May 24, 201014 yr comment_320654 Thanks Mitchell! The link you provided shows a good picture and it shows that it is the SK version. I'll be getting that one and the DVD that Ztherapy offers. Both great buys in my opinion, as I had no good reference material for a dual carb set up in my bug and the unisync was not worth the money or hassle to use. Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320654 Share on other sites More sharing options...
May 24, 201014 yr comment_320660 My experience,New carbs (1980) 4 screw front, 3 screw rear, 96 miles on them then the car parked 26 years. Looked in front bowl, after gasket fell apart in multiple pieces, full of varnish. Tried getting rear lid off for 1/2 hour until it was decided surgery was needed. Trimmed enough to get the lid off, full of varnish and gasket parts.Never been in a carb before 2006. Got the video, watched it twice, took both carbs apart, cleaned, reassembled and back on in under 3 hours. Fired right up, minor adjustments like the video showed. Found out the rear 3 screw was best at 2 1/4 turns down, front was 2 1/2 for plug color to match.One other difference in the two styles is the choke cable attachment. The 4 screw uses a 'P' clamp with 2 clamping screws. The 3 screw carb has a single screw clamp attachment and has a steel cable stop swedged to the end of the choke cable.Three weeks ago I changed out the above set for a set of rebuilt polished 4 screw carbs with cad plate attachments. Added a polished euro balcance tube and a polished valve cover. They were synced and set in less than 20 minutes. Light brown plugs. My advise is get the video and either sync tool, these carbs are too easy, just misunderstood.I remember seeing a motion emoticon (on here?) showing a SU carb working, at idle small amount of fuel flowing, choked the nozzle went down and more fuel flowed, at wot the butterfly opened, suction piston went up more fuel flowed. Anyone remember it or have it avaliable?Bonzi Lon Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320660 Share on other sites More sharing options...
May 24, 201014 yr Author comment_320675 Bonzi,What did you trim to get that cover off? That's exactly what I'm curious about.p.s. - contacting Ztherapy now to order that video =) Edited May 24, 201014 yr by BTF/PTM Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320675 Share on other sites More sharing options...
May 24, 201014 yr comment_320681 You don't need to trim the cover. Turning it 90 degrees and giving a bit of a tilt, it comes right out. Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320681 Share on other sites More sharing options...
May 24, 201014 yr comment_320690 Remember how you got the cover off and the positioning - you will need to put it back on - be sure to order some gaskets before you take that cover off - you can order them through Z Theropy or directly from the Nissan warehouse from your local stealer. Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320690 Share on other sites More sharing options...
May 24, 201014 yr Author comment_320692 I've ordered Bruce's "Just SU's" DVD as well as the other tune-up DVD, I figure it's a really cheap way to educate myself before I dig into the carbs. Soon as I can fix (or replace) the severely warped tail light housing flanges I'm currently dealing with and get the car put back together I can finally visit a fellow forum member who has offered to help me tune things up with all the proper tooling. Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320692 Share on other sites More sharing options...
May 27, 201014 yr comment_320948 Bonzi,What did you trim to get that cover off? That's exactly what I'm curious about. I didn't trim the lid. It was the ear with a hole sticking out above the lid. It is about 7mm long now, started about 12mm. I sold a set of 3 screw carbs and never thought to look to see if that ear was on them. :stupid: Bonzi Lon Edited May 27, 201014 yr by Arne Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320948 Share on other sites More sharing options...
May 28, 201014 yr Author comment_320951 That's ezzakkly the protrusion I'm referring to, thanks! I wonder if that was part of the internal boring process that they later figured out could be done differently. I'd bet that there's a ball bearing plug at some point in that little hole; anyone know for sure? I can't smash my face down next to the carbs close enough to look. Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320951 Share on other sites More sharing options...
May 28, 201014 yr comment_320954 The hole is empty. There is the same protution on the other side of the carb, that is where the choke cable clamp is held on. Bonzi Lon Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320954 Share on other sites More sharing options...
May 28, 201014 yr comment_320997 Eric - I actually bought this one:http://www.thezstore.com/page/TZS/PROD/60-9976Did you need the Syncrotester too? What is it used for? Link to comment https://www.classiczcars.com/forums/topic/35981-swap-3-screw-su-set-for-4-screw/?&page=2#findComment-320997 Share on other sites More sharing options...
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