Running cold?
 

hey. i got an auto79 z28.

when it isn't warmed up for more then 10 minutesbefore the first driveit will die when put in gear. but the the funny bit is when its driven then left for more then an hour it has to be warmed up for even longer.
It also has to drive for a good 15 minutes before it has any decent power. The engine heat never shows higher then a quarter of the way on the dash, and sometimes dips way down when warm. does anyone have any thoughts on the situation. thanks

RE: Running cold?
 

As for the power part and the getting into gear problems the car might be running to rich. Doesn't fit the temperature to much though. I'd check you spark plugs and see if they need to be changed or if they have a bunch of carbon build up on them as well to see if the car is indeed running rich. I've actually had trouble with the carberator on a few cars before including a 79 Z28 I've got where it would do some similar things, I just finally got it adjusted to where it ran great after 10, 15 minutes of warming it up.

RE: Running cold?
 

Try putting in a proper thermostat as it sounds like you don't have one, and see if the heat riser hose is still there and working properly to provide the carb with warm air when the engine is cold.

RE: Running cold?
 

What octane gas are you running?

BC Canada..How cold areyou talking here?

Sounds like as detailed above, tune, thermostate..also a loose timingchain might also contribute to the problem..

RE: Running cold?
 

i think the octane is 87. im getting a new holly to put in this week, i know mines done. we will see if that helps. i changed the plugs lead wires and dist. cap a while back which it needed but it didn't solve the problem. coldest it gets here is negative 10 maybe. thanks all for you help!

RE: Running cold?
 

The first question should be, does the carb have a choke and if so is it working properly? Then.........

Does it idle up high when you first start it up? If not. that's your first clue the choke isn't working.

Does it blow a lot of gray smoke when you first start it up or better yet,does it blow a lot of gray smoke on that second startup of the day when it takes an hour for it to run right?

Does it do this in the summer and the winter?

What carb?

Pete is right about checking that thermostat, but I will say that an engine can run just fine when the water temp is 100-120° and it's not uncommon for these older carbureted engines to take 10-15 minutes to "get going".

RM

RE: Running cold?
 

When i was in the Dakotas I had a 73 with a 350..beign from Texas, I had had no problems with cold weather driveability however...like yours it was a bear to drive in thedakotas in the winter until it got somewhat warmed up. My roomate was a native of the great lakes area and a wiz at cars. I was running an open element air cleaner and a rochester and headers..I got a holley with mechanical choke set the coked Idle up. wefabricated a closed twin feed air cleaner setup. (we used two old air cleaner housings to make a dual feed both with heat riser valves)that we connected to fabricated cowlings we put over the headders on both sides. This helped to get the incoming air temp up which cuts down of fuel puddling.I ran the hottest thermostate i could find and ran a termo clutch type cooling fan from a truck. regaurdless i had to let it warm up to at least 150 before I tried to go anywhere...

One other thing is are you running headers? if not have you checked the manifold heat riser to see if it is working? If it's not then this will dramatically slow down your engine warm-up...

Greg

RE: Running cold?
 

Those iron pistons take a long time to warm up. The choke suggestion is a good one. Those automatic chokes can be a bear on a lot of cars. If you aren't worried about originality, I'd put a manual choke on it. I've never been a huge fan of the automatic chokes because they hang up to easy and run the engine at a lot higher RPM than I like to start it off in the cold at.

RE: Running cold?
 

number on what compression is ur motor if ur 8.1 or 9.1 87 octane should be fine and u need to check ur hoses going into ur carburator, if u have 10.1 11.1 compression or higer u need atleast 93 octane to run properly, check ur thermosat and the thermostat housing gaskets for cracks, and last but def not least sparks and wires people dont realise how much power and damage it does to simply change sparks and wires

RE: Running cold?
 

mine does about the same thing.i get it fired up and i have to baby it for 5-10min.after that it idles a little low but after i drive it for a little it runs fine.i got a 195 thermostat in it.the temp. outside the other day was around 38-40degrees.i got up on the freeway and drove 20miles and it barely made it to 195,as soon as i let off the acelerater,getting off the freeway the temp went back down to 180-185.they say chevrolet makes its best power at 200.i dont know its just something you have to play with to get it right.as for a choke,i got a manuel choke on mine and it aint worth a cow pattie.the choke cable i used is for a lawnmower i guess and just couldnt pull it back open after being fully closed.i unhooked it and operated the choke by hand.i closed it a little it idled down a little,iclosed more and it start running rough and blowing black smoke,iclosed it almost all the way and it tried to die so i opened it back up and it recovered just fine.moral of the story -dont use the dam choke if it want work right just set in the cab a little longer untill it warms up (LOL)