BB. But you can not successfully set total advance at say 38 degrees at 2500 RPM's unless you have your distributor calibrated so that it is fully advanced at that RPM. If you were to set it at 38 degrees at that RPM with a stock distributor you would have considerably more advance left in the distributor and it will still be advance way past the designated RPM.
Clean it, if it's Dirty. Oil it, if it Squeaks.
But: Don't fix it, if it Works!
|
|
|
Re: Dial back timing light question
[Re: MoparforLife]
#180808
01/01/09 08:50 PM
01/01/09 08:50 PM
|
Joined: Feb 2003
Posts: 2,138 tucson az
frank
OP
top fuel
|
OP
top fuel
Joined: Feb 2003
Posts: 2,138
tucson az
|
Quote:
38 total seems to work good on many BB. But you can not successfully set total advance at say 38 degrees at 2500 RPM's unless you have your distributor calibrated so that it is fully advanced at that RPM. If you were to set it at 38 degrees at that RPM with a stock distributor you would have considerably more advance left in the distributor and it will still be advance way past the designated RPM.
How do you set the dist to have total advance at a certain RPM? And how can I check my dist to determin when exactly total advance is achieved?
|
|
|
Re: Dial back timing light question
[Re: frank]
#180809
01/01/09 08:57 PM
01/01/09 08:57 PM
|
Joined: Jan 2003
Posts: 25,200 Upper Midwest
MoparforLife
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 25,200
Upper Midwest
|
The mechanical advance weights must be change. There are spring kits available to do this. In order to check where your advance will take you you can hook up your timing light and watch the timing mark advance as then engine speed increases but with a stock distributor the RPM's will be quite high before the mechanical advance is fully advanced.
Clean it, if it's Dirty. Oil it, if it Squeaks.
But: Don't fix it, if it Works!
|
|
|
Re: Dial back timing light question
[Re: frank]
#180810
01/01/09 09:06 PM
01/01/09 09:06 PM
|
Joined: Mar 2007
Posts: 3,285 West Coast, USA
jbc426
master
|
master
Joined: Mar 2007
Posts: 3,285
West Coast, USA
|
Quote:
How do you set the dist to have total advance at a certain RPM? And how can I check my dist to determin when exactly total advance is achieved?
You change the springs to set when the advance comes in. To check when total advance is achieved you use an rpm gauge and your timing light. When it quits advancing at high rpm, it's all in. Write down the rpm when it starts coming in, how much it advances and at what rpm it is all in. It's easy.
Now the harder part. In order to alter how much advance you get out of the mechanical advance mechanisim, you will have to weld up the slots and then grind them back until you get the amount you want. Some guys run about 18-20 degrees initial advance with 16 to 20 degrees mechanical or there abouts. I have read threads where guys have epoxied the slots and then filed the slots with long term sucess.
It takes some time, but the results are worth it.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's 1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
|
|
|
Re: Dial back timing light question
[Re: frank]
#180811
01/01/09 09:10 PM
01/01/09 09:10 PM
|
Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
|
Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
|
I'd rev it until it wont advance anymore(vac adv disconnected) & lock it down at 38. You would need a tach hooked up to know the rpm at that point where it wont adv any higher. Is this a stock dist w stock springs? 38 total will get you pretty close to ideal & if there's no pinging as you run it up thru the gears you're Ok though if it still has the original springs, the light one & the heavy one with the elongated loop on one end you would very likely gain by changing it(still keeping the total at 38). Also note what your initial is at idle before/after(any)changes.
live every 24 hour block of time like it's your last day on earth
|
|
|
Re: Dial back timing light question
[Re: frank]
#180813
01/01/09 09:55 PM
01/01/09 09:55 PM
|
Joined: Mar 2007
Posts: 3,285 West Coast, USA
jbc426
master
|
master
Joined: Mar 2007
Posts: 3,285
West Coast, USA
|
I believe those have reasonably light advance springs. Your advance may be all in at a relatively low rpm like you initially posted, but you still need to verify that. The issue with those dizzy's is that they provide too much mechanical advance, which forces you to use less initial timing, which reduces your performance at lower rpm. They solution is to reduce the amount of mechanical advance by limiting the travel of the advance mechanisim itself. This allows you to have more initial timing, less mechanical advance and end up around 38 degrees total. Once you have that squared away. They work nicely. You may want to find and keep a spare control module stashed in a ziplock bag in your trunk though. If you're still not happy, you might also want to pull the heads, have them ported and decked to increase the compression, install a bigger cam, a bigger carb and a looser torque converter...
|
|
|
Re: Dial back timing light question
[Re: jbc426]
#180814
01/02/09 02:02 AM
01/02/09 02:02 AM
|
Anonymous
Unregistered
|
Anonymous
Unregistered
|
Also, DO NOT TRUST these delay timing lights too far. Sometimes something like a reluctor which is just slightly misadjusted can cause a multi-fire condition in an ECU, or the light itself can be dodgy, and give false readings.
I recommend ONLY that you take the time to scribe the wheel or get an accurate timing tape and CHECK the marks with a dead stop, very easy to do.
MANY of these guys will post "I've never had trouble," or "MY light is accurate" but the fact is, you may not know for sure whether it is or not--all the time.
|
|
|
|
|