Jeff Berk

Might be a job for a "Fuse Buddy". I'm not sure if they make one that will connect with a glass tube fuse. This would tell you the draw on the circuit so you can tell if you are always very close to the 10 amps or if certain conditions trigger the over amp condition. I was having similar issues shortly after purchasing my car. For a while I had so many fuses blown on one of my circuits that I replaced the glass fuse with a breaker. If I recall correctly, I changed all my bulbs to LEDs and installed turn signal relays to lessen the amp load and that fixed (or hid) the issue. I had also rewrapped most of my wiring harnesses and discovered in the process several damaged wires and many ground wires from different components connected to a single ground wire. This was concerning because the single wire might not be able to handle the load from this old car. The circuits in your car has more resistance than when it was new. That turn signal stalk likely is a point of high resistance from close to 50 years of arcing and it may be time to flip the contacts over to a clean side. The wiring harness connectors are also likely in need of cleaning. Electrical issues are not fun to track down but a part of owning a classic.

No more noise, no more bees, and as far as I can tell, all good. Plus, I think I successfully rebuilt that ancient Hein Werner jack I use to remove my transmission.

It looks like the clutch pucks bed in after a bit more of driving. Thanks everyone for the help.

Captain Obvious, do you think its advisable for DadAndLadZ to reestablish that return line to the fuel tank to minimize the potential for vapor lock?

As long as it's not indicative of a problem I'm OK with it. Actually, the 5-speed that I rebuilt using parts out of a 4-speed that sounds like it has straight-cut gears would go well with this clutch ; )

I think my next step is to contact tech support.

I’m going to have to try a few more scenarios but I don’t think this problem occurs in 3rd, 4th, or reverse (4-speed). It doesn’t matter if the vehicle is at a complete stop or is coasting. As you can tell from the recording, the sound doesn’t always occur. I haven’t tried pressing the brake while doing this. There was a little grinding getting into 1st gear. I installed a pilot bushing about 5 years ago. The problem didn’t start until after installing the new clutch disk so maybe I need to contact M-Pact (https://www.rockauto.com/en/moreinfo.php?pk=6084348&pt=10605&jsn=4) and ask if this problem could be related to a resonance matching the springs. The transmission has been in there maybe a year with no problem until the clutch disk failure, specifically, the cupping of the disk possibly due to improper installation. However, the car has not been driven much this past 1 ½ years due to bad luck with camshafts failing. I’m somewhat limited in what I can do with the transmission right now. My ancient Hein-Werner floor jack that my transmission adapter is mounted on just failed and none of my other floor jacks fit the adapter. One last thought… Did I install the clutch disk backwards? Please look at the attached photo.

Could it be the throw out bearing 2022_07_28_13_45_10.mp3 ? But then it should happen in all gears, right? For what its worth, here's a sound recording I made yesterday on a drive to try and reproduce the sound. It kind of sounds like a swarm of bees on the recording.

The problem developed a little while after installing the new clutch disk so hopefully its not the transmission, not after spending $25 on it! Ill keep an eye on it and see if if anything changes. Thanks for the input.

I'm currently on my $25 four speed. I have a five speed in my shed but I'm not emotionally ready to tackle that right now.

I'm going to try and meet up with the area Datsun expert tomorrow and see what he says.

The new disk is in and the car is working fine except for one annoyance. With the clutch disengaged, there is a slight grinding sound in 1st and 2nd gear. The sound goes away as soon as I let the clutch out or when in neutral, 3rd and 4th gear. Could the clutch slave not disengaging far enough? On a side note, anyone go to the vintage car race in Pittsburgh last weekend? There were not too many Z's racing but quite a few parked in the car show area.

Kully... I ended up cutting my vapor line at the right rear fender. While at it tried pulling a suction on the line. The line to the top of the reservoir tank drew air when a suction was applied. When applied to the line from the right rear wheel to the engine compartment, it held a vacuum. There was some water accumulated in the line I cut which was a low point. The car seems to be running fine at this time and the pressure issue (and I think the fuel overflow at the carb) seem to be resolved. I don't think the reservoir tank has a valve at the top but I cannot tell for sure since I cant open the top. The connection on the gas filler neck I think just drains into the reservoir.

Kully, The carbon can was removed by a PO and the car seemed to run correctly except for a vapor lock issue. Unfortunately, a PO also deleted the fuel return and made this a dead head system. That likely contributed to vapor lock under certain conditions (e.g. between autocross runs). I recently reestablished a return fuel flow by connecting to the abandoned return line. My car had a fuel pressure regulator installed before the carburetors but it seemed more straight forward to have the regulator after the carb's if I was adding the return line back in. It appears that my vapor line to the canister is plugged as I cannot suck air out of either end and cannot blow air into the canister end. I am going to cut the vapor line at the right rear fender to allow the vapor to escape. Hopefully that will take care of the pressure buildup in the tank and fuel line.

“O Captain, My Captain!” I see that orifice thing in the FSM but if it was located adjacent to the carbon canister, it is likely missing as well.

It seems that if all this tube does is route fumes from the overflow tank to the engine compartment and dumps it there (the carbon canister is missing), could I just cut the hose off beneath the car next to the gas tank and let it vent there?

I found what I think is the charcoal vent line. It terminates at the front right fender, engine compartment. I blew air at about 30 psi into the tube while my son listened for air at the filler port. Nothing. I'm assuming that the charcoal vent tube originates at the overflow tank inside the right rear fender so I'm going to start stripping panels. Update: I used a hand vacuum pump on both the tube that terminates in the engine compartment and the hose that connects to the top of the overflow tank in the trunk. Both ends hold a vacuum.

I'll check for the vent line tomorrow morning. The fuel return line was capped off until I reestablished a return flow fuel system a few months back. Is there some way of adding a signature line or information in the block to the left of messages that includes vehicle information? I think that image is sideways to permit fuel to drain back into the tank:)

Is the vent line the one on the top of the reservoir tank in the right rear fender? As long as I'm pulling interior panels out, are there any suggestions on how to get them to stop creaking? Silicone on the plastic to plastic contact seams perhaps?

I noticed that my gas tank seems to build up pressure, is this normal? Also, and possibly related, I had fuel leaking out of my rear SU carb after a few miles last week and the fuel pressure gage recently was showing 7.5 psi after a drive. The carbon canister was deleted by a PO. The return line to the fuel tank was reconnected after ? years so it has not been tested other than to confirm it was not leaking. My fuel system is currently as follows: 1) Fuel is pumped from the fuel tank, through a fuel filter using an after-market electric fuel pump to the engine compartment. 2) Fuel is pumped through the mechanical fuel pump and into a DIY fuel rail with three outlets. Two of the outlets flow into a pair of round top S.U. type carburetors. The third port is connected to a low-pressure fuel-pressure regulator. 3) The fuel-pressure regulator has two active ports and a pressure gage. One port is connected to the fuel rail and the second port is connected to the return fuel line.

Yes, they were a little off but not enough to prevent them from working. I should of used a drill press and not a hand-held drill but my drill press did not have the reach to clear the steering wheel and I didn't want to wait a few days to get access to one of the ones at the maker space. At least they were both off in the same direction so the separation was correct. And for the first time in 9 months, my horn is working!

The wheel is a strange construction of cast aluminum hub and steel spokes. I had the welding instructor at a local makerspace do the welding for me. It did pop a little due to the casting having bubbles, but he had no problem welding it. I personally would of not attempted as aluminum is very tricky to weld. At home, I drilled and tapped the holes to 4mm and was able to mount the hub. There's a little gap between the hub and the horn button but I can fill that in with a ABS printed part (once I can get one of my two printers working again).

GOT IT OPEN Thanks for the help and support.

Should I keep trying the pry bar then, or go with a can opener?

So far, no luck with tripping the hood release, too much engine and transmission in the way. If I just undo the bolts on the front of the hood, wouldn't the latch at the rear of the hood keep me from removing it?