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I was stimulated to investigate my Carbs when I continued to accumulate soot around the exhaust after my engine overhaul while the plugs showed the classic tan. I was also not particularly happy with 0-60 times of my 186K mile AT car. Even after a fresh overhaul, I was able to post a 10.9 second 0-60 without over-revving the engine prior to launch. An August 1971 Road & Track review of an AT 240Z said the best 0-60 time they could achieve was 10.4 seconds. This serves as my benchmark. My engine is otherwise completely stock and wouldn't benefit from going to triple DCOEs. Researching Webers, in Pat Braden's HP Book on WEBER CARBURETORS, the author states the magic of Webers is that the can be tuned to fit your needs whether it economy driving or for the race track. It turns out DGVs have seen track service on Escorts and other smaller cars. In addition, Theory of operation for the DGV is almost identical to a 40 DCOE. So I began to wonder just how many people install DGVs accepting the jetting that came with their kits. And just how much more performance could be attained by proper tuning. For those unfamiliar with DGVs, they are two barrel progressive carbs with 32mm and 36mm barrels. Common opinion is that they are sedan carbs with decent fuel economy but definitely non-sporting performance. So I contacted Redline, the US distributor for Genuine Weber (as opposed to Asian knock-offs) for any additional information they might have about proper tuning on out 240Z's. I received fantastic support from them and was able to make substantial improvements. One of their first comments is that modern gasoline formulations burn much leaner than even 5 years ago and that any carb that was tuned more than five years ago is likely to under perform. Second, they stated that they have changed the specs for the plastic floats, lowering the closed level and reducing the range of travel. They now measure plastic floats from the top of the float as opposed from the previously specified bottom. 17mm closed and 21-22mm fully open. Redline also suggested a 10-15% performance improvement could be made by converting the linkage from progressive to synchronous operation. With a progressive linkage, the throttle travel operates only the first barrel for the first half of travel and starts opening the second barrel after that. With synchronous operation, both barrel open together. While this doesn't affect wide open throttle performance, it provides the equivalent of a 49mm single barrel carb compared to the 48mm of our SUs. The standard 32/36 DGV operates solely on the primary about 90% of the time. First, I documented the jetting that came with the car, these turned out to be standard jets for a generic 32/36 DGV 5A carb and were not at all tuned for a 240Z. The standard idle speed/mixture setting procedure indicated that the primary idle jet was in fact too rich. There is a half size jet difference between the primary and secondary idle jets. swapping the jets so the primary had the leaner jet made an improvement, but it now indicated the main jets were too lean. This was enough to confirm my need for a pair of jetting kits. I order a set of synchronous linkages at the same time. I have installed the linkages and richened the main mixtures by three steps as well as leaning the idle mixtures to the proper sizes. Mid throttle response, where we live 90% of the time, has dramatically improved since I'm using the full 49mm equivalent rather than the 36mm of the original setup. It makes driving the car a much more enjoyable experience. I haven't had time to do a 0-60 run, but if there is any wide open throttle performance improvement, it will be from the richer jetting and not the synchronous operation. The original progressive linkage The new synchronous linkage All in all, for less than the cost of one new carb, I've gotten a significant boost in performance. ​

Nice times at ACS, so far lapping at 2:00 min flat, better than I expected. Pics and other Datsun contingents. Next event Oct 3, 4.

Moi? There was discussion that the car might be an almost original condition, low-miles, "survivor" type car. But it looks more like a normal, been worked on, not quite right car now. More fun in the long run because you don't have to worry about ruining something special. Considering the loose wiring and the missing parts and the fact that it doesn't have what it needs to run anyway, it's in perfect position to get a multimeter, and the Engine Electrical, and Engine Fuel chapters, and the 1980 Electronic Fuel Injection Guide, and just spend some time taking measurements, and making everything right. Then when you're ready to put a battery in it and see what works, you won't get any surprises.

When you get so far as to trying to start the engine, search for a thread with the tittle that goes something like "wakening the beast". Its a good "how to" thread on starting an engine thats been sitting for a loooong time.

Bought the 240Z 15 Aug 1970. Traded it for a station wagon it in 1972 with second child on the way. Contacted by second owner 9/89 with offer to give me first choice to buy the car before he put it on the market. He contacted me thru the Air Force personnel system. I was in Shreveport , LA and he was in Dallas, TX. We went to Dallas the next weekend and paid him $3000 the same as I paid in 1970. Currently being restored. Wally Dill Bought Montgomery, Al and driven to Craig AFB Selma, AL. Original 85 miles. Craig AFB Craig AFB Marry Me! 30 Dec 1970