ok im convinced my trucks rough idle is due to a vaccum leak, im going to replace my pcv line and my disributor advance line, my brake booster line looks new, and all other ports have new plugs( emissions removed by previous owner). my friend told me wd40 works well at findin vaccum leaks so ill use that to check carb base, intake etc..

this truck has a newer holley 4 bbl with 2 idle mixture screws put on by the previous owner so im thinking if its not a vaccum leak it must be timing and or carb. i dont have a timing light or a vaccum gauge so my question is, is there a old school trick to setting timing with no light? how about tuning the carb with no gauge. im on a strict budget and this thing is gettin 9mpg so thats where my tool fund is going oh the trucks an 86 351w

 

I just read about this in the 335-series forum a week or so ago, iirc what you basically do is put the #1 piston in the tdc position, I think the rest of the procedure involved a wire and a light bulb and you adjust the distributor one way or another until the light lights up. Or shuts off, I honestly don't remember the exact procedure but I think it can be done, at least for the initial timing upon engine reassembly.

Just tried to search thru the 335-series forum but apparently the search function isn't working yet.

-ct

 

There is a way to set the timing without a light, but it's not that easy.

First thing you have to know is that when setting timing for best performance, you only go by total timing and generally do not worry about timing at idle or with the vacuum advance hooked up.

However, this is even more difficult to set without a timing light, so I'll go over how to set your idle timing without a light.

First step is to set your engine at #1 tdc. Set the balancer to tdc and then pull the dist. cap to see if the rotor is facing the #1 plug. If it is, move to the next step, if not it'll probably be facing the #6 plug which means you have to rotate the engine another revolution to get it facing #1.

Next, pull the plug from the #1 cylinder and leave the spark plug wire hooked to it. Rotate the engine from zero to the desired timing (probably 12deg btdc).

Loosen the dist. Ground the electrode of the plug you pulled (and make sure there is no flammable liquid or gas around) and then turn the ignition to run. Grab the dist. and rotate it back and forth until the plug fires. When you can find the exact point that the plug fires, you have your timing set to what the balancer says. You'll usually want to move the dist. back and forth a few times to find the exact spot.

Turn the ignition back off, tighten down the dist. and put the plug back in and you should be set.

If you want to set the total timing, you have to pull the rotor off the dist, remove the springs from the mech. advance and set the dist. to full advance, lock it there and put the rotor/cap etc. back on. Then you have to measure the balancer and mark either the timing cover or mark the balancer relative to the zero dash on it at whatever you want your total timing to be. I would make a mark on the balancer at 30 degrees. Then do the same as above except instead of setting it to 12 degrees, set it to around 32 degrees (line up the 30 deg. mark on balancer with 2 deg timing mark). Then repeat the process of making the #1 plug spark with the mech. advance at full advance in the dist. making sure when you're done you pull the rotor back off and replace the springs and then put it all back together.

However, all of that will take you an hour or so, where if you had a timing light you could do it in 5 minutes. Borrow one if you have to.

Set the idle mixture screws to where the truck idles the best, then back them out another half turn.

 

yeah im going to try and find a timing light i do appreciate the help if all else fails im gonna give it a shot