Page 2 of 3 FirstFirst 1 2 3 LastLast
Results 21 to 40 of 44
  1. #21
    Join Date
    Apr 2013
    Location
    cape Town - 0825509200 / 0624206806
    Age
    61
    Posts
    2,454
    Thanked: 505

    Default Synchronize Twin SU Carbs on Series 3 R6

    You basically connect a vacuum gauge to the manifold and advance the timing to get the maximum vacuum (21 - 22 inches) then you back off about 2 inches. Set your carb mixture and go for a run to listen for pinging.

    BUT.... major disclaimer- I donít advise this method unless you know exactly what you are doing. This method only applies to older engines
    Last edited by GaryFrank; 2021/01/10 at 11:43 PM.

  2. #22
    Join Date
    Jun 2009
    Location
    Barberton
    Age
    63
    Posts
    6,165
    Thanked: 1969

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Thanks for explaining.
    Have you checked with a timing light to compare results?
    I remember my dad used to listen to the engine, when setting the timing. Intuitively one would imagine that "sweet spot" he was listening for, would also give the deepest manifold vacuum. Then he got me a test and tune kit one birthday (I was still in school, I think) and it transpired that his seat-of-pants method was out by quite a bit.

  3. #23
    Join Date
    Apr 2013
    Location
    cape Town - 0825509200 / 0624206806
    Age
    61
    Posts
    2,454
    Thanked: 505

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    It is ďout a bitĒ if you compare it to a timing light, but what guarantee do you have that the mass produced crank pulley on your motor is ......

    Iím not saying that a vacuum gauge is the only or best option, just pointing out that itís nice to have a decent one in your toolbox.....

    (Iím obviously covering my arse here.... this has been discussed before and I got slammed by keyboard warriors)

  4. #24
    Join Date
    Oct 2011
    Location
    Midrand
    Age
    49
    Posts
    3,265
    Thanked: 1583

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Quote Originally Posted by GaryFrank View Post
    It is ďout a bitĒ if you compare it to a timing light, but what guarantee do you have that the mass produced crank pulley on your motor is ......

    Iím not saying that a vacuum gauge is the only or best option, just pointing out that itís nice to have a decent one in your toolbox.....

    (Iím obviously covering my arse here.... this has been discussed before and I got slammed by keyboard warriors)

    Well I took my carby R6 to a caruburettor ace in Dbn North, and after fiddling with it all day, he eventually left me with no charge and said he could not get it working.

    Then took it to an old timer at Umhlanaga Ski boat club. Main issue I had was float levels, which he immediately picked up and corrected. He then set the timing and synched the carbies with a vaucum gauge and it ran sweetly.

  5. #25
    Join Date
    Jun 2009
    Location
    Barberton
    Age
    63
    Posts
    6,165
    Thanked: 1969

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Quote Originally Posted by GaryFrank View Post
    It is ďout a bitĒ if you compare it to a timing light, but what guarantee do you have that the mass produced crank pulley on your motor is ......

    Iím not saying that a vacuum gauge is the only or best option, just pointing out that itís nice to have a decent one in your toolbox.....

    (Iím obviously covering my arse here.... this has been discussed before and I got slammed by keyboard warriors)
    No criticism from me. I haven't maintained cars for at least 3 dacades now. I loved to service and tune my old cars back in the day. Setting the timing using "static" method also worked well for me. I had a vacuum guage, but just never knew it could be used for timing. Sure is better than my dad's do it by ear method.
    Thanks for sharing.
    Last edited by RoelfleRoux; 2021/01/11 at 09:47 AM.

  6. #26
    Join Date
    Jun 2009
    Location
    Barberton
    Age
    63
    Posts
    6,165
    Thanked: 1969

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Quote Originally Posted by stephenplumb View Post
    Well I took my carby R6 to a caruburettor ace in Dbn North, and after fiddling with it all day, he eventually left me with no charge and said he could not get it working.

    Then took it to an old timer at Umhlanaga Ski boat club. Main issue I had was float levels, which he immediately picked up and corrected. He then set the timing and synched the carbies with a vaucum gauge and it ran sweetly.
    Love it.
    Thanks for the update.
    Nothing more satisfying than getting that tune just right. And thanks for starting up the old (forgotten) petrol juices in my veins.

  7. The Following User Says Thank You to RoelfleRoux For This Useful Post:


  8. #27
    Join Date
    Apr 2013
    Location
    cape Town - 0825509200 / 0624206806
    Age
    61
    Posts
    2,454
    Thanked: 505

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    I normally take the valve cover off and check the pulley timing mark when Iím ďtuningĒ

    The factory timing mark is for optimal performance & economy...... you can get way more performance at the cost of economy

  9. The Following User Says Thank You to GaryFrank For This Useful Post:


  10. #28
    Join Date
    Aug 2020
    Location
    Pretoria
    Age
    56
    Posts
    35
    Thanked: 2

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    I need advice please - Twin SU - HIF carbs.

    OK, managed to sync and set the mixture very well. (according to me after watching many videos) The exhaust gasses are very even with no popping noiceand the color is a more grey type color. It idles very even, and while it is hot, it starts with just a tick on the ignition.

    When I try to start it the next morning, it does not want to start, even using the choke.

    To get it starting, I have to turn the carbs about 2 full turns to make it more rich. Then when I touch the ignition, it starts.
    What can be the cause of this behavior?

  11. #29
    Join Date
    Jun 2014
    Location
    Zululand
    Age
    55
    Posts
    194
    Thanked: 197

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    I donít know that carb, but if it runs well, I would leave it and check the timing. Perhaps advance timing a bit

  12. The Following User Says Thank You to Andrew D For This Useful Post:


  13. #30
    Join Date
    Nov 2011
    Location
    Langebaanweg
    Age
    43
    Posts
    2,220
    Thanked: 1668

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    I take it that your vehicle doesn't have a choke.

    My old Landy never needed a choke to start until I installed 2 "new" Stromberg carburators.
    From then on it wanted to be started with a choke.
    '07 Land Rover Defender 110 TDI 300 Kalahari (Meisiekind≤)
    '84 Land Rover Defender 110 V8 4-speed Hardtop (Meisiekind) Sold after 12 years of fun and hard work.
    The only thing needed for evil to triumph is for a good man to do nothing.

  14. #31
    Join Date
    Jul 2013
    Location
    Gauteng
    Age
    34
    Posts
    90
    Thanked: 40

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Hi Boetie, nice seeing you in person earlier today!
    I am not exactly familiar with the SU HIF (worked on H-type and HD-type), so could be mistaken. SU carbs dont have chokes they have 'enrichers' and without an accelerator pump circuit need the enricher working to start generally. Are you sure the internal choke/enricher linkage that would push the jet down is working? To eliminate this without stripping the carb, try start the car with Quick Start spray, it if starts then I would double check the enricher/choke linkage inside the carb - it should have the same mechanical function as the mixture setting, it just pushes the jet assembly down.
    If not, could also be the timing slightly off.

  15. #32
    Join Date
    Aug 2020
    Location
    Pretoria
    Age
    56
    Posts
    35
    Thanked: 2

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Quote Originally Posted by Andrew D View Post
    I donít know that carb, but if it runs well, I would leave it and check the timing. Perhaps advance timing a bit
    I will definately check the timing again. I know it was initially agout 4 inches away from TDC towards the advance side.

  16. #33
    Join Date
    Aug 2020
    Location
    Pretoria
    Age
    56
    Posts
    35
    Thanked: 2

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Yes you are correct, it did not had one initially, I added one 2 weeks ago, unfortunately it did not have any impact on the start issue.
    Quote Originally Posted by jfh View Post
    I take it that your vehicle doesn't have a choke.

    My old Landy never needed a choke to start until I installed 2 "new" Stromberg carburators.
    From then on it wanted to be started with a choke.

  17. #34
    Join Date
    Nov 2011
    Location
    Langebaanweg
    Age
    43
    Posts
    2,220
    Thanked: 1668

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Maybe it just needs some adjustment, I'm not very familiar with this engine and setup, but on the one I had I initially had to pull it out all the way.

    After playing around with the setup, I only had to pull it out by half.
    '07 Land Rover Defender 110 TDI 300 Kalahari (Meisiekind≤)
    '84 Land Rover Defender 110 V8 4-speed Hardtop (Meisiekind) Sold after 12 years of fun and hard work.
    The only thing needed for evil to triumph is for a good man to do nothing.

  18. #35
    Join Date
    Aug 2020
    Location
    Pretoria
    Age
    56
    Posts
    35
    Thanked: 2

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Quote Originally Posted by kevin4x4 View Post
    Hi Boetie, nice seeing you in person earlier today!
    I am not exactly familiar with the SU HIF (worked on H-type and HD-type), so could be mistaken. SU carbs dont have chokes they have 'enrichers' and without an accelerator pump circuit need the enricher working to start generally. Are you sure the internal choke/enricher linkage that would push the jet down is working? To eliminate this without stripping the carb, try start the car with Quick Start spray, it if starts then I would double check the enricher/choke linkage inside the carb - it should have the same mechanical function as the mixture setting, it just pushes the jet assembly down.
    If not, could also be the timing slightly off.
    Hi Kevin, yes it was a big surprise for me. Next time we must organise a braai or a picnic type get together.

    Kevin I agree with the term en richer - based on the video I looked at, it is exactly what happens - the yet is lowered when you pull the choke, which then results in the mixture be much more rich.

    OK, part of the carb setup is the fast idling setting, which I did on +/-100rpm.

    Difference is on the HIF type, the yet remains in the same position. In other word the choice does not lower it at all. (a bit frustrating because I know, when I lower the yet it starts 100%)

    Question on the quick start spray - do I spray it inside the carb, and must the butterfly be open or closed? (I assume closed)

    I will definately check the timing again.

    Thanks for all the advice - appreciated.

    Quote Originally Posted by kevin4x4 View Post
    Hi Boetie, nice seeing you in person earlier today!
    I am not exactly familiar with the SU HIF (worked on H-type and HD-type), so could be mistaken. SU carbs dont have chokes they have 'enrichers' and without an accelerator pump circuit need the enricher working to start generally. Are you sure the internal choke/enricher linkage that would push the jet down is working? To eliminate this without stripping the carb, try start the car with Quick Start spray, it if starts then I would double check the enricher/choke linkage inside the carb - it should have the same mechanical function as the mixture setting, it just pushes the jet assembly down.
    If not, could also be the timing slightly off.

  19. #36
    Join Date
    Aug 2020
    Location
    Pretoria
    Age
    56
    Posts
    35
    Thanked: 2

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Apologies, not 100rpm but 1000rpm.
    Quote Originally Posted by BRaats View Post
    Hi Kevin, yes it was a big surprise for me. Next time we must organise a braai or a picnic type get together.

    Kevin I agree with the term en richer - based on the video I looked at, it is exactly what happens - the yet is lowered when you pull the choke, which then results in the mixture be much more rich.

    OK, part of the carb setup is the fast idling setting, which I did on +/-100rpm.

    Difference is on the HIF type, the yet remains in the same position. In other word the choice does not lower it at all. (a bit frustrating because I know, when I lower the yet it starts 100%)

    Question on the quick start spray - do I spray it inside the carb, and must the butterfly be open or closed? (I assume closed)

    I will definately check the timing again.

    Thanks for all the advice - appreciated.

  20. #37
    Join Date
    Dec 2014
    Location
    Cape Town
    Age
    55
    Posts
    3,502
    Thanked: 2742

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Cheers,
    John Kilfoil

    Rover P6
    Land Rover Discovery II Td5 Manual
    Range Rover P38 HSE
    Moto Guzzi LeMans
    Aprilia Tuono V2

  21. The Following User Says Thank You to JohnnoK For This Useful Post:


  22. #38
    Join Date
    Aug 2020
    Location
    Pretoria
    Age
    56
    Posts
    35
    Thanked: 2

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Quote Originally Posted by JohnnoK View Post
    Thanks for this article - very good.

    Confirmed that the yet is not lowered for cold start, but but change the level when using different types of petrol and the temp of it.

    Not saying a lot regarding cold start.

  23. #39
    Join Date
    Jul 2013
    Location
    Gauteng
    Age
    34
    Posts
    90
    Thanked: 40

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Quote Originally Posted by BRaats View Post
    Hi Kevin, yes it was a big surprise for me. Next time we must organise a braai or a picnic type get together.

    Kevin I agree with the term en richer - based on the video I looked at, it is exactly what happens - the yet is lowered when you pull the choke, which then results in the mixture be much more rich.

    OK, part of the carb setup is the fast idling setting, which I did on +/-100rpm.

    Difference is on the HIF type, the yet remains in the same position. In other word the choice does not lower it at all. (a bit frustrating because I know, when I lower the yet it starts 100%)

    Question on the quick start spray - do I spray it inside the carb, and must the butterfly be open or closed? (I assume closed)

    I will definitely check the timing again.

    Thanks for all the advice - appreciated.
    Yeah - absolutely - perhaps a drive in our Landies to the Leeupoort lookout!

    So I read up a bit further on HIF's and you are correct, they no longer employ the "lowered jet" method to enrich the mixture - it apparently has a separate passage from the float chamber that the choke/enricher linkage opens and closes per https://sucarb.co.uk/technical-carbu...s-introduction
    "On later integral float (HIF) carburetters, the cold start enrichment is provided by means of a separate fuel path between the float chamber and the constant depression region close to the jet orifice. The fuel flow through this path is controlled by a rotary valve."
    I would guess this passage is blocked in one or both of your carbs? Carb cleaner and/or compressed air should hopefully clear it?

    For spraying in the Quick Start, I lift the Piston up with a screw driver (best with insulating tape on it to not scratch/damage it), spray it in liberally and then let the piston drop and try start. You may only need to do it with one carb to get things going.

    Hope you come right!

  24. #40
    Join Date
    Aug 2020
    Location
    Pretoria
    Age
    56
    Posts
    35
    Thanked: 2

    Default Re: Synchronize Twin SU Carbs on Series 3 R6

    Morning Kevin.

    Feedback - I spayed it with carb cleaner and after everything was dried out, I sprayed Quick start.
    It started immediately and idle for 2-3 seconds and dies.
    Feels like it does not get petrol. Even lowered the jets to make it more rich, same results.

Page 2 of 3 FirstFirst 1 2 3 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •