Cascade Crew

Quasi-Traction · Posted: Thu Jun 01, 2006 1:57 am Post subject: no Z/28

Ok.......85 Z/28 runs now (yay!) It is running rich however and I can't seem to get it to lean out enough without stalling. When I back out the screws to where I think it should be...it starts hesitating. I turn them in 1/2 to a full turn..smooths out, but still rich. I can smell unburnt gas when I stand behind the car. Not sure what to do. Tried raising the curb idle and very slightly adjusting Idle bleed screws inside the carb. Nothing seems to help.

Also having trouble finding Timing marks on the balancer. Tony and I took a timing light only to discover, WE DONT HAVE A REFRENCE POINT FOR TDC. Can't seem to locate a timing pointer on the motor anywhere (did the LG4 even have one stock.....I figure if the computer adjusts timing, it might not?) Found one big groove in the balancer, but I've seen it before on other SBC's and I don't think its TDC. Took Carb cleaner and a Xenon light to the Balancer. Can't find timing marks on it ANYWHERE. Its idling on the rough side, and I'd like to correct it. Tried Moving the distributor to Advance/Retard postions, but it only gets more rough. Right now its at the best setting i can have it at. Idles now around 900rpm (a little high).All the spark plugs are VERY clean, Plug wires are re-used from what orginally came on it. Carb is as lean as I can get it without hesitation (still too rich IMHO).

Brandon, Paul, Anyone? any ideas?

I dont' feel right about driving it to Cows in the state its in. Don't want to foul my plugs too much or potentially have a breakdown.

got it up to 70 mph tonight. Acceleration is much more responsive now than with stock equipnement. Especally down low. Secondaries seem to open smoothly enough. Just still too friggin rich.

Twilightoptics · Posted: Thu Jun 01, 2006 7:58 am Post subject:

Alrighty.... As for the carb.... Get yourself a vacuum gauge and tune the idle to the highest vacuum.

As for timing... try looking straight down behind the water pump. Sometimes the timing mark is there.

The big slit in the balancer IS TDC in reference to the timing tab IF the balancer has not slipped. Measure your balancer. If it's an 8" balancer or like 6 7/8"or something like that you can go to baxters or maybe shucks and buy a timing tab that bolts onto two of the timing cover bolts. I think that may just be for the 8" balancer though.

I'd tune the carb to highest vacuum, advance the timing (Turn counter clockwise on dizzy.) If it gets better, tune the carb again! I think for emissions you want like 1/4 turn in past high vacuum. But that's irrelevent.

I run 28º of timing at idle. Do you have your vacuum advance hooked up properly?

If it's running better at this point, go take it for a drive. Does it ping? If not, I'd give it another degree or two based on how it's idling.

Twilightoptics · Posted: Thu Jun 01, 2006 8:00 am Post subject:

Does the idle surge? Vacuum leaks are hell too.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

Bring it up to cows, if it gives you any problems I'll have my car trailer and can give you a lift.

Xophertony · Posted: Thu Jun 01, 2006 8:58 am Post subject:

you will be bringing a car trailer to cows?

Twilightoptics · Posted: Thu Jun 01, 2006 9:07 am Post subject:

Quasi-Traction · Posted: Thu Jun 01, 2006 11:51 pm Post subject:

Tweaked with timing a bit, still a bit off. Dad came over with a timing light and vaccum gauge and we screwed with it a bit. Running about 24 degrees of Idle advance. It seemed to be where it liked it best. no evident vaccum leaks. Seemed to hold around 16-18hg at idle off the dizzy. When you first start it it idles around 1400rpm, but after sitting for a minute it drops down to around 900rpm. Still higher than I'd like. Factory setting says 750 +50rpm in Neutral.

It makes a "ping" sound but no pre or post detonation. Its really less like pinging than like a valve rattle or a rocker out of adjustment. Doesn't really do it unless you're going above 45 or above about 1/2 throttle. I have a bit of blowby but it not real bad. Messed with the Idle Air Bleed Screws a bit and mixture screws. Still on the rich side, but I got it as good as I can.

I REALLY don't feel good driving it to skamakowa. Especally not at speeds over 50mph. I'd hate to get stranded Even if Rod can give me a tow. Secondaries seemed to open ok again today, without hesitation.

I'll decide tomorrow if I feel brave enough to drive it.