What air filter do you have???

[gator]

yep ... I just cant understand why it goes into only the back carb.

Should I be concerned about some gunk coming from this hose in the winter or is it likely just from condensation? I have driven this car all winter here and it is very cold.

[jackboxxx]

yep ... I just cant understand why it goes into only the back carb..

I think its just because the inake of air through the front of the air cleaner

kinda forces it back to the rear carb more..and of course the carb is a big vacuum as well..so once pushed by the incoming air, the suction of the rear carb takes in most of the gunk.

Should I be concerned about some gunk coming from this hose in the winter or is it likely just from condensation? I have driven this car all winter here and it is very cold.

how much gunk is there? when you say gunk, i kinda picture a lot....of thick sludgy stuff..

[gator]

Thanks jackboxx ... Datsun has intentionaly directed this breather into the back carb and i wonder why. If it was just an inlet into the filter box, I guess what you are saying would happen, but the metal pipe directs it into the back air horn.

As for the gunk .. no not alot of gunk .. but my back carb did freeze up once and the was enough gunk to cause it. It happened when I was alittle low on oli too (I have a small oil leak) .. not sure if being low on oil would cause more fumes and in winter create more gunk .. or of I simply have a motor that need some head work. The junk is a light to mid brown colour and is sledgy. I have not run this car in summer yet so have yet to see if the problem clears up in the heat.

Cheers B

[Curtis240Z]

I am guessing that you made some custom choke return springs because my OEM setup is purely a push/pull thing, no spring assist.

[beandip]

Thanks horn.

As for the gunk .. no not alot of gunk .. but my back carb did freeze up once and the was enough gunk to cause it.

Cheers B

A couple of issues here . First of all the 3 screw SUs have the domes fitted specifically for that one carb at the factory when it is assembled . There are supposed to be some ''plastic'' type cone shapes that align the dome to the carb base. This is the only adjustment for the needle and it is what is fitted at the factory. If the needle is not centered in the nozzle it will either wear them both which will alter the fuel mixture , were only talking of thousands of an inch . Eventually it will not be rubbing and the piston will rise and fall as it should but the damage is already done. Nozzles are NLA as far as I know. At least form Nissan USA. The Gunk is blow by from a tired engine usually , sounds like a candidate for a rebuild in the near future. Compression rings are failing . Now if the seals on the air box are not sealing properly , then dust and dirt will collect on the oil being blown in from the engine. Check the fuel line that runs from the float bowl to the mixture adjustment . If it is stiff or brittle this will cause the nozzle to stick also. Parts store hose is too stiff. Nissan or Ztherapy have the hose. VACUUM HOSE WILL NOT WORK HERE ! It looks the same but it will fail and dump gas all over the header. I hope this of help . Gary

[gator]

Thanks Gary .. I have re-built the carbs with a Z Therapy kit that has new hoses, nozzels etc ..carbs are in great shape .. May need choke return spring though. I think you may be right about the motor .. and I will tell my wife you said so ! I need a new motor. What is your phone number .. just in case she need to confirm that ?? HAhahahah

Thanks .. guys for all the feed back ... I think I have some work to do here to get this thing set up righ. I guess I will pull it all apart again.

Cheers .. Bruce