Fuel System: Fuel pump pressure testing an R2

[IMJ]

[11SecAvanti]

On the R2 clone project here I have 5.5 to 6lbs fuel pressure at the carb ( just an inch) from final connection. No flooding at that level and no fuel return path from the pump (at the moment). Should go up of course on the road but don't have an inside gauge to tell. Check your float height and drop because that can cause it to run out of fuel under load if incorrect. Your fuel pressure is increasing 3.5 to 4 lbs so that indicates the blower is adding that increase to the fuel pump diaphragm side. That increase should fuel support the 3.5 to 4 lbs the carb topside is seeing as boost. If so, then recheck the carb float levels and recheck the jetting and metering rod values. Also a clogged fuel filter can kill the fuel support. But you are seeing fuel pressure at 4k + so volume should be adequate to the carb inlet.

Baseline jetting should be .101 primary and .089 secondaries with a .052 rod end tip. I am trying to get a front end alignment here this week and once that is finished I will be checking mine under load at various rpm. Do you have an A/F gauge on the engine? That is a "must have."

[IMJ]

[rb63gt]

What brand of fuel pumps are u fellows using? Rebuilt originals or the Mopar pumps that are modified??

[drrotor]

And I also have a related problem-- my '64 Daytona R2 clone leaks fuel from the carb with aggressive driving-- fuel seeps out of the carb gasket and the car reeks of fuel, not a safe condition I'm sure. I have the genuine fuel pump, the genuine glass fuel filter, and a Myers-built R2 carb (he built it up from various parts to be correct). I DO NOT have a fuel return line from the filter, and no provision that I'm aware of to get return fuel back into the tank, since it's a standard Daytona tank. Is this why I'm leaking fuel all over the place? Is there a simple way to get a return line back into the tank? Is it really necessary? All my supercharging experience before this is with "draw-through" systems, this is my first car with a "blow-through" system (other than modern F.I. stuff). My wife doesn't like to ride in it because it stinks of raw fuel. Help, anyone?

[IMJ]

The fuel pump that I'm using is a rebuilt, modified Mopar unit. I can't answer the importance of the return fuel line but I've seen people plumb a 1/4" line back on the left side of the frame to the tank and drill and tap a 1/8" pipe fitting into the fuel gauge sending unit at the top of the tank. I would probably check with Myers about the leaking carb. I didn't experience any leaks at the carb. even when I plugged the return line while testing fuel pump output.
regards,
Jay

[Mike]

You should have two gaskets between the top and midsection of the carb. These used to be available at Summit, Five bowl/airhorn gaskets EDL-1499. They should be used with sealer, which goes on a couple of screws as well. See the Avanti manual.
There are a LOT of differences between R! and R2 carbs.
Mike M.

[11SecAvanti]

It should have the fuel return with proper restriction section IMO. This avoids excessive pressures and keeps the fuel cooler. I plan this upgrade. IMJ, I suspect your carb is experiencing fuel shortage due to vapor locking either from carb boiling the fuel in the bowels or fuel turning to vapor in the line between the pump and carb. Its been brutally hot on the east now and the under hood temps get crazy high under the hood.

[Marvin7]

I am going thru troubles with my fuel system also on my 289 engine. I recently cleaned out the filter on the original Carter MO 970 pump (ceramic with glass bowl). I found a ton of rust in the inline filter and the filter on the pump. After cleaning it and reinstalling it with new lines and gasket, my car would idle okay once started but cut out and die sometimes when I gave it the gas. Then it would not start. When I looked at the filter on the pump, I noticed more rust coming in. I am in the process of dropping the tank and getting it cleaned since it sat in my dads barn for about 13 years. I will probably replace all lines involved. My uncle told me that this original pump does not have a lot of pressure comparably, but I have not tested it to see what it actually is.

I would be glad to let you know if I find anything out.

[Chicken Hawk]

And I also have a related problem-- my '64 Daytona R2 clone leaks fuel from the carb with aggressive driving-- fuel seeps out of the carb gasket and the car reeks of fuel, not a safe condition I'm sure. I have the genuine fuel pump, the genuine glass fuel filter, and a Myers-built R2 carb (he built it up from various parts to be correct). I DO NOT have a fuel return line from the filter, and no provision that I'm aware of to get return fuel back into the tank, since it's a standard Daytona tank. Is this why I'm leaking fuel all over the place? Is there a simple way to get a return line back into the tank? Is it really necessary? All my supercharging experience before this is with "draw-through" systems, this is my first car with a "blow-through" system (other than modern F.I. stuff). My wife doesn't like to ride in it because it stinks of raw fuel. Help, anyone?

My guess is the accelerator pump seal is bad and the gas (under boost) is being blown out there. I would doubt not having a return line would cause your problem.

Ted

[SScopelli]

... With the boost line connected to the fuel pump I get 8 1/2-9 psi at 4500 rpms. I imagine with the return line connected to the fuel filter the pressure would be less. With the return line connected, the needle on the gauge fluctuates too much to get an accurate reading...
regards,
Jay

In theory, there should be a 1:1 pressure increase of fuel pressure to boost pressure, which sounds like you are getting that, but you did not note the boost pressure to verify the 1:1 increase ratio..

The pressure fluctuation with the return line connected is a concern.. I'm assuming this is at Idle or 1000 rpm? If it is, it should be steady or fluctuate no more than 1/2 psi.

Did you do a test run with the return line capped of? Did the problem go away? If so, let examine the following:

As Tom noted:

... That increase should fuel support the 3.5 to 4 lbs the carb topside is seeing as boost. If so, then recheck the carb float levels and recheck the jetting and metering rod values. Also a clogged fuel filter can kill the fuel support. But you are seeing fuel pressure at 4k + so volume should be adequate to the carb inlet.

Float drop is important.. That is because the orifice for the return in the fuel filter casting is drilled a certain size. If the float drop is not adequate for the needles to open up, then the path of least resistance for the fuel is via the return line, especially under Boost...

If you examine the fuel filter casting, you will see the orifice is also on the inlet side of the filter. As the filter clogs or if the filtration is to dense, the path of least resistance is again, the return path.

If you are using the paper cartridge replacement, the filtration density is greater than the porous stone ones. And when paper gets wet, the density increase opposed to the stone filter..

The return line is really meant for engine at idle conditions. If the return line is robbing fuel flow under power, that is not good... If you look back to 1963, gasoline was more dense with lead additive. With the removal of lead and the addition of ethanol, PLUS the paper filter issue, the orifice for the return should be reduced.

I believe the original orifice size was 0.060 (#53 drill). I've peened mine close and re-drilled it at at 0.047 (#56 drill). At idle, I still get a considerable flow at idle where the concerned about vapor lock exists.

[studebaker-R2-4-me]

And I also have a related problem-- my '64 Daytona R2 clone leaks fuel from the carb with aggressive driving-- fuel seeps out of the carb gasket and the car reeks of fuel, not a safe condition I'm sure. I have the genuine fuel pump, the genuine glass fuel filter, and a Myers-built R2 carb (he built it up from various parts to be correct). I DO NOT have a fuel return line from the filter, and no provision that I'm aware of to get return fuel back into the tank, since it's a standard Daytona tank. Is this why I'm leaking fuel all over the place? Is there a simple way to get a return line back into the tank? Is it really necessary? All my supercharging experience before this is with "draw-through" systems, this is my first car with a "blow-through" system (other than modern F.I. stuff). My wife doesn't like to ride in it because it stinks of raw fuel. Help, anyone?

You might also be leaking fuel threw the throttle shaft while under pressure. Check for fuel staining around the throttle shaft. Your carburator may need to be rebushed to fix the problem. An expensive tool is available to rebush the shaft, something my R2 carburator is in need of because of the leaking raw fuel and losing supercharger pressure.

http://www.throttleshaftrepair.com

I managed to borrow this tool from my friend who repaired his R2 Carburator, it's on my list of things I have to do before the Pure Stocks this September so I can return the tool to him.


Allen

[kirkdob]

I have dialed in the fuel delivery system on my GH and it works perfectly. Holley Blue electric pump, Aeromotive boost sensing pressure regulator and 3/8 return line plumbed back to the tank. The pressure regulator is as close to the carb as possible and being a return style regulator I have cool fuel circulating right before it enters the carb. I also mounted a fuel pressure gauge and bonnet pressure gauge under the dash inside. I run it at 3.5 psi at idle and it will hit about 9psi at redline. While driving I can see fuel pressure increase at 1 to 1 with bonnet pressure. No more vapor lock, no more fuel starvation. Only gripe I have is the Holley Blue is a noisy pump. I have heard that Edelbrock has a similar spec electric that is much quieter. Once underway I don't hear it, just at start up and idle.