Datsun Roadster Forum-311s.org

tjp wrote:on side trim: Are the front and rear also different side to side?
Thanks

yes. arc and end angle.
3 rights and 3 lefts.

They are all different. The angles at the ends by the door are the differences.

Thanks guys!!

Some quick questions I hope:

One little issue with carb and throttle return springs:
I am having some issues with some rebuild SU carbs not always wanting to return to shut/full idle position some of the times when foot is off the pedal. The throttle cable is loose and lubed and carb linkage are lubed with silicon spray and move easily. but the new springs on the carb throttle returns are a little weaker than my old ones.

So I went back to the old carburetor return springs (from Dean) that I was using on the old carbs as they are stronger than the ones that came with the rebuilt carbs and that seems to have fixed the issue. Is that a common problem. replacement springs too weak?

I also have that issue with the spring on the throttle cable on the fulcrum disc on the intake manifold. I but the old one on there too and it helped some but it is still not quite strong enough even though it is quite jigglie loose when at the bottom. It currently has one full twist for resistance when it was installed. I could try doing another full turn on it but I think it would just bend the little part that hooks over the fulcrum. The cable is all lubed and slides easily. The issue is just at the bottom of the arc return. Like the spring needs to be re-sprung. Is that common? Any solution?


Another little issue:
My Tach in the roadster reads about 1000 RPM but my shop service tach reads about 750 and it sounds like 750. So I think the roadster tach is off calibration. Any way to adjust the calibration easily?

How do I tell, by looking at it, measuring it, or part numbers on it, if the cam in the U20 is stock or not? Where might the part number be (I haven't looked for a number yet)

I think there is a stamping on the rear of the cam shaft, closest to the fire wall.

Hey Ralph -
Like Nissanman says - there is a stamp on the firewall end of the cam. Remove the valve cover and use your phone to take a picture of the end of the cam. The stamps from the factory range from very light and hard to detect, to quite obvious. They will generally have A, B, or in the unlikely event C. A is the stock SU cam. B is the "Solex Kit" cam, and C is the highest performance factory option - I think best run with 44's with big chokes or 50 mm Solex... but I am far from an expert on the C cam. Often reground or aftermarket cams will have additional cryptic stamps on the end of the cam that I don't know how to decipher...

with regard to the cam type.... as in my case, it says it is an A cam but was reground to a B cam by Deans people/supplier. so then you only know by what the box was marked when you got it and sales receipt said unless they tried to restamp it.

Got it...thanks... will look for the stamp on the cam.
Cam came with the car...and the car was too big to fit in a box

Does anyone know the specs on the idler box Nut? I went to put everything back together and seem like I misplaced the nut!

spags1986 wrote:Does anyone know the specs on the idler box Nut? I went to put everything back together and seem like I misplaced the nut!

The easiest thing to do is measure the OD of the male shaft threads, then use pitch gauges to find the pitch. The pitman shaft is an uncommon fine thread. With any luck, someone will have a spare.

Carburettor Issue.
Ran out of gas.
Put gas in
Car wouldn't start.
Towed home.
Disconnected fuel line at Carb 1 (C1) - cranked - no gas coming out of fuel line.
Disconnected input fuel line from pump and put it in a gas source (bottle - bypass crud issues) - cranked - no gas at C1
Took top of pump off - no apparent leaks nor holes in diaphragm
Cranked engine - diaphragm moved up and down.

Thorts????

\Thx

There are two one way valves in the FP body: they are identical and are installed opposite to each other.
Aside from a line blockage between pump and carb perhaps the valves are kaput?

Blew them out with bottled air - they seemed to still have spring in them. And weird that this would happen at same time - not a great believed in concidences.
BTW - I think I know, but for certainty - the valve that goes IN to the top is INPUT, whereas the valve that 'sticks' out is OUTPUT, or v.v. Hard to tell from the schematic, and of course I didn't think to take a picture. DUH
Thanks

Pete

Does anyone have a general idea of how much can be taken of the bottom of a U20 head before you start getting detonation due to high compression?
Is .018 going to be problematic with stock pistons/deck hight/timing?