cylinder output?

[drip]

When pulling plug wires to check cyl. output on a running engine I would have thought that the rpm drop should be close to the same on all four. When I pull #1 & #3 plug wire the have very low output compared to #2 & #4. Compression and leakdown good on all four, good cam lobes, good dist, cap, wires and rotor and no vacum leaks. Good strong single springs, swivel feet and valves adjusted. Carbs are working well and have tried
vacum and mechanical distributors. Exhaust pipes have even heat, engine seems to run fine and has 400 miles on it. What am I missing here? Is this because of cam overlap?


1600 dp stock heads, manifolds matched
kadrons ported for vacum with steel manifolds
Bugpack cam #4062 .415/284*
14# flywheel

Glenn

[Alan_U]

What exactly are you doing?? That test is suppose to indicate something???

If your testing for engine "efficiency" you can get the engine on a scope and do an actual efficiency test. All that is required by the scope/gas analyser is hooking up a coil and #1 cylinder inductive pickup, +ve and
-ve terminals of the coil and you can get the engine scoped. The firing order also should be punched in the scope for data.

Pulling a coil wire only increases the KV output from the coil just on that particular cylinder since its more than likely arcing to ground at that point. The thing is its meaningless since obviously theres no combustion in that cylinder. I see no valid data by pulling out plug wires.
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11.92sec pump gas true daily driver. Who says it cant be done.

No more time for VW's.......

[drip]

Ok Alan

Tell me why when I pull #1 wire it makes very little change in rpm, but pulling #2 or #4 the engine falls on it's face. Nothing is crossfireing in the cap or out of the cap. It's the same result pulling a plug wire grounding an extra spark plug to the block. Useing a old scope Sun, Allan, Bluepoint any of those old wizzard of oz inventions were ok but they were mostly pushed in the corner and more precise hand held tools used. Yea they called it a electronic compresion test. Go pull wires on your engine and tell me if it reacts the same way.

[danimal]

i think you guys are actually kind of on the same page... pulling the plug wire at idle is the first step in troubleshooting for a lack of combustion, but alan is saying we already know that... except that the exhaust pipes are all hot, so there has to be some kind of combustion going on.

just for drill, how do the plugs look? have you actually swapped out the plug wires? i've seen nice looking plug wires that are bad.
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[drip]

These cyl. output differences are starting to be a bit challenging and kind of pissing me off. Like I said the engine seems to have good power and runs even but it sure makes me think there could be more there. I like to assume there's 70ish hp in there, 17 or 18 a hole and I don't need no slack asses fakeing it. Yes theres new Bosch solid core and I have swapped them around, with the plugs. I modified a couple Mittsibushi 2.6 distributors to fit the 1600 one with vaccum a the other full mechanical. At first I thought they were at fault then tried a 009 with points with no improvement. The mitts dist. worked out good really easy to recurve and well built electronics. Have'nt tried a different coil yet but thats kinda crazy I guess try another one. The kadrons are a little rich so I'll put the 130's back in. Pinching the manifold balance hose does change the idle a bit but no cyl. change. I did not degree the cam when building the engine I only quickly checked valve lift. I'll put the wheel on the crank and make sure #1 & #3 lobes have the same profile as #2 & #4, would'nt that be a cluster f**k. Engle would have given that one to Bugpack.
Like I said the 1600 seems ok but I really have nothing to compare it to. I've only built three vw aircools in the last 20 years, lots of cast iron power though. This is in a 1340# f/g street car mabe it should pull a little harder. Any other suggestions I'm all ears.


thanks Glenn

[jamestwo]

I suspect that you have a valve not seated, or the valves are not adjusted properly.