Cammed 430 running hot

Discussion in 'Wet behind the ears??' started by Jbgs430, Jul 15, 2021.

  1. Jbgs430

    Jbgs430 Member

    Hello gents I’m
    New to the forum my father purchased a 67 Buick gs 400. It has a 430 in it from a 67 wildcat the heads were re done it has an aluminum intake manifold Rochester 4 barrel, headers and a mild cam in it. My question is the car constantly runs hot 240-250 degrees. It also has an aluminum radiator installed and a 16o thermostat. Any suggestions to get it to run cooler? Electric fan would prob work but it’s not really solving the problem. Only other thing we can think of is a high flow water pump. BTW car starts fine when hot so we ruled out timing.
  2. Bens99gtp

    Bens99gtp Well-Known Member

    I would be wondering how well the pump is flowing.

    There are major differences in flow rate and cooling capacity of radiators. Just because its aluminum doesn't mean its better
    69GS430/TKX likes this.
  3. 455monte

    455monte Well-Known Member

    Check for
    Timing too low
    Block/heads corroded plugged up with rust crud
    Fan shroud?
    Fan clutch wore out?
    Infared thermometer on hoses and thermostat housing to verify gauge is actually correct should be 1st step.
    Timing cover severe corrosion where pump impeller turns causing cavitation.
    67s have small radiators so low speed idling and cruising needs a high cfm fan and healthy shroud to maximize radiator air flow to keep engine temps down.
    Kind of a scattered write up for u but im half asleep lol.
    I spent months testing different fans with a anemometer checking cfm at idle and playing with the timing curve to keep mine cool in long traffic patterns with the ac running.
    69GS430/TKX likes this.
  4. Jbgs430

    Jbgs430 Member

    There is a larger fan in it now but it’s not a clutch fan. The info red thermometer is my plan for this weekend. The mechanical guage reads high and the temp light come on in the dash. Chances of both being bad are slim but I will shoot it with the infored this weekend and check back in.
  5. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    If you drive fast does it cool down?
    Brian Albrecht likes this.
  6. Jbgs430

    Jbgs430 Member

    Yes if it sits idling or really slow speeds the temp climbs right up
  7. techg8

    techg8 The BS GS

    Lean carburetor will heat things up too.

    I'd look at the fan clutch first
    69GS430/TKX likes this.
  8. DaWildcat

    DaWildcat Platinum Level Contributor

    I'd still have a look at ignition timing, including a potential bad vacuum advance canister. Can you share timing as it is now? With the vac advance can unplugged and the vac hose plugged, that includes initial, mechanical advance as RPM rises and again idle with vac advance plugged in.

  9. Jbgs430

    Jbgs430 Member

    I did not check timing yet, I do plan on doing that soon. The only reason I didn’t yet is because when it hot it has no issue at all starting right back up. The vacuum advance comes off of the intake manifold so it’s advancing at idle. Is that the correct place for these cars our should the vacuum advance be be pulled off the base of the carburetor?
  10. TrunkMonkey

    TrunkMonkey Well-Known Member

    Typically, manifold vacuum is higher and pulls in more advance than ported (carb).

    Can help smooth idle (if surging or hunting is an issue and not a a result of vacuum leak) with more radical cam and give a ltlle more vacuum for braking on boosted brakes.

    Depending on vacuum advance and springs, sometimes manifold vacuum can cause hunting and unsteady idle by pulling and then dropping vacuum advance as rpm increases then engine goes lean and rpm drops timing retards, fuke gets fat, vacuum increases, timing increases, etc.

    Similar symtoms caused by two different conditions and why you might hear conflicting "solutions" or opinions.

    Try both, make notes of everything and only make one change at a time and note each change and effects.

    Knowing you have a proper baseline on all the tune points, ie. plugs, initial, total, when vacuum and mechanical advance comes in and is full in fir each, carb settings correct, no vac or exhaust leaks, are all correct before changing vacuum source will help you determine which is better for your engine.
  11. LARRY70GS

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

    Just because it starts right up hot does not tell you much. With the stock distributor, initial timing was very low, 2 1/2* BTDC. That is retarded timing. If it idles at that timing, that will heat it up all by itself. The vacuum advance will advance the timing so that it is running between 16 and 20* IF it hooked to manifold vacuum, and IF it is in fact working. You need to check that with a timing light. A quick check of the vacuum advance can be done without a light. Just unhook it with the engine running. The idle RPM should drop noticeably and then increase when you reconnect the vacuum line. There should be a hiss when you unhook the line if it is connected to manifold vacuum.

    What kind of aluminum radiator are you running. Some of them are worse than the stock radiator. If it has more than 2 rows, it might be one of them.

    Does the car have a fan shroud?
  12. Jbgs430

    Jbgs430 Member

    The car was purchased 2 weeks ago and im pretty sure we didn’t get the whole story from the seller. Not sure how many cores are in the radiator it’s pretty large, why is it that they are worse than the stock radiator? It does have a fan shroud with. Larger size spacer which puts the fan pretty close to the radiator. Is it a possibility that the fan could be to far in the shroud?
  13. LARRY70GS

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

    I didn't say it was worse, I said "some of them are". I explain that in this thread,

    It helps if the fan blades are halfway into the shroud. Maybe a clutch fan would be a better choice.

    The timing is very important. Do you have a timing light?
  14. avmechanic

    avmechanic Active Member

    I have had a similar issue. No problem cooling when moving but temps would climb at idle. I had been chasing cooling issues at idle on my 66' with transplanted 455 for years. Last year I installed a new Aluminum rad with 2 row 1.25" tubes. While it did run cooler I still have had issues with cooling at idle especially in traffic. I noticed that I had almost no coolant flow at idle. After some research I found out that BB Buicks can have this issue when mixing parts from different applications. A/C Buicks used a large crank pulley with a small Water pump pulley to overdrive the water pump by 31%. The A/C cars used a 5 vane pump because it turned faster than the Non A/C cars. This was also to increase the fan speed for the clutch fan that was used. On an A/C car they had a 7 3/8" Crank Pulley driving a 5 5/8" Water Pump. 800 RPM idle would equal 1049 RPM for the Water Pump. On the non A/C car they used a 6 vane pump that was under driven. They had a 6 1/4" Crank Pulley driving a 6 3/4" Water Pump Pulley with a fixed blade steel fan. This would be 7% under driven for the Water Pump and Fan. 800 RPM idle would only equal 741 RPM for the Water Pump. Finding A/C pulleys or using a high flow pump from TA or Flowcooler were looking like my only options for more coolant flow at idle. I ended up purchasing a Flowkooler pump. It is a very nice high quality piece. Turns out I had a 5 vane pump installed which would have made the cooling issue even worse. With the pulleys I have it should have had a 6 vane. I just installed a FlowKooler pump and it made a huge difference. You can see significant flow at idle now. Temps are in control and much cooler now. I have posted a picture of the two OEM pumps. You can also find lots of info in the link below about the pulleys and pumps. If you are having issues with temp at idle on your BB Buick consider this info. I have a fixed pitch 18" fan out of a big Cadillac sedan deville along with a pusher electric fan on a thermostat. Temps are holding right on 180 now pretty much no matter what. That is running a 180 thermostat. Sounds like you have a plan to check a few things but I think you should consider water pump and water flow. Good luck with it.
    Greg FlowKooler pump Impeller.jpg IMG_7642.jpg IMG_7647.jpg
  15. Chi-Town67

    Chi-Town67 Gold Level Contributor

    ^^^Lots of good info there^^^
  16. Quick Buick

    Quick Buick Arlington Wa

    Posting a few pic's of the TA water pump. VERY NICE... Reminds me of the impeller used on the SBC & BBC marine pump..... The casing differs a bit from a stock buick.. you will see that in the gasket overlay pic.....
    IMG_0633.jpg IMG_0635.jpg IMG_0637.jpg
    FLGS400 and 69GS430/TKX like this.
  17. Jbgs430

    Jbgs430 Member

    Lots of great info there it was very helpful. I did find a 5 blade impeller in the car. I ordered a ta performance high flow pump and that did the trick! My new issue is that the fan belt is rubbing the water pump. This car was an original gs 400 when the 430 was installed I think a 350 was used to salvage the power steering pump and brackets. It appears that it’s a “high mount” style pump It sits up the the top of the valve covers. I believe the 430 pimp and brackets should set the pump lower to fix this. Anyone have any pictures of there set up possibly

    Attached Files:

  18. avmechanic

    avmechanic Active Member

    That 5 blade impeller pump was my problem too. I am glad I mentioned it. The Flow Kooler and TA Pumps are both excellent products that help in this situation a bunch. Since I swapped in my Flow Kooler pump my 66' with a 455 swap has been running nice and cool. I had used the power steering pump and pulleys from the 70' Riviera doner car I grabbed my motor from. The power steering pump was mounted too low and the belt interfered with the steering box. I ended up pivoting the pump on one of the bolts to mount higher and drilled a new hole for one of the other bolts to the head. It has worked great for 25 years. You might have to find the correct power steering pump brackets or do some modification to your current one to lower it down.

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