Datsun Roadster Forum-311s.org

Hey, folks,

Over the course of several months, with much help from this list, I was able to bring my '66 up to being a decent daily driver -- for a week.

Then, on the way back from a Friday "free night" at the museum, the front carb started to pour fuel out the base intermittently.

I was happy for the excuse to put a pair of Z-Therapy rebuilts on, and at first they seemed super smooth, quiet and delightful.

But, under load it was stuttery and rough and the idle became more and more uneven, to the point that it shudders and shakes crazily, now.

I've checked the timing and valves and compression (feared I may have coincidently lost a cylinder or something). Balanced them again & again.

I'm baffled & simply want to pay someone to make it right. A new job precludes my working further on this, even if I had the energy left.

So, after that long preamble, who can you all recommend on the West Side of Los Angeles to be my hero mechanic? I worry about drive too far.

Thanks,

Jesse.

Hey Jesse,

Sorry, I do not know anyone in the area, but...

That really sounds like the ignition is having trouble. How are the points and condensor?

You might want to try Jon Frampton (search member list) he has a shop in Huntington Beach and has a beautiful 67 1600 that wins at Solvang all the time, If he doesn't work on them personally I'm sure he can recommend someone good that does.
Hope that helps!

You can try Ed Johnson at Classic Datsun Service in Northridge, the last number I had for him was. (818) 606-1066 . If it doesnt work, cal Dean @ Fairlady Products (818) 363-2015 , since Ed is a couple of doors down from Dean. That way if you need some parts they are not far away.

Lou Smaldino
66-1600
67-2000
64-1500

I agree with TR,

Just a thought...

Maybe put in a Boone distributor and a set of really good wires and coil just for the drivability/dependability upgrade, might fix it, nice upgrade if it doesn't.
These parts would be an investment rather than a guess. Between this and the Z therapy carbs, you are going to be very low maintainance.

Also, does it run worse fully warmed up?? Might be a tight valve adjustment if the valves cooled off before you set them.

After some quiet time, I came up with two avenues to pursue:

1. Air/vacuum leak
2. Ignition oddity

As for the first, spraying starter fluid around the carb mounts and manifold caused no change in RPM. Spraying it in the carb mouths actuallly lowered RPM. I removed the carbs anyway and coated all the gaskets with Permatex sealant before replacing them. This changed nothing.

I also checked the vacuum to the distributor and it had no leaks. It also seems to advance properly. Certainly, the problem is across the RPM band, anyways.

I replaced the condenser, points, rotor and cap. Set the gap and checked the dwell. This all changed nothing.

The timing was spot on, but I fooled with the distributor some and found that when I radically advanced the timing, the engine smoothed out. When I put it back at 16 BTDC, it actually backfired out the rear carb.

So, I advanced it as far as the distributor would turn (maybe 40 degrees) and drove around the block. It's definitely a bit "off" but it accelerates smoothly and relatively strongly, and the engine doesn't shake the car.

Also, I don't think I mentioned before that there is a definite change in the pattern of vibrations about when the thermostat opens. So, there is some temperature sensitivity.

But, I hot-set the valves only a few weeks ago (and checked them even more recently).

What do we make of all this? Ignition? Valves?

Independent of all this, I'm going to get the Boone distributor and a new coil. As DBrick notes, it's a decent investment in the future, even if it doesn't fix this problem.

Best,

Jesse.

Sounds like you're on top of it. If it were a an american car, I'd think maybe the distributor was 180 degrees off or firing order, but with a 4 cylit would be VERY rough running.

Just a noteI would avouid useng starting fluid, way to explosive. Brakekleen or even Gumout is safer. If you use brakekleen, the fumes from the exhaust are really toxic, Phosgene (sp.) gas I think, so only try outside. If you suspect a particular spot leaks and it isn't too hot, a blob of grease will seal it for a test.

Keep me posted, whatever breaks on yours will likley break on someone else's.

Good luck

Weird about the timing, are you sure your pointer hasn't been banged out of its proper location?

Good point, bring #1 to TDC with valves closed and see where the pointer sits. I know that Chevrolets can have the outer part of the harmonic balancer, the inertia ring, with the timing mark on it slip and rotate around the inner hub if the bond betwen the rubber layer breaks, This would explain alot, running and vibration wise. Last time I saw that, the crankshaft broke in 2 places, although he should have stopped driving it when the vibration started.

Bringing the motor to TDC on #1and checking the timing mark and the position of the rotor in relation to the cap and #1 sparkplug wire terminal should confirm or eliminate the possibility, and it's free!. I took an old dist cap and drilled 4 holes in it so I could see the rotor position to set up the electronic ignition and "phase" the rotor. I never looked, but assume Datsun has a keyway on the crank and balancer. If anyone knows the relation between the keyway and the timing mark, that may tell too.

(90% of what I know is American V8, so please pardon all the references)

Good luck, I think I'm up to 8 cents