I've had dual DGVs on my 260Z since the early 90s. They ran fine for years, and passed smog. At certain high throttle loads I've always had a bit of ping, but not enough that I ever worried too much about that.

My '70 145S project Volvo had a brand new DGV kit and that's gonna be for sale as soon as I get around to installing Rhys's SU kit. After that, the Z is next in line to lose DGVs in favor of Hitachi SU carbs.

My big gripe is that on my Z I can't fix needle valve excess leakage at idle. Stock Weber needles have a rubber tip that gets misshapen and turns as hard as ceramic within a matter of months (at least when exposed to Calif street gas - I prefer to run ethanol gas from 76 to reduce MTBE pollution hazard.) I switched to Grose Jet fuel valves and find that these do not seat reliably even with fuel pressure regulator set below 2.0 psi. Also, it's my impression that the Grose Jets tend to cause float lever bending more than stock needle - especially on bumpy roads. I haven't found any resolution of this in spite of several requests for assistance with varioius Weber supplier/specialty firms.

So on the Z I often (not always) get excess rich idle. Occasionally it gets to the point of stall due to flooding, and then it's a real bitch to restart. Fortunately, the DGV kit for the Z uses a gooseneck adapter that will puddle quite a bit of gas before raw gas runs over into the cylinders. Almost every time when I look down through open throttle w/ stopped engine, I'll see a nasty puddle of raw gas there. Hate to think what the smog readings must be.

Oddly enough, running continues to be excellent, fuel economy and ping zone are the same as ever. I suspect that the float and needles are controlling level OK under load, but are not shutting off tightly enough at idle.

Just recently I've had a couple of very loud exhaust explosions while cranking after approx 6 hours shutdown. Apparently one of these instances involved a pressure spike to the crankcase as I found the dipstick blown completely out of block and insertion tube. It made quite an oily mess driving around with dipstick out. Seems to me this must be related to needle-seating problem and excess-fuel-in-manifold situation.

If someone will suggest how to find reliable needles for the DGV, I might give that a try, but short of that my DGVs will soon be history.

A couple of months ago I heard from a guy at Pegasus Racing parts that Weber is going through bankrupcy and they cannot re-supply out-of-stock parts. Something to consider if you are thinking about a new DGV or DCOE install.

Any comments or suggestions are welcome.

Later,
Al