front carbie not drawing air
#1
front carbie not drawing air
Hi all, set the static timing of the car -- engine runs sooooooo much better -- and turned to tune the carbies only to discover the back works great but the front doesn't draw air at all, and the piston is a bit sticky in comparison to the one nearest the bulkhead.
Any thoughts why it wouldn't draw air? Is this related to the piston or do I have two issues to solve?
Thank you!
Graham
Any thoughts why it wouldn't draw air? Is this related to the piston or do I have two issues to solve?
Thank you!
Graham
#2
Are they SU or strombergs?
Dont know a whole lot about the strombergs but its lilkely almost the same, the piston has to move up and down freely with oil as a dampner, engine vacuum is what operates teh piston and when the piston rises it pulls the needle up and more fuel goes in! thats kinda it, in a simplified manor anyways!
Dont know a whole lot about the strombergs but its lilkely almost the same, the piston has to move up and down freely with oil as a dampner, engine vacuum is what operates teh piston and when the piston rises it pulls the needle up and more fuel goes in! thats kinda it, in a simplified manor anyways!
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Series1fan (10-09-2014)
#4
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Here is link to setting/tuning SU's, it may be helpful. Link below
https://www.jaguarforums.com/forum/x...17/#post928571
See mine below.
Last edited by o1xjr; 10-09-2014 at 04:36 PM.
#6
As you have Strombergs, the diaphragm is the most likeley culprit.
The fact the piston is more difficult to slide UP than the rear carby, indicates a very dirty carby housing.
My suggestion is to get 2 diaphragms, 2 minor kits (some of these include that diaphragm, so ASK the questions), and give them both a favour and refresh thm both.
SOME, and I repeat, SOME, USA market cars have what is known as a "secondary throttle plate" between the carbies and the actual inlet manifold. This is controlled by a linkage arrangement to synchronise the opening with the carbies. I have never seen one in the flesh, but have read about that plate being a nightmare, and most owners have removed it.
The fact the piston is more difficult to slide UP than the rear carby, indicates a very dirty carby housing.
My suggestion is to get 2 diaphragms, 2 minor kits (some of these include that diaphragm, so ASK the questions), and give them both a favour and refresh thm both.
SOME, and I repeat, SOME, USA market cars have what is known as a "secondary throttle plate" between the carbies and the actual inlet manifold. This is controlled by a linkage arrangement to synchronise the opening with the carbies. I have never seen one in the flesh, but have read about that plate being a nightmare, and most owners have removed it.
Last edited by Grant Francis; 10-10-2014 at 03:57 AM. Reason: Spelling still sucks
#7
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#8
TR250/TR6 Carbs Part I
Above is an outstanding source for Stromberg overhaul and tuning. A real blow-by-blow account with pics Special tool needed to alter the mixture.
Thank you all. Yes, switched the diaphragm and cleaned both carbies. They weren't very dirty at all but, hey presto, once cleaned, all is working nicely.
The plugs previously showed over rich mixture and now nice and clean. Drove the car a lot today so tomorrow will pull the plugs again and check. If sudden change I'll be back here for advice
Thanks so much,
Graham
Above is an outstanding source for Stromberg overhaul and tuning. A real blow-by-blow account with pics Special tool needed to alter the mixture.
Thank you all. Yes, switched the diaphragm and cleaned both carbies. They weren't very dirty at all but, hey presto, once cleaned, all is working nicely.
The plugs previously showed over rich mixture and now nice and clean. Drove the car a lot today so tomorrow will pull the plugs again and check. If sudden change I'll be back here for advice
Thanks so much,
Graham
The following 2 users liked this post by Series1fan:
Grant Francis (10-18-2014),
o1xjr (10-18-2014)
#9
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EDIT actually ,looking at the clock that road trip would be today!
Last edited by o1xjr; 10-18-2014 at 09:16 AM.
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https://www.jaguarforums.com/forum/a...-127568/page3/
Car ran sweet, sat on 65-80 mph all the way down and back(it seems to have a real sweet spot at about 75 mph). Passed lots of unsuspecting drivers in my old banger.
412 km, used 62 litres of fuel. Averaged 15L/100km. A far cry from the 21L/100 it was using when I got it.
Good to hear yours is running sweet too.
#12
Australia no longer uses Imperial?
Hi Clarke, looked over the pics of the trip you took. Nice! Yours the eldest there?
Love that avatar pic of the MK 2 (?) pulling the caravan.
Thanks for these mileage numbers. I'll run mine but they aren't as good as you're getting, I'm pretty sure. Still got one or two issues to resolve and then maybe.
Hi Clarke, looked over the pics of the trip you took. Nice! Yours the eldest there?
Love that avatar pic of the MK 2 (?) pulling the caravan.
Thanks for these mileage numbers. I'll run mine but they aren't as good as you're getting, I'm pretty sure. Still got one or two issues to resolve and then maybe.
#13
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1.Australia no longer uses Imperial?
2.Hi Clarke, looked over the pics of the trip you took. Nice! Yours the eldest there?
3.Love that avatar pic of the MK 2 (?) pulling the caravan.
4.Thanks for these mileage numbers. I'll run mine but they aren't as good as you're getting, I'm pretty sure. Still got one or two issues to resolve and then maybe.
2.Hi Clarke, looked over the pics of the trip you took. Nice! Yours the eldest there?
3.Love that avatar pic of the MK 2 (?) pulling the caravan.
4.Thanks for these mileage numbers. I'll run mine but they aren't as good as you're getting, I'm pretty sure. Still got one or two issues to resolve and then maybe.
1. We use km but my car is in mph.
2.Youngest member, oldest car!
3.That was Ken's MkII on a family holiday in the Blue Mountains parked outside his inlaws house I believe.
4.Those carby's have been apart a few times now, I think every part that can be replaced has. I have tried 2 sets of needles as well. Still doe's not idle as smooth as I would like. But will have to live with that,when I have had it idling smooth the fuel burn goe's up to 17-18L/100km.(richer mixture)
Best compromise I guess,until I learn a bit more.
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