Motorcycle shops sell single weight "fork oil" in bottles ranging from 5-20 or so. For my tastes 20w can make the carb a bit too slow to respond in cooler weather, ATF flutters a bit in hot weather. I've found Bel-ray 15w to be about right.

http://www.belray.com/bel-ray-high-performance-fork-oil

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Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

should you be able to pull both dipsticks out all the way. one of mine pulls the plunger up with it.

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Mike Tubiak
1978 Datsun 280Z - HLS30-438694

Also if there was no oil would that cause bad hesitation and sputtering?

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Mike Tubiak
1978 Datsun 280Z - HLS30-438694

Not "bad" hesitation. A bad stumble is usually an ignition vacuum advance indication. Carbs can cause that but it wouldn't be from this damper issue. With a dry damper, the carbs do everything right, but it takes longer for them to transition from open to closed, and it's not a smooth experience. It sort of 'slams' on/off when you change speeds with dry dampers. Acts much nicer when the pistons are lubricated.

Never saw a damper piston pull the vacuum piston up with it. Can you tell what's causing that? Suction (unlikely if it's dry), a burr, or dirt maybe?

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1970 240Z

Norm the 12 second SU dude doesn't run any oil in his carbs. He experimented with all kinds of oils and found it ran best with nothing. He said the throttle response is much better and he didn't experience any drivability issues. I personally think running a very low weight oil will at least keep things lubed. I ran 5 weight oil a long time ago and it ran pretty good. I had been running actual SU oil from MSA for the past few years. The difference wasn't noticeable enough for me to not run wht was recommended.

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Rob
1971 240z

It pulls up because it appears that the thing at the bottom of the dipstick is stuck on it. I can't actually pull the dipstick all the way out. I'll take pictures.

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Mike Tubiak
1978 Datsun 280Z - HLS30-438694

["Norm the 12 second SU dude doesn't run any oil in his carbs"]. Lots of racers don't, and many of them run modified flat top SUs with the accelerator flap circuit for harder acceleration. Smooth engine performance isn't as important in racing as it is on the street. Racers want immediate throttle action and usually only run full ON or full OFF. Street drivers want a smoother ride.

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1970 240Z

Frank I changed the oil to the 3in1 you was talking about and it feels good .maybe tomorrow ill hit the highway see how she feels at 100 mph ...

DAVE!!!
You're driving a perfect, 42 year old classic car. If you wreck it at 100mph there is little chance of either of you surviving it (you OR the car).
Changing the carburetor damper oil is NOT a justification for risking your life or a classic Z. (And, our families drive on those same roads). A high speed run won't test anything except your tires, reaction time, and luck.
Please take a leisurely drive in the country and get your beautiful 240 home safely?

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1970 240Z

You are right Frank... just want to car to drive right for the trip next weekend... also i putting her on the track for the first time..

To test your SU's, it would be more like how quick you get through the gears up to 100 mph. IM mechanics opinion, if there are no vibrations at 100 mph, then your all set for the track.

Ok the key is how long it takes to get to a 100.. thank you Im new on playing with the su but everybody on the site has help me work with them.

And if you don't have a meter to tune them, you can do so with a rubber hose and listen........each carb should have the same decimal of air being sucked in.

I have the meter. the car is driving smooth . i also get the video from Z therapy . that help me too.

HAHA! Dave, I'm watching that exact same video today! Is yours the 1996 version or the 2000 version?
I'm thinking about converting it from DVD to CD and making it available to all CTZCC members.

Frank

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1970 240Z