[Schurkey]

Originally Posted by MidnightAuto

I back my car into the garage. When its colder out, say 50 and below, i can back down the grade with no issue. When its warmer out, as i begin down the grade, the tripower starts acting up, sputtering, and usually the car conks out and I have to glide the rest of the way down the hill with no motor.

What would cause the carb to act this way, only when its warmer out?

1. Not enough air in the rear air-shocks.

2. Drive forward into the garage.

[Bill Hanlon]

[QUOTE=pfilean;6233501]I thought that in road work the "percent grade" was a way of using the tangent of the slope angle as a way stating how steep it is. That would make a 45 degree angle a 100 percent grade. /QUOTE]

Exactly.

[MidnightAuto]

I have not messed around with the choke, but will take a look. I did just figure out a new driving strategy that seems to be working and having me not lose power steering going backwards down a hill. Glide down the hill in neutral with one foot on brake, one foot on gas at 1500 RPM. So far this has been keeping the motor from conking out.

[KEN CROCIE]

Although tripower secondaries have no idle circuit , it is easy to have them spill fuel out of the boosters if angled enough.
I'm a tripower user since "62"

[george kujanski]

Short story...I once rented a Chevette, manual trans in San Fran. I was going uphill on Nob Hill one day and there was a stop sign near the top! Really excercised the manual trans driving skills that day!

george

[Jonsie]

[QUOTE=aceaceca;6233553]You haven't lived till you have driven some of those streets in SF. They are scary big time.If you are ever out here go try them in a rental car if you have not driven.

Agreed, first time perpendicular parking on these streets, you'd swear the car is in danger of "tipping over"

[Tom Vaught]

Originally Posted by GTO3DEUCES

Totally agree, the end carbs don’t have anything to do with idle, as they only dump gas. There’s no fuel ‘circuit’ on them. The center carb does everything that’s important.

"There’s no fuel ‘circuit’ on them." TOTALLY Not True, Why have fuel lines running to them then?????

The carbs may not have a IDLE circuit but they DO HAVE all of the other circuits with the most obvious visual circuits being the two Accelerator Pumps and linkage to activate them on the end carbs. Then you have the Nozzle Clusters, etc, etc, etc.

Tom V.

[Gastiresandoil]

Originally Posted by george kujanski

Short story...I once rented a Chevette, manual trans in San Fran. I was going uphill on Nob Hill one day and there was a stop sign near the top! Really excercised the manual trans driving skills that day!

george

I did the same thing in my GTO on the opposite side to the Lombard Street twisty section. If you have not been there, it is a hill that goes straight up to a stop sign, plateaus, and then you go down the twisty section on the other side of the plateau. Not very fun when attempting to crawl a cars length at a time to get up to the stop sign with a manual transmission car.

[Region Warrior]

Originally Posted by MidnightAuto

I was not good in science. Am sure that is faulting me now. Here is the setup. I have a long driveway to my garage. the last 100 feet is 45 degree grade down into the garage. I back my car into the garage. When its colder out, say 50 and below, i can back down the grade with no issue. When its warmer out, as i begin down the grade, the tripower starts acting up, sputtering, and usually the car conks out and I have to glide the rest of the way down the hill with no motor.

What would cause the carb to act this way, only when its warmer out?

That's a head scratcher for sure.
Other then that, idles and accelerates fine when warm?

[TRADERMIKE 2012]

Originally Posted by Region Warrior

That's a head scratcher for sure.
Other then that, idles and accelerates fine when warm?

MIKES ANSWER TO THIS: I have a Tri- power for about 7 years down here in sunny flat Florida. I was Informed over the Internet to lower the Float level to keep the vehicle from flooding after Heat Soak, especially down here.

I blocked off the cross over on the Intake gaskets. I Invented a Phenolic to go over the valley pan and under the Intake Manifold. I took a Hollow Diamond metal barbecue type steel and placed the heat resistant material under the metal and ran out of that very expensive material that was supposed to be glued under the intake manifold. Then I added some Fiberglass Woven Roven HD material over the Metal Diamond Steel, taped it together with metal duct Tape and Walla it worked for me.
The cool air passes under the intake manifold and the center Carb. will not get Heat soak anymore. You may need a Choke. Buy the Electric one mentioned. I added an additional electric pusher fan to the front of the Radiator.

I Installed a Low-Pressure Electric Fuel Pump and installed it at the rear of the Vehicle at the lowest level of the Fuel tank. I doubled up the Fuel lines by Teeing off the Fuel pump using the old Canister line because it was already routed in my direction. This almost doubles the volume of Fuel forward. The Return line is operating and I have 3-4 lbs pressure only to the carbs. Use no more pressure on Tri-Power units. I have a Fuel pressure gauge Inline up front near my Remote Oil Filter that is also in the air stream. I use a Trans. cooler, an oil cooler and a Power Steering cooler. Of course, the Radiator is also a Heat Exchanger for the fluid to the Transmission. Also, I just installed an additional Trans. Remote Filter and Temp. gauge.

I use a Gear Vendors Unit behind my TH 400 with a shift kit. I use the B+M Shifter with the GV button on the handle. Then, I Tightened the Tolerance in the water pump. Installed that special thermostat with 3 holes in it also. The biggest difference was ripping out the stock standard Temperature clutch and replacing it with a Heavy-duty Truck unit. I use the stock 7 Blade fan also. First, I worked ass backward but I learned so much over the Internet from you people. I made a side kick from a Used Heater core and ran a 110 AC Current Homemade Squirrel cage fan across that and put the Inverter in the Trunk with my dual batteries and Sudbury switch.

The water goes through the Heater core in the Vehicle then to the side kick (that I manufactured from a used core) out front in the air stream, cooled and back into the water pump where it mixes. Then, through the Thermostat with 3 bypass holes and out to the Radiator. When you pull the Cap, you can see the water Jump across the top of the fins Internally, plus water flows like its shot from a Garden Hose from the mod.

I did to the water pump previously. I have wrapped the Carb. Bowls In insulation and put phenolics under the carbs. Added a Metal plate (made of Aluminum) that was originally to block off the 2 outer Carbs. when testing the middle one. I then converted all 3 Aluminum plates to Phenolics by insulating them and installing them over the front bolts of each Carb. and forward under each Float Bowl. Since the holes were drilled into these plates anyway made the job that much faster. I told the man that makes the Aluminum plates as tools that cover the Intake Manifold Bores that the Carbs. sit on. How I use them and he now has a second reason to produce and sell this product as a Phenolic. You simply sneak them in when you rebuild your Carbs. next time. No heat gets to my Fuel to cause Percolation or Vapor Lock, I have beaten the Heat Soak Mystery that has Plagued me for so long. I wrapped my fuel lines in insulation also.

The AC added another 30 F degrees to the Heat under the Hood. At one time I pulled the Snorkel's out of the Formula Hood that I run on my 1979 Pontiac TA, to let air in because of the Headers additional Heat. Then I wrapped the Headers in Header Wrap and they are Ceramic coated internally to. I have since returned the Snorkel's to their rightful home. I am now in the process of removing some of the insulation wraps previously installed over various parts on this Engine to see if this Vehicle can operate without the Heat soak returning.

If the Excess Heat reappears back on with the Wraps that were doing their job. The Temperature activated clutch fan should simply have to work a little harder as I remove the ugly wraps that I have installed to maintain normal operating Temperatures over the years. I also bought one of those Lazor Temp. gauges to measure everywhere so I know all. The radiator Cap even uses a Temp. gauge on it.

I bought a proper water sending unit to match the 1979 Rally gauges. All this I learned by reading your posts. Giving it back. P.S. in your case I would build a Level Ramp to park on to. P.S.S. I Remember that people said to buy Aluminum Heads or lower the compression or this or that. I run 10.75 Factory "D"- Port 670 Heads on Rec 90 Fuel, all day long and I never get Percolation or Vapor lock any more. Heat Soak we can't help, when you stop the car, it is inevitable. Rec 90 Fuel Has no Alcohol in it. The Unleaded Fuel without Alcohol boils at a Higher Temperature than the Unleaded Fuel that contains 10 percent Alcohol by volume.

By using any Alcohol in the Fuel on these old cars is wrong. I drive a 1967 428 ci Pontiac Engine In a 1979 Pontiac Firebird TA on 2021 Pump Fuel and It works for me. Persistence beats Resistance. One more big thing to do is add Air Induction to your Hood. Most Pontiacs had some version of it started-just complete the job. I Installed a Trans Am Scoop to my Formula Hood facing the wind shield like the racers do to capture the High Pressure there. By "not" pulling the Hot air from under the Hood, cool air Temps. get to the Carbs. and makes a big difference.

You're "not" getting into Percolation or Vapor Lock issues. Plus, you pick up lots of HP. My Hood (at one time) when I opened it to shop for example would be too hot. When I stopped anywhere here in Florida it would be so Hot under the Hood that the "F" fitting used on my 1966 Tri-power system melted. I still open my Hood when I stop but that is to show the motor off.

I still like to keep the under the hood temps down so the car starts easier and I will always leave the Hood up because the AC compressor heats the Engine compartment a lot. One more thing I made sure that my Carbs. have all the parts that the Factory used like the screen in the Float Bowl area, AC Valve Hot Idle Compensator, Main well Inserts with the holes in them against percolation etc... New Power Piston and Valve. Proper Gaskets too. In closing I run a Mini Starter with lots of Torque. I also use Watter Wetter in the Block that Helps because of the heat built up around the pistons. We used the proper amount of Anti-freeze with distilled water. Mike out.

[TRADERMIKE 2012]

One last thing I am Installing the Exhaust Shields that the Factory used over my Headers, If I can get them to fit. This may reduce the Under the Hood Temperature to. I would think that part of your problem to begin with is Under the Hood Temp. Get your car to sit on a level place to begin with and see what happens the next time you go to drive it. Take the un-levelness out of the equation all together.

That is the way my roommate who is helping me thinks. We make one move at a time so we know exactly what fixes what. Otherwise use Process of elimination. A simple rebuild of all three Carbs. at once is the next step. When were your Carbs. last completely disassembled anyway. I have my carbs for 7-8 years and I go through them Offen because I want to be at Max performance. I buffed them out shinny last time but I did not clear over them like I did on the Motorcycle and they now are dull and the Motorcycle ones look like the day I rebuilt them.

Now that I am painting the inside of my Engine Compartment and installing wire loom over the wires from Painless Performance these details count. First, I had to get this second-hand project running, then I had to build the wire harness from scratch under the hood anyway. Then we modified the wire harness as we went during testing and tunning. Now some 8 years later were ready to do the final wire loom over this Engine Harness.

Between soldering and shrink wrap we are hard wiring every junction for durability. We are not Interested in Plug ends that can fail in time. I bought new Gaskets for the Carbs. and there next to be done. I am thinking of the finish. Do I buff and shine them and then clear this time or do I media blast and paint with Eastwood products? Mike out.

[TRADERMIKE 2012]

Originally Posted by Gastiresandoil

I did the same thing in my GTO on the opposite side to the Lombard Street twisty section. If you have not been there, it is a hill that goes straight up to a stop sign, plateaus, and then you go down the twisty section on the other side of the plateau. Not very fun when attempting to crawl a cars length at a time to get up to the stop sign with a manual transmission car.

MIKE ANSWER TO THIS: george kujanski Are you the person that wrote the modification on the water pump on Pontiacs that I read 7-8 years ago? If you, are It worked in my car well.

[george kujanski]

Glad to hear it....you owe me a buck

Credit where credit is due.....the same mod appears in Appendix "E" of Jim hand's book "How to build max performance Pontiac V8's. it seems we independently discovered the same mod...I'm happy to share the Nobel prize for Pontiac mods with him.

george

[TRADERMIKE 2012]

Originally Posted by george kujanski

Glad to hear it....you owe me a buck

Credit where credit is due.....the same mod appears in Appendix "E" of Jim hand's book "How to build max performance Pontiac V8's. it seems we independently discovered the same mod...I'm happy to share the Nobel prize for Pontiac mods with him.

george

MIKES ANSWER TO THIS: I can't believe that I remembered your name from 7-8 years ago. All that I've learned and explained on this site is because of people like you, I just hope I will be of some good use to somebody building a Vehicle. All I can do is thank the both of you and confirm that the tightening up of the tolerances works.

For those of you who don't know what we are talking about here it is: See John Wallace, on his site he posts "The way to increase water flow in a Pontiac Water pump" by modifying the plate within the Pump itself to a very tight Tolerances so that the water pressure is much stronger and you won't have to buy one of those expensive new or rebuilt ones over the Internet.

Mine works so well that when I remove the Radiator Cap you can see the water jump over the top of the inner core fins. I have a 4 core Radiator and 7 blade stock Fan. I Added the (Special) Hayden, I think?

Thermostat with the 3 holes in it to bypass all the time. I also use a Heavy-Duty Truck Type Temperature controlled clutch fan to keep the Engine cool. I added one pusher fan in front of the Radiator as not to block it off completely...

[TRADERMIKE 2012]

Originally Posted by pfilean

I thought that in road work the "percent grade" was a way of using the tangent of the slope angle as a way stating how steep it is. That would make a 45 degree angle a 100 percent grade. And if you ever had to drive one that steep you would be wishing for a carb off an old acrobatic airplane.

MIKES ANSWER TO THIS: I thought that in road work the "percent grade" was a way of using the tangent of the slope angle as a way stating how steep it is. That would make a 45 degree angle a 100 percent grade. Mikes answer: Think Rise over Run, so 100 feet line on the "X" axis and 45 feet on the "Y" axis, is the known factor. Now, draw a line out from that intersection were (0,0) is to the (+, +) Quadrant for example: would be drawing a line @ a 45-degree angle to the right. Now, bisect that line and open up the circle until you meet both (X, Y) line and snap your circle and that's done (in Auto Cad- say) Now, were the 45-degree line intersects the Circle edge is the Tangent and that is the same Bisecting line. That would be a 90-degree Perpendicular that is equal to the Tangent point. So, you called that Point/degree angle 100 percent Grade. I just learned something. Thank you. I would think that 180-degree line is Zero Grade then? Note, I can draw what I said better than I can explain it in words. Just trying to keep up with you people.