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Dave WM

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Posts posted by Dave WM

    1. water temp switch on my 75 Cali car was for the EGR system. It is disabled during warm up with an electrically controlled vacuum source. I have had a few of both the thermotime as well as the temp switch. Most of the used ones did not function. I presume corrosion was the factor. The temp switch in my case was a NC below 140f IIRC, I ended up making my own with an old housing and a new temp controlled reed style switch, epoxied into place. I think the main problem I had finding a new temp switch was most were NO at below 140f and would close once the engine would warm up. Not what the EGR wanted.

    I think on others the temp switch had to do with switching the dual coil distributer pickups for different advance one full temp was achieved.

  1. for me it was going back to steel rims and new tires. I never tried the new tires on the slotted alum mags, so it may have been just a defect in the old tires. I have the orig struts (the stock rebuildable ones) on the front and some non gas filled carts on the back. I have ZERO vibration at any speeds. My guess is the tires, I may go back to the slotted mags if I lose another wheel cover, I have thrown 2 now and its getting aggravating. 

  2. one thing I wish I had done when I had mine apart would have been to put the main shaft on some V block when it was stripped down, then take some run out measurements. 

    I don't recall if the FSM has a spec on that, but I have done some research on this and now know that they can be bent, and straightened if needed by a machine shop. they just lay it up in a jig and apply pressure, sounds easy but I presume its not as easy as it sound. 

  3. 8 hours ago, ckurtz2 said:

    Lol, love to see the discussion, nice to learn something new:) 

    Replaced plugs (gapped to 0.04), cylinder 5 came back to life. Ran waaay better, but it would still surge a little bit and miss. So I think that my whole electrical problem was fixed. Ended up being a loose plug at the dropping resistor, and spark plugs. Go figure, sometimes the most complicated of issues are quite simple. The new plugs are starting to already carbon foul again. So my plan is to replace the connections at the WT sensor.

         The vacuum sits at around 15.5hg so I think having it vacuum tested will be a very smart thing to do. And if it doesn't climb to something better, than another solution will have to be figured out. I think the main reason those plugs are fouling is due to the fuel pressure being too high (low vacuum means the fuel pressure climbs significantly:(. Maybe an interesting solution will be a fuel rail with a different fuel pressure regulator. Who knows at this point, time will tell. 


    vacuum will be effected by warm vs cold engine and ign timing as well. 

    • Like 1
  4. 10 hours ago, Zed Head said:

    You guys are reminding me of something I see on some of these youtube repair videos.  You can see proper voltage but it's best to put a load on the circuit to make sure the current is there.  The guys that seem to know make up their own test lights with a headlight bulb.  A cruddy connection might show proper voltage, especially with today's digital meters.  But it disappears when a load is on.

    and I have a video for that!



    • Agree 1
  5. I too agree with ZH and an air leak at an injector o ring. I suggest you seal up the intake at the entrance to the AFM and smoke it out using the brake vacuum port. You dont even need an expensive smoke machine, just a cheap cigar and puff the smoke in. Look for the smoke. I found I had missed an o ring this way. I can not recall the problems I was having with the car at the time, or if they were the same as you are currently having. But it was def a running issue.

    • Like 1
  6. This is where a "color tune" plug  would come in real handy, lets you see inside the combustion chamber while its running. If they were not so darn expensive I would have 6 and use them anytime I was diag a problem with fuel mix/spark.  With one you can observe the problem cylinder then compare to a know good cylinder. Two would be easier just look at them and compare. All 6 is overkill but would be cool just to see if how the mix is on all at the same time. 

    • Like 1
  7. 12 hours ago, siteunseen said:

    If you don't want to say I understand but where did those new bolts come from?

    Inquiring minds want to know.

    really dont recall, smallish vendor datsun specialist. sells the whole shabang, including the hard to find long skinny one. If I run across it I will post up. it was a few years ago. pretty reasonable too IIRC. oh and they were NOT stainless either. 

    • Like 1
  8. I used thread seal. I too never had a leak until I used BRAND NEW bolts, then even with anti-seize, it leaked.


    So Z Kars, were the bolts new or used (with residue of some kind on them) enquiring mind would like to know.

    • Like 1
  9. mov would not work for me.

    That being said hope you dont break off the skinny bolt that goes back to the block. they frequently seize there and snap off. If that happens you will need to pull the front cover making it a much bigger job. I would try what ever trick you know to see if you can remove them with out breaking. 

  10. fyi I went back and looked at the fsm, the device in line between the overflow tank and the canister is indeed a check valve so you should check by injecting smoke at the fuel nozzel not the tube at the canister. You prob inject smoke at the fuel filler, should confirm that the smoke goes to tje canister line, if smokes then clamp it off and add some pressure to the tank (again at the filler neck), I would not go over just a few psi though. OR if you are pretty sure you found it I guess you could just go for a retest. 

  11. well you will have to build pressure in the tank before very high resistance, you should not go overboard, just a few PSI really. the line from the canister could be blocked (mine was with rust on the metal line under the car) completely. This presents as a whoosh of compressed vapors when you open the fuel cap on a hot day. There is a considerable about of restriction from on that line from the canister to the overflow tank. IIRC there is a small restricter right at the end of the rubber tube near the canister that chokes down the opening, and there is a special designed device near the over flow tank as well. IF you can fill the tank with with out any issues when filling up with gas, and you get no whoosh when opening the tank on a hot day, then you likely have venting. the question is does the line from the canister to the overflow tank work as it should. Smoking out seems the only way to find a gross leak. Low pressure and smoke should find it.


  12. 2 hours ago, 240zadmire said:

    This car was “restored” by me, so all hoses and bolts were connected or tighten something 😉


    im trying to build a smoke machine.  Saw some one build on YouTube using bicycle pump…. Very effective.


    if I were to disconnect the hose that connected to the charcoal and pump smoke to that rubber hose, is that the same as from the gas filler neck? 

    I think so, but it seems more logical to use the same approach as the tech did, since its that test that will count. IIRC the restriction device works both ways, but more restriction on way than the other. So I would stick with the hose in the filler neck, with a damp rag sealing it up while the same canister hose clamped off as done during the test. 

    I must say i am impressed by the through testing done in your state.

  13. you may want to take look under car, rear pass side, look to make sure the rubber line from the overflow tank is even hooked up. On my car the hard line was rusted closed so to keep the tank from over pressurized the rubber hose had been removed (venting directly into the air). Maybe someone did the same "fix" to yours...

    IF the hard line is rusted closed you may want to look into removing just the bottom most section, that is likely where the rust is. Much easier to just patch in a replacement there than trying to replace the entire hard line.

  14. ok yes if he clamped the correct hose and it did not hold, then you have a problem. I would start by smoking out the system, you should be able to feed back thru that same hose and look for smoke. If i recall correctly you can back feed that line. However a better solution to duplicate his test would be to clamp the same hose an rig up a way to smoke from the filler since that is what he did. maybe just a smoke hose and some damp rags to fill around the opening.

    fyi the correct canister hose would be the one that goes to a hard line and heads back to the tank.

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