02-09-2004 11:52 AM #1
Small Block Chevy Problems
Hello guys, I have been building, engine swapping and running chevy engines for years, not an expert not an idiot either. I just bought a 72 c-10, I had posted a subject as 350 gone crazy, well i have since reworked the choke on a new 1406 edelbrock carb, the truck still will just about cut off when placed into a drive gear, In park or neutral the thing idles fine, I have never had this problem before, I have set timimng, set the idle to 900 rpm, replaced plugs , wires , cap, rotor. I am wondering if any one out there has had this problem before, I am wondering if it may be a tranny prob, or a vaccum advance, It is just straigt out weird to me, I dont understand nor can I figure out why this thing does that, Idles great , put it in gear and it drops off to about a 200 rpm idle stalls out, will crank back up and idle fine, place it in gear and stalls out, I have tried everything I know, and any help on the subject would be GREATLY appreceated. thanks
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Sounds like the vaccume advance is wrong and is not working properly.
You don't know what you've got til it's gone
Matt's 1951 Chevy Fleetline- Driver
1967 Ford Falcon- Sold
1930's styled hand built ratrod project
1974 Volkswagen Super Beetle Wolfsburg Edition- sold
... ....Sure sounds like a vacuum leak....Try closing the choke butterfly a litttle as the idle falls off to see if it changes..Power brakes.??.....Pinch off the vacuum hose to the booster with vise grips....Automatic transmission.??.....Block off the line to the modulator.......Same goes for the vacuum advance unit.....Intake gaskets.??....carb mounting gasket.??.....carb mounting gaskets can be tricky...Lay the gasket on the intake and make sure it really is sealing around the bores.....make sure the gasket is sealing on the carb too...like the port for the booster...
|The cylinders have to be inline.!!!|
Crazyboy; How does it sound when you rev it in park ?Did the thing run good before you did the carb. I would start it, let it idle till it got good and warmed up. Then I would check the choke and make sure it was opening up all the way,this is a new carb right? Do you have all the lines hooked up right. Take a water hose with the car running and spray some water around the base of the carb and intake see if you notice any differance in the idle, if there is, you have a vacuum leak. If not your torque converter might be looking up or some other trany problem. It's hard to tell with out seeing it. Hope you find it,let us know what you find.OK
Do you have a wild cam in that thing? do you have a vacuum canister on it? check vacuum leaks, or whats your timing set at? maybe you have your idle cranked up cause you have timing issues and your trying to compensate for it.
thanks for all the info, the motor is a very strong one, when in park or neutral it is very responsive, I think it has a rv cam in it not positive but it lopes like one, I had thought about by passing the choke all together , today while fooling with it I noticed thechoke was not opening up much at all, I would manually open it it would run fine, UNTIL putting into drive/ reverse, I have tried just about everything you guys have suggested besides capping off the vaccum advance and the modulator will do that tommorow, the truck has no vaccum canister on it, It does have power brakes , but it does seem that they are unusually stiff, so will pinch that one off as suggested to see if it makes any difference, THANKS for all the info I just got out of the military and have gotten a little rusty on my small block knowledge I am grateful to you guys for the info, Thanks Everett