Datsun Roadster Forum-311s.org

Ok, last update for the day. One of the guys that was helping me with the carbs yesterday suggested that its probably the emissions stuff that is causing the RPM to not return fast enough. And as Linda said previously in this thread... "Get rid of that smog stuff ASAP".

So, this morning I removed all the smog stuff including the air pump and it runs MUCH better! Now the RPM comes down between shifts like I think it should. It also got rid of exhaust backfire type rumbling I would get on deceleration. This car is getting better everyday! Nice to have the help and suggestions from this group as well as a couple Datsun friends near by.

Thanks all,
Dale

L320 wrote:Ok, last update for the day. One of the guys that was helping me with the carbs yesterday suggested that its probably the emissions stuff that is causing the RPM to not return fast enough. And as Linda said previously in this thread... "Get rid of that smog stuff ASAP".

So, this morning I removed all the smog stuff including the air pump and it runs MUCH better! Now the RPM comes down between shifts like I think it should. It also got rid of exhaust backfire type rumbling I would get on deceleration. This car is getting better everyday! Nice to have the help and suggestions from this group as well as a couple Datsun friends near by.

Thanks all,
Dale

That's the great thing about this forum. Always help and advice.

Dale
Removing the smog stuff means also getting the springs and weights to put inside the distributor to make it an early type instead of a late type like you have for smog. Then you time it differently. i'm sure your Roadster pals can help you.
But getting the pump off and plugging all the holes sounds like it helped.
A 4 blade fan with the spacer is necessary , in my opinion, too.
Nice to see how each step can make an improvement that you can notice.
Wait till you step up to the EI distributor to replace yours, a hotter coil and bigger wires. Vroom, vroom!

Linda

Well today I got a few more things done on my newly acquired roadster. I was having trouble with the clutch not working very well. So, I installed a new clutch master and slave cylinder today. I bled both and it's working much better however not quite normal yet. I get a better clutch pedal after I pump it a couple times. If I don't pump it and just depress the clutch, it works but engages closer to the floor. If I pump it just one or two times, I get a higher pedal, it engages after about an inch or so. Has me a little stumped. Maybe I will try bleeding it again. Any suggestions?

Also, I bled the brakes while I was messing with brake fluid. They feel pretty good now. I'm still have an annoying squeal from the front during a medium apply only. No squeal during light or real heavy apply. I've already had the discs out and lubricated the back of pads and piston with some disc brake grease. Maybe I'll clean that off and try some of that "disc brake quiet" goop.

We did drive it about 20 miles today and its running pretty good.

Dale - AZ

Did you replace the slave hose as well?
You could try raising the rear of the car till the master is level and crack the slave bleeder. Fluid should flow rather quickly by gravity alone, if not, there may be a restriction.

pebbles wrote:Did you replace the slave hose as well?
You could try raising the rear of the car till the master is level and crack the slave bleeder. Fluid should flow rather quickly by gravity alone, if not, there may be a restriction.

Thanks, I didn't replace the slave hose. I blew from the line at the top to clear out the old fluid. I did gravity bled it as well, but the car was jacked up on the driver side. I will try by jacking the car at the rear. Might help?? When I gravity bled it, I wouldn't say it flowed quickly. More like 1 or 2 drips per second.

Thanks,
Dale

Hey All,
I drove my Roadster around town a bit more today. Its running better every day. I ordered some plugs for the head (smog removal plugs) from the Dean at one of the Roadster places. I have not installed them yet but will in the next couple weeks.

Anyway, I have a question about the gas pedal feel. Mine feels awkward because its not linear. By that I mean when I push the gas pedal I try to move it smoothly, but as I increase my foot pressure its, like push...push...push then whoa to much! It feels like really heavy springs, but I think they are right. When I ordered the smog plugs from Dean I also ordered 2 new springs that say on his web site they are the correct tension. After putting them on, the stiff initial feeling of the gas pedal felt worse. So I put on a set from the hardware store that were even lighter than the ones that were on the car when I got it. That made it somewhat better, its drive-able, but not very comfortable and still awkward.

So, how does ya-all's gas pedal feel, near the beginning of the pedal stroke? Do you have this stiff spot? I think my cables move freely, but I will check them again tomorrow without being connected to the carbs. By the way, when I get past this stiff spot it feels smooth through the rest of the acceleration.

Its a fun car though. Still some bugs to get worked out but like I said, better every week.

Thanks, Dale - AZ

I would look for binding on the pedal, is it too tight? Also, perhaps the clamp that holds the cable in place at the firewall might be too tight?
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Is the pedal stop in place under the pedal? should be a bolt and jam nut.

There should be a small clip common to the cable end and pedal shaft arm, pop that off, lift the cable end out then push the pedal. if pedal motion is smooth, this will eliminate the shaft as the culprit. lube the pivot points on the firewall.
As notop stated the cable sheath may be crushed. disconnect from carby and do the cable pull pull test. Dont push cable, it may kink.
My cable was frayed and the sheath was crushed about 4inches from the carby. I replaced the cable and massaged the sheath, cleaned and lubed cable and sheath interior, pedal mashes easily now. almost too easy.

Check the length on the dogbones. I can't remember which way it is, longer or shorter, but the length of the dogbones can alter how the gas peddle feels. I had it happen once to me just like you described and Sid pointed this out to me. It fixed it.

Bob

L320 wrote: That is, the RPM comes down very slow when driving the car. For example when I accelerate in 1st to 3500 RPM then let off to change gears, the RPM hangs there to long. It doesn't drop between gears making it awkward? Any suggestion on probable causes? All the linkages look good and seem to return just fine, no cables hanging up.

I don't know a 70 for sure, but that sounds like a smog system issue.

The engine speed slows slowly to burn cleaner. Low for a dash pot or controlled leak for the solution.

L320 wrote: That is, the RPM comes down very slow when driving the car. For example when I accelerate in 1st to 3500 RPM then let off to change gears, the RPM hangs there to long. It doesn't drop between gears making it awkward? Any suggestion on probable causes? All the linkages look good and seem to return just fine, no cables hanging up.

This may not be your cause. it's just a guess from my own experience. My 70 had the same issue (de-smogged).

For some reason when I adjusted the throttle cable, at idle and without any load, it would decelerate just fine. Everything looked good. however when running and warmed up, I experienced the same thing. The rpms would not drop enough during gear changes. Drove me nuts for a long time. How I solved it was to just put a bit more slack in the cable........then it performed well.

You hit it Roman. The plastic sheath on the throttle cable is what I suspect to be the culprit. Extra slack in the cable is what I think will solve the problem.

Thanks everyone, you have given me some great suggestions to review on the car. I didn't get a chance to work on it last weekend, but I plan on spend some time on it this weekend. I will report back with findings!
Thanks,
Dale - AZ

What I'm doing today.............

I'm not sure when my white roadster was painted, but I know it was over 10 years ago and maybe longer. It's not a bad paint job, but not a great one either. This car has been stored in the previous owners garage for years and not really driven. Probably hasn't been washed in years either (however it wasn't too dirty). I figured I had some time this today to mess around with the paint a little bit. I can tell its really old paint.

The first step was to wash it real good, then I went over the whole car with a clay bar to remove any contaminates.


Next I hit with a rotary buffer and a foam pad.


After that I went over it in two stages with my orbital buffer, from rougher cut to fine cut polish




I still have the front of the car to go, then I will follow up with a good quality wax job. I can tell from the spots that I have finish compared to what I haven't done that the paint had "yellowed" a little bit over the years. But it's coming back to a bright white pretty nicely. I enjoy working with paint.

Ok, back to work on it................. Dale