carb issue ?
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- 356 Fan
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carb issue ?
Fellow members, my 1964 C has developed a miss in cylinder #3. I have checked all the usual issues ,i.e. timing, valve settings, plugs ,wires,etc. the car has Solex 40PII carbs I cleaned the jets and have observed fuel spray from the spray tubes on both throats However if I pour a small amount of fuel into the throat of cylinder #3 it briefly smooths out Any suggestions or advice would be greatly appreciated thank you
- Vic Skirmants
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Re: carb issue ?
Did you clean the IDLE jets?
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- 356 Fan
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Re: carb issue ?
Yes I did and I blew compressed air through the passages. As an aside ,the mixture screw on number 3 cylinder produced no change when screwed all the way in or out
- David Jones
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Re: carb issue ?
Sounds suspiciously like an air leak. The base of the carb may be warped. When do you detect the miss, at idle or when driving?
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715
Cymru am byth
David Jones #9715
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Re: carb issue ?
Anthony
Can't you try spraying some easy start around the base of the carb on Cylinder 3 and see if it affects the running at tick over?
It will prove or eliminate a warped base flange. I believe that these 40 P11 Solexes are prone to warp, usually from over tightening the base flanges. Problem being that when they get machined up to true or get them flat, they end up thinner and the problem can get worse!
Regards Jay
Can't you try spraying some easy start around the base of the carb on Cylinder 3 and see if it affects the running at tick over?
It will prove or eliminate a warped base flange. I believe that these 40 P11 Solexes are prone to warp, usually from over tightening the base flanges. Problem being that when they get machined up to true or get them flat, they end up thinner and the problem can get worse!
Regards Jay
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Re: carb issue ?
Wow, I did not even consider an air leak to be the issue. And in retrospect,I did detect a "chuffing"sound near cylinder #3. I will investigate this morning. Thanks to all that took time to chime in. Will report back
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Re: carb issue ?
The out-of-flatness can vary between .010" to .025" and when I rebuild Solex carbs, I un-stress the "feet" to minimize machining them
to match each other. You can't flatten them correctly using a file! When mounting the carb to the manifold(s), don't use the thick gaskets
and torque the nuts to 15 ft.lbs. to prevent re-warping!!!
The injection nozzles can be taken apart to clean the insides, but DON"T lose the tiny ball check!!! I do have some in stock.
Also, I have small diameter wire probes to "poke out" clogged passages which can't be done w/an air gun.
to match each other. You can't flatten them correctly using a file! When mounting the carb to the manifold(s), don't use the thick gaskets
and torque the nuts to 15 ft.lbs. to prevent re-warping!!!
The injection nozzles can be taken apart to clean the insides, but DON"T lose the tiny ball check!!! I do have some in stock.
Also, I have small diameter wire probes to "poke out" clogged passages which can't be done w/an air gun.
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Re: carb issue ?
If you need to "unclog" the tiny jet holes you can do it with a syringe needle. I am diabetic and use a #31 gauge needle on my pen style syringes. It is 0.01025" in diameter which is smaller than the hole size in the accelerator pump jet. As it comes with a screw on fitting of about 1/2" diameter it is easy to hold and use. Find your local friendly diabetic and scrounge a few or just buy a box at your local pharmacy for $5. Much cheaper than a set of jet needles.
If I had known I would live this long I would have pushed the envelope a little harder.
Cymru am byth
David Jones #9715
Cymru am byth
David Jones #9715
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Re: carb issue ?
Dick Weiss said "I unstress the "feet" to minimize machining them.
What does that mean and how is that done Dick?
Michael Foster
What does that mean and how is that done Dick?
Michael Foster
MICHAEL FOSTER
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Re: carb issue ?
I think Dick soaks them in beer.
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Re: carb issue ?
yes the beer makes them less stressed
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Re: carb issue ?
David, A needle won't go around internal curves.
("Yuengling" beer is used)
If the "feet" are outa flat over .020", the "un-stressing" is done in a strong vice or a hydraulic press; It won't flatten them completely,
but enough to minimize machining, the carb face(s) won't get damaged, and the "feet" should be matched to each other.
Finally, DON'T use the thick after-market gaskets or you'll eventually create warpage again! Torque the nuts to 15 ft.lbs.
Dick
("Yuengling" beer is used)
If the "feet" are outa flat over .020", the "un-stressing" is done in a strong vice or a hydraulic press; It won't flatten them completely,
but enough to minimize machining, the carb face(s) won't get damaged, and the "feet" should be matched to each other.
Finally, DON'T use the thick after-market gaskets or you'll eventually create warpage again! Torque the nuts to 15 ft.lbs.
Dick
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Re: carb issue ?
Hudepohl not doing the job?Dick Weiss wrote: ("Yuengling" beer is used)
Dick
Agreed on the 'thick gasket' comment. Popularized by Harry, folks spend hours sanding Zenith top covers flat (ever hear of a disc sander? This ain't optical quality), and then screw 'em down on a mattress of a gasket, pretty much guaranteeing that the flatness so laboriously gained is now lost courtesy of a thinner bolt surface and that oh, so accommodating gasket.
If you need a thick gasket, you have a problem with the mating surfaces. Fix that; the gasket will fail.
Ron LaDow
www.precisionmatters.biz
www.precisionmatters.biz
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Re: carb issue ?
Hi Ron
It would seem that Harry the 'Maestro' had a few different ideas from a lot of people ref the 356. From the use of the 050 Bosch Dizzy and 44 IDF Webers , thick gaskets etc ! We have his Secrets tome, very informative with some amazing facts but written in that hillbilly Ifin style. It makes you laugh ! Dick, You are correct Ref the warped Solex Feet, on page 69 of Duane Spencer's book The 356 Performance guide, there is a picture of a flat file resting on the upturned Solex 40 P11 ready to file flat! You would have to be very accurate with that file to get a good flat surface.
Both Harry and Duane sadly missed.
Cheers Jay
It would seem that Harry the 'Maestro' had a few different ideas from a lot of people ref the 356. From the use of the 050 Bosch Dizzy and 44 IDF Webers , thick gaskets etc ! We have his Secrets tome, very informative with some amazing facts but written in that hillbilly Ifin style. It makes you laugh ! Dick, You are correct Ref the warped Solex Feet, on page 69 of Duane Spencer's book The 356 Performance guide, there is a picture of a flat file resting on the upturned Solex 40 P11 ready to file flat! You would have to be very accurate with that file to get a good flat surface.
Both Harry and Duane sadly missed.
Cheers Jay