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Hey there,
long-time lurker, first time poster...
My little blue 122 with a b20 and a weber carb isn't running quite right and I'm running out ideas... I've had this one for over 2 years and it's been a constant struggle to achieve peak performance, but it's never left me stranded and it starts up every morning, even in the cold. After doing some basic maintenance and tune up stuff and then driving it around for a day or too, things went bad fast.
Some of the symptoms I have observed are rough idle, low power, engine sounds like a drunken tractor. The engine revs up to 4-5k within the first 1/3 of linkage travel. There is a knocking sound like someone is erratically tapping on the exhaust manifold with a ball peen hammer. At this point, I don't know where to turn next. It was parked on the street certain to get towed so I drove it around the block and put it in the garage at my apartment. This is the only driving I've done since the noise began.
I pulled the plugs and none seem damaged although the #2 wasn't firing for a bit, swapping in a new plug fixed that.
Prior to this troubling noise, I'd set the static timing (15 btdc), valve clearance using the nines method (.020), jetted the weber to ipd's suggestions (as a starting place, the noise developed before I got a chance to play around with different jets). new plugs, new wires, new cap/rotor. The coil hasn't been changed, but it's giving a spark, so i figure it's working enough. It's definately getting fuel/spark and I can't find any air leaks in the intake. There's no oil leaking out of between the head and block so I don't think it's a blown head gasket. I haven't checked the compression yet in the cylinders yet, don't have a gauge handy. I need to get a look at the timing gears, there's a good chance they've gone bad. I've got a set of Cloyes Alum/Steel replacement gears but I still need to source any additional bits I would need for the repair.
Last weekend I had it running perfect, the engine pulled strong all the way through the range with no hesitation or flat spots and plenty of reserve power even at 60-70 mph with the overdrive engaged, in the past it had felt much more sluggish than this. It was beautiful. I didn't drive it for a day or two and came back to hard starting and the idle was rough at first and then eventually smoothed out and the power was gone and the aforementioned noise presented itself. It's been like a bad dream ever since.
I've hit the end of my knowledge and experience here and I was hoping someone out there might have some ideas. I've been spending all of my free time obsessing over this and I've got finals coming up and I need to get it off my plate. I'm hoping the problem is with the timing gear rather than something I screwed up while setting the valves (it was my first time doing the procedure by myself). I did lose track of screwdriver bit while setting the fast idle screw but i can't fathom any path from below the intake into the cylinders that would lead to the noise I'm hearing.
any help would be appreciated,
thanks.
Brian
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