Vacuum pipes
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Topic author - Posts: 86
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#1 Vacuum pipes
Does anyone know why the vacuum pipes on my ex.US 2+2 (with twin Stromberg carburettors) have been blanked off by a previous owner?
Tim
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
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#2 Re: Vacuum pipes
If you view SNG catalogue for Reservac vacuum pipes
https://www.sngbarratt.com/uk/#!/Englis ... %20-%20RHD
https://www.sngbarratt.com/uk/#!/Englis ... %20-%20LHD
It will show the vacuum pipes and differances between RHD and LHD
might help anwer your question
https://www.sngbarratt.com/uk/#!/Englis ... %20-%20RHD
https://www.sngbarratt.com/uk/#!/Englis ... %20-%20LHD
It will show the vacuum pipes and differances between RHD and LHD
might help anwer your question
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#3 Re: Vacuum pipes
Hi
I think you will find that a PO will have got rid of emission control gear. On the stromberg there is a temperature controlled bimetallic device on the side that can be vacuum controlled on some carbs there is also an overrun enrichment device also vacuum controlled that is often blocked off.
If you do a google search for buckeye triumph they have a brilliant article on repair and overhaul of strombergs.
Cheers
I think you will find that a PO will have got rid of emission control gear. On the stromberg there is a temperature controlled bimetallic device on the side that can be vacuum controlled on some carbs there is also an overrun enrichment device also vacuum controlled that is often blocked off.
If you do a google search for buckeye triumph they have a brilliant article on repair and overhaul of strombergs.
Cheers
Mark Brown
1971 S3 Etype, now sold, sadly.
1971 S3 Etype, now sold, sadly.
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#4 Re: Vacuum pipes
They do, this is the link:
https://www.buckeyetriumphs.org/carburetors
but be aware that the Strombergs fitted to E types only had fixed needles. Removing the emissions gear is the right thing to do along with holding the secondary manifold permanently open.
https://www.buckeyetriumphs.org/carburetors
but be aware that the Strombergs fitted to E types only had fixed needles. Removing the emissions gear is the right thing to do along with holding the secondary manifold permanently open.
John
1969 Series 2 FHC
1969 Series 2 FHC
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Topic author - Posts: 86
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#5 Re: Vacuum pipes
Thanks folks.............all helpful stuff.
My question relates to why the ignition vacuum advance/retard take off point on the front carb manifold flange has been blocked off?
My question relates to why the ignition vacuum advance/retard take off point on the front carb manifold flange has been blocked off?
Tim
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
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#6 Re: Vacuum pipes
Most/many of the Stromberg fitted US emissions engines had distributors with no vacuum advance so if a Stromberg had been fitted at some point which had a vacuum advance take off it would need to be blocked.
John
1969 Series 2 FHC
1969 Series 2 FHC
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#7 Re: Vacuum pipes
Or if the vacuum advance mechanism had failed, a common complaint, then some owners just blanked it off, and the pickup on the carb.
Cheers
mark
Cheers
mark
Mark Brown
1971 S3 Etype, now sold, sadly.
1971 S3 Etype, now sold, sadly.
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Topic author - Posts: 86
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#8 Re: Vacuum pipes
I must confess I thought all Lucas distributors had a vacuum system. Mine has. I'm not sure that U.S. cars were any different, in that respect, and I don't see how they got around the problem of advancing the ignition under acceleration without a vacuum.
The last posting, from Mark, is more feasible, but in my case the pickup has been soldered closed so it was a permanent modification. The car seems to run very well without the vacuum system so perhaps it's something to do with big capacity engines in that you don't notice anything is amiss!
The last posting, from Mark, is more feasible, but in my case the pickup has been soldered closed so it was a permanent modification. The car seems to run very well without the vacuum system so perhaps it's something to do with big capacity engines in that you don't notice anything is amiss!
Tim
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
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#9 Re: Vacuum pipes
There was certainly a significant period when cars destined for the US had no vacuum advance capsule. They still had mechanical advance and that is sufficient to let the engine run seemingly quite well but your mpg will suffer considerably without vacuum advance. I think some of the later cars had a vacuum capsule but it was configured for vacuum retard. You can tell by which side of the diaphragm on the vacuum capsule the take off pipe is mounted if it's a vacuum advance or retard capsule.
Lucas distributors without vacuum advance capsules were fitted to Mini Cooper S's and Lotus Esprits as standard from the factory to name two other examples.
Lucas distributors without vacuum advance capsules were fitted to Mini Cooper S's and Lotus Esprits as standard from the factory to name two other examples.
John
1969 Series 2 FHC
1969 Series 2 FHC
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#10 Re: Vacuum pipes
The opposite applies, in that light cruise vacuum advance is *abolished* under hard acceleration.Bigcatfrankie wrote: ↑Wed Aug 14, 2019 4:28 pm... I don't see how they got around the problem of advancing the ignition under acceleration without a vacuum....!
1E75339 UberLynx D-Type; 1R27190 70 FHC; 1E78478; 2001 Vanden Plas
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Topic author - Posts: 86
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#11 Re: Vacuum pipes
Not sure I'm quite with you there, Peter..........my understanding of the system is that under any sort of acceleration you need to advance the ignition timing so the fuel/air mix is ignited earlier because the pistons are moving faster, but the time it takes for the fuel mix to ignite and cause a bang doesn't change.
Tim
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
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#12 Re: Vacuum pipes
Peter is right, vacuum is biggest at part throttle (and max at idle), and advance used for fuel economy. Vacuum is immediately lost during acc and not present at wide open throttle.
Mark
1963 OTS 880436
1963 OTS 880436
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Topic author - Posts: 86
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#13 Re: Vacuum pipes
Thanks............most helpful, everyone.
Tim
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
1970 ex.U.S. Series 2, 2+2, in course of restoration
1965 Austin Healey 3000
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