A little late, but congrats! So happy to see success. You are an inspiration to me to get moving on my 10+ year stalled out project!
A little late, but congrats! So happy to see success. You are an inspiration to me to get moving on my 10+ year stalled out project!
Just read the link to the post with SU info. Good stuff. Ill have to save that in case I ever get - ahem - have to work on one. Only thing I remember driving and working on with them was a MGB. Fun little car. But never had to touch the carbs. My friends ex built and maintained it for her... And he was top notch! I only had to fix whatever broke while I was driving it
Come to think, my GT6 prolly had 'em, but the "Prince of Darkness" electrics kept me busy, I never touched the fuel system. Had her 3 weeks, only drove twice. One of the ones from my 20's I wish I'd kept.
CJ said:I have made a poor attempt to find this info, but can't - what are the SUs off of? British something? Early Z?
Do you know the year of the carb donor?
Early 240Z. For some reason I think I remember 1971
Here's another idea....would capping this port on the head help her to stop sputtering and trying to die at part throttle?
I had figured it was there for a reason, we should let it breathe.
Oh, the broken cap super glued together nicely.
jfryjfry said:A little late, but congrats! So happy to see success. You are an inspiration to me to get moving on my 10+ year stalled out project!
Thank you. It is great to have her legal to drive. The next goal is to get her reliable enough to feel confident driving in traffic. Right now she's having trouble at low throttle.
Toyman01 said:Well, I can't help with the carbs but it definitely sounds like it's running out of fuel in transition.
.....well, this video (at 8:56) makes me think that you are right and I have it too lean
JoeyM said:Here's another idea....would capping this port on the head help her to stop sputtering and trying to die at part throttle?
I had figured it was there for a reason, we should let it breathe.
Oh, the broken cap super glued together nicely.
The valve cover is a positive crankcase vent - you don't want to plug it. Typically that would have a hose that'd run to the air intake, and I'm fairly certain it went to the air filter housing.
I see a plug on the fuel bowl vents now - did that change how it runs? I really think that needs an atmospheric vent. Have you checked the fuel level in the bowls? That's the coarse mixture adjustment, with the fine adjustment being the screw on the bottom of the carbs that sets the fine mixture. You can also mess with the needle taper or seat diameter, but I don't think we need to mess with those variables, I think there's a simpler tuning issue at play.
I used to have a Datsun SU tuning DVD, I'll see if it's still in my toolbox.
Brotus7 said:
The valve cover is a positive crankcase vent - you don't want to plug it
Oooh, thank you!
I see a plug on the fuel bowl vents now - did that change how it runs?
That was a quick and dirty attempt at plugging them right before driving to the car club meeting; i.e. shrink wrap, wire, and zip tie. At first, I thought it was less likely to die, but I changed my mind later...not sure if air was starting to get by, or if the "improvement" had been my imagination.
Have you checked the fuel level in the bowls? That's the coarse mixture adjustment, with the fine adjustment being the screw on the bottom of the carbs that sets the fine mixture.
I haven't done that yet, but hope to get out to the garage tomorrow. We will see if I can make sense of it.
You can also mess with the needle taper or seat diameter, but I don't think we need to mess with those variables, I think there's a simpler tuning issue at play.
This makes sense. All the simple things should be adjusted before the advanced settings.
Brotus7 said:I used to have a Datsun SU tuning DVD, I'll see if it's still in my toolbox.
Cool! Let me know if it says anything about fuel starvation happening when you press the accelerator.
Okay, here's another Guide to Datsun carburetors that I'm hoping will be helpful.
starting a thread here to get more input/ideas
I heard only run 20w oil in the carbs but I doubt that's your problem.
Are the needles adjusted? I had an SU tool kit used to adjust everything. Do the chokes work properly?
a guy that taught me to rebuild my carbs first taught me to rebuild my distributor.
Datsun310Guy said:I heard only run 20w oil in the carbs but I doubt that's your problem.
Are the needles adjusted? I had an SU tool kit used to adjust everything.
I haven't done anything with them myself, but I expect that they're OK....they were rebuilt just before we started using them.
Do the chokes work properly?
Great question. Their linkage isn't linked to a cable, but yes, moving them works when I stand next to the car. The front choke's return spring was not hooked up on one side until this morning, but I found and fixed that.
a guy that taught me to rebuild my carbs first taught me to rebuild my distributor.
OK, I'll count that as another vote for "fix the ignition problems first." Do you think that fouled spark plugs could cause these symptoms?
I've been driving it, despite the issues. We now have 100 miles on the odometer.
JoeyM said:I've been driving it, despite the issues. We now have 100 miles on the odometer.
Proud of you Joey.
wheels777 said:JoeyM said:I've been driving it, despite the issues. We now have 100 miles on the odometer.
Proud of you Joey.
Thanks. That means a lot.
Today, we are running with the fan set to kick on after the engine has warmed up slightly.
The engine still isn't perfect, but it runs a lot better at the slightly warmer temperature. Here's another test where the missing and sputtering is greatly reduced
Taking a break from whining about throttle response/carb issues. Let's talk sheet metal. The real 1932 and 1933 datsuns had a skirt between the rear fenders. (still taken from this video)
My friend had to replace their water heater, and asked if I wanted the sheet metal. It had a full height access panel (painted blue) on the front
That is more than a sufficient amount of metal to make a skirt out of.
I think I may use the end of it that has the RHEEM logo on it to emphasize the "built from scrap" nature of the car. 
I vote definitely on the logo!!!
The metal on the side of the cowl had been bare of paint since I welded the flange onto it just prior to my DOT inspection, and had gotten rusty.
The area below the windshield was also dusted with rust. Last week I used an acid-based rust dissolver on both areas, and today I brushed on Rust-Oleum to cover those areas.
I love that stuff. A quick and dirty brush job with Rust-Oleum will never look like a Riddler winning paint job, but it isn't supposed to. For a track rat or a rat rod, I think the results are fine.
I drove the car to a street rod club meeting during daylight, and returned home after dark. The light on the speedometer was out when I started the car after the meeting. That was the first time in a while that I had driven the car after dark. I bet the wire had come loose some time prior during daytime driving and this was just the first chance I had to notice it. I'll have to either remove the dash from the cowl (ugh) or crawl under the dash (almost as annoying) and see what's happening, but I expect the wire for the light just vibrated loose.
I brushed on a coat of rustoleum smoke grey to change the color of my windshield frame.
I stll haven't pulled the dash off to fix the light on the speedometer
I am glad that the speedometer is lighting up again, but I dislike Heisenbugs.
I pulled the dash, and there were no loose wires on the back of the speedometer. No obvious free wires around it, either.
There was a nice big cluster of red wires, with one for each gauge, and another one that extended over to the light switch. The junction where they all were shrink-wrapped together looked a bit ugly, and I was thinking that I might need to dig into it and redo it. first, though, I needed to check that it was indeed the cluster of wires that powered the lights on the back of gauges.
I I pulled the red wire off the back of the voltmeter, and sure enough, the light went out. I plugged it back in, and both the voltmeter light and the speedometer light came on. I have tried the lights a half dozen times since then, and each time the speedometer lights up like it should, so I went ahead and put the dash back in place. I'm not sure this is the right choice, I probably should have torn into the wires and made sure that any marginal connection was fixed.
took the car out for a while this morning. Put 25 miles on it. She ran OK at first, but started to worry me at the end with some missing and running rough.
Datsun310Guy said:I heard only run 20w oil in the carbs but I doubt that's your problem.
Are the needles adjusted? I had an SU tool kit used to adjust everything. Do the chokes work properly?
a guy that taught me to rebuild my carbs first taught me to rebuild my distributor.
I have only run 10w oil in SU pots. Marvel Mystery Oil preferably but ATF works too.
You'll need to log in to post.
