I had an off-and-on problem at the last race, when I would lose two
cylinders. No change took place in fuel pressure. After a whole day of
screwing around, I took both float chamber tops off and ran the car,
watching the level of the fuel in the float chambers. The fuel level in the
rear one went down significantly slower than the front one. on disassembly
of the rear carb I found that when the tube from the float chamber to the
jet was pushed through the rubber sealing ring, it sliced off a little flap
of rubber that would occasionally swing down and block that tube. You may
have something equally goofy going on.
At 09:20 PM 6/6/2004, you wrote:
>I raced in the SCCA National at Lime Rock this past weekend. First
>time that I have run a 30 lap race here, which is about 45 miles. I
>got down to a 1:02.311 during the race, which is my fastest time at
>LRP, but still 2 seconds off of the front running RX7s. The car
>handled great on the 9" slicks - like it was on rails! I sure missed
>the Weber carbs that I can run with the vintage SCCA group. I
>finished 5th in class (EP) out of 8 cars and 10th overall out of 29
>cars. I am happy with that for my first time at this level of
>competition. My car needs to loose 300 pounds to be at the minimum
>SCCA weight, but not sure that I can get that much off of it. Still
>waiting for some fiberglass rear fenders from England.
>
>Anyway, with 3 laps to go, I started loosing power right after the
>downhill. This is the last turn before the main straight. It is a
>flatout righthand turn at the bottom of a hill. I am doing about 6000
>rpm in 4th gear here and wide-open-throttle (WOT). This is after 2
>other righthand turns, connected by short straights, which were also
>at WOT. My first thought is that I was running low on fuel, since
>this was the longest that I ever went, but the car finished with 1/4
>tank, which is 2 gallons - should be enough. I have an 8 gallon cell
>with 2 pick-ups - one in each rear corner, and 2 fuel pumps. I lost
>one overall position due to this problem and could not catch another
>car that was in front - oh well.
>
>I was using SU H6 carbs, which feed from a Holly pressure regulator
>set to 3#s. I am using viton tipped float needle jets.
>
>The loss of power was like I lost 2 cylinders. It did not missfire,
>but just lost power. When this was happening, the fuel pressure was
>going up to 4 #s. I was thinking that a float was hanging up, but
>not sure why the pressure was going up like that - maybe the regulator
>is on its was out? There was not sign of fuel in the overflow/vent
>hoses, but they may have all dryed out by the time that I got back to
>the paddock. I did have the tubes T into one hose that I ran out down
>by the frame - not sure that was such a great idea and will run
>separate lines for each. Any ideas of what is going on here from
>the group? Joe(B)
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