383 Vacuum advance leaking

Mopar Big Block Talk
money_one_four
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Joined: Mon Mar 03, 2008 1:59 pm
Location: Dartford Moor

Re: 383 Vacuum advance leaking

Post by money_one_four »

Not sure if you have fixed this problem , but I would say it’s a choke problem rather than advance problem, if you try to give it more fuel and the choke is not working or fully closed it will miss /splutter even stall .How do I know this ? my car hasn’t got a choke fitted and does the same as yours, just needs a little more time to warm up before driving off and all’s fine .
CHEERS BE LUCKY ALAN
Jensen 111/440/1317 /OAR 298P
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Eddie
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Re: 383 Vacuum advance leaking

Post by Eddie »

money_one_four wrote:Not sure if you have fixed this problem , but I would say it’s a choke problem rather than advance problem, if you try to give it more fuel and the choke is not working or fully closed it will miss /splutter even stall .How do I know this ? my car hasn’t got a choke fitted and does the same as yours, just needs a little more time to warm up before driving off and all’s fine .
Thanks for the heads up.

Yes nothing is leaking, so it’s starting to narrow down the causes. It only happens when the engine isn’t up to temperature so looks like it could be the choke.

Ta Eddie
Eddie

JOC 10030
Interceptor II 123/3901 CEA 1J
1970 Earls Court Motorshow Car
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RayR
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Re: 383 Vacuum advance leaking

Post by RayR »

Another one to try is the distributor cap. I had exactly the same problem, the engine needed to properly warm up before the sputtering went away 5 or 6 miles or so with no choke. New cap and never happened again. Theory is a small hairline crack, and moisture condensed in the crack causing the misfiring and needed to get truly warm before the moisture evaporated out again.

Ray
MkIII Interceptor (140 8488)
RichardGibson
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Re: 383 Vacuum advance leaking

Post by RichardGibson »

Hi All.
My 1971 Mk2 Interceptor has the same issues regarding a lack of smooth running when cold. It coughs and splutters if I drive it immediately on fire up after sitting for a few days. Once warmed up it behaves as it should.
On returning from the International at Hull I found I had an increasingly worsening issue with an intermittent back fire, investigation revealed a leak in the fuel feed pipe to the carb, it was cracked. I changed this. At the same time I changed the plugs, HT leads, dizzy cap and rotor arm. I noticed that the off side plug nearest to the bulk head (forget the number) was well carboned up showing intermittent firing, the next one down was not a lot better.
Anyway tomorrow the car goes in to my local tune up specialist (one who does not need a plug in computer to set the car up) to have the points and condenser fitted before tuning the old fashioned way.
Richard
money_one_four
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Re: 383 Vacuum advance leaking

Post by money_one_four »

Just goes to show how different things can give off the same symptoms, keep us posted Richard will be interesting to hear what they find.
CHEERS BE LUCKY ALAN
Jensen 111/440/1317 /OAR 298P
Jaguar 420G
Jaguar Sovereign v8
Winnebago M/H
RichardGibson
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Re: 383 Vacuum advance leaking

Post by RichardGibson »

Hi again.
Just got the car back from the tune up specialist.
Three issues were discovered:-
1 The points were on their last legs so to speak, almost worn away. I asked the garage to replace these as I had no gap set information to do it myself, whereas they have equipment to check dwell angles etc.

2 When fitting the new dizzy cap I had bent the spring steel connector on the rotor arm and it was only just making contact. Apparently this is easy to do due to the access of the distributor and the fact that you do not know you have done it until you remove the cap again. This however is probably not the cause of the original misfire as I do not remember the rotor I took out as being bent. All is now bent back to its correct state.
Some thing to remember if removing the dizzy cap etc.

3 The points had been over greased when last fitted and there was grease everywhere, this can cause connection issues.

The car feels and sounds a lot better now although we suspect a very slight leak in the off side exhaust manifold, may need a new gasket in the future.
I will drive around a bit to see if it is better.

Richard
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Eddie
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Re: 383 Vacuum advance leaking

Post by Eddie »

slotcarone wrote:I would fix the advance unit if it is not working. Could possibly be the cause of your problem. Could also be a choke/carb adjustment issue. :)
I am thinking I have finally solved the problem with my spit back in the carb when cold.

The advance unit seems be working & the choke seems to be working.

Watching youtube carb tutorials I firstly moved the pump drive link one hole closer to the carb body. This seemed to make quite a big difference. With this there was no spit back, but I still had a mid range hesitation.

For mid range hesitation I had read about changing the metering springs for a stronger one. I am not 100% sure what was in the carb spring wise, but I have swapped them out for the pink metering springs, these are second stiffest pair in the calibration kit.

The combination of the 2 items seems to have totally eliminated any spit back and and mid range hesitation. The car is probably driving the sweetest I have ever known.

But could my meddling have any adverse effects?
Eddie

JOC 10030
Interceptor II 123/3901 CEA 1J
1970 Earls Court Motorshow Car
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Grant
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Re: 383 Vacuum advance leaking

Post by Grant »

If it's performing at it's best as you have had it Eddie then that is brilliant and use it as is and enjoy, if it was running lean it would "Ping" if it was running rich then that's not particularly great as it can wash the oil from the bores, but having it as it was backfiring etc was not good so it seems like you have concored it Eddie well done, here you goImage, if you feel it is good Eddie then I would treat it to a rolling road run, they will run it with an air-fuel meter pushed up the Gilbert Pipe :shock: (aka exhaust).. this will confirm your fetteling correctnessImage,.. you normally come out of a rolling road tune happier than you went in.. slight minor adjustments make all the difference Ed..It's a nice treat for any old classic and it's driver I think anyway, find one that is good at tweaking EddieMan.. some just want to give a print out of power, but you want one that can tweak old school stuff..have an ask about EddieMan :wink: do you run super unleaded in that Old "E" series engine EddieMan?.. it is an E series engine isn't it?.... If you do run it on super Unleaded you should definitely make sure you have that in it when you treat it to the engine tune on the rollers Ed :wink:
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RockyUSA
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Re: 383 Vacuum advance leaking

Post by RockyUSA »

Agree with Grant 100%

Rocky
‘71 TVR Vixen 2500 - (M Series Tribute)
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slotcarone
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Re: 383 Vacuum advance leaking

Post by slotcarone »

If the car is running great then all is fine and you did no wrong! :)
1972 Interceptor III
133-5612
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