A couple of SU questions

[grannyknot]

3 hours ago, dutchzcarguy said:

Yes but only sealed to the axle as it has to be able to move.. it will wear out pretty fast as the axle has play. But we will see how long it takes i'm sure.. 😉

It is not sealed to the axle, it is sealed to the carb body, the axle moves freely, nothing to wear out.

[AK260]

A good discussion here

https://www.classiczcars.com/forums/topic/43876-n49-n54-needles/

The N27/54 needles don’t appear on SU needle charts as I believe (and happy to be corrected) they were not SU needles, they were Hitachi / Datsun needles.

As mentioned above, the best bet is to mark and measure them at 3mm intervals (stations).

I did this with my modified SM needles to model them on excel and compare to other off the shelf (SU) needles. It only takes 10 mins to do and then you can post it here for anyone else looking in the future too! :p



I then went a bit nuts and tried to video what positions where in use at what loads / RPMs ;)

[RIP260Z]

On 7/4/2023 at 9:25 AM, dutchzcarguy said:

Does anyone know if you can use the needles from a HMB46W  (boatanchors ? )  flathead carbs  in a roundhead HJG46W

Boat anchors, far from it!

Looking at https://www.classiczcars.com/forums/topic/60309-were-bringin-back-the-flat-tops/?&page=8#comments HMB46 needles, depending on market (and what has been found so far) are N61, N62 (North American found) and parts microfiche (Europe) N56A, and I have pulled out N57 marked needles.

I suspect HMB46 needles could fit into the HJG46W round tops... whether they work....?

[Mark Maras]

Some time back I found a site that has a "0.100" SU needle search interface". Teglerizer.com/cgi-bin/needle100db.cgi. If the page appears blank, scroll down to the bottom.

[AK260]

This is also a good resource for comparison of needles

http://www.mintylamb.co.uk/suneedle/

[dutchzcarguy]

17 hours ago, RIP260Z said:

Boat anchors, far from it!

🙊 I had a questionmark behind it!   I personal don't think they are anchors.. (worthless) ..  These flatheads are just much more complicated to tune right!  Also they are more sensitive to wear i think..  Never tuned one as i'm not a carb specialist..  a HJG46W  (roundtop)  is a simple carburator that even a twat like me can get running very well ( 🙊 ) hihi..

Years ago i bought a complete L24 with everything on it (also gearbox euro 5 speed!) and it had flattops.. 1 carb was seriously damaged

so i took the needles from them and saved them.. hence the question..

On 7/7/2023 at 9:59 PM, AK260 said:

The N27/54 needles don’t appear on SU needle charts as I believe (and happy to be corrected) they were not SU needles, they were Hitachi / Datsun needles.

It's common that the american guys talk about SU carbs on our z cars, i stopped to correct them on that years ago .. THEY ARE NOT SU.. THEY ARE HITACHI CARBS! 🙈🤣

There are A LOT of small differences between the SU and Hitachi carbs.. (It's like a improved version of the SU.)

[dutchzcarguy]

Btw.. i think i never have seen that clip on that wheel to prevent it from turning, is it a HMB46W carb? (flattop) 

[Captain Obvious]

5 hours ago, dutchzcarguy said:

i never have seen that clip on that wheel to prevent it from turning, is it a HMB46W carb? (flattop) 

It's a 3-screw round top. 1972 only.

[Captain Obvious]

On 7/8/2023 at 8:28 AM, RIP260Z said:

I suspect HMB46 needles could fit into the HJG46W round tops... whether they work....?

They fit just fine. Fuel profile is different (no surprise), but mechanically they mount identically. 

[grannyknot]

I'm starting to reassemble the 4 screw SU's and I have been looking around for an article or vid that gives all the baseline measurements/settings and tricks to get the nozzle centred. I've read the FSM but their images are kind of dark, wondering if you guys have some go to links that have what I'm looking for?

Thanks.

 

[Yarb]

@siteunseenTime to hit the library!!!

[Patcon]

If I remember right I ran the mixture nuts all the way up and used the needle to center the jet...