I just wondering which part of the carb is the "damper"? I understand you put some oil on it!

lets not get too carried away, they do have some limitations in performance engines.

when you use even a moderate street cam, idle quality and mixtures are quite poor due to the lack of (or fluctuations of) idle vacuum. once off idle though everything is OK. I think the lumpy idle was a major factor in the breaking engine mount problem I had.

The exposed fuel bowls are also very sensitive to heat soak, and fuel is prone to boiling or vaporising during extended idle periods in warm weather. This is more of a problem if you have extractors - which most of us would. Good heat sheilding and thermal wrapping the fuel bowls overcomes the problem pretty easily and cheaply.

On the up side, they are great for fuel economy, especially on the highway. And have very good low end transitional response.

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Huzzah. I've been saying this for years, except that i always refered specificly to the Hitachi's as i have many driving years of experience with mine. The only genuine SU's i ever actually used were on my '52 Morris Minor [i didn't know any better, OK]

Nobody really wants to know about this, as a pair of these SU / Hitachi's don't look as sexy, or sound as horny, or make as much top end power as Webbers, but on a car that you actually drive,... a lot, they are a very good choice.
Low maintainance, modest initial cost, & good all round performance are attributes that are hard to beat in a driver. Thats why the factory used them.
If you are going to use the Genuine British SU's on an A12 or A14, then I guess that a pair from a Mini or Sprite / Midget might be a good start.

Sarav1200
You got the linkage problem absolutely right. This is probably one of the reasons that the stock GX setup is so good. The factory linkage is well designed & the carbs stay in phase. I think we have all seen some linkages that could have stood a little improvement,... well, OK, a lot of improvement.

Hi

Dodgeman & L18_B110 know their stuff.

I just want add a couple of things,being a Carby guy.

The biggest problem with SU carbs besides the excessive wear they are prone to in the throttle shafts & bushes which happens because they are both made out of brass,(this can be fixed permanantly by installing teflon bushes & new shafts) is LINKAGE SETUPS thats where the myth comes from.

The "coming out of tune thing" is because the majority of people out there using multiple SU's have absloutly disgusting linkage setups. You can NOT tune and balance any multiple carb setup which has crap linkages.

Always use rosejoints, high quality thottle arms and correct tension return springs on each carb(SU). Theres only two main jet sizes for SU's,90thou & 100 thou,depending on the model. There are many metering pins. Once you get the pins right and good linkage system SU's are excellent.

Theres a lot less stuffing around with a 32/36 weber, and they are a good carb so dont go chucking your DGV just yet.They are very low maintanence once jetted correctly.

As for the Hitachi's (SU type) definatly dont throw them out. They are original equipment, and in my opinion work better than a lot of the SU models. The kits are getting very expensive for them.

Anyway, hope that shed some light.

P.S LINKAGES!!!!!!!!!!!

Yes, I agree that the SU's are a better choice if you are going to set them up properly (professionally rebuilt and dyno tuned). I've run just all the popular types of induction on my A15, stock Hitachi, Weber 32/36 DGV, GX dual SU's, and 40mm Dellorto's. I think the SU's were the best for all around performance and reliability. They performed a lot better than the 32/36 Weber and got the same gas mileage (~35-38 miles per gallon), and while the Dellorto's definitely give the most power, the SU's weren't far behind and the gas mileage is worse with Dellorto's and it's constant upkeep. The SU's once set right don't require a lot of attention at all. I cheated mine and instead of going with a different needle/spring (not much SU support in the US) to set my mixture richer, I just thickened the damper oil and it worked great! They really are a simple carb when you learn them too.

I'm still anxious to see how a properly tuned EFI setup would go on the A series though in comparison to the rest. My poor A15 that I've been running for about 8 years now has never been truly "tuned" with a dyno or wideband O2. I bet there's still a lot of power to be had out of it. Maybe when I return to the US I'll give it a shot.

-Andy

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L18_B110
Thanks for your kind words in a previous post, & yes, you are absolutely right. About the only other thing to watch for in a used carb is the amount of wear in the throttle shaft & its bushes. If the carb sucks air at this point it upsets the low end tuning.
If you are using the Hitachi / Datsun carbs [recomended] you should check both your Nissan dealer & Repco for repair kits.

They are in fact quite simple to rebuild & are well sized to the engine. I used plain old ordinary engine oil in the dampers which probably reduced my acceleration times by a nanosecond or two, but most of my driving was longer distance cruising, so i figured it wasn't a problem for me, & besides, i was lazy.

The quality of genuine SU carb construction seemed to vary with the class of car that they were used on. The 1-1/8 carb on my '52 Morris Minor [oh the shame of it] was rubbish, but the ones from a Jag are very nice. I'm told that the throttle shafts in Bentley ones ride on roller bearings, but i've never owned a Bentley, so i cant say for sure.

Fix 'em right, fit 'em right, tune 'em right, & they will be good friends for many years.
Chris

Someone send me exploded diagrams of the Hitachi Carb. I have looked for Owner's Manual in English in vain (Datsun 1200 Pickup - see the image).

I would like to know which part is which because mine needs a lot of service...

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thanks blown1400 for that web page. its pretty good for a refrence
thanks dude

Yeah SU's over the 32/36 is proably the way for morepower

But there is another option WEBERS or the only option depending on how bias you are