Datsun Roadster Forum-311s.org

I was having a similar issue (well... technically I still am since I haven't installed my fuel tank yet)

I recommend first making sure it's not your fuel pump since you might replace it when it was something else.

Also I've never seen the fuel filter where you have it - I thought it goes before the fuel pump... maybe it's just preference? I'm not sure

Devo, I like your idea there. I actually blew air into the tank as suggested and it pushed the fuel into the glass filter, but fuel is still not reaching the carbs. Nick, as far as the filter location goes, that's where it was when I got the car. I guess it's simple enough to relocate it just before the pump, which I have to assume is bad, and only 13 months old with zero miles on it, and a 12 month warranty. Figures!

I have been using an electric fuel pump located in the exact same place for at least 10 yrs. They are all pretty similar and come under various names. My current one is a Mr. Gasket, 2-4 lbs pressure. Nissan made a nice pump that's a lot more quiet, don't recall what car. I too don't have an inertia switch, which frankly is a bit unsafe should an accident occur as it could continue to push fuel through what could be broken lines. I actually have one from a Ford escort somewhere but have never installed it. Time to look.

I went ahead and ordered another mechanical fuel pump, if I run into the problem again, I'll go with the electric pump. I was able to get it to try to start with starter fluid, and of course it would only run for a moment, but, I noticed it is popping through the carbs. Haven't touched the distributor, so I have to assume I am off on the valve settings. I did the cold setting of .020 in the firing order rotating the crank but failed to go the extra half turn.

Should I let it go until the pump comes in and see if I still have the same problem, or go back through the valve again.

Be sure to check your firing order... 1 3 4 2, counterclockwise as I recall (I don't have a distributor any more). I ran my first engine rebuild with the wrong order while running mikuni carbs. It would idle but snarf through the carbs. Would even go 80mph. Imagine my surprise when the neighbor asked " what's your firing order?" Doh!

Well, it's up and running again, replaced the mechanical fuel pump and got an electric one too, haven't done anything with the electric pump yet.

Miss fire was firing order, had 2 and 3 mixed up, thanks Greg.

I think after setting the timing and adjusting the carbs, I'll be back to a full 96 horse power. LOL Unfortunately, I have a water leak at the filler neck with my homemade gasket, so, I'll need to address that first.

Thanks again for all the help.

Yea! That moment, probably 32 years ago, continues to serve its good purpose!
I was baffled by the engine. I'd run it for miles like that (ya, what a great way to break in my first engine!). My good friend and mechanical engineer (who had built many a performance engine) was there and we couldn't figure it out. What the hell was wrong with these stupid carbs (Mikuni. New to me)? Snarf snarf they would sound. Neighbor decides to go out of his way to come over, and in seconds solves the problem we could not see. Cool! Sometimes it's the obvious stuff...
Glad to pass on the moment! Thanks for the memory prompt!

I finished tuning the carbs, timing is @ 16*, car seems to be running really good with the exception of the cooling system. I had the radiator out, and flushed with the garden hose, I am confident the radiator is in good shape, as it had great water flow.

Prior to removing the head, I had the same problem, tried all the burping procedures, finally ran it up and down the driveway which seemed to clear the air pocket and it started running mid range on the gauge.

Now, after putting it back together, it's running hot again, haven't pulled temps with the gun yet, but just like before. Hot upper hose, cold lower hose, temp gauge pegged at the top. Burped it until I was blue in the face, don't see any bubbles in the expansion tank, squeezing both upper and lower hoses. Drove it around the block to see if I could blow the air pocket out with no luck.

I'm so close, what else should I try.

check the temp sensor wire. Then check with the temp gun for accuracy
Linda

I put my HF temp gun on it, nothing over 180, most of the head is 170, same with the thermostat tower, block is cooler. 180 or so at the temp sender. Top of radiator and hose a170ish, bottom of radiator and bottom hose 70 -80*. Guessing the sender is bad? Gauge slowly creeps up to the top 240 amlost 250*. Also, it is not building any pressure at the expansion tank, so I guess that's good.

The temp senders can go bad but they can be tough to get out. I left mine alone. Be sure there are no breaks in the wire. The VR regulator under the dash has to be good and grounded well to the steering column, may need to be cleaned and sanded.
If nothing is boiling over I think you are good. All caps have good seals, I assume, and no leaks at the watertower?
Maybe someone else will chime in for you
Linda

Just replaced mine for similar behavior (U20).

VR has been converted to solid state, and I had the sender out when I did the head.

Greg, is your gauge reading more accurately now?

Yes, it reads about 10-20 degrees cooler from before it went totally bad (pegged 240. Sometimes it would read normal, but would suddenly go hot).

bossbob wrote: ↑Sat Apr 18, 2020 8:58 pm VR has been converted to solid state, and I had the sender out when I did the head.

Greg, is your gauge reading more accurately now?

Bob, can you elaborate on having the sender out? I just replaced the sender on mine though I haven't run it yet. I have changed senders on other old motors where there is a bulb that is locked to the wall of the opening by corrosion and is very difficult to get out. When I was replacing mine I probed with a long narrow screwdriver to be sure that I didn't have the remains of an old bulb that I was putting the new sender into.