1971 Datsun 521

[wayno]

I have no idea if they are good or not from that photo, it does look like an L block manifold, did the guy give you a reason why he took them off an engine?

Did he do an engine swap, that would be a good reason why he does not need them and then they may be good.

I have seen New Dual SU linkage packages on ebay in the past for a reasonable price(under $30.00), but I don't see any now.

I would hate to see you miss out on a good deal, in that photo they look alright, I expect if it were me I would inspect real close, if the pistons slide up and down freely and everything is there except the linkage and he had a good reason for removing them I might buy them, but I am old and have disposable cash, keep in mind that I know them and understand how to set them up and would know in 5 minutes of starting the engine up if they were serviceable or not.

[wayno]

I cannot tell what SUs them are in that photo, I see what appears to be a early Nissan E1/J13 intake manifold in that photo also, but it may be a MG manifold and if they really are HS4 carbs(British) then you likely would need to make your own linkage, I am not sure if there is linkage to be had for HS4 carbs on a dual SU manifold.

The more I look at the photo I am starting to wonder if them are HIF carbs, I don't see any fuel bowls and the bottom looks kinda square, the photo below is of HIF carbs I have, if that is what is on that manifold I am unsure what to tell you, that could be a real can of worms to deal with.

 

[Zonargx]

Yea I’m only 26 and really don’t know anything about them not even the Weber’s I just got into the Datsun cuz I saw the truck I now own at a tire shop and it said for sale after that I been trying to leave about them. I have had many car before I buy and sell if I don’t like them only two car I sold cuz I got my self into some problems and needed some quick cash so I had to get rid of them. Like I said I’m trying to lear about them and all the Datsun stuff basically also what about Webber’s are they better than the su and easier to rebuild?

Edited October 14, 2020 by Zonargx

[wayno]

Did you see my last post?

3 minutes ago, Zonargx said:

Yea I’m only 26 and really don’t know anything about them not even the Weber’s I just got into the Datsun cuz I saw the truck I had at a tire shop and it said for sale after that I been trying to leave about them. I have had many car before I buy and sell if I don’t like them only two car I sold cuz I got my self into some problems and needed some quick cash so I had to get rid of them. Like I said I’m trying to lear about them and all the Datsun stuff basically also what about Webber’s are they better than the su and easier to rebuild?

 

[Zonargx]

Yea but honestly I don’t know much Ans don’t really want to get my self into buying something it’s not worth it I’ll see if I can get more pictures and ill post them up

[wayno]

OK, as long as you seen the post and know what MG carbs look like, I believe they will bolt to the Datsun dual SU manifold, but I don't know if they will work the way they are supposed to work even if they are good, I bought that manifold/HIF carb setup to possibly use on my Datsun 320 which the manifolds will interchange, but it is a complete MG setup with linkage and everything, if it will not work for me I will sell it to an MG guy, but I am not struggling money wise right now, when I was 26 I was living hand to mouth so I could not afford to buy nice stuff like that.

Personally I think you need to keep it simple, you can buy a brand new Weber from Pierce manifolds for under $400.00 I think, and if the carb you have now works then go with that for now, then drive the truck and make plans, see if you can find a running L20b and put that in your truck with your 4spd, get it reliably running and then decide if you want a 5spd, maybe you can find an L20b with a 5spd then great, but just keep it simple right now.

Edited October 14, 2020 by wayno

[Zonargx]

Understandable I guess I’m just use to having 5 speeds since two cars I had before has 5 speeds and one of my recent sold cars was a 6 speed. I also found a Webber with the intake set up on offer up the guy wants $400 but like you said I’ll wait to get a hold of a running L20. I have money saved up and I can buy this parts but just like you said I want to keep things simple and not just jump in things I have two daughter that get spoiled every-once in a while like just the other day I bought them a switch instead of replacing my two front tires on the 521 cuz I gone birthday money to spend haha.I guess I should worry about getting tires instead of a dual carbs haha

Edited October 14, 2020 by Zonargx

[wayno]

I just looked up where you live and where Pierce Manifolds is, you are within 5 miles of them.

https://www.piercemanifolds.com/category_s/336.htm

 

They are selling a brand Weber 32/36 DGEV carb for $219.95 and a Weber DGV 5A with a manual choke for $228.00, all you would need is the adapter to bolt it onto a stock L20b intake manifold if you want a Weber.

I am not saying do this, I am saying if the L20b you find has a stock carb and it is not so great you could go the brand new Weber route for less than that $400.00 setup you mentioned, I would go new over used every time, this is something to keep in mind, I hate down draft carbs myself, I will go Dual SU every time, but you are not me.

[datzenmike]

It will probably have SU cast into the body of the carburetor if a British SU. If Hitachi it will probably have this little round symbol 

 

 

[Charlie69]

I ran the British SUs on my harleys in the 70s & 80s.

[Stoffregen Motorsports]

On 10/13/2020 at 10:19 PM, wayno said:

I cannot tell what SUs them are in that photo, I see what appears to be a early Nissan E1/J13 intake manifold in that photo also, but it may be a MG manifold and if they really are HS4 carbs(British) then you likely would need to make your own linkage, I am not sure if there is linkage to be had for HS4 carbs on a dual SU manifold.

The more I look at the photo I am starting to wonder if them are HIF carbs, I don't see any fuel bowls and the bottom looks kinda square, the photo below is of HIF carbs I have, if that is what is on that manifold I am unsure what to tell you, that could be a real can of worms to deal with.

 

Those are not HS4, they are HIF.  I just dug up a pair of HS4 carbs for my vintage racing Sprite. Never thought I'd get rid of my Mikuni, but the SU's are more period correct.

 

For a Datsun, I would definitely stick with a DGV. So much more simple and easier to tune.

[datzenmike]

That's what I thought. I have a pair of 40mm? From an old Volvo. I researched and figured they were HS4s but I'm no expert on 'real' SUs. They have the float in the bottoms.

[wayno]

9 hours ago, Stoffregen Motorsports said:

Those are not HS4, they are HIF.  I just dug up a pair of HS4 carbs for my vintage racing Sprite. Never thought I'd get rid of my Mikuni, but the SU's are more period correct.

 

For a Datsun, I would definitely stick with a DGV. So much more simple and easier to tune.

 

If you read my complete post you will see I said that the photo I posted was of HIF carbs, I also said I could not see the bowls on the carbs in his photo he posted.

On 10/13/2020 at 10:19 PM, wayno said:

I cannot tell what SUs them are in that photo, I see what appears to be a early Nissan E1/J13 intake manifold in that photo also, but it may be a MG manifold and if they really are HS4 carbs(British) then you likely would need to make your own linkage, I am not sure if there is linkage to be had for HS4 carbs on a dual SU manifold.

The more I look at the photo I am starting to wonder if them are HIF carbs, I don't see any fuel bowls and the bottom looks kinda square, the photo below is of HIF carbs I have, if that is what is on that manifold I am unsure what to tell you, that could be a real can of worms to deal with.

 

 

[Stoffregen Motorsports]

Oh, it was confusing. I thought I read that you could not tell what they were.

 

No harm, no foul.

[Zonargx]

So I might end up getting a Weber soon. One question .... do I need to tune my carb? I put new plugs about a month ago on the 521 gapped them to 035 can’t remember what ngk I got anyways today I notice that I have been smoking black the sidewalk it didn’t use to do that before so do I need to gap them tighter or just adjust my carb I have a feeling my carb might be going bad mainly because when I been shutting it off this past couple weeks the truck doesn’t turn off right away sometime it might but other times it try’s to start back on like there some left over gas? Any help would be nice.

[Stoffregen Motorsports]

If you buy a new Weber, the baseline jetting is usually close, but yes, some tuning would help. Remember, it's not just air and fuel jets. There are also emulsion tubes and pilot jets.

 

I like the manual choke Webers because they use two of the same pilot jets (one on each side) where the electric choke carb uses a different jet in the fuel shutoff solenoid. But then again, the fuel shutoff solenoid on the electric choke carb gets rid of any dieseling that may happen when you turn off the engine.

[mainer311]

You need to buy the Weber that is pre-setup for the Datsun L-series. I think depending on application, you can get them setup a couple different ways. Pierce Manifolds will know what you need.

[Greaser2]

1 hour ago, mainer311 said:

You need to buy the Weber that is pre-setup for the Datsun L-series. I think depending on application, you can get them setup a couple different ways. Pierce Manifolds will know what you need.

Agree.  Mine worked out the box with minor tweaking 

[Greaser2]

This is the setup I got. You don’t need a 38/38.  I only switched the throttle cam and cable bracket from my original L16

[Stoffregen Motorsports]

You don't need the manifold either, but it is nice to not have an adapter that comes loose once a year.

[Zonargx]

So then my carb is going bad right. Could that explain the reason why it won’t turn off right away like it still stutters after the key is on off and also smokes black from my exhaust on start ups

Edited October 20, 2020 by Zonargx

[datzenmike]

Black is over rich. This can cause hot spots to glow and cause your run on. The usual cause is the choke, yours is manual on the '71 and '72 was the first year electric. Over rich will cause 'run on' or 'dieseling' on shut down. Check the choke is actually off when you shove the knob in. If you have an electric choke make sure it shuts off when the engine is warmed up.

 

Look at the glass on the front of the carb. Is the gas at the level line when running??? Higher and it may overflow or flood.

 

Idle set way too high will also cause run on.

 

Wrong heat range on the spark plugs can also. B6ES I think for the early L16. 

 

 

Fixing the problem is way cheaper than a Weber.

[Zonargx]

I’m off tomorrow so I’ll check it out. I might have those plugs already but I will have to double check that and if I do how much do I need to gap them to. I’ll update my findings tomorrow

[mainer311]

Gap them to about 0.032-0.035 if you're running the stock points distributor. 

[Zonargx]

5 hours ago, mainer311 said:

Gap them to about 0.032-0.035 if you're running the stock points distributor. 

I’m running a pertronix