Locking out the advance on Daytona distributor

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Steve Meltzer
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Locking out the advance on Daytona distributor

Post by Steve Meltzer » Thu Dec 28, 2017 2:00 am

I want to do a test with the distributors' advances locked out on my '71 Daytona (Euro). Since the centrifugal weights are below the breaker plate, how do you do this? Or can you? thanx s
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

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John Vardanian
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Re: Locking out the advance on Daytona distributor

Post by John Vardanian » Thu Dec 28, 2017 2:37 am

Steve, I'm assuming you want to seize the weights in the engine-off position. If so, just stuff some semi-hard material between the weights and the inner wall of the distributors-- folded paper, pieces of bottle cork, etc. The material needs to press against the weights and not the plungers within the weights. Now, what is this test going to tell you, just curious?

john
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Steve Meltzer
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Re: Locking out the advance on Daytona distributor

Post by Steve Meltzer » Thu Dec 28, 2017 10:24 am

If you must know....for some time now, after starting the car (Daytona Spyder convert) you can synch the Webers (excellent numbers near 7) nicely and then for no apparent reason with all hands off the engine, the accelerator pedal dc'd, the engine starts to rev spontaneously from a normal 950 to 2200 or so. Smooth, persistent and inexorable. This occurs about 10 minutes or less after setting up the carbs. Occurs so consistently that it is impossible to set up the carbs for more than 5-10 minutes, and then they go wild again. I thought this was a vacuum leak, but after carefully replacing the intake manifold o-rings, cleaning everything up carefully, replacing the vacuum hoses to the booster and having the carbs blessed by Pierce, it still does the same thing. Happens with or without the linkage attached.

Well, you asked, so here's more. Thinking that maybe it ain't a vac leak, I was wondering about a problem in the distributor's advance mechanism. Furthermore, I thought if i could lock out the advance, i could see if the problem recurred when the dizzy was fixed. I also thought about seeing if I could get a nice long problem free, steady idle with just one side running, to isolate the problem. (stock points, Euro setup, no microswitch)

The weights are below the plate, so i'd have to remove the plate, right? In which case, i might as well send them out to be checked on the machine.
I welcome your thoughts and anyone elses. Had hoped not to post this, as I feel like I'm always "whining" about one thing or another. s
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

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tyang
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Re: Locking out the advance on Daytona distributor

Post by tyang » Thu Dec 28, 2017 10:55 am

Hi Steve,

If the distributors are advancing on their own, it would show up on a timing light.

Is this a USA Spec car? Is the idle control disc still hooked up if it is?

Tom
'63 330 America #5053

Steve Meltzer
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Re: Locking out the advance on Daytona distributor

Post by Steve Meltzer » Thu Dec 28, 2017 1:33 pm

Thanx Tom. it's a Euro car, no disc nor microswitch. Help me to understand this...say the problem is due to a vac leak and you have a timing light (as you know, to do it on the flywheel under the car is awkward, on a good day) the light will show advance no matter what, because the rpms are climbing. (unless the dist won't advance at all, in which case i suppose, the revs would rise and the timing wouldn't change, or wouldn't change on one side only, and the car wouldn't accelerate smoothly as it does). I suppose you could make a mark near the pulley and thus have a temporary, arbitrary pointer to do this. I've tried to do this before, and I couldn't get satisfactory info. thanx for your interest.

Looking at our "Doppelgänger" pictures, I see my hirsuitism is misplaced! s
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

Jimmyr
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Re: Locking out the advance on Daytona distributor

Post by Jimmyr » Thu Dec 28, 2017 3:47 pm

Get them on a Sun machine and don't try to jamb things up while running them in the car. While in the distributor machine all parameters and service work are at your finger tips. Most shops with a machine should do this at a reasonable cost. The improvements with a well set up distributor are quite noticeable. Jim

Steve Meltzer
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Re: Locking out the advance on Daytona distributor

Post by Steve Meltzer » Thu Dec 28, 2017 4:26 pm

Jim, i was thinking the same thing...might just pull 'em and run them on the machine. s
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

Jumprun
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Re: Locking out the advance on Daytona distributor

Post by Jumprun » Thu Dec 28, 2017 11:23 pm

Steve does this mystery rise in RPM occur as the engine goes from a cold engine to warm? Will it re-set itself if you shut down and re-start?

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John Vardanian
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Re: Locking out the advance on Daytona distributor

Post by John Vardanian » Fri Dec 29, 2017 1:05 am

Steve, to get to the weights you'll need to take the distributors off the car and separate the body from the bottom plate.

Question, are the carbes linked together when this happens? Have you tried decoupling all the carbs from the actuating rod. This way when the rise in the RPM occurs you can at least see if it can be narrowed to a single carb with your synch meter?

john
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Steve Meltzer
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Re: Locking out the advance on Daytona distributor

Post by Steve Meltzer » Fri Dec 29, 2017 1:15 am

I suspected that my theoretic idea wouldn't be doable, and it ain't. The problem def'n occurs sans linkage, and, as noted, all of the carbs were done by Pierce and later, and independently, confirmed to be w/o vacuum leaks by him. I may be forced to get some adult supervision here. thanx. s
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

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John Vardanian
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Re: Locking out the advance on Daytona distributor

Post by John Vardanian » Fri Dec 29, 2017 8:18 pm

Steve, do all six carbs suck at the same rate before the RPM change as they do after? Have you checked the timing before and after the RPM change?

john
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tyang
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Re: Locking out the advance on Daytona distributor

Post by tyang » Fri Dec 29, 2017 10:55 pm

Besides sending your distributors out for testing, if you want to check the timing on the car without climbing under to peek into the bottom window of the flywheel, you can easily mark the front pulley with a paint marker. Just transfer the AF and AM marks to the front pulley referenced to a pointer as you see them through the window.

If the carbs have been checked for vacuum leaks, have the o-rings, and intakes been checked? Have the right o-rings been installed? Too thin of an o-ring will not seal the intake manifolds to the heads.

Tom
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Steve Meltzer
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Re: Locking out the advance on Daytona distributor

Post by Steve Meltzer » Sat Dec 30, 2017 10:20 am

Jumprun wrote:Steve does this mystery rise in RPM occur as the engine goes from a cold engine to warm? Will it re-set itself if you shut down and re-start?
Yes, it only occurs about 5 minutes after it is warm...however, i don't know with certainty that it resets itself. I've been working on this off and on for several months and when it starts to jump in RPMs to 2200 or so, i get disgusted, shut it off and quit. My recollection is that when I return, the RPMs are below what I'd like, meaning instead of the 950-1000 I want, I have to fiddle around with increasing the idle speed to get to run right, then we start all over again. May look at it again this AM, if I have time.

I've not looked with a timing light, as I figured, wrongly I guess, that as the RPMs smoothly and annoyingly accelerated, the timing would of course increase, and I wouldn't no which was the chicken, and which the egg.

Tom, yes I thought of transferring the timing marks up top, but as noted above, I was sure it wouldn't help. Sometimes when you get an idea in your head (like the wrong diagnosis, here, or in my office) you just don't see other thoughts as valid. "When you're a hammer, everything in the world looks like a nail".

On Thrs, much to my chagrin, I'm getting my first bit of adult supervision.

thanx for everyone's thoughts. s
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

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Re: Locking out the advance on Daytona distributor

Post by Jumprun » Sat Dec 30, 2017 2:49 pm

Steve, since the throttle plates are not being moved and no extra air is getting in, it does indeed sound like a distributor advance problem.
There may be some undo friction or bad springs, or things are just gunked up, so when things get warmed up you get inconsistencies. It could also be some other distributor drive problem, something loose or worn.

I'd pull them to inspect and clean, there are worst ways to spend the day.

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John Vardanian
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Re: Locking out the advance on Daytona distributor

Post by John Vardanian » Sat Dec 30, 2017 4:50 pm

The stock distributor should not begin advancing until after 1000 (engine) RPM and thereafter the advance would be gradual and proportionate to engine speed. Just theorizing here, but if for some reason the weights on one bank just suddenly fling all the way outward, then that could cause a quick rise in engine speed.

john
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