Datsun Roadster Forum-311s.org

Hello everyone,
I aquired SRL311-12037 a couple months ago in Puyallup, WA. The previous owner, Mr. Hayter, kept it well maintained and clean, and I have fallen completely in love with it. Before Mr. Hayter, it was the property of Mr. Cole, who I understand raced it before moving on to Z-cars.

I came across it while looking for a unique and fun car on Ebay, and almost bought a 70-something Opel GT. Glad I didn't, because now I know this Fairlady would dust the GT without a thought. Despite a bit of research, I didn't really know what I was buying.

Through recent research, I've come to realize that I might have quite the "omlette car." It's a U20 with Solex 44PHH carbuerators with a Megaflow air filter, supposedly a "B" cam (have not physically verified), Protronix 3 Ohm ignition coil, and Purolator electronic fuel pump. The car is lowered, and Mr. Hayter provided me with the original suspension parts. The distributer appears aftermarket (the cap at least), and has the vacuum advance capped. I understand that this is the result of the Solex's not having a vacuum line from the intake, but wonder if one should be added.

I've enjoyed driving it immensely! When I first got it, I had Josh at Dubwerkz, a local aircooled VW shop on Whidbey Is., synch the carbs and give it a look-over. He gave it an outstanding bill of health, and I put it to good use cruising scenic western Washington for a good two months. Recently, I figured I should have the carbs synched again, and instead of returning to Dubwerkz, I foolishly asked a friend who had attended UTI and was ASE certified to teach me how to synch the carbs. To make a long story short (I think it'd belong in a different forum anyway), it took him and 2 other "experienced" mechanics about 4 hours to turn my beautiful, unique piece of automobile history into a redneck lawn ornament. Biting my tounge and choking on expletives, I had the car towed back to my apartment, with the proverb "If you want something done right..." repeatedly echoing through my head.

Thus have I arrived at 311s.org, in search of knowledge and experience from people who actually own roadsters. I'm sure you'll see many posts in the future along the lines of "wtf is this thing?" from me, but I hope that along with any accusations of sheer idiocy/incompetency/ignorance comes the knowledge I need to get my baby back on the highway.

Thanks much,
John L.

Some VWs had two solexs. I know some VW guys that can fine tune twin carbs like a Swiss watch. Mikunis, dells, and webers. Dubwerks Not up to snuff? Sounds like you were pleased with the work?
There are some sharp folks here, and lots of tech. Also lots of owners here in Puget sound.

Dubwerkz is great, I'll probably be towing it back to Josh if I can't figure it out. He only works on aircooled VW's, and does really good complete resto's. I'm sure many of the old Bugs driving around this area have passed through his hands at one point or another. I'll start a thread in "Tech Discussions" to document my work, research, and questions as I go. I think that way, more experienced people reading it can cue me in to something I've overlooked, or offer useful insight.

Greetings John, I believe I am familiar with your car and actually did some minor work on it, coming to the conclusion as I recall that the carbs needed a thorough cleaning (which I believe they got at least some, as the PO said it was running better). Mikuni carbs are not rocket science and they generally don't go out of tune without something happening. I suspect that as you drove it some gunk got into the jetting and started messing with it, then you had some well meaning people who are unfamiliar with carbs let alone Mikunis muck about and here we are!
My first suggestion is to 1) go back to what ever jetting it ran good with before (if they changed anything), 2) take some carb cleaner, remove all the jets (under the mikuni cover, each carb will have 2 pilot jets closest to you, then closer to the engine you see your air jet, screwed into the jet block, which screws out and once removed will have the main fuel jet on the bottom, also removable), clean all of these and using the carb cleaners spray tube blast cleaner down all the holes you can see, watch out for fuel spray! 3) remove the brass slot screws on top of the carbs (4 on each carb), under two of those (one per throat) you will find your accelerator jets which also can be removed and cleaned, being careful to not lose the little washer that goes on the bottom around the jet, clean here too, then replace (they only go in one way). Then under the other set of slotted screws you will find tiny 3 holes and if you move the throttle you will see the edge of your throttle plate move to progressively expose these holes... that is what feeds fuel at low speed... clean these with carb cleaner blasts too. Replace everthing, then remove your idle screws (4) (brass slotted screws closest to the engine and clearly on the engine side of the throttle plate), clean these and the hole, then CAREFULLY screw them back in JUST BARELY SEATING THEM IN THE BOTTOM OF THEIR TRAVEL ONLY AS THEY ARE BRASS AND FORCING THEM TIGHT WILL DISTORT THEM, then back them out 2 turns equally... that should get you close to an idle mix when the car is warm... See if it will fire up (may take a while with all the carb cleaner, may want to change plugs), then play with them a 1/4 turn at a time to see what the engine does until you are happy and it's not too rich or lean at idle. In order to balance the carbs you will need a balancer (see posts on "Homemade manometer" on this list for tool options), and some instruction that really works best with pictures to reference.

I highly suggest you get a manual. The original has a write up on the older styple mikuni/solex carbs but it is generally the same, or see tech write ups on this board. Check your fuel filter for gunk and replace, watching for leaks both fuel and air. I also believe the car has a rear sway bar on it... they can cause oversteer if you are not used to them so be aware. DROPS (Datsun Roadsters Of Pugest Sound) is local and somebody should be able to help you out sometime... what city are you in? Might be a good reason to go for an extended drive...

And welcome! It is a nice car and should be fun!

As far as the distributor, it is likely an electronic ignition conversion from Gary Boone or East Coast Roadster (pre-me). The lack of vacuum advance is correct for your set-up as the internal advance has been curved appropriately. You do not want to convert it back to a vacuum advance unit, and it is not easily done regardless. You can learn a little more about the distributor and process in the tech wiki or at the East Coast Roadster website

Great writeup Greg - very helpful.

Cheers
James

jamesw wrote:Great writeup Greg - very helpful.

Cheers
James

+1 on the write up. Very thorough.

Thanks much, Greg. I got it running fine after cleaning everything, and printed a copy of the carbuerator manual. I've just moved across country to NC, and after I get settled in here, I'll give it a good tune up, and see if I can get some pics posted. Thanks again for the help, and also for the info, Notoptoy.