Looks like you read too much internet. After 34 years of buicks, head porting, engine building, building buicks in most cases I can look at a problem like the OP has and be pretty successful at seeing the problem at hand ie: I know that the pulley combo is wrong from the factory on his car so that is the place to start. As far as your operating temps, todays fuel injected engine run high temps around 205* because of emissions etc. Cup cars run 220* Drag cars use coolant chillers to try and start @ 45*-50* Run those high temps on my BBB's and your warranty is done. for a street car 175*-190* max. At the track, as cold as possible. Your theme seems to be all about more is better as in this statement: more of everything: "will require more of everything: volume, air flow, and coolant flow." If you remove the T-stat the coolant can travel too fast across the bores etc there for not removing as much BTU's as a slower moving coolant so there is a sweet spot that needs to be found there. I got to say, yesterday I read another thread on head porting on 350 heads and same deal there other then talking points for optic's, there wasn't much in that thread that was correct/applicable there also. Here is a quote from RM: My fellow back-page columnist Warren Johnson has described the chemistry of internal combustion in detail. An engine is really a vessel that contains the energy released by chemical reactions. Petroleum is the remains of prehistoric plants, plankton and protozoa. Eons ago, these organisms banked the suns energy in their cells. We harvest this stored energy to heat our homes, cook our dinners and propel our race cars. As W.J. noted, gasoline molecules release energy when they break down into water and carbon dioxide lots of energy. Every gallon of gasoline contains roughly 114,000 British Thermal Units (BTU) of heating value, enough energy to raise the temperature of 1,000 pounds of water by 140 degrees. Where does this energy go? Roughly 25 percent is converted to useful work, five percent is used to overcome the engines internal friction and five percent is radiated directly into the air. The largest portion, about 35 percent, goes out the tailpipes as exhaust heat. The remaining 30 percent is heat that must be dissipated by the engines cooling and lubrication systems. I just want to help the fellow at the top of the page fix his issue, this banter is why I don't post here much anymore.
I agree with Chris, I would start with later AC crank and WP pulleys and the TA pump, their advertising states that the pump is specifically designed to flow more water at low engine speeds, to prevent overheating at idle. Living on the face of the sun in Phoenix, it's very likely that Mike and his dad, as well as now his Kids, have faced every possible overheat scenario. I do believe his yellow GSX had the hot at idle issue, and the pump alone fixed it. Plenty of these cars were marginal at best when new. JW
As you know Jim from being around these BBB's your whole life these engines also are prone to head gasket failure because of the surface area to bolt ratio, I believe that is why you almost never see the original steel head gaskets in them. Pretty much every BBB my father had back in the 70's and early 80s had head gasket failures. Buick suggested a 190 or 195 stats and mix that with lack of head bolts and bad pulley combo's it finds the weak spot in a hurry on a hot summer day.
Ya, I recall changing the head gaskets with my Dad on the family 74 Lesabre Luxus in about 1982 or so.. We had 4 different 70-74 full size Buicks growing up, and they all ran hot in the summer with the AC on.. never had a temp gauge, but you sure could smell them, and hear them making all kinds of noise cooling down when you got home. I strongly advocate a composition gasket for every BBB street build, I have used the cometic mulit-layer steel ones in the past on high compression applications, and seen the evidence of combustion leakage into the valley (right were the bolt is "missing") at 12 o'clock. I also am not a fan of the factory stamped steel stuff, they went away from them for a reason, I think I recall seeing the service bulletin. TA has done a lot of work in the head gasket area over the years, hard to go wrong with the TA1723C gasket, just make sure you follow the re-torque guidelines. JW
Wow, that's a lot to read. What I'm hoping to get is someone who has access to the 2 groove 67-70 pulley (1375146). I'd like to get a measurement of what the axial offset is between the waterpump mounting surface and the pulley grooves. If one of the grooves has the same offset as the single groove pulley (1375141), than it would be swappable and give the same pulley ratio as the 71-73 Non-AC cars which is what my engine would have had originally. I'd like to actually do a couple of things. I agree that I don't like the no-shroud set up, but I also don't like the oversized pully issue. With time I'd like to address both.
I have a wall covered in pulleys and I am not far from you and we have Cole out in BC that you can help with pulleys but I will assure you that the small ID crank pulley and large ID water pump pulley are the place to start here those pulleys were a mistake from the factory. What don't you like about going to the Large crank pulley and small ID W/P? You can still keep the old under drive pulleys to put back on later date.
I am interested in improving the pulley ratio. Going to a PN 1375146 WP pulley would reduce the pulley size from 6-3/4" to 5-5/8". That would be a 20% increase in water pump and fan speed and match the initial ratio of a non-A/C 71 which is what the motor's from. That would then keep the same alternator speed I currently have. The only confirmation I would need is if one of the belt grooves lines up with the single groove of the current pulley I have (1375141). If it doesn't, then I'd have to do both the WP and the crank pulley and get the alternator bracket too.
I know this is an old post but I just got a '69 GS400 Stage 1 and am chasing my tail with an overheating problem. Re. changing the pulleys, does anyone have definitive part numbers for them? Are they even still available? Sounds like a simple thing to try first off. I'm also thinking of Flowkooler water pump, Derale dual fans for 4000 cfm flow. Looking into the rad, I seem to have flow although it doesn't seem too great... A heavy dribble rather than a steady flow that I'm used to in my Chevys. And I'm not sure how to differentiate between a water pump issue as opposed to a blocked radiator issue. I checked the face of the radiator with a temp. gun and it seems equal top to bottom and has a definite drop driver's side to passenger side. Any comments/suggestions on original style vs. race style (aluminum) radiators? Any and ALL comments are appreciated... Thanks! P.S. First thing I did was to change to a 160 degree thermostat.
Can you take pictures of your upper and lower pulleys, fan, shroud etc? When is it over heating, at idling around town, highway or both? What is the initial and total timing?
Installing a lower-temperature thermostat does nothing productive if the original thermostat wasn't the problem. Initial, total, AND VACUUM ADVANCE AMOUNT, including inches of vacuum to begin vacuum advance, and amount of vacuum for full vacuum advance. There's a hundred things that lead to overheating; including semi-unusual stuff like a missing hood-to-cowl rubber seal, cowl-induction hoods that aren't sealed to the air cleaner, missing OEM air dams under the radiator support, aftermarket air dams ahead of the radiator support, lean fuel mixture, dragging brakes, and incorrect pulley ratio. Then there's the totally-usual stuff like plugged coolant tubes in the radiator, corroded radiator air fins, damaged water pump impeller, dreck, garf, and garfelderfarb in the water jacket, failed fan clutch, slipping belts, backwards-rotation fan or water pump, etc. Stuff you don't really need to be concerned with: Excess anti-freeze in the coolant (I have sometimes run as much as 80% antifreeze and have zero problem with overheating) and lack of expensive "water-wetter"-type product in the coolant mix. If someone tells you that you need to drill holes in the thermostat to "let air out" of the cooling system of any vehicle that has a functioning OEM coolant bypass system, or tells you that the coolant has to be slowed-down so it spends more time in the radiator, ignore their other cooling system advice.
I had a overheating issue with my 70 455. Once the carb was gone through......problem solved. Something to consider. Cheers, Mike
O.K., just went outside and started her up. Temp went smoothly to 160 and continued to 210 when I shut her off. She was sitting there idling with the exception of driving 25 feet, turning around and backing up 25 feet to park her. While watching the radiator with the cap off and running to look at the temp gauge inside the passenger compartment. Total time- 10-15 mins. tops. Flow seemed minimal judging by the fact that the fluid was right to the level of the overflow and the surface of the fluid was smooth. Don’t know how else to describe it. But if the unknown temp. thermostat was, in fact, not opening, it would make a huge difference. That’s why I changed it. I changed the oil, plugs and checked the Ignitor ignition. I haven’t done that yet, didn’t think of it. That’s why I ask here. Thanks! She’s all stock, as far as spoilers and such are concerned. I would consider the seals, etc. but she even overheats sitting with the hood open. I believe the fuel mix to be close to good since, when I changed and labeled the old plugs, they all looked similar and just lightly tanned. Not sure about the pulley sizes, I’ll have to measure them tomorrow. What I’m not sure about is the “usual” stuff: plugged radiator or failing pump? Fins are perfect, no bending over at all but some of the tubes sealed off by the seller? Freshly painted radiator and a multitude of other issues (wiring, steering components, etc.) make me wonder. Belts are good, not sure about the fan clutch though. Everyone has their own theory on how to check them. At idle it pushes a massive amount of air past the engine though. Shroud setup is good. Nice and tight to the radiator, fan is just about half and half, steep pitch and 7 blades. How could the water pump be rotating backwards?!? I’m not questioning you, I’ve just never heard of such a thing. It’s turning in the same direction as the crank. (I did well on my ASVABs). Antifreeze is just shy of 50/50. I mixed a touch more water than 50%. When I need to get wetter, I hit my ex-partner’s bar. Cavitation IS an issue, hence the hole-drilling idea, and that’s why I never start up a fresh motor with a thermostat in place. I considered that but the system seems to be full when I checked it after it’s very brief run down the road. WHEN I can see flow it seems to be steady, but not super strong... Also, no thermostat can be as much of a detriment as spoilers and such in that the coolant CAN flow too quickly, hence restrictor plates in race cars that don’t run thermostats. That's certainly not the problem though. If anything, it's the opposite. So… I’m back to square one. How do I further check the water pump or do I check the radiator first? If I’m going to bring the radiator to the rad shop, it’ll cost me half the price of a new radiator and still might not be the problem. It’s also a 48 year old radiator. Do I just spring for a new one? Do I just spring for the new water pump? It, too, is old and could probably use replacement anyway. I’m going to sleep on it and wait for, hopefully, more input from you guys. Thanks again!
A 48 year old radiator even if it isn't plugged, the tubes can be worn very thin and the cooling fins could be corroded away from the very thin tubes causing your problems? 48 years old I think it may be time to think about re-coring the radiator or replacing it. Being that old isn't a matter if it will fail, its a matter of when will it fail? GL Derek
Don't over think it, start with the basic's. 9 times out of 10 the few things I listed are the problem, if you get some decent pic's I will tell you if you have a under driver crank pulley, or too big of a water pump pulley and yes a 160* stat will help the system get a bit of a head start. 400/430's have thicker cylinder walls etc unlike thin 455's that are thinner and can contribute to the heat so that is not your case. If you take pictures of your upper and lower Take pictures of pulleys, fan, shroud etc? When is it over heating, at idling around town, highway or both? That will tell us if the rad/flow is holding you back, or if it cools off on the high way rule it out. What is the initial and total timing? If its too retarded it will run hotter. Don't care about vacuum advance much at this point, 95% of the engines I build never use vacuum advance as it can cause detonation under part throttle depending on carb, compression etc but if you are chasing fuel mileage you can deal with that later but more often then not its a pain in the ass. Most of the time I stick the hood seal on the shelf because I see no need to trap hot air under the hood to raise ambient air temperature to only kill hp. If you don't want to post pictures here PM me and I will give you my e-mail addy.
On the contrary, please let us think this through... Here's an example of "thinking". WHICH WAY is the air traveling at that missing "hood seal"? Is it hot air getting "out" of the underhood area, or is it "cold" (ambient) air going into the underhood area? Hint: Think about Cowl Induction hoods--which way is the air traveling? Hint: Where is the air intake for the vehicle's heater/air conditioning system? Yes, the hood seal keeps high-pressure COLD air OUT of the engine compartment, which means that if COLD air is leaking into the engine compartment, filling it from from the rear, you're NOT pulling as much cold air in from the front, through the radiator...making the engine run HOTTER. This is exactly why all OEM cowl induction systems sealed the incoming "cold" air to the air cleaner. They didn't want to reduce the airflow through the radiator by pressurizing the engine compartment from the high-pressure area at the base of the windshield. This is why practically every vehicle uses the high-pressure area at the base of the windshield to "ram" air through the heater core or A/C evaporator.
But the cowl area air pressure is kind of low with the car idling, hood open and me reaching under the hood...
Generally speaking, two things cause overheating. Lack of airflow or lack of waterflow both thru the rad. The fan should move a LOT of air which is easy to check. Next, if waterflow is slow, which it sounds like it is, then a plugged or corroded rad is the issue. It could be age or someone could have used some Stopleak which will do it too. But when the stat is open, there should be water moving swiftly thru the radiator. If not, well, there you have it.
If it were me, I'd do exactly as Gary posted. Certainly makes sense to me with the combination of parts you are currently using.
