Coldblooded Chev question

I've heard for years that old Chevs are cold blooded beasts.  I've seen this to be true for the most part.  Not being a mechanic, can someone explain to me why they are so cold blooded?  Is this something that can be corrected during a rebuild?  As I put my plans together for my '77 C30 I am wondering if this is something I'll be able to fix with my 454.  

a few things...

choke adjustments are critical on these...

there are several different adjustments..

the choke thermostat..

the primary choke pull off

the secondary choke pull off..

....

another issue you MAY be having and i have had it on a LOT of cars and trucks..

since you are good at disconnecting the carb... disconnect the fuel line at the carb... figure out a way to extend it with some hose into a clean clear 2 or 3 liter soda bottle..   disable the HEI so it cannot create any sparks..

have a friend crank the engine while you OBSERVE the fuel pulses into the bottle...  each pulse should be equal to the others... and should begin instantly.. not after some cranking..

then see if when you stop.. that it holds pressure..

i have found a LOT of Red dUST issues in all brands of cars and trucks fuel systems..  this ultra fine dust gets into the fuel pump check valves and holds them open ... allowing some of the fuel above the needle and seat opening and all the fuel in the lines to drain all the way back to the tank...

i have had some that had one check valve dirty and it had terrible issues pumping fuel up...

installing a better usually fuel injection type fuel filter right before the pump inlet.. then doing the fuel flow test again will sometimes clean the check valves out because of the full flow pulsing of clean filtered gasoline..

there is a secret if you need to change the fuel pump... on a chevy V8..

set the engine to #1 TDC.. usually by pulling the #1 spark plug or the distributer cap..

then you can glue the gasket to the pump .. disconnect the battery...  pull the engine oil dipstick..   use the tip of the dipstick to slip vertically down through the opening to wiggle infront of the fuel pump pushrod...  then you can slip the end of the pump lever against the dipstick to retract the pushrod enough to slip the pump into place.. pull the dipstick out and bolt the pump up;.. this saves a lot of grief... and swearing..

the pump cannot be installed with the crank at TDC when the cam is set to fire #6... just turn the crank one turn and it will be in position..

did you guys rebuild the carb.. do you have the instructions with it???

or at the autozone repair info site..  you can log in.. look under repair info.. look in fuel systems.. look for the proper section on quadrajets or M4mc.. . there is enough there to adjust the choke systems properly...

since you have had the  top off the carb.. did you manage to not hook up the choke rod.. between the choke blade and the lever inside the choke housing.. ??????  

check out this section over at AZ...

it covers it better than the truck version for some reason..


http://www.autozone.com/autozone/repairguides/GM-Full-Size-Vans-1967-1986-Repair-Guide/CARBURETED-FUEL-SYSTEM/Carburetor/_/P-0900c1528007b84c

you will have to pick and choose through this section as all of the carbs are grouped together..  

Right now it has a manual choke.  When we did the rebuild the carb had an electric choke but it wasn't wired up and we didn't see any evidence that there was ever a circuit going to it.  We added the manual choke during the rebuild.  This was my first experience working with a carb and so I don't even pretend to know what I am doing.  I am trying to learn though.

If the weather is decent Thursday, I may pull the fuel line and check the pressure there.  I've been wanting to add a second fuel filter anyway and I can do that while I test the pump.  

that year chevy truck had an electric choke...  and they were VERY CREATIVE the way they wired it..

it involved a 2 terminal or 3 terminal oil pressure switch..  i have a wiring diagram for it someplace... have to search it out in my other computer..


got pictures...


this kinda shows it...  warning... look carefully.. you will see TWO oil pressure switches.. one with a single terminal is for the oil light on the dash board...

one with 2 terminals is for the choke..      with the 2 terminals. as the oil pressure comes up... the pressure switch closes and bridges the contacts... sending power to the choke  coil...   but .. you will also find that there is a wire going to the cluster.. that is for the choke light...   if the choke switch circuit fails...  because there is power coming thru the bulb.. to the switched side of the circuit.. it will show power there.. but NOT enough current to heat the choke coil to warm it to open it...

it will also turn on the light if the switch does not close..  or thepigtail on the switch is disconnected as the load of the choke coil will cause the electrons to flow thru the light and turn it on...   once the switch closes and powers the choke coil.. there is equal power on both sides of the light and the choke light goes dark as the electrons have stopped flowing..

told you it was a tricky circuit..



 

you are going to want to spend some time flipping thru the many pages of this book showing pictures of the parts..


http://www.gmpartswiki.com/getpage?pageid=54959


then you can find the part numbers below after you identify the group numbers in the above catalog...


http://www.gmpartswiki.com/getpage?pageid=60412


enjoy... and i hope you have a nice and large hard drive so you can save a lot of the images...

click a page in the middle and it opens for you....  

oh... this is the connector for the electric choke usually...

 

Bosketti:
I've had 425/427 Fords and 390FEBB's that were cold blooded.
I also had a 1970 Plymouth Duster that when it sat in the
extreme cold of New England it was a bear to start. But
you have probably had a lot of GM cars. I agree I use to
get a new Company car every 14 to 16 months, before the fuel
injection corrected all those problems. When you had a GM car
that functioned you didn't breath on it.
 I think it was just the way they were calibrated, and set
up at the factory. Carburetor and choke pull offs are a thing
of the past. All you can do is check the adjustments. If you
get them correct leave them alone.....Good luck

Bob  

Wayne,

Looking at your wiring diagram I think it may not be accurate for my truck, correct me if I am wrong.  The second oil pressure switch is labeled for v6 engine only so that would not apply, correct?

Bob,

I understand GM isn't the only manufacturer to have the coldblooded issue.  I still remember my dad's '71 F100 where to start it cold it took 2 sticks: 1 between the seat and throttle and one to hold the butterfly valve open.  What I am hoping to get to, and I understand there is a lot to learn to get there, is how to properly adjust the whole system so you don't have to warm it up for 10 minutes to get it to stay running.  I can understand and deal with a short warm up period but this strikes me as excessive and wasteful.  I know, talking about waste while trying to keep a 454 running seems contradictory, but HEY, I roll like that.  

I guess at 42 I'm a bit late to the game as far as learning this stuff, but I figure it isn't too late to do so.  I guess I need to find a good tutorial on carbs because at this point there is way too much theory I am missing to make sense of all this.

Thank you both for your replies.  Hopefully I don't turn into a PITA as I try to absorb all this.

Scott  

yea... i know it says 6 cylinder..  look under the drivers side of the distributer..

how many oil pressure switches do you see..

one or two...  

this is a 77 to 80 chevy V8 truck wiring diagram.... HMMMM

where is the choke wiring...

i will have to dig out a printed manual.. take a look...  

 

Scott:

I remember my very first 49 Dodge flat head 6 cylinder. 6 Volt battery. I would stuff a shop towel in the carb to start it. Thats how much it had to be choked. Then with a 6 volt battery it only cranked about 4 revolutions....LOL...
  I think Scott on the Q-Jets there is so many adjustments, for the choke pull off. Too much and the weight drops too fast. Not enough and it will take you to work with touching the throttle...
  Scott there is a company that has very good self help books. I've bought some back in the 70's before a lot of our hobby became what it is today. If you want.
The website is www.cartechbooks.com They are very good. In fact they have one for the Q-Jet...They are a good carb. if it wasn't for that...Hang in there.

Bob aka-pepsi1  

Scott:

This is the very god's honest truth. When my oldest son who is 1 year older then you. He brought his new girlfriend home for my wife and I to meet. He introduced her as PITA her name is "Christine". I'll tell you she lives up to that too...LOL...

Bob aka-pepsi1  

how about one version of a quadrajet manual..

Chevy_Rochester_Quadrajet_4MV_4MC.pdf

you will want to right click on this.. to save the file as...


i tested it..  look at the amount of posts i have.. its not spam..  

Wayne,

I'm not worried about spam.  You have been providing great information and I appreciate it.  Thank you for the manual.  It takes me a bit to digest this kind of information as I am learning the theory as I go here but I am reading through it.  Thank you.

Bob,

Thanks for the link on the books, I've bookmarked that and already started putting together a shopping list of car tech books.

Scott