Hitachi "SU" part numbers

[mperdue]

Anyone know the parts numbers for the various "SU" style Hitachi carbs used on the early Z's? For example, the Roadster used the Hitachi HJB38W-1 and later the Hitachi HJB38W-3. The 510 used the Hitachi HJL38W6, at least for the early years. Are there similar numbers for the Z's? I'm also looking for tech info such as needle types, bore sizes, inlet/outlet sizes, flange shapes etc, basically to figure out interchangability. Figuring out the P/Ns is the first step to finding the rest of the info. Anyway I'm trying to collect as much info on them as possible - I'll likely make it all available on my webpage at some point or write up a tech article. I'll check out my FSM tonight but I only have a '72 FSM. Also, I'm not sure how they differed in the different markets - that should complicate things somewhat. Thanks

Michael

edit: I did check ztherapy by the way and have done a lot of google searching and still haven't found the Z P/Ns.

[ChrisA]

Michael,

I can only help you with numbers for the carbs below.

HJG46W-3A Manual Tranny up to 8-71

HJG46W-4 Auto Tranny 8-70 to 8-71

The microfiche doesnt list model numbers for the others after 8-71.

FWIW,

Chris

[26th-Z]

Michael,

Ztherapy has all this info. http://www.ztherapy.com/

[mperdue]

Michael,

Ztherapy has all this info. http://www.ztherapy.com/

Any idea where? As I mentioned in my post, that's where I looked first. Didn't find it on the Z car page, spotter's doc or the price list. In fact, they incorrectly refer to the Hitachi's as SU's throughout and save the name "Hitachi" for the flat tops. Anyway, you'd think they'd have it but I didn't see it.

Oh and thanks ChrisA - that's the kind of info I'm looking for!

Michael

[Bambikiller240]

In fact, they incorrectly refer to the Hitachi's as SU's throughout and save the name "Hitachi" for the flat tops.

I believe that is because they are copies of the real "SU's" manufactured by Hitachi under license from SU. The Flat tops are a "Hitachi" design.

[ChrisA]

I believe that is because they are copies of the real "SU's" manufactured by Hitachi under license from SU. The Flat tops are a "Hitachi" design.

Ditto.

Chris

P.S. Michael, I have a 71 and 73 FSM at home, I will look for part numbers and post them tomorrow unless someone beats me to it.

[mperdue]

Ditto.

Chris

P.S. Michael, I have a 71 and 73 FSM at home, I will look for part numbers and post them tomorrow unless someone beats me to it.

Yeah I know why everyone calls them SU's. It just seems to me that a site that rebuilds and sells them could get it right - even if we don't. I still haven't found P/N's there. But Chris, using the number you gave me I was able to find more info by searching the web. The flat tops are Hitachi HBM46W type carbs, and I found this on zcar.com:

"The guage shown is a stepped bar 12mm,14mm,16mm thick

float bowl #-HJG46W-R3A 70-71 man. trans. rear carb. 13.5-14.5mm.

F.B.#-HJG46W-F3A 70-71 man. trans. front carb 13.5-14.5mm. F.B.

#HJG46W-R4 70-71 auto trans rear 13.5-14.5 mm. F.B. #HJG46W-F4

70-71auto. trans. front 13.5-14.5mm. #HJG46W-R8B 72 man.trans. rear 11.5-12.5mm. #HJG46W-f8B 72 man.trans. front 15.5-16.5mm.

HJG46W-R9A 72 auto.trans rear 11.5-12.5mm.#HJG46W-F9A 72 auto

trans. front 15.5-16.5mm."

Of course I'd like to confirm all of this with real Nissan lit. Thansk again

michael

edit: Taking a closer look it looks like those zcar numbers are float bowl P/N's, but it would lead me to believe that there was an HJG46W-8B carb and an HJG46W-9A car also.

[ChrisA]

My 71 FSM showed either the downdraft carb for the L20A/L24 and the twin "SU type" carb for the L24.

I thought it interesting that my copy of the 71 FSM showed two different numbers for twin carbs on the same page in different pictures(page EF-17 for those following along). It shows HJG46W in the first picture and HJL46W in the second picture. Maybe the HJL46W carbs are for cars made after 8 of 71.

Tech specs on the 71 twins are:

Bore=46mm

Weight=6.834lbs(3.1kg)

Venturi=34mm

Fuel Pressure=3.414 lb/sq in

Needle valve diameter=2.0mm

Nozzle A

Jet Needle N-27

Suction Spring #23

And for some useless info: The single carb was listed as a DAF342-6A on the G130 model cars. And a DAF342-8A or DAF342-9A for the H130 and HA30 model cars.

I thought maybe the 73 FSM would show numbers for carbs before Nissan went to the flat tops but it didnt list any but the number you already stated. "HMB46W-1".

I went through the whole fuel section in the 71 & 73 FSM and that's all it showed.

Hope it helps you some.

Chris

[Bambikiller240]

Here' photo's of the data in 1972 L20A / L24 Engine FSM, and the 1973 Complete S30 FSM

Interestingly, they refer to the Round Top AND also Flat Top carbs as "SU Type". No mention of Hitachi at all.

Guess it would be unrealistic for Nissan to refer to parts by the individual manufacturer used in the outsourcing.

[mperdue]

Carl, I didn't see "SU" mentioned in the "Two Barrel Carburetor" section of the Fuel System chapter where the "DAF342" carbs are covered (downdrafts?). Maybe it's called that somewhere else in the book but not in the Fuel SYstem chapter.

Chris, just so that I have it one place here's similar info from my '72 FSM (from the "Specifications and Service Data" sectino and the end of the Fuel System chapter):

Applied Engine: L24 (S30)

Make and Type: HITACHI HJG46W-8 (MT), -9 (AT)

Construction: Side-draft, SU type

Bore: 46mm (1.811 in)

Weight: 3.1kg (6.834 lb)

Venturi: 34mm (1.339 in)

Float Level: 23.0mm (0.906 in)

Fuel Pressure: 0.24kg-cm^2 (3.414 lb / sq in)

Needle valve dia: 1.7mm (0.067 in)

Nozzle: A

Jet Needle: N-54

Suction Spring: #23

Note that the Needle valve diameters and the jet needles are different between 71 & 72. And my manual doesn't mention the HJL model - not sure what that is Chris.

Anyone have data on the '70 model?

[Zedrally]

I've noticed that MT & AT have different p/nums. I've never noticed any difference between these carbs, but now I'm not sure?

Is there a difference? If so what is it?

MOM

[Bambikiller240]

Carl, I didn't see "SU" mentioned in the "Two Barrel Carburetor" section of the Fuel System chapter where the "DAF342" carbs are covered (downdrafts?). Maybe it's called that somewhere else in the book but not in the Fuel SYstem chapter.

Michael;

I'm not sure I understand what you are referring to. I didn't even look at the 2bbl carb section, since we weren't discussing them here. I have no idea who manufactured them, or even which market(s) received them.

I read and photgraphed only the first pages of the "SU Type" sections of the Fuel System part of the manual, where P/N's were mentioned.