Macca X
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| posted on 28/1/12 at 11:40 AM |
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Weber 40's Problems
Hi, I am new to the Forum and hope someone can help with the problem I am having getting my Xtreme to run on Weber 40's.
I have looked at historical poss, but cannot see anything similar
The car was IVA'd last year and I have not been able to get the carbs/ engine running correctly since.
Chokes and jetting is as per recommendations for a 2.0l pinto with fast road cam: Car will tick over correctly and timing seems okay (although a bit
rough) Car will rev up fine when stationary and I can drive it with slow acceleration to 70mph.
The problem is when I try to "floor" the accelerator; the car just stutters and only accelerates slowly in a very jumpy manner.
Standard pinto mechanical fuel pump is fitted and seems fine when checked.
Air flow is okay as I have driven the car up and down the street with no bonnet fitted and it still stutters.
Any ideas what may be causing this problem: feels like air or fuel problems but I do not know where to go now?
Thanks for your help
Ian Mac
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Autosri
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| posted on 28/1/12 at 11:45 AM |
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Accelerator pump jets are probably wrong if it's as soon as you hit the throttle
The engine should idle pretty smooth if the carbs are in ballance and there is enough timing I run 14degrees at 1000rpm on the same setup as you minus
the cam
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Paul Turner
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| posted on 28/1/12 at 11:46 AM |
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Rolling road set up is your only solution, no amount of fiddling ever works, you just end up spending a fortune on jets etc. My money would be on
either pump jets too small or idle/air jets unsuitable, possibly a combination. Won't be fuel pump since the float chambers should be full, fuel
pump problem usually manifests itself after a short period of flat out running if it cannot cope.
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ali f27
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| posted on 28/1/12 at 12:31 PM |
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Sounds as though it strugling on progression can you post your settings eg emulsion tubes air correctors pump jets idle jets etc
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cliftyhanger
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| posted on 28/1/12 at 12:36 PM |
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Have you checked the accelerator pumps are working (I remember my dellortos used to give a very healthy squirt)
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John Bonnett
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| posted on 28/1/12 at 01:38 PM |
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quote:
Originally posted by Macca X
Hi, I am new to the Forum and hope someone can help with the problem I am having getting my Xtreme to run on Weber 40's.
I have looked at historical poss, but cannot see anything similar
The car was IVA'd last year and I have not been able to get the carbs/ engine running correctly since.
Chokes and jetting is as per recommendations for a 2.0l pinto with fast road cam: Car will tick over correctly and timing seems okay (although a bit
rough) Car will rev up fine when stationary and I can drive it with slow acceleration to 70mph.
The problem is when I try to "floor" the accelerator; the car just stutters and only accelerates slowly in a very jumpy manner.
Standard pinto mechanical fuel pump is fitted and seems fine when checked.
Air flow is okay as I have driven the car up and down the street with no bonnet fitted and it still stutters.
Any ideas what may be causing this problem: feels like air or fuel problems but I do not know where to go now?
Thanks for your help
Ian Mac
Ian, a standard mechanical fuel pump will not supply enough petrol for twin DCOE40s. I had the same problem on my 1650 pre-crosflow. Best to fit a
Facet Red Top and Filter King pressure regulator in my opinion.
John
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britishtrident
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| posted on 28/1/12 at 02:55 PM |
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A standard AC mechanical pump can supply more than enough fuel for twin 40DCOE on a an road going Pinto without any problems ---- Lotus
used it on the Ford based Twincam, Chrysler used it on the Hunter GLS/Rapier H120 1725cc H120 engine and the Avenger Tiger and and the Sunbeam
1600TI and I am not 100% sure but ISTR the original RS1600 also had the AC mechanical pump.
My starting point as already suggested by other posters would be to to check the accelerator pumps are actually squirting and correctly sized for
the engine..
I would also the check the float levels are correct, and the jets are screwed in properly. Are you running without an air box or air filter; this
will make any weakness of the l mixture worse particularly when moving.
If you have a mechanical advance distributor check the mechanism is advancing and not stuck
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Dusty
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| posted on 28/1/12 at 06:00 PM |
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I used to run twin 40's and the standard pump and 129bhp at the wheels of my pinto.
Float chamber levels are important and an easy check.
Balancing the carbs is also simple.
Accelerator pump is an easy check. Just look down the chokes for a squirt when you bang open the throttle. Volume the pump delivers can be altered on
Dellortos but the adjuster nuts and plungers are so delicate you stand a good chance of breaking one. I did. So that is fiddled with by the RR
operator.
Progression holes are important but you cant do much yourself about them without the knowledge.
Then it's onto a RR and let an expert have a look at them. Mine used to run so smoothly and economically after they had been done by an ace on
his RR.
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Craigorypeck
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| posted on 28/1/12 at 09:08 PM |
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An easy way to test the accel pumps is to unscrew the carbs, keep them level, pull back slightly and watch for a squirt being delivered into each
runner when the throttle is pressed quickly to the floor.
really sounds like accel pump issue from what your describing..
My webers used to drip prtrol from the trumpets when being fuelled by mechanical pump until i stuck a wee sytec regulator on, yes the float valves
were new too. never had a prob with under fuelling.
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Xtreme Kermit
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| posted on 28/1/12 at 10:28 PM |
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Hey Ian! Nice to see another Xtremem owner over here, it's a great place to hang out.
The float level is critical on dcoe carbs, so if you are looking for something to check, that would be well worthwhile. That having been said, it
sounds like the pump jets aren't doing what they should.
It would help if you posted your jet sizes. Idle, main, air corrector, emulsion tube and pump jet along with the choke size.
Ian
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Macca X
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 posted on 30/1/12 at 11:12 PM |
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Weber 40's Problems
Thanks for all the prompt replies to my weber 40's problem.
For clarity, they have the following currently installed
Choke venturi 36mm
Main Jet 145
Emulsion Tube F16
Air corrector 190
Idle Jet 50/ F9
Pump Jet 45- this is the only one I did NOT change when trying to set the cars up for recommended 2.0l pinto with fast road cam: cannot remember why I
did not change.
Timing seems okay at about 14-16 degrees and carbs are balanced
Fuel delivery seems okay when idling, etc and revving when stationary.
Rolling Road is next step, but no idea how much that would cost (do not expect a mobile tuner would have the knowledge to set up carbs like this)
Also, only aware of one RR locally: Interpro at Thornbury, but they sound like the cater for the "big" boys as opposed to my lowly pinto
Xtreme
Thanks in advance for your help
Ian Mac
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se7ensport
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| posted on 31/1/12 at 08:53 PM |
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Ian
Can't remember if we checked the float heights, having consulted Des Hammill it should be 7.5mm shut off and 15mm at full droop.
What other jets do you have to hand? 55F2 idles with 180 air correctors would be worth a go if you have them.
Other thoughts are to check throttle spindles for wear and if the dizzy is advancing correctly; would be worth swapping the dizzy for a spare one to
rule it out.
Alex
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