If we are going with VP we can go back to the 55 Buick Dynaflow, which I believe had a mechanical linkage that changed the angle of the blades in the converter. The VP made the Dynaflow a little more respectable back then. Bob H.
The GM bean counters. The switch pitch was more expensive to produce, and most of Buick customers couldn't tell the difference. I read that somewhere.
Why a VP, and why gone in 68 In a word, the nailhead. I asked that question when I got to speak to Cliff Studaker, back in about 2007. Cliff was a design engineer in the Buick Powertrain Division, he started in 1950. Cliff told me that in the 60's the HP wars were heating up, even in the big cars. Because of their unique, flow challenged cylinder heads, this was prompting longer and longer camshaft timing for the 401 and 425 engines. To smooth the operation of both the long cammed Nailhead, as well as the odd-fire V6 introduced in 1962, powertrain engineers proposed to revive the Variable pitch converter theory of operation that the dynaflow trans used. Although this time around it would be electric/hydraulic operation. They had trouble convincing the brass, due to the much higher cost of the converters. But in late 63 there was a rumbling from the service departments throughout the network, that customers were complaining their new cars were running "rough" at stoplights. This of course was the normal operation of the nailhead camshafts. The VP then went into design and testing, and was introduced in the 1965 model year, across the car lines. It was a huge help for the odd-fire V6 of the day. The addition of the VP option, with a special linkage switch that put the converter in high stall at idle, helped considerably, but according to Cliff, it was not quite enough, and in 66 they actually shortened the duration on all but the Super Wildcat camshafts. The new 400/430 engine was introduced in 1967, with it's bigger 15* angle valves and wedge shaped chambers, it's breathing ability was on par with the best GM had to offer at the time, so the need for the VP was not really there anymore. 400/430 camshaft timing was considerably shorter than the earlier nailheads. The V-6 Buick engine was replaced by the Chev 250 straight 6 in 1968. With the nailhead and V-6 gone, the VP was discontinued in 1968. JW
Jim is right on the Nailhead cams. I got one of the last (if not the last) 091 Nailhead cam that had never been run. It does have a bit of a lope at idle. It's nice in my Buchev pickup and pulls very well, but if I were an old geezer in a '65 Electra, I'm not sure that I would be happy with the idle. Oh wait - I am an old geezer!:laugh:
Ya, but your a car guy, who loves the cam music.. The average Buick owner of the day, not so much. Reminds me of a story told to me by fellow board member Tim Hol. His dad was the GM of Stevens Buick in the 60's and 70's. Stevens was one of the largest Buick stores in the Twin Cities at the time. One customer kept bringing their 70 Electra into the service department, complaining of a rough idle. After several visits, where no issues were found, someone bothered to look at the stamp code on the block. Yep, you guessed it, it was an SS engine. And 70 Stage 1 motors do not idle perfectly smooth at 550 rpm. They bought the car back from the customer, if I recall correctly, it was the easiest solution to the issue. Not sure what ever happened to it, it was probably sold on the used car lot, or put into demo service. JW
