4x4 Action Group

Bugger wrote: ↑

Tue Sep 17, 2019 8:46 pm

For the Clutch shudder look on the top side of the chassis in the back where the Gear coupler is situated
The clutch cable runs through a steel tube there that is tack welded to the Chassis
If the welding comes loose this causes bad clutch shudder


For the Flat spot on Acceleration make sure the Spray jet is adjusted correctly
With carb in hand give the throttle lever a jerk and the fuel must spray out the bottom of the Carb
It must not first spray against the Throttle body or side of carb

The spray jet is the small copper tube on top of carb.

Hope the info helps...

Thank you very much.

Car is at the auto electrician today, will check tonight and let you know.

No problem
Check that the Bendum tube (clutch flex tube) have a slight bow in it
Otherwise that will also cause clutch shudder

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Bugger wrote: ↑

Wed Sep 18, 2019 6:00 am

No problem
Check that the Bendum tube (clutch flex tube) have a slight bow in it
Otherwise that will also cause clutch shudder

Sent from my SM-G965F using Tapatalk

This I have seen - it is basically as straight as an arrow (see pic below).

Should I just use spacers to create the bow?

After adjusting the clutch and the timing, the shudder was not more and the flat spot is virtually non-existent.

She purrs...

https://www.youtube.com/watch?v=jk_xe8W7VWg

Awesome build !!!!

ThysleRoux wrote: ↑

Mon Sep 23, 2019 12:09 pm

Awesome build !!!!

Dankie Thys!

I need to source me a fuel pressure regulator. Apparently a 0.3bar pump is too much for the carb float to handle. The bently manual requires 2-3psi and if my maths don't fail me, its about 0,2 bar. At 0,3 bar the carb gets flooded.

Is there any other way, apart from either sourcing a regulator or a new pump, to lower the pressure by 0,1 bar?

I may live in the "land of milk and honey" but that's about all you can buy here...

I always used a Facet pump with a max pressure of 3psi that was available from Midas and other spares shops. They weren't expensive and are super reliable but can be a bit noisy.

I have just been through this fitting a motorcycle carb to a nissan A15 motor.
How I ended up getting around the pressure issue while maintaining a decent flow was:

1/ You will need a return line to the tank for all the "extra fuel". This line must be the same if not a larger internal diameter than the feed line.
2/ Get a fuel line T-piece from the local spares shop along with another inline fuel filter.
3/ Plug the T-piece into the feed line and the return line so that the return line is on the bottom of the T and the Feedline crosses the top.
4/ Fit the fuel filter between the T-piece and the carb to act as a high flow pressure reducer.
5/ you will need to fit a small restriction orifice into the return line so as to maintain some pressure on the carb inlet. I ended up after much testing with an orifice of 1.35mm (I used some old carb jets but a section of round bar with a hole in it will also work)

Point 5 will take some testing to balance the pressure restriction against max fuel requirements under acceleration / load.
Start at the smallest orifice that you can use without the carb flooding and work from there.

Using the above I have a fairly constant pressure of ~1.5 to 2 PSI across the rev range and no fuelling issues under acceleration / load.
This is with a 3-4 psi Facet pump.


Another method would be to fit a surge tank near the engine and gravity feed the carb from that.
I would have gone that route but didn't have the necessary space in the engine bay to fit it.

Cheers

W

If I understand you correctly, you mean something like this?

Like this.....

I did the whole T-piece, second filter and restriction in the engine bay as it was easier to work on.
Not sure but think it should be possible to do it closer to the tank which will shorten the return line required.

The return line will need to be free flowing back into the tank.
Like you had it (T-eed into the pump suction) will cause the fuel to circulate through the return line and pump and remove all flow to the carb.

Thanks Wooky, it makes sense. I'll give a try.

One thing to watch out for.... If the return orifice is slightly to small you could end up with "pressure creep" at idle.

What I did was work on the Orifice size to get get the flow to the carb correct for max load / acceleration and then check for overflow in the carb with the engine off but the pump running (max pressure on the needle and seat).

Are you sure the float level is correct?

it should close the needle valve at 3psi without any problem.

A return line with a restricted orifice will certainly help as Wooky says, but it shouldn't really be nessecary...