Hard working cylinders vs lazy ones

[fgc]

I adjusted my cam shims and later was fiddling with the webber to balance the engine.

I discovered that when I pull 1 plug wire at a time
No 1 cylinder, the engine rpm drop somewhat
No 2 cylinder the engine rpm didnt drop all that much
No 3 cylinder the engine rpm drop quite a bit engine sputter a little
No 4 cylinder engine rpm drop a little.

So what does this mean? That eg No 2 is not doing much work and therefore I should increase the idle screw adjustment?

No 3 is doing alot of the work for the rest of the engine and I should leave it alone or adjust it down so that I can increase No 1 and 4?

Is this how I can interprete this?? Is this how to get all cylinder to do similar amount of work at idle? My car at idle is a little like a massage chair on low setting so I want to iron it out as much as I can.

I did what papajam described sometime back about pulling the front 2 plug wires then the back 2 wires and adjust the balance so that the 2 halves of the engine are balance.

But in view of the fact that each cylinder seems to be doing different amount of work, how do I balance it? Can I use this pull one plug wire technique to balance the whole engine?

[sono veL.O.ce]

First of all, are your cams timed properly?

if so then did you have your webers apart?
Im no expert but here are a few other things I would check:

Maybe your throttle butterflies arent seating properly in each barrel.
Or maybe you need new sparkplugs, or maybe you have a leaky jet somewhere making the idle mixture too rich, or a clogged idle cuircuit making the mixture too lean.

I think first thing I would do is verify that your cams are properly timed,
second that it isn't a spark problem, check the timing , cap, rotor, and plugs.

lastly, I would try to specifiy whether or not it is a fuel problem (leaky jet, clogged idle circuit, etc,) or an airflow problem (butterflys not seating properly)

An important rule is that if the webers were working properly DON"T MESS WITH THEM! they do not tend ot get out of tune by themselves.

good luck!
Im sure a real expert will chime in soon....

[fgc]

Thanks for your reply.

the cam timing is set up to specs. I adjusted the cam clearance to ensure that its as uniform as possible by grinding down the shims etc. they are all within 0.01mm of each other or there about. Before this they were miles apart due to a wrong adjustment previously errhuumm by me - some cylinders got more gap than the rest so I had pretty loud tapping! But I didnt know and I sent the car to my mechanic who then just adjusted the idle mixture screws. so the webbers were adjusted to the wrong value

The webbers have not been apart but my plugs are pretty loaded with ash (i think they are ash)

I want to try tuning the webbers myself, never really did bec I didnt think that I would be able to get it idling nicely.

Anyway, I will attach a jpeg of my No 3 plug in my next post for comments

[fgc]

This is my No 3 plug. I have some questions about it. All my plugs are indexed where the electrode is pointing NS and not EW direction. This is to minimize or should I say Maximize the gap between the corner of the electrode and the valves. I get this strange and curious deposites on only the exhaust side of No 2, 3 and 4 plugs. But the Intake side is clean for all three plugs. As for No 1 it is clean on both sides.


Pic 1 shows the exhaust side and its covered with what I think is ash. It can be easily chipped away


Pic 2 shows the Intake side. it faces fully intake valve. It is completely clean.

Pic 3 shows the back of the electrode. Not sure if you can see the clear half and half of the deposites

Pic 4 is another curious one. Notice the rust at the top. This only happens on Plug 3! I have changed out a few plugs and it seems that plug 3 would rust the top bits. No idea why.

I have been postponing a rebuild and I will not do it for another few months.

Thanks in advance for input on this plug thing and also on webber tuning

fgc

[sono veL.O.ce]

I wouldn't mess with the webers yet, I'd get new plugs and wires (thats probably why #3 is rusting) and check the rotor and cap. start from there and see where you end up.

[Ianc]

First, new plugs. If the wires are more than four years old, new wires. Make sure the manifold and carb nuts are tight - they don't have to be honked right down, but better than snug. Start car, warm up. Spray choke cleaner or ether on manifold gasket and carb-to-manifold join. If no difference in engine note, no leaks. If the note changes, you have a leak. Easiest way to synch carbs is to listen at the intake throats with a length of hose. A louder hiss means the carb is doing more work. Adjust the synch screw until the sound is equal. (Note you only need to listen to one throat on each carb - both throats on a carb are the same, as far as throttle setting is concerned.) Good luck.