1972 Scout 2 out of wack

S

stephenjimenez

New member
Hey guys,

im pretty automotive savy but for some reason I cant for the life of me figure out whats going on. Its a 1972 Scout 2 345 5.7 v8 with a 2bbl holly carb. For a while I knew it had a pretty good vacume leak but I had the carb adjusted to compinsate that. Two days ago I removed the heads and the intake manifold to do a little tlc. I replaced the head gaskets, intake manifold gasket, valve cover gaskets, water pipe rings, exhaust manifold gasket, completely deleted the smog system, plugged the old a.I.r pump ducts on the head and gave it a new hemi orange look. But when I fired it up it runs stronger but the timing is way too advanced. I never took the distributor out or even touched it. Ive been trying to set it correctly but if I move iot either way I runs worse. When I put it in gear it dies. Please help!! :mad2:
 
Most likely the vacuum advance hose is on a port that is supplying the wrong vacuum signal. Disconnect it and take another timing reading...
 
I can't find my vacuum schematic but the port is in the middle on the back of the carb if it is the oe carb if I recall correctly. I believe it should be timed vacuum not ported. Basically at idle there is a very small if any suction as apposed to ported which is manifold suction all of the time...
 
Ok. I might of crossed a vacuum hose?? Right now I have a hose running from two vacuum ports on the manifold running to the distributor. Is that right? Ill try to look for a schematic as well.

Thank you for your time.
 
I havent had a chance to run it with it disconnected yet. But right now its about 4 inches from the timing gauge near the harmonic balancer.
 
So over the weekend I corrected the vacuum hoses and the timing was even more advanced. It was a little more that 180 degrees off. I tried lining up the # 8 cylinder with the # 8 spot on the distributor but the timing stayed the same. I tried taking the distributor out and moving it over a tooth.I put it back. Then moved it back a tooth and now it just wont start. Im starting to think that my timing chain might have jumped. The truck has 135,000 miles on it so it might be time change it.

Also, my original carb had the vacuum advance port on the very bottom front of the carb and no port on the side taward the top but the carb I have now has one on the side toward the top and one on the bottom in the front that was not being used. I tried plugging the one on the side and just using the one on the bottom. I noticed the one on the side had much more vacuum pressure. Other that the chain and gears being worn im lost. If I missed anything please let me know.

Thank you for your time.
 
No timing chain on a sv engine so that's probably not the problem. Some times it's so hard to diagnose these problems when you can't see and hear the engine.
 
Well now its just back firing out of the carb and or exhaust. I know thats an indication that the timing is way off.
 
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Ok, you had the heads off, so you had the plug wires off I assume. Re-verify the firing order. 1-8-4-3-6-5-7-2. Distributor turns clockwise, so remove #8 plug, and have an assistant hand crank the engine to the "0" degree Mark while you feel for air being pushed out the plug hole. If no air is felt, you're not on the compression stroke. Have your buddy crank it around again. Normal up the #8 plug/wire situation. Then trace that plug wire back to the cap. That is #8. Verify the firing order from there. Then pop the cap off and peek at the rotor. If the timing marks are still at "0" then the rotor should be pointing at the #8 spot on the cap.
If not, then you'll need to re-stab the distributor to get the rotor in the right spot. When you're done, make sure you have enough room to swing the distributor both ways without the vacuum advance canister hitting the water neck or manifold.
Let us know how it goes.
 
Ok, the firing order is correct. The distributor is lined up with the # 8 piston. Still shoots mist out of the carb overfill port on the top center of the carb. Is it possible that the timing gears jumped or something? This doesnt make sense. It ran when I originaly put it back together then I tried to fix the timing and boom wont even start. If all this toying around sent the piston to hit a valve would it still start? How noticable would it be?

Thank you for your time
 
If you didn't take the timing cover off or remove the cam gear or the crank gear, then no. There is no way the cam has "jumped some teeth." there is no way you have bent a valve by doing what you described. You say it ran after you got the heads back on? Just because its running bad doesn't mean its not a simple fix.

I'm not convinced the distributor is dropped in correctly. Firing order on the cap and plugs might be right, but if the distributor's rotor isn't pointed at #8 when the timing marks are at "0" on the compression stroke, then you're still chasing your tail.
 
You've got a sticking intake valve... Just my take on it...
Do another compression check.

Or

as db wrote there are two positions (revolutions) you could have the #8 timing marks lined up.
Line up the marks. Yank the dizzy and rotate the engine by hand one turn stoping when you line up the marks and restab the dizzy to fire # 8.
Try and run it.
 
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Alright. So its running now. Thank the lord and all my good buddies at IH america. I took the wires off and had my buddy watch the # 8 piston and lined up the timing Mark with the piston then re installed the wires usinf a diagram. Cranked it kinda iffy, restabbed the dist then boom its alive dr frankenstein. I do think a valve is sticking though. Lastnight I tuned the carb and it ran like a dream. But this morning it has a put or it feels like its missing. The timing was spot on yesterday. The miss eased up once I turned it off and went in the store and came back out. Maybe some lucas oil stabilizer will help? It ran better after it ran for a but. Its the first day its been driven since I put it back together.

Thank you and I appreciate your help. :smilewinkgrin:
 
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Nice!!!! Good job!!

Liberally,spray good carb cleaner in the carburetor (both barrels) while it is running at say 1500 rpm until it wants to quit and let it clear up. Repeat a couple of times... The sticky intake valve should clear up. Make sure you have new clean name brand fuel in the tank and drive the snot out of it. A long highway drive.
The name brands have better cleaners in them. The old fuel varnish on the valve stems can be a big reason for the sticking. The cleaner will remove it so oil can get in and keep it free...
 
Thanks! Yea I noticed that when I drive it for a while it goes away. I might also be the carb not being 100% correct. Ill work all the kinks out over the weekend. :smilewinkgrin:
 
I've found that marvel mystery oil is about the only thing that will cut the gunk that builds up on the stem of a stick valve. Use it in the gas and oil and see if it frees up.

Also sometimes a good italian tune up works too. These engines need a good hard run from time to time to burn out the carbon deposits. After all that is how they were designed to run in medium sized trucks.
 
So im not convinced its a valve. It only acts up when I start it for the first time of the day. Then when I start it again after that it goes away. There might be something in the carb bowl. Im ganna take it apart today to see if there is any build up of crap in there. Even in the morning it purs like a kitten when it idles its just when I give it more gas to accelerate or maintain speed. Does that sound more like a fuel delivery problem?
 
That's the symptom I've had and witnessed exactly. Limp at first cold start. You could hear it crank faster as the weak cylinder came up under compression that was not there...

After I worked new fuel in to it and a few starts with carb cleaner in the throat it has been fine since.
 
Ok, sweet...you got it running again! Now help us understand the rest of what's going on.
Robert and some of the oregon fellas have experience with sticky valves. In a nutshell, fuel varnish "glues" the valve stem inside the valve guide. Not even the valve spring can return it to the closed position. But like rk says, it tends to get better with heat. The carb cleaner trick is good and with a long drive and fresh fuel should clear that up. No experience w/mystery oil personally.
But you are also mentioning a stumble or bog off idle or at low rpms. Is this a new problem? Have you looked at the accelerator pump? Should squirt a nice stream down the barrels when you rock the throttle.
Other than that, it looks like your carb May need some love. Any chance you could borrow another one to try?
Let us know what you find.
 
By the way I just went through another round of this with my Scout about 1 month ago... Started fine after a long spell of inactivity. Took it for a long freeway drive. Had lots of old fuel. Stopped at a buddy's house for a long evening and bbq. Went out and it would barely start. Had the bad limp upon cranking, like maybe 2 cylinders had compression. Had to run for about 2-3 minutes before magically smoothing out... The next morning the same thing... Smoothed out after about 2 mins. The following weekend I filled the carb bowl through the bowl vent and shot a bit down the carb. Started better. Filled the other tank with new gas and topped the other one off. Drove the snot out of it. Been ok since..
 
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