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Posted by: Gint Sep 30 2008, 05:38 PM

My carb'd 2056 (1.8 case/heads, 96mm P/C's, Mallory dizzy) has been running kinda crappy and pinging lately. I found the problem. The distributor clamp was loose and it was running too much advance. Corrected that problem and reset the advance to about 7 degrees at 1000 rpm idle. Much better...

But that leads me to a question for the collective. What do y'all run for initial advanced on your carb'd Type IV motors? Or for the professional types, what do you recommend?

Posted by: r_towle Sep 30 2008, 05:43 PM

Try 27 BTDC at 3500 rpm.

Rich

Posted by: Gint Sep 30 2008, 05:47 PM

I'd have to go out and check to see what max advance is on the Mallory anyway, but I'm probably all in by 3500 rpm (probably more likely by 3k) for sure.

More interested in initial advance at idle at this point. Put another way, even if you are setting your advance to 27 degrees at 3500 rpm, what would the resulting advance setting be at idle?

Posted by: sww914 Sep 30 2008, 07:58 PM

Mine is about 4 at idle and 32 full advance with the much maligned .009 distributor.

Posted by: ejm Sep 30 2008, 08:17 PM

Would depend on how the advance was setup. Check out http://www.malloryperformance.com/pdf/29014.pdf instruction sheet from the Mallory spring kit.

Posted by: DBCooper Sep 30 2008, 08:59 PM

Timing at idle is almost irrelevant. You spend time and horsepower at cruising speeds, where the timing is already fully advanced. If you get that timing wrong when you're spending time at highway speeds your engine overheats and starts to die. And if you're cruising you'll probably never notice a problem until there's been some damage. Like a valve seat going through a piston. So the idea is to get the full advanced timing right.

It depends on the motor but between maybe 28 and 32 degrees at 3500 RPM, full advance. Distributors are different too, but if your distributor has 20 degrees total advance that puts the default idle timing at 8-12 degrees, which is fine. Four degrees at idle doesn't seem like much, but if you don't have problems that's fine too. Idle timing is a lot less critical than timing at cruising RPM.

Posted by: Gint Sep 30 2008, 10:00 PM

With regard to timing at idle, you're correct with the exception of timing's effect on emissions.

I checked it later in the afternoon. With 7 degrees at idle I had 39 degrees at 3800 rpm which appeared to be max advance. With the timing set to 29 degrees at 3500, idle timing is a degree or two ATDC.

Posted by: Gint Sep 30 2008, 10:09 PM

Looks like the 32 degrees I found would correspond to Mallory's documentation. Thanks for the link Ed. And before someone asks, I bought this Mallory from Raby. Back when he was selling them of course.

And it's running better, except at idle. Not that it's bad at idle, just... different. Waiting until tomorrow to drive it to and from work while cold, warmed up, hot, etc...

Posted by: Eric_Shea Sep 30 2008, 10:14 PM

I was going to say 6 so it sounds like you're close.

Posted by: Mark Henry Sep 30 2008, 10:58 PM

28 degrees BTDC, advance will max out around 2800rpm

Posted by: Jake Raby Oct 1 2008, 06:17 AM

With the Mallory, most engines will optimize at 12/28 timing. Initial set at 950 RPM with full timing set at 3,300 RPM.

And grey advance springs.

Posted by: Gint Oct 1 2008, 06:55 AM

Jake, why am I getting 32 degrees of advance out of this distributor?

Posted by: Jake Raby Oct 1 2008, 08:08 AM

Don't really know... Was it one of ours?? When did you buy it if so?

I have discontinued Mallory sales due to the units not holding settings and having reliability issues. We have not sold them in months and never will again.

The unit went to hell when it started being made in Mexico.

Posted by: Gint Oct 1 2008, 08:56 AM

One of yours. I bought it at least a couple of years ago. It sat for a long time before I installed it, but it's been in the car for over a year now. I dropped it straight in and never touched your setup.

Posted by: Mark Henry Oct 1 2008, 10:14 AM

That sucks "was" a good product. Guess I won't be selling the one on my bus.

What are you doing now?

Posted by: Racer Chris Oct 1 2008, 11:27 AM

Mike,
Your distributor probably needs to have the advance mechanism adjusted.
Check out ejm's link above. In particular, figs 2 & 5 are important. As Jake mentioned, two grey springs should be installed for the correct curve. If you don't have two grey springs you need the #29014 advance curve change kit.
The total range of mechanical advance should be 16 deg, and the spring tabs need to be bent to raise the rpm where advance begins.

Posted by: Jake Raby Oct 1 2008, 12:32 PM

If it came from us, the advance was pre-set so double check your timing light and ensure that you actually saw 32 degrees of total advance.. We tested the dizzys on a running engine on the dyno prior to shipping them and I would have personally certified the advance your unit had.

The Mallorys have changed. When the newer units are compared to older units several components are thinner and even the optical windows have been found out of position on the rotor...

Lack of reliability and constant advance changes as well as spark scatter is what has taken them off my shelves. Anyone who sells these and hasn't found the issues either doesn't actually use them or lacks the experience to properly compare these to the earlier versions.

The beauty with us actually using and testing these items in engines is the fact that we immediately know when something goes down the drain.

Posted by: type11969 Oct 1 2008, 06:18 PM

What dists do you recommend now Jake?

Posted by: SGB Oct 1 2008, 06:33 PM

Yep, inquiring minds want to know...


Glad my mallory is from a few years ago. To address Gint's original situation, isn't 39 total advance way too high? I've got the gray springs and I'm testing the last brain cell but I thought TOTAL of 32 was Jake's recommended setup. I know I lost a little bottom end (from the 009) but the mid was much stronger and it could run 5K all day long without going past mid-temp.

Posted by: Borderline Oct 1 2008, 06:57 PM

Adjusting the total advance on a Mallory is really easy. Jake told me how to do it over the phone a couple years ago. All you need it a small torx driver to loosen the the advance plate. Then you can rotate the the adjuster plate that limits the total advance. There are two windows with a tabs that closes the window as the adjuster plate is rotated. You want the tab to close off about half of the window and then tighten the torx screws and you're done. this will yield about 16* of mechanical advance. So if you adjust the total advance to 28* @3500 rpm then you should get about 12* BTDC at idle. Works gud on my 1911! If you're not happy with your initial adjustment, try again. It's easy and cheap.

Posted by: Jake Raby Oct 1 2008, 09:26 PM

I currently have no dizzy recommendation. We are testing and searching for alternatives outside the air-cooled world...

Posted by: type11969 Oct 1 2008, 09:28 PM

You might want to update the glowing Mallory reference you have listed in the type4store ignition section!