Quote:
Originally Posted by Dick Boneske
The power valve would come into play if you're cruising at high speeds with only the center carb. I would like to see how your mech. linkage is set up--the pictures only show the passenger side.
With the '65 "J" center carb lever, you have a choice of two positions for the top stud that operates the slotted rod. The top hole int the lever gives you more throttle opening with the center carb before the ends engage. IMO, that position gives you the best driveability. If using the lower hole, center carb opening before the secondaries begin to open is really limited.
It's amazing to me that elimination of the power valve has so little effect on overall driveability. This very likely is the key to eliminating the bucking problem so many Tripowers have at light loads/low speeds. I've "fixed" several of these, but only after making a lot of changes which always included changing the power valve spring pressure.
FWIW, I checked a dozen power valve rods for spring pressure last night. The weakest spring required 100 grams to compress, the stongest 180 grams. Then I checked a dozen power valves for spring pressure (not the rod, but the power valve itself). They all require less than 35 grams to open. The ones with the large (.073") holes take about 15 grams to open. The ones with the smaller holes (about .060") have stiffer springs. Nearly all of the Tripower center carbs I've worked on use the power valve with larger holes. That tells me the 8 coils cut off the power valve rod spring with the resulting 75 grams of pressure still comfortably will open the power valve.
I'm going to set one up for about 50 grams of pressure and see what it does for my setup--and my wife's setup. They both exhibit some bucking at low speeds in third or fourth gears at light loads.
Thank you very much for your efforts and postings. Your efforts to troubleshoot your Tripower and your postings are really thought-provoking and helpful. What's that expression---So many Tripowers and so little time!!!!!
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Dick,
Your info about the power valve is very interesting. If your info on the power valve hole sizes are correct, I think I found a problem.
I decided to reintroduce the PV spring today, now that I'm somewhat happy with the center main jets. No matter which spring I tried I still had a lean area during heavy part throttle acceleration. Very aggravating!
So, I pulled the PV out for inspection and measured the holes. The holes in mine are about .060". If this is the incorrect PV, this would explain a lot. I don't remember is this was the PV that was in this carb, when I bought the car, or if I installed a new one when I rebuilt the carbs several years ago. I don't think a new PV came with the rebuild kits but, I honestly don't remember.
What's your thoughts on this?
Thanks!
Eric