Ist drive with the IDA's

Rick · 08-24-07, 12:14 AM

1st drive with the Webers
After much tuning , inquiring, asking, fretting and applying I finally got the "tune" where I felt comfortable to take it out on the road with the IDA's. After reading about all the possible transition problems and considering the potential need for the "3rd Transition hole" I was relieved to find that as of now the car and carbs seem to flow seamlessly from 1500-4000 without ANY hickups or hesitancy. I only drove it for about 20 minute and went down to visit a friend who wanted to see the final install. Unfortunately the 2 piece upper radiator hose began to slide off of the metal tubing piece that forms the joint for the 2 pieces of hose and I began to lose the coolant after I stopped. While we had it idling one of the floats appeared to stick and raw fuel began to get dumped so I shut it off. It continued to drip for a couple of minutes.
Have any of you had a float stick like this? What caused it? I have fuel filters inside each carb and in the line prior to the mechanical pump and 2.5# constant pressure. Looking for a answer for that (????)
Also.......
While the bypass hose is eliminated with the dual outlet manifold I am using and the thermostat that Ingelese markets which fits inside the upper hose (I drilled several (10?) small holes) around the perimiter in an attempt to allow a small amount of flow and create a means for any steam to escape but I wonder if the thermostat (1 1/2" diameter) which has a smaller center opening could be causing the increased pressure build up.
No air filters............
Thanks
__________________
Rick

Ban Low Performance Drivers, Not High Performance Cars!

BigB98 · 08-24-07, 01:43 AM

Quote:

Originally Posted by Rick

1st drive with the Webers
While we had it idling one of the floats appeared to stick and raw fuel began to get dumped so I shut it off. It continued to drip for a couple of minutes.
Have any of you had a float stick like this? What caused it?

Rick, I had this very same problem yesterday! Never happened before and I hope it never happens again. I ended up pulling the top of the carb off and found the bowl full and the float...well, floating....Pulled the tang on the float up a bit, put the top on, flipped the fuel pump on and pulled the top again to start adjusting the float....Repeated the process until it was proper again.

I have a tendancy to turn off the pump before I actually stop the car and run a bit of the gas out of the bowl. I am "thinking" that the bowl started filling up when I turned on the pump, the valve that the tang hits somehow stuck and then the pressure of the float trying to float bent the tang further and just kept it wide open. That's bad news.

I really don't know why it happened, but I don't want that to happen again, so I hope someone can help the both of us on that.

Rick · 08-24-07, 02:24 AM

I am using a mechanical pump monitored at 2.5 lbs. But it was still dumpng fuel after it was shut off. It dribbled untill it looked like there was a pool 1/4" deep on both throttle plates. I sure will be changing the oil more often.
I noticed too that while "kiting" the carbs that the hourglass (for lack of a better description) shape of the floats allowed them to wedge against the accelerator pump bore in the float bowl. This was at the limits of travel.

Jac Mac · 08-24-07, 03:17 AM

Rick & B98,

When checking your float settings make sure that the limit tang that prevents the float dropping TOO far down in the empty bowl is set correctly( this is the other 'tang' that controls the stroke of the float). In the case of turning the pump off prior to shutdown this can catch you out if the needle valve drops too far & 'cocks' in its bore. Rick your particular problem may be the float 'dragging or catching' on the side of the float/bowl.

Hold fire on the 'other tang' folks , I was looking at the DCOE dwgs, my mistake, dont see this feature on IDA dwgs.

Jac Mac

Rick · 08-25-07, 02:30 AM

The new floats that I received in the carb kits DO have a tang on them unlike the nice floats that were already in the carbs. My error (?) was that I thought it was intended to press against the wall of the float bowl and limit upward travel DUH! After closer inspection I think it is intended to contact the side of the installed needle & seat assembly and limit float DROP (?) That makes more sense, since the contact between the other tang on the float and the needle valve would limit it's upward travel when it closes off fuel flow. Make sense? Comments............

Jac Mac · 08-25-07, 02:52 AM

Quote:

Originally Posted by Rick

The new floats that I received in the carb kits DO have a tang on them unlike the nice floats that were already in the carbs. My error (?) was that I thought it was intended to press against the wall of the float bowl and limit upward travel DUH! After closer inspection I think it is intended to contact the side of the installed needle & seat assembly and limit float DROP (?) That makes more sense, since the contact between the other tang on the float and the needle valve would limit it's upward travel when it closes off fuel flow. Make sense? Comments............

If thats the case Rick and that tang was preventing the NV& Seat from closing properly then you might have that problem solved-hopefully.
Jac Mac

Dean Lampe · 08-25-07, 10:18 AM

The cool thing about Weber's is that they are simple carbs. In this case it has to be Float hieght, fuel pressure or NV& s problems. It sounds like it might be float realted in this case. I hope you have your problem solved.

Bill D · 08-25-07, 11:00 AM

Along thse lines of IDA float anomalies, I'm using Carter pumps rated at 7PSI. Is that going to be a problem?

Dean Lampe · 08-25-07, 02:25 PM

Bill, you are going to need to regulate the pressure down to 3 psi max. There are no exception. If you have a return line, use a bypass regulator for much greater flow or use a low pressure holley regulator if you don't have a return line.

Bill D · 08-25-07, 03:40 PM

Thanks Dean. No return line so I'll get a regulator that doesn't require one like this Holley (from 1 to 7 PSI)

Bill

Rick · 08-26-07, 01:19 AM

They make 2 different springs for that type regulator. Search Summit, Jegg or your local speed shop. Spring is about $4.50.

Neal · 08-26-07, 12:13 PM

I had issues keeping the pressure down to 3 psi with the Carter pump / Holley regulator setup. In the end I put in a return line. Works great.

Canuk40 · 08-27-07, 10:31 AM

Hi Rick,

I had to read your description of the problem and events leading to it a couple of times. All the comments thus far are sound advice.

If I can ad one more, I believe your 1/4 inch of fuel sitting on the throttle plates was caused by fuel boiling in the float bowls. The engine was off, fuel pressure stopped and fuel is still coming.

I've seen carb body temperatures over 160f idling or after shut down due to heat soak. Something to keep an eye on, also a good reason for the heat shield around the carbs. Was it one of the carbs closest to the headers that was percolating?

Hope that helps

Cheers