New rebuilt 401 overheating...

Discussion in ''Da Nailhead' started by 1966buickgs, Apr 8, 2016.

  1. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Is it overheating just idling? Stop and go, highway? When is it overheating? Have you checked the ignition timing? Mechanical and vacuum advance working?
     
  2. CJay

    CJay Supercar owner Staff Member

    And just to be clear, this radiator was an installed beforehand with the old engine and it was running cool and all was fine? This is a new problem? What temp did the old engine run with this radiator?
     
  3. 1966buickgs

    1966buickgs 1966buickgs

    The radiator is a 2 row Griffin universal and was cooling fine before the rebuild.The timing was supposedly set at a shop near me an carb tuned. I have been swamped with work an no time to do it myself and have never set the timing and have never done it before let alone on a newly rebuilt motor so my confidence level was low on doing it myself. I wasted my money cause i don't think the timing is acurate and I don't think they tuned the carb properly either. We have to spray starter fluid just to get it to crank an I shouldn't have to do that. So I did order a fan shroud today so maybe that will help a little but the timing an carb are the main culprits. Of you want something done right you do it yourself but least it is running just can't run it long an definitely can't drive because temp wants to keep going up even while driving. The timing needs to be rechecked an possibly put back a factory radiator back in. Thanks everyone.
     
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    OK, that Griffin radiator is more than up to the task, leave it in. Evaluating the timing is easy with a dial back light. When you are ready, I'll walk you through it. I need to know what distributor you are using. The part number is on the circumference below the cap parting line. Also, get a vacuum gauge on it to see what it is pulling at idle in Park. What carburetor are you using?
     
  5. 1966buickgs

    1966buickgs 1966buickgs

    Oh I did spray the inside of radiator out with water. How could this have messed it up?
     
  6. 1966buickgs

    1966buickgs 1966buickgs

    I'm using the factory distributor an factory Carter carburetor.
     
  7. 1966buickgs

    1966buickgs 1966buickgs

    Ok I have a factory distributor an Carter carburetor.
     
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    It may be the factory type of distributor but it may not be the same one the car left the factory with. Lots of parts get changed in 50 years. That can make a difference. Get me the part number. Also, the thermostat can be defective right out of the box. I've also seen them put in backwards, just sayin:grin: If you run the engine with the cap off, you should be able to see when water starts to circulate in the radiator. Correlate that with the temperature on the gauge. What stat are you using, 180?

    Same thing with the carburetor. Part number?
     
  9. 1966buickgs

    1966buickgs 1966buickgs

    The metal tag on the distributor says 11110055 Delco. The carburetor is A7B 4331S Carter AFB.
     
  10. 1966buickgs

    1966buickgs 1966buickgs

    Not sure of the rating of the thermostat I did test it in a boiling pot of water an it opened an I put it back in with the spring side down into the water crossover. Oh I do know the said it was a new thermostat also. Thank you
     
  11. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    OK, 1111055 is a 1966 distributor for the 425 according to my Steven Dove book. It has between 28 and 32* of mechanical advance at 3900 RPM. Initial timing is 2 1/2* BTDC. The vacuum advance should add 14-18* at 16" of vacuum. You need to verify the timing is correct.

    Not sure about the carburetor, but it should be OK.
     
  12. wkillgs

    wkillgs Gold Level Contributor

    That carb is for a 1967 340. Not the best match for a 401.
    Larry, here's post on the AFB numbers:
    http://www.v8buick.com/showthread.php?98044-Carter-AFB-carburetors-assigned-to-Buick

    If you have a IR temperature gun, you can check the temperature of the exhaust ports at the cylinder head. That will at least tell you if it's running hot due to carb or timing problems. I'll try to get you some numbers on what it should be, I checked mine when I did the initial break-in. One cylinder was running hot due to a missing seal in the power brake booster..... it was adding air to the manifold thru the pb vacuum line.

    Edit: Temp of exhaust manifold at the exit from the head was 447 degrees on most cylinders, and 524 degrees on the one that was running lean.
     
  13. Schurkey

    Schurkey Silver Level contributor

    I have never seen a four-blade fan and fan clutch. Please post a photo.

    You've never said how you've verified that the temp gauge is accurate.

    I think it's a stretch to believe the carb "should be OK". It may be the "correct" carb--or close enough--but that doesn't mean it's functioning properly.

    Doesn't take much of a particle to obstruct tiny fuel passages and make the engine run lean.

    For that matter, the same could be said about the distributor. Just because the number stamping is "correct" doesn't mean that the vacuum advance is still working, or that the point-plate hasn't seized, or that the weights 'n' pivot posts aren't wiped-out.

    I would much rather know whether the part is functioning than what the number-stampings on it are. I am not saying that number-stampings are useless; as it seems he's got a small-block carb on a big block which is unlikely to work well without recalibration.
     
  14. gs66

    gs66 Silver Level contributor

    My nailheads seem to run on the very warm side too. The ones with guages anyway. The one with only the factory idiot lights seems OK, maybe because there's no gauge for me to keep looking at.
     
  15. 1966buickgs

    1966buickgs 1966buickgs

    It has a five blade fan clutch. Rebuilt carburetor. New vacume advance on the distributor,points,cap,spark plugs,and wires. Distributor was not completely rebuilt or recurved and worked fine before the rebuild. The springs seemed fine an it shuttered with no problems an as for the weights I do not know. Thanks for the info, I will eventually get a bigger carb now for sure though. The gauges are a newer sunpro model that were working fine.
     
  16. ttotired

    ttotired Well-Known Member

    Just to be another spoon mixing the soup, lets get back to basics here
    Timing first, especially base timing and do it properly, as in, make sure your valve timing is correct first, then check your ignition timing, once thats confirmed right, then look at the carburetor, does the choke work, does the accelerator pump work?

    I am interested as to why you need "starter fluid" to get it started, all of the above can make the engine require this, as well as vacuum leaks, so, check the vacuum.

    I get concerned when I hear that someone has pressure washed a radiator. They are generally very fragile and its very easy to destroy them with high pressure, you said you washed it inside and out, I would be looking for folded over tubes inside the tanks and the other thing is if the radiator corroded internally while it was waiting for the engine.

    You might want to consider getting professional help on this because if you have any warranty on this engine (who built it) and there is something wrong with it, the builder might not take your word for it (wont want to take theirs for it either really, but it will be on paper)
     
  17. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Thanks, couldn't find that number in my sources.

    Yes, I said i wasn't sure about the carburetor. And yes, I've said several times that the mechanical advance and vacuum advance have to be looked at to verify whether they are working or not.
     
  18. schlepcar

    schlepcar Gold Level Contributor

    It still sounds like something is fundamentally WRONG. Even if the carb is not set up,or timing....This thing should not be reaching 220 even if you pulled off two plug wires. Are we asking the wrong questions? How does it run? Is the oil clean after warmup? It sounds like it is getting this hot just idling,so I must wonder how high does it have to idle to run? Are you able to keep the temp down by running cold water into rad with hose?
     
  19. 1966buickgs

    1966buickgs 1966buickgs

    The oil looks good new break in oil. The car will not start without a spray or two of starter fluid but once running it idles high then put into gear the idle goes down low. The temperature continues to go up.
     
  20. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    X2. I wonder how long it takes to get to 220*.
     

Share This Page