first vette trying to make drivable
Thread Starter
7th Gear
Joined: Sep 2009
Posts: 7
Likes: 0
From: Pendleton Oregon
first vette trying to make drivable
Just purchased 76 from auction, has 123,000 on it. Engine has been rebuilt but to what degree have no idea. Had to replace harmonic balancer so checked timing chain/ gears. it has a double gear/chain with little to no wear, chains have about 1/4 slack/play in them. Replaced distributer cap rotor plugs and wires. I have read through all the post, great info. I set my inital timing at 8 and all in at 36 at about 3,000 rpm. Drove it and runs reasonable, first question when I hook vacum back up timming goes to 36 at idle. number on vacuum can is 23. I cant get the Idle to stay steady it will stay at 1100 for while then drop to 700 then hunts back and forth.The best vacuum I can get at about 800 rpm is 12 from port at bottom of carb(which is an eldebrock, manifild is eldebrock performer) I have a scondary problem that may be related and is reason idle set so high. when i put in drive(obviously an auto) the Idle drops 4 to 500 rpm, if i set idle to 7 or 800 rpm then in drive(or reverse) it drops to 2 or 300 and I beleive would eventually die. I allways put into nuetral when at stop sign. Any sugestions on where to go from here ? Is the distrubuter just wore out or would bad vac can cause these problems.
Le Mans Master
Joined: Oct 2000
Posts: 6,362
Likes: 30
From: Oak Harbor WA
You should post this in the Tech section instead of general.
Sounds like a vacuum leak to me. A hunting idle, if the carb is in proper working order, is going to be a vacuum leak.
That vacuum can doesn't sound stock and might be adding all the vacuum advance at idle which isn't good. It may be adjustable using an allen head wrench.
Did you remove the cam sproket to look at the cam lobe face while you were in there? Sometimes they are marked if aftermarket with the grind info.
There are some real experts on this forum so accurately describe all the info you have in tech and help will surely come along.
Sounds like a vacuum leak to me. A hunting idle, if the carb is in proper working order, is going to be a vacuum leak.
That vacuum can doesn't sound stock and might be adding all the vacuum advance at idle which isn't good. It may be adjustable using an allen head wrench.
Did you remove the cam sproket to look at the cam lobe face while you were in there? Sometimes they are marked if aftermarket with the grind info.
There are some real experts on this forum so accurately describe all the info you have in tech and help will surely come along.
ED 
Thread Starter
7th Gear
Joined: Sep 2009
Posts: 7
Likes: 0
From: Pendleton Oregon
Thanks I'll try the vacum line plugging and elimnate by re connecting one at a time. When the idle changes its not a quick back and fourth. will stay at a 1000 for a minute or 2 then drop to 600 and stay there for awhile then back up. anyway will continue to look a vacuum problems.
As far as the idle speed I would be happy if I only had a drop of 200 rpm but I'm talking a 4 to 500 rpm drop when put in drive, and drive train loads emidate even at 800 or less idle in park. So i'm thinking I have some tranmission or torq converter problems
As far as the idle speed I would be happy if I only had a drop of 200 rpm but I'm talking a 4 to 500 rpm drop when put in drive, and drive train loads emidate even at 800 or less idle in park. So i'm thinking I have some tranmission or torq converter problems
