Tune up?

[69gmc]

I made a different post in the older trucks section, and didnt get much of an answer, so i thought i would do the same here. I am going to pick up my 1969 GMC short-step 4speed on friday, and i plan a complete tune up of it. What oil is best for this? What about sythetics? The engine has less than 100k miles, and we put synthetic in my bro's truck with 100k, and it did not leak any. What are the best spark plugs to use? What about wires? I have some coolant, so i am not worried about that. Also, does anyone know how much of the fluids I am supposed to use? (I.E. how many quarts oil/coolant). Thanks, and believe it or not, this is the first gas engine i have owned, but i am no dummy about them either, i have helped my brother do stuff on his ford. Also, where are the fuel filter locations? Are they hard to change? Thanks in advance, the engine is just a plain old 350.

 

I appriciate it

 

Steve

[Haulin' 8.1]

Is the engine original? 5 qts. of high mileage 5w30 non synthetic. I would be to worried about synthetic cleaning off some residue that's now preventing a leak.

 

Best plugs: AC Delco or Champion platinums will do well.

Wires: a similar brand with spiral wound wire conductors. Carbon core wires won't last as long. Avoid Bosch plugs and house brand wires.

 

Coolant depends more on radiator size, HD cooling, AC or no, etc. Two gallons will cover you. Mix 50/50 with distilled water. I would install a fresh 190* thermostat. Check those hoses for wear, age.

 

The fuel filter on that engine is most likely to be in the carburetor, right behind the fitting for the fuel line. Use line wrenches and penetrating lube to avoid headaches. You disconnect the fuel line then the large line fitting nut on the carb and the filter will come out with it due to a spring pushing it against the fitting you are pulling off. Find at auto parts.

Also there's a good chance that someone has installed a larger external filter in the engine fuel line itself some where between the mechanical pump down on the front cover and the carb. It will look like a small canister with the line going in and out each end. Those kind are universal and can be found at auto parts.

 

Find an "Old Pa" that can school you on the installation and setting up of a points based distributor, unless someone has installed an electronic distributor you're going to need to install points and set the dwell at every tune up. At that age a new ignition coil is good medicine. Inspect the cap and rotor closely. Make sure the springs and wieghts in the bottom of the distributor aren't rusted stiff, you should be able to wiggle/move the rotor a slight bit and it should pop back when let go. Spray them with penetrant etc. The springs and wieghts are you're WOT timing advance. The small can on the side of the dist. with a vacuum hose is the cruising/milage timing advance. Check that the vacuum canister on the distributor is air tight and will move with vacuum applied to the hose fitting, use a hose from the intake with the engine running at idle to check. The vacuum hose that's supposed to be connected to the dist. will have almost no vacuum at low idle, lots of vac at a slight throttle as in fast idle, and no vacuum at WOT. If it's not acting like that or has full vacuum at idle then it's hooked to the wrong nipple on the carb, find the right one near the front down low.

 

Those old ignitions are weak by todays standards, everything has to be right or you'll have troubles. The good news is that they are cheap and predictable, problems are easily found and repaired. A dwell meter/Tach and timing light are needed to do this tune-up. Beg borrow or steal them, try a pawn shop for bargains. Cylinder #1 is the Driv. side front, that's the one you set the timing with. #2 is pass front, #3 is drivers 2nd etc. The firing order will be cast into the intake manifold 1-8-3-2 etc. This is how the plug wires should be arranged on the distrubutor. By the way don't pull the distributor out unless you're sure you can put it back exactly where it pointed before.

 

Buy a can of carb cleaner and with the engine off hose down the carburetor inside and out (don't take it apart just spray everything including holes) until the can is empty. Work the linkages by hand to free them up when spraying. Let it sit for an hour then crank it up. This will help the carb work properly, it's a machine and it gets gummed up with petro residues.

 

This should have you worried LOL. It's not as compicated as it sounds, get an old shop manual or check the library for detailed instructions and specs.

Vernon