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On 26 Aug 98, at 15:37, oofacts@earthlink.net wrote: > 72 Sqbk, 1600, dual Weber 34 Icts, distrib off a 76 Bus (not my choosing) > > So I did the timing thing last weekend. Very enlightening. I got an advance > measuring gun which proved extremely helpful. According to the gun, my > ear-based timing that I did last week was WAY OUT THERE! 15 BTDC at idle. This is almost ALWAYS what happens when ANYONE times by ear. Seems great now, burns up later on its own time. > Hoo boy. Managed to get the advance to 32 BTDC at 3500 rpms, hoses on, as > Jim said was right for my advance, and that brought the idle timing down to > 0 but then it idled really hard. > When I set centrifugal (hoses off) speed to 7.5 BTDC, the advance at 3500 > rpms was like 40. Hmmm. So this dist has about 32.5 deg of mech advance. It is best, when there is any doubt, to time with the vacuum hoses removed. Little of this will change when you change distributors. TDC is still TDC. If it won't idle there, then there is some other problem. I would wonder about your carb idle settings. > Brought the advance to an agreeable middle point since I'm going to be > replacing it soon with a stock distributor instead of this one for the 76 > Bus I have in my car now. A week or 2 more shouldn't do too much more > damage. Such damage can happen quite quickly if you ask the engine for full output for more than a few moments at this much advance. > So one final look at the timing with the engine at 3500... out of nowhere > the engine cut and BANG a backfire, a puff of black out the right exhaust > (I was talked into a LeMans muffler last year...oh well). Uh oh. I let it > sit a while, and thought maybe something hapened with the hookup of the gun > and/or the tach but everything looked ok. Car started back up. No funny > sounds.Thought Maybe I should just quit for the day. Carbs again, or just a fluke. > Later read about that series of events in Muir. Potential valve swallowed. > Yikes. Is there a visual way to check for this? Anyway, I thought a > compression check would tell me if I had no valve. No, not that bad. > Did check two ways: Muir says turn engine over 6 times, says nothing about > throttle. Doing it this way got #1=95, #2=120, #3=110, #4=135 > Bentley says turn engine over "a few moments"at full throttle. So I figured > about 4 turnovers. Results: #1=125, #2 = 120, #3=140, #4 = 135 The highest numbers are the right ones. Do this test with the throttle fully open (WOT.) > Finally, My new sparks are already coated in carbon! TOO TOO RICH! Weber > instructs are damn near useless. No precision to them whatsoever. Regarding > idle air screws "Turn them in until rpms fluctuate, then turn them out > until idle evens out" is all they say. This is caveman stuff. Isnt there a > slightly more precise way to measure mixture without buying a computer? Which brings me to one of my pet peeves: Everyone thinks FI is too complicated, but assumes they can understand a carb. I don't, and I would be willing to bet that there is not a single person on this list who REALLY understands them in detail. They are every bit as hard to understand as FI. > 2)Someone tell me what these compression figures mean. If you do them a few more times you will probably get all the cylinders to come out rather evenly. I think these already look like your compression is fine. > 3) Does anyone have access to Weber's # so I can call them for tech support > and/or some more accurate specs? Aren't they Italian? Would that be Milano? Jim - ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ------------------------------------------------------------------- Unsubscribe? mailto:type3-request@vwtype3.org, Subject: unsubscribe