SHORT VID CLIP OF ENGINE RUNNING ON PREVIOUS PAGE..

would like to get thing running a bit better, so i can run the engine in properly. and id like to be able to drive it to go get it tuned on the dyno, i dont really want to tow it to sydney or newcastle to get it tuned.

basically the car is behaving about exactly the opposite as i thought it would have.
idles well, light throttle and take off is great. and drives well with light to mid throttle up to 3000 rpm.
but anything half to full throttle it just wont rev past 3500 it just stumbles and wont rev anymore.

any one care to hazard a guess at what my jets should be.
current set up is.......

ENGINE
2.3l
cam 306 deg, 590. lift
ported head, 44mm inlets 36.5mm exh valves.
s2 bb electronic dizzy, standard advance curve at the moment.


CARBS
48 dco
chokes 42mm
aux vent 5.0
mains 180
em tubes f7
air correctors 160
idle jet 65f8
pump jet 45
pump exh 100
needle 2.50

_________________
When the sign says "don't feed the bears", man you better not feed the bears.

180 mains 160 air seems a bit on the rich side
The 65f8 is a bit strange as well
150 main 155 air with 50F6 idle may be closer to the mark.
Ign timing try 36BTDC @4000.
I assume the valve timing is not too far advanced.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

what about the tubes baz mine are f7?

valve timing is 0 adv. ive got an 8 hole sproket. i can go 3 deg adv or retard by moving a hole back or forward. i checked valve to piston clearance on those settings to and thats all good.

ign timing will be set as you said, ill do that tommorrow its currently about 15 at 1000 rpm i think.

_________________
When the sign says "don't feed the bears", man you better not feed the bears.

I like F9s with 48s they are on the lean side, so nice and crisp.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

ok cool, are f7 too rich?
new plugs already heavily black and sooted up.

_________________
When the sign says "don't feed the bears", man you better not feed the bears.

That's possibly the idle jets.
Have you got the fine thread idle adjusting screws?
If the carbs are synched correctly you should have approx. 3.5 turns out from fully seated.
On all throats.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

here is an old post of mine from the 510 realm, just may help.

Jeez!!!!!!!!! if listening to carbs suck thro a tube isnt old school???????????.
Thats an old SU trick before unisyns.
Learnt that on my days with Cooper Ss.
Ok have plenty of tricks for webers ( know them better than Solex but still the same thing)
Learnt most of my tricks from a factory weber engineer back in my Alfa days.
We do have a weber manometer but its a pain due to having to fill the tubes with mercury.
there are many ways to tune these type of carbs.
this is just one of them.

First ensure that the butterfly shafts are not twisted,
easy to do.
Solder 4 mini globe bases together with 12" leads.
remove transition port caps.
poke the globes in the throats until the globes are near the butterfly.
using the idle screw open the throttle until light can be just seen at the edge of the first trans port.
must be equal on both throats of carb.
then if both carbs are ok, adjust the synchonisation between the carbs using the light.
This is just the starting point.
Now screw the mixture screw fully home (lightly)
then open all screws an equal amount, not sure on the solex, corse screw webers 1.5 turns,fine thread 3 turns.
Do the plug drop & synch the carbs again.
adjust mixture screws equally 0.25 turns in or out to obtain smoth idle at 900 rpm.
recheck synch.
All the above is dependant on new plugs,valve clearances set,close or equal compressions,etc.etc.
Note idle mixture & carb synch is vital for light throttle operation & smooth responce.
this should be correct B4 tuning the main circuit.

Oh! and do not forget that accelerator pump setting on the solex can give a rich sog on fast thottle opening.

Starting point for 50PHH is
choke size 43mm
air horn 50mm
main jet #180
Main air jet #180
float level 24mm (0.94")

By the way, arnt carbs "old school"

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

Carbs are sync by ear at the moment, I'm going to get a synchro meter when I order some jets.
Idle screws seem to work best at 2 turns off seated. I tried 1,2 and 3 turns.

_________________
When the sign says "don't feed the bears", man you better not feed the bears.

Do not concern your self with main jets & emulsion tubes. The critical part of weber tuning is the idle synch
and idle mixture with a clean transition from the idle circuit to the main circuit.
Its possible to light throttle drive with the main jets blocked OFF.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

Sorry should have said .5, 1, 1.5 turns.
I think there coarse thread.
1 turn was best.

_________________
When the sign says "don't feed the bears", man you better not feed the bears.

Jeez I hate typing call me now.
08 8186 2100
I have 15mins spare.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

This is not the problem you have,
but when you get to know webers it all becomes easy.

https://www.facebook.com/video/video.ph ... 9957026943

BTW don't waste money on a snchro meter. Not the way to go on webers.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

Bit late on that post before, thanks baz your always willing to help out with your knowledge, It would be good if you could run me through it on the phone.
I really wish I was closer to adelaide so I could get you to tune it.

_________________
When the sign says "don't feed the bears", man you better not feed the bears.

Had a bit of time to give it a tweak this arvo.

I've just been working on getting the balance right with the linkages.
If I balance the throttle plates at idle speed. One carb was way off at full throttle.
Then if adjust them balanced at full throttle they were way off at idle.

So having a close look one carb was sitting a little higher than the other on the manifold.
So i had to take both carbs off file a small amount of the mounting holes to give me a bit of play.
With the carbs remounted and as level as I could get them, I adjusted the balance again.
Now I can get the balanced at full throttle then returning to idle position they are still synced but only if I'm using the idle speed screw a bit a decent amount. If I'm using zero idle speed screw they are still very slightly out of sync still, as using the idle speed screw gives me a bit more balance to play with on the coupler.

Listening to the throats with a piece of tube they seem pretty similar, but number 2 has a distinct tapping/drumming sound coming from it, anyone have any ideas what that is?? It sort of sounds like a tapping noise you get from a leaking exhaust manifold gasket. But can only be heard when you listen to the carb with a piece of tube.
I also checked every where for vacuum leaks and sprayed around everything but couldn't find anything

Played with the idle mixture screws a bit more. 1 to 1-1/4 turns out seemed the best.

Ign timing was set 17 at Around 1000 and 34 at 4000.
Does that seem about right. I only gave the ign timing a quick check I'll revisit next time.

Car drives way better, still no 3/4 to full throttle it just coughs and splutters, but light to mid throttle up to and a bit over 3000 it's very drivable.

_________________
When the sign says "don't feed the bears", man you better not feed the bears.

Got a chance Monday afternoon to do a bit more fine tuning after having a good read and understanding of how to set the idle mixture screws work, I spent some time setting them up using a digital tach, then syncing the carbs, they are the same while listening with a tube in the throats and when I pull a plug lead off any cylinder there is equal rpm loss.(not sure if that bit is common practice)

Anyway ended up with a real nice idle at 1000rpm.

Went for a quick test drive same deal again but even better light to mid throttle but won't rev over 3000-3500 and no 3/4 to full throttle.

_________________
When the sign says "don't feed the bears", man you better not feed the bears.