Slammed tailpipe, dropped muffler, vapor locked then idiot light came on...

Wierd progression of events today. We took the Wildcat to a local show here in Glendale, AZ today (for the ride, not to show yet). Ran fine to the event. On the way out I went out the exit "ramp" a little too fast to beat traffic and slammed the pipes/muffler on the hump. Tore out driver's side hanger/tail pipe. Fortunately we were only a couple miles from home. I pulled over and used a spare pulley belt to tie up the pipe. This caused it to angle over towards the frame.

We made it home and just as we were going up the driveway the car cut out. Would not start. Some loud popping and split second running but no go. Could not get it up the driveway. So I parked it in the street and thinking "vapor lock" let it sit during lunch. Started right up after an hour in the "shade". (Its still 104 here on our shaded patio!)

Have not gotten under it (too hot on driveway) but am thinking the tied up pipes angled too close to fuel line causing the vapor lock? Car is not overheating, even in the current heat.

Now the idiot light that says "Stop Engine" is flashing. It is located on the dash right next to the Engine Temp light. Question-Is this the Oil Pressure light? This thing has never lit up before and I can't see how the progression of events would cause this?

Thanks for any suggestions!

 

Well, my assumption that the exhaust pipe was too close to the fuel line was incorrect. Not even close. So that leaves what I think is vapor lock a mystery? It was very hot today, but the fuel lines don't run close to anything except the power steering pump/lines and we really had not driven that far and with minimal turns. I guess I'll have to try and replicate the situation and then slap a fuel pressure guage on it to see if it truly is vapor lock?
Anyone know if that "Stop Engine" light is the oil light? Probably a stupid question (again) but where is the oil pressure sender located on the engine? I have a set of up under dash gauges still in the package in the garage left over from another project. Might put those in to sub for the idiot light...

 

Im not sure but I think your cat has the same insterment cluster my 68 Riv. does. Right side of speedo on either side of the fuel gage theres GEN light and OIL light. I installed an 3 gage pod on my A piller becouse I didnt trust the lights. See pic.

 

Thanks guys. If the "Stop Engine" light is a temp sensor then it must be a short as the engine was off for an hour before I restarted it after what I think was the "vapor lock". It had not over heated or lost any fluid when it was shut off either. The light started flashing immediately upon startup. This is more encouraging than low oil pressure!

Would an electic fuel pump (and regulator) keep a vapor lock situation from happening again if that is what it is? I'd love to purchase Jim's billet mechanical unit but the price is a little out of my league right now. The car does have a return line from the mechanical pump already. I just don't see any point where the line goes near a hot area other than the steering pump. It was 104 that day but it was a very short trip...The car ran fine after sitting for an hour. The carb is a brand new Edelbrock with less than 50 miles on it. New filter, full tank, etc... Weird how it made it all the way home and then stopped right as the car went UP the driveway.

 

You've just discovered on of the biggest problems with the Buick big block; its propensity to vapour lock. The "stop engine" light is associated with the temp sensor, so check the sensor, chances are it's shot. An electric fuel pump will help, if your old pump is a little weak. However I would tend to think the problem is fuel boiling out of the fuel bowl caused by excessive heat under the carb. If your heat riser was dinged up, or is stuck closed, it'll also cause a lot of heat to go to the carb. Chances are your heat riser is sticking, if not, then check the steel carb spacer plate, if it has burned through, then that could be why you're getting a lot of heat to the carb. If the car doesn't have one on it, then I'd seriously think about putting one back in. If these conditions exist, then an electric fuel pump or any pump for that matter won't help.

My experience with BBB is that they hate heat, and they run hot to begin with. All of my late 60's Wildcats used to cook and vapour-lock on very hot days regardless of what I did. The only way around it is to get a heavy duty cooling system installed or detune the motor, but then you wind up with a dog that'll fall flat on its face and give crappy mileage. From what I can remember, the cooling systems in those engines wasn't the best to begin with, and Buick never really got it cured until about 1971 or 72. I had the best success with an A/C cooling system (4 row rad) and the bigger water pump.

 

Thanks for all the info. I'll go through your list. It does have the AC system and it has never overheated, but it probably needs help. Especially when the temp hits over 100!
It does have a spacer. Aluminum I think. Would a synthetic spacer provide better protection for the carb?
What water pump do you recommend?
What about either a single or dual electric fan(s)? The previous owner put an aftermarket aluminum fan on it but then butchered the fan shroud to make it fit. Been thinking of going electric to clean it up. Thanks again.

 

I you metioned that it wasn't getting hot even in those Arizona temps, but I would still get rid of that aftermarket aluminum fan and go with the stock setup with a HD fan clutch and stock blade. It's hot here, too. At least you have a "dry heat" as they call it. We have the humidity but hot is hot no matter how you slice it. I put an electric fan in mine and the only thing I gained is a few horsepower, but the current draw was too much when the a/c and everything else is on so I'm putting the clutch fan back on tomorrow.

 

Electric fuel pumps will prevent vapor lock if they are mounted close to the fuel tank. They will pull "cool" gas from the tank and pressurize it to pump fuel hard enough to collapse the heat caused bubbles leading to vapor lock. They also provide a positive flow when starting the engine overcoming the empty fuel bowl syndrome. The one caution with installing an electric pump is to have a shutdown switch inline with it so in the event of an accident, etc. it will be shut down and not continue pumping fuel with the engine not running.

 

Thanks for the added info. So putting the fuel pump after the mechanical pump or maybe right before it would not help?

Would a synthetic spacer help keep the carb cooler than an aluminum one? I might be mistaken, but I thought I saw one advertised somewhere...

Thanks again for all of the suggestions. Would be a bummer not to be able to drive this thing in the summer here!

 

on that car you need a good working 4core or equivelant rad, fan shroud, 7 blade fan or good electrics,,,, but first pressure ck the system,,,to make sure it is holding pressure...and correct if it aint....then install a new robertshaw thermostat of 180 deg...
heat is the thing that will kill an engine, quicker than anything,,, when the factories bumped the temps up in the late 60's to please the government, the general consensus was that they were running them too hot... true you pick up a little milage, and that is minimal, but at what cost... the excess heat destroys the wires, hoses, carb gaskets, pops head gaskets, and the power falls off, ect...our cars spend 99% of their time sitting, not running,,, so pollution is not a factor any more.... no need to run that hot... oil is not good enough any more now that the factories have taken the zinc out of it... no, heat is not good....

 

Electric fuel pumps push fuel rather than pull it like a mechanical pump so you would need to mount an electric pump back by the tank, preferably with the inlet lower than the fuel level. A word of caution with electric fuel pumps is they are noisy. I have a Holley Blue pump on mine and I finally got so tired of hearing the constant drone of that pump that I put the mechanical pump back on it. I still have the electric pump on the car but wired it to a toggle switch just in case I ever need it. Might be an option for you if you are having a vapor lock problem.

 

Excellent advice. Thank you. I remember from our Ice Racing Cold Stone Creamery Ice Cream Truck build (Jesse James Monster Garage) that the fuel pump was pretty loud. I think I read somewhere that the mechanical can be left on even with the electric fuel pump? Sounds like what you are saying, correct?

 

The mechanical pump would only be there for decoration, it would not do anything. Hook it up in line with an electric and there's going to be a fire. You have to do either one or the other, but not both. The steel plate up by the carb was made from a type of tin, and it's sole purpose was to prevent an electrolytic reaction from destroying the aluminum on the carb base. You could use a synthetic, but make sure it's rated for heat.

Check your oil pressure, check your cooling system, get rid of the aftermarket fan and put the original clutch fan back on. The water pump for the AC model was about the best one could get. Figure out a way to set up an over-flow can for coolant like a modern car has. These early big-blocks loved to blow coolant out all over the road because they were always running within a degree of boiling. Make sure your pressure cap is in good working order and pressures up to at least 16 psi. And like Doc suggests, run it cooler, go with a 160 degree thermostat and higher pressures in the rad. I'd try and avoid overly heavy motor oils as well, and use ZDDP additive.

Hope this helps...

 

Thanks guys. Unfortunately, the stock fan went away with the last owner so I may have to do some searching. Really leaning toward electricals though. Any CFM info on the stock fans vs a pair or single electrical fans? THis would also save having to track down a stock fan shroud...

The 1" spacer/adaptor on there now is aftermarket. The last owner put it on there when he removed the Rochester and went with a Holley 600. I left the spacer and put on the Edelbrock. Strange thing is that the fuel boil or vapor lock never happened with the 600cfm, just now with the 800cfm? This should not have affected anything though since we were almost at an idle when it died.

It has an overflow tank now. Going to put a temp guage on there though it has never shown any indication of overheating in the past. Will also go with the thermostat. 160 or 180?

Does the AC Radiator have an advantage over the Non AC version? A new 4 core radiator costs a pretty penny...Hoping that the stock radiator is enough if we are not using the AC right now. Most of the AC parts are removed waiting for repair. In fact, I am looking for a non AC Alternator bracket to use until the big bulky bracket needs to go back on with the AC.

Thanks again for all of the suggestions.

 

While searching for the Robert Shaw thermostat I came across the Stewart web site. (EMP/Stewart-Robert Shaw Thermostats) EMP sold by Summit for $15.95 for a 160 degree. (Stewart site also has it for sale for $3 less but the shipping charge is about $10 more than Summit)
http://www.stewartcomponents.com/tech_tips/Tech_Tips_4.htm

The info below comes from the site. Good info.
Coolant
UNEQUIVOCALLY WATER IS THE BEST COOLANT! We recommend using a corrosion inhibitor comparable to Prestone Super Anti-Rust when using pure water. If freezing is a concern, use the minimum amount of antifreeze required for your climate. Stewart Components has extensively tested all of the popular "magic" cooling system additives, and found that none work better than water. In fact, some additives have been found to swell the water pumps seals and contribute to pump failures.

In static cooling situations, such as quenching metal during heat treating, softening agents (sometimes referred to as water wetting agents) will allow the water to cool the quenched part more evenly and quickly. The part will cool quicker, and the water will heat up faster. However, an automotive cooling system is not static. In fact, the velocities inside a cooling system are comparable to a fire hose forcing coolant against the walls of the engine's water jackets. If the softening agents actually aided in cooling the engine, the temperature of the coolant as it exited the engine would have to be higher because it would have absorbed more heat.


Fans
Electric fans have improved tremendously in recent years, in both quality and reliability. Electric fans now outperform mechanical fans in nearly every application, except towing and dirt oval track racing.

When using a mechanical fan, a properly designed shroud must be used. Most mechanical fans are not designed for high RPM use: they can have serious vibrations problems, due to air turbulence, when run over 6,500 RPM. This is a turbulence problem, not a balance problem, and will destroy the water pump and components in front of it. The large fans preferred by dirt oval track racers can consume up to 18 horsepower at 6,500 RPM. Do NOT run a mechanical fan that is any larger than required for the application.

Flex fans are a poor design for performance applications. They move less air at higher RPM, and only consume a fraction less power than standard fixed pitch fans.

Clutch-style fans are inconsistent and we do not recommend their use for any application, if possible.
Radiators
Thicker radiators do have slightly more airflow resistance than thinner radiators but the difference is minimal. A 4" radiator has only approximately 10% more airflow resistance than a 2" radiator.

In past years, hot rodders and racers would sometimes install a thicker radiator and actually notice decreased cooling. They erroneously came to the conclusion that the air could not flow adequately through the thick radiator, and therefore became fully heat-saturated before exiting the rear of the radiator core. The actual explanation for the decreased cooling was not the air flow, but the coolant flow. The older radiators used the narrow tube design with larger cross section. Coolant must flow through a radiator tube at a velocity adequate to create turbulence.

The turbulence allows the water in the center of the tube to be forced against the outside of the tube, which allows for better thermal transfer between the coolant and the tube surface. The coolant velocity actually decreases, and subsequently its ability to create the required turbulence, in direct relation to the increase in thickness. If the thickness of the core is doubled, the coolant velocity is halved. Modern radiators, using wide tubes and less cross section area, require less velocity to achieve optimum thermal transfer. The older radiators benefited from baffling inside the tanks and forcing the coolant through a serpentine configuration. This increased velocity and thus the required turbulence was restored.

Radiators with a higher number of fins will cool better than a comparable radiator with less fins, assuming it is clean. However, a higher fin count is very difficult to keep clean. Determining the best compromise depends on the actual conditions of operation.

Double pass radiators require 16x more pressure to flow the same volume of coolant through them, as compared to a single pass radiator. Triple pass radiators require 64x more pressure to maintain the same volume. Automotive water pumps are a centrifugal design, not positive displacement, so with a double pass radiator, the pressure is doubled and flow is reduced by approximately 33%. Modern radiator designs, using wide/thin cross sections tubes, seldom benefit from multiple pass configurations. The decrease in flow caused by multiple passes offsets any benefits of a high-flow water pump.

Gross flow radiators are superior to upright radiators because the radiator cap is positioned on the low pressure (suction) side of the system. This prevents the pressure created by a high-flow water pump from forcing coolant past the radiator cap at high RPM. As mentioned in the radiator cap section, an upright radiator should be equipped with radiator cap with the highest pressure rating recommended by the manufacturer. The system will still force coolant past the cap at sustained high RPM.


External PlumbingStreet-driven vehicles seldom need auxiliary plumbing or coolant lines. SBC race engines with aluminum cylinder heads usually require extensive external plumbing to address two design problems:


<TABLE id=table75 border=0 cellSpacing=1 cellPadding=1 width="100%"><TBODY><TR><TD vAlign=top width="4%" align=right>1.</TD><TD width="96%">Aluminum heads have much smaller water jackets than cast-iron heads because the external dimensions are similar, but the ports are usually larger, the deck is thicker, and the material near the rocker stands is thicker, all leaving less area in the water jackets. This decreased internal area leaves less area in the water jackets.</TD></TR><TR><TD vAlign=top width="4%" align=right>2.</TD><TD width="96%">The siamese center exhaust ports are a design compromise that presents additional problems when aluminum heads are used. The area near the center exhaust valves is thicker, thus allowing providing less surface area for cooling.</TD></TR></TBODY></TABLE>

We recommend installing a pair of 10 AN lines that connect the rear of the aluminum cylinder heads to the thermostat housing crossover in the front. This step will help offset the smaller water jackets. A pair of -10AN lines connecting the pressure side of the water pump with the area in the center of the cylinder head (just below the exhaust ports) will offset the lack of surface area due to the extra material.
Thermostats & Restrictors[FONT=Verdana, Arial, Helvetica, sans-serif]
We strongly recommend [FONT=Verdana, Arial, Helvetica, sans-serif]NEVER[/FONT][FONT=Verdana, Arial, Helvetica, sans-serif]</B>[/FONT][FONT=Verdana, Arial, Helvetica, sans-serif] using a restrictor: they decrease coolant flow and ultimately inhibit cooling.

For applications requiring a thermostat to keep the engine at operating temperature, we recommend using a Stewart/Robertshaw high flow thermostat. This thermostat does not restrict flow when open. The Stewart/ Robertshaw thermostat enhances the performance of the cooling system, using any style of water pump. However, the Stewart Stage 1 high-flow water pump may require this thermostat to operate properly, and Stewart Stage 2, 3, and 4 water pumps simply will NOT operate with a regular thermostat because these pumps have no internal bypasses.
[/FONT] <TABLE id=table75 border=0 cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD height=2 vAlign=top width="72%" align=left>[FONT=Verdana, Arial, Helvetica, sans-serif]Stewart further modifies its thermostat by machining three 3/16" bypass holes directly in the poppet valve, which allows some coolant to bypass the thermostat even when closed. This modification does result in the engine taking slightly longer to reach operating temperature in cold weather, but it allows the thermostat to function properly when using a high flow water pump at high engine RPM.[/FONT]</TD><TD height=2 vAlign=top width="28%" align=middle></TD></TR></TBODY></TABLE>[FONT=Verdana, Arial, Helvetica, sans-serif]A common misconception is that if coolant flows too quickly through the system, that it will not have time to cool properly. However the cooling system is a closed loop, so if you are keeping the coolant in the radiator longer to allow it to cool, you are also allowing it to stay in the engine longer, which increases coolant temperatures. Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures.

Years ago, cars used low pressure radiator caps with upright-style radiators. At high RPM, the water pump pressure would overcome the radiator cap's rating and force coolant out, resulting in an overheated engine. Many enthusiasts mistakenly believed that these situations were caused because the coolant was flowing through the radiator so quickly, that it did not have time to cool. Using restrictors or slowing water pump speed prevented the coolant from being forced out, and allowed the engine to run cooler. However, cars built in the past thirty years have used cross flow radiators that position the radiator cap on the low pressure (suction) side of the system. This type of system does not subject the radiator cap to pressure from the water pump, so it benefits from maximizing coolant flow, not restricting it.
[/FONT]</SPAN>[/FONT]

 

The good news is that following your advice I was able to get what he says is the stock fan (with clutch) from the last owner. I still need to either repair or get another shroud. Big portion cut out of the top... This route will save my having to get a bigger alternator for electric fans... (current alt is 60amp 1 wire)

Is there a way to test a fan clutch? After reading some of the other fan threads I saw a couple that mentioned that some clutches did not work properly? Anybody know at what temp the stock clutch is supposed to engage?

Thanks again for all of the great input!

 

I went with a duel Electric fan set up(< for Sale) on my Riv. 1, I thought it was a cool after market look,2, I thought that it would cool better than stock fan and free up some HP and better milage, 3 I always have wanted to be different. well 1,2 and 3 cost me about 500$ and I am back to the stock fan and shroud. The electric fans pulled so much power my alt wouldnt keep up. I bought a chrome 95 amp Alt. Killed the Battery, I bought a yellow top optama battery. It sucks and wont charge right. when the Battery charge drops to low nothing in the car works and the fans run to slow to cool the engine. End result. Dead Battery on a hot overheated car. Lesson learned. Back to the stock fan, Taking the optima battery back. now I have another piece of chrome under the hood to keep polished.