Steven Whitaker Posted October 28, 2023 Report Share Posted October 28, 2023 (edited) So, I’ve stripped, cleaned and rebuilt my hs6 su carbs for my 4a project. The car will be totally stained except for a phoenix tubular manifold and exhaust. I got the carbs back together and I’m now looking to fit them back on the manifold. But before I do I’d like to think they are set up as well as possible but I cannot seem to find a simple explanation how to do this. Can anyone point me in the right direction on where to start please. Many Thanks, Steven Edited October 28, 2023 by Steven Whitaker Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 28, 2023 Report Share Posted October 28, 2023 Things I recall are. Step of the needle is flush to the bottom of the piston. The jet starts 2 1/2 turns down from flush to the bridge. Piston drop in chamber, both must drop equally Jon Twins’s at University Motors did a good video on that. It checks the pistons have not been swapped from their matched dash pot. have you got this info? http://tr4a.weebly.com/uploads/2/1/9/8/21980360/type_hs_tuning__tervicing.pdf Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 Thanks for the info. I’m starting blind as never done this before! Wish me luck. Cheers! Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 28, 2023 Report Share Posted October 28, 2023 Check the pistons both drop at the same speed even if you have not mixed them up. Someone before might have. Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 Very useful, thanks. Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 I also read about float level somewhere. But I can’t find the thread.. Is float level important? Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 28, 2023 Report Share Posted October 28, 2023 (edited) 22 minutes ago, Steven Whitaker said: I also read about float level somewhere. But I can’t find the thread.. Is float level important? Yes But it is not detailed here http://tr4a.weebly.com/uploads/2/1/9/8/21980360/type_hs_tuning__tervicing.pdf Have you renewed the needle valves in the float chamber lids? What type of floats do you have? All plastic or plastic and brass hinge connector? The second type are adjustable. First are fixed. go to this link and find the service manual for your car and download the pdf.s http://tr4a.weebly.com/triumph-tr-pdf-downloads.html Edited October 28, 2023 by BlueTR3A-5EKT Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 I did the test. When I swap them around the fast drop swaps so guess this is not good? Will this give me issues later on? Is there anything I can do to improve the difference in drop time? Thanks. IMG_1984.mov Quote Link to post Share on other sites
stuart Posted October 28, 2023 Report Share Posted October 28, 2023 Whats the tape wrapped round the piston bases? If theres more on one than the other then that biases the drop anyway. You can polish the outside of the slower piston with some Duraglit lightly to lessen the drag on the slower one to match. I see the bodies have been blasted I hope the inside wasnt. Stuart. Quote Link to post Share on other sites
Lebro Posted October 28, 2023 Report Share Posted October 28, 2023 Any traces of oil on the sliding surfaces will affect the drop time. Bob Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 29 minutes ago, stuart said: Whats the tape wrapped round the piston bases? If theres more on one than the other then that biases the drop anyway. You can polish the outside of the slower piston with some Duraglit lightly to lessen the drag on the slower one to match. I see the bodies have been blasted I hope the inside wasnt. Stuart. Thanks. The tape is to block the holes as per the YouTube video. Only the outside of the dash pot was Vapour blasted. Ill give it a go with Duraglit thanks, Are my findings likely to affect the running? I don’t really understand how these work. Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 29 minutes ago, Lebro said: Any traces of oil on the sliding surfaces will affect the drop time. Bob I’ll give everything a good clean again after Duraglit. Tnx. Quote Link to post Share on other sites
stuart Posted October 28, 2023 Report Share Posted October 28, 2023 7 minutes ago, Steven Whitaker said: Thanks. The tape is to block the holes as per the YouTube video. Only the outside of the dash pot was Vapour blasted. Ill give it a go with Duraglit thanks, Are my findings likely to affect the running? I don’t really understand how these work. They do need to rise at the same time to allow a balanced airflow. Stuart. Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 1 hour ago, BlueTR3A-5EKT said: Yes But it is not detailed here http://tr4a.weebly.com/uploads/2/1/9/8/21980360/type_hs_tuning__tervicing.pdf Have you renewed the needle valves in the float chamber lids? What type of floats do you have? All plastic or plastic and brass hinge connector? The second type are adjustable. First are fixed. go to this link and find the service manual for your car and download the pdf.s http://tr4a.weebly.com/triumph-tr-pdf-downloads.html What a great link, thanks. I’ve got the brass and plastic floats. And yes I fitted new float chamber valves and housings. Thanks. Quote Link to post Share on other sites
rcreweread Posted October 28, 2023 Report Share Posted October 28, 2023 (edited) The pistons are normally matched to the bodies so you shouldn't muddle them up - if you haven't recorded which goes with what , then try swapping the pistons and bodies around Cheers Rich Edited October 28, 2023 by rcreweread Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 IMG_0253.mov Much better. Quote Link to post Share on other sites
stuart Posted October 28, 2023 Report Share Posted October 28, 2023 Not really a fair test, it needs to be the other way round so pistons drop as different weight covers would skew the test. Stuart. Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 Not as easy to film but I think looks fine now. IMG_0254.mov Quote Link to post Share on other sites
stuart Posted October 28, 2023 Report Share Posted October 28, 2023 Near enough for the minute, I usually take the needles out to save any possible bending. Stuart. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 28, 2023 Report Share Posted October 28, 2023 2 hours ago, Steven Whitaker said: What a great link, thanks. I’ve got the brass and plastic floats. And yes I fitted new float chamber valves and housings. Thanks. You need to explore the forum. There are shed loads more of info in The Bonanza. In general technical. Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 49 minutes ago, stuart said: Near enough for the minute, I usually take the needles out to save any possible bending. Stuart. I’ve just fitted new needles after all the above. Thanks for your advice. Quote Link to post Share on other sites
Steven Whitaker Posted October 28, 2023 Author Report Share Posted October 28, 2023 43 minutes ago, BlueTR3A-5EKT said: You need to explore the forum. There are shed loads more of info in The Bonanza. In general technical. Will do. I’m relatively new to the forum but will certainly have a dig around going forward. Thanks, Steven. Quote Link to post Share on other sites
Michel Higuet Posted October 29, 2023 Report Share Posted October 29, 2023 23 hours ago, stuart said: Near enough for the minute, I usually take the needles out to save any possible bending. Stuart. Two holes in a plywood to put the bels and do the test upside down, no risk. Quote Link to post Share on other sites
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