Question about engine balancing?

[ChgrSteve67]

yep move on to plugs, cap and compression checks.

[Steve P.]

I checked the wires, I pulled each one and three of them made no difference when idleing.

I would start with a wet/dry compression check to rule out anything mechanical.


Ron

100%  Many things can cause a cylinder to NOT FIRE. a wet/dry compression test will answer the most questions. Biggest one being (are you making good compression).

[Rob R]

My first guess would be unhappy cam lobe but it could be really really lean with that E carb...how big is it 800 cfm I hope..

that plink plink plink has the sound of a rod nut hitting the edge of the tray or the rear counter weight hitting maybe the pump every once and a while...

[1BAD68]

did a compression check...
#1 - 159
#8 - 170
#4 - 172
#3 - 156      I would say these are good numbers right?
#6 - 160
#5 - 158
#7 - 158
#2 - 159
first I checked compression dry and then wet but numbers didn't change much at all.

I bought a new dist. cap and wires, changed cap first and started engine, total difference... shaking is gone and it runs good! I think the old wires were still good but i changed them anyway, the cap had carbon on the terminals causing too much resistance.
The only thing I noticed now is a popping through the exhaust, it pops from idle to 2500 rpm.
I tried advancing the timing and it goes away but only when timing is way too far advanced.
Tried playing with the mixture screws but that didn't make any difference.

[1BAD68]

My first guess would be unhappy cam lobe but it could be really really lean with that E carb...how big is it 800 cfm I hope..

that plink plink plink has the sound of a rod nut hitting the edge of the tray or the rear counter weight hitting maybe the pump every once and a while...

its a 600cfm

[firefighter3931]

did a compression check...
#1 - 159
#8 - 170
#4 - 172
#3 - 156      I would say these are good numbers right?
#6 - 160
#5 - 158
#7 - 158
#2 - 159
first I checked compression dry and then wet but numbers didn't change much at all.

I bought a new dist. cap and wires, changed cap first and started engine, total difference... shaking is gone and it runs good! I think the old wires were still good but i changed them anyway, the cap had carbon on the terminals causing too much resistance.
The only thing I noticed now is a popping through the exhaust, it pops from idle to 2500 rpm.
I tried advancing the timing and it goes away but only when timing is way too far advanced.
Tried playing with the mixture screws but that didn't make any difference.

Those compression numbers are fine.....it's safe to say that the cylinders are sealing up fine so this means it's a tuning issue. I noticed you said it has a 600cfm carb....that's way to small for a stroker of this type. I don't like Eddy carbs either....they tend to be all over the place on the fuel curve. Rich at idle, lean on the transition then rich again at wider open throttle positions.

My advice would be to ditch that carb and get yourself a holley double pumper and start tuning. That motor will want at least 16* timing at idle and 36* total all in by 2800 rpm.

If adjusting the mixture screws has no effect on the idle then you are running onthe carb's main circuit and not the idle circuit. This is usually what happens with bigger cams with more overlap and a mismatched carb....you have to idle the engine up to keep it running so the idle circuit is no longer functional.


Ron

[1BAD68]

I meant that when adjusting the mixture screws it didn't help the popping through exhaust, but it did change the smoothness of the idle and I was able to get a 600 rpm idle that sounded fine except for the popping.
Are you sure the carb is too small? This calculator says its ok...    http://www.4secondsflat.com/Carb_CFM_Calculator.html
What size carb would you recommend?
Thanks Ron