help with a 68 c-10

[barn]

hi, i bought a beatup 68 c-10 awhile ago. it has been having some problems but untill recently it ran well enough to drive.

the truck wouldnt start the other morning, i messed around with it for awhile and it still didnt start...later i went and bought some starter fluid and tried that. it would run as long as their was the starter fluid to burn..i tried it a bunch of times and then gave up.

i took a closer look and found a big screw missing on the underside of the carburator. its a rochester M monojet...anyways the thing seems to be falling apart. if anyone could recomend a new carburator for a 250 straight six, that would be great.

my two other big problems....one, is that sometimes...most of the time while driving i have to shift into 2nd before i can shift into first...if i dont it grinds. its a 3 speed shift on the column.

the other one ...two, is that exhaust fumes are leaking into the cab from the engine compartment. and im having a hard time telling where exactly its coming from.


if anyone could help me with one or more of the problems it would be appreciated

[Ole Blue 68]

What are you looking for in a carb? If you want a daily driver, consider having the monojet rebuilt.

[shifty]

Seriously? Just go to your local auto parts store and buy a replacement monojet. It will be around $80-120 for a refurb/rebuilt one and you will need to turn in your old one as a core. You could buy a rebuild kit for $30-40, but you will still have a missing screw and stuff, and it's a hassle to bother with learning how to rebuild the things.

I just gave away two with a recent sale I'd done. Wish you'd have popped in asking about 6-7 months ago.

[boundstaffpress]

A kit is good if you have a complete but gummed up carb. Since you are missing pieces, I'd do like others have said and buy a reman job.

Now for some fun.
To find your fume leak.
1. Dissasemble entire cab.
2. Media blast cab removing all paint and caulking.
3. Re-caulk as outlined in the Assembly Manual
4. Repaint cab
5. Replace all grommets on the firewall.
6. Reassemble entire cab.
Try to be done by dinner time.

Seriously if you want to find a fume leak, inspect all the small openings in the firewall from inside your cab. Put a shop light under the truck and another in the engine compartment. You should see several places where exhaust could get in. I use dum-dum (a sticky, greasy putty) to temporarily fill small holes. Bodyshop guys will have this on hand to use as window putty.

Lots of us have enough rust that we'll never fill all the holes.

[shifty]

I missed the other two items.

For the shifting problem, could just be the linkage is shot or your clutch is poorly aligned. Mine did the same thing until I ended up putting a new clutch in mine out of frustration - I noticed it was out of alignment when i pulled the engine (first time ever pulling one here, and the people on this board helped me out!), and it was a little worn, so I just got a new one, aligned it proper, than reinstalled - one of the two things fixed the problem...I don't think the transmissions are synchronized in 67 and 68...could this be part of your dilemma?

For the leak, is the air on when you smell it or not? If it is, check the big bulky box on the passenger side of your firewall - this is where the blower fan is located. It's probably cracked and you have a header leaking or something. I guess it would be advisable to put a light inside your cab at night and light it up, close the hood with it in there, then get under the dash and look for light coming through. Move the light around. Try stuffing something in your rear cab corners in case they're blown out and that's where it's coming through.

EDIT: Nevermind, The light idea was already given

[70c/10barebone]

Daily driver tip- If you're like most and have missing or badly rusted cab corners driving in the winter can feel unbareably drafty. Before I had time and money to replace my cab corners/rockers I used a can of $3.00 expandable foam from the depot. It is better then stuffing rags that collect water, making your problem worse. When the stuff hardens you can shape the outside to follow the cab lines. Make sure you have newspaper or something to catch drips. Just might make winter driving a little more comfortable/safe if you have a leaky exhaust.

[67chevemall]

new carb

WD 40

scrap your carpet and you'll find all the holes you need.

[barn]

thanks for all your advice.

the carburator has been rebuilt numerous times. last time i looked for a rebuild kit i had a hard time finding one that worked right, i did find a MV/M one that seemed to work...the carburator seems to be warped, so some edges dont sit exactly flush. the kits gaskets arent thick enough to fill in the gaps. i looked up the serial numbers i could find and the carburator or at least part of it is from a 64 pontiac...i dont know if that means anything or not.

i use the truck mainly to haul stuff, but i do like taking it for drives on the weekend. so i dont mind spending the money to buy a brand new carburator, so unless anyone can suggest something better i guess ill buy another rochester M.

thanks for the help.

[Americanrider]

Try running some SEAFOAM through the engine, when she starts to smoke you will locate every exhaust leak in the system. I think it would be best to fix those in along with sealing the cab leaks. A trip or two to the wrecking yards and you might come up with another carb or at least parts to build one good one from the two.

Check the shift linkage grommets where the linkage hooks into the column and on the tranny end, they wear out and the linkages will bind, it's a cheap fix too.

[shifty]

Sea Foam can be found at the local auto parts store. The trick is to use a vacuum tube (power brake vacuum line works great) to suck up the stuff slowly - key is slow speed - until you finish off your load, at which time you want to dump in enough to kill the engine and let it sit for 5-10 miniutes to break stuff up, then fire it back up and it will smoke like hell while burning all that loose carbon out.

This isn't something you want to do on a 150k mile + engine.

[azolakov]

Originally Posted by 70c/10barebone

Daily driver tip- If you're like most and have missing or badly rusted cab corners driving in the winter can feel unbareably drafty. Before I had time and money to replace my cab corners/rockers I used a can of $3.00 expandable foam from the depot. It is better then stuffing rags that collect water, making your problem worse. When the stuff hardens you can shape the outside to follow the cab lines. Make sure you have newspaper or something to catch drips. Just might make winter driving a little more comfortable/safe if you have a leaky exhaust.

Super idea! I'm gonna try that for my holey rockers.

[mvfd70]

Originally Posted by azolakov

Super idea! I'm gonna try that for my holey rockers.

except that stuff absorbs water like a sponge. It might be ok for a temporary fix but you're gonna have a real fun time gettin it out when/if you go to fix it. If you don't intend to fix the rust, that will just make it worse.