# Is taking off all the plug wires a bad idea?



## Cedar Ed (Jan 6, 2013)

I am having trouble finding the timing marks,so it's and older '78 GMC 350.Friend say the distributor,or plug wires are off,it runs ok,but put in a new distributor,borrowed a tool,it is a plug/screw that goes in #1 plug,instructions are take out plugs then turn crank by hand until it stops,then I am at TDC,then reinstall distributor,plugs,Then I don't know the next steps,but it should be close to good.Probably using the timing light,but last time we couldn't set it due to not seeing the marks,but it did run o.k,just trying to get it right.


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## Uncle John (Jan 10, 2013)

If you cant find a timing mark, advance timing till it kinda kicks back a little when starting. Then back it up till it doesn't. 
Drive it and if it pings (rattles) on acceleration back it up a little till it doesn't.


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## Uncle John (Jan 10, 2013)

If you are absolutely sure its at TDC, put a mark on it with chalk.


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## Uncle John (Jan 10, 2013)

Guess I didn't answer your first question.

If you have to move wires around you didn't install the distributor properly.

No big deal as long as the vacuum advance doesn't hit something preventing setting timing properly.


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## ft. churchill (Jan 10, 2013)

Your way of finding top dead center can put you off 180 degrees. The for sure way is to remove the driver's side valve cover and watch the valve over the number one cylinder. Both valves will be stationary if your at TDC on the firing stroke. If the exhaust valve moves your at TDC center of the exhaust stroke. You can still use your piston stop tool if you wish, lie if your timing marker is gone. I've run them before in a pinch, one or more teeth out on the distributor, you have to move the wires around. It's a royal PITA. Keep foolin' with it you get it right. The previous posts are all good info as well. I usually "road time" my engines anyway as they are not stock and the factory settings are not close. Listen for the pinging and back it off. Another sign of too much advance is hard, slow cranking when starting. To little advance starts easy, runs good at low RPMs then is a weak dog at the upper rpm range. Perfect will be when it never pings and if you go any more advanced it will ping.


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## Cedar Ed (Jan 11, 2013)

When I had the old distributor in, the vacuum advance pointed behind the right wheelwell,now with the new one in,it's more towards the firewall. If I move it back the old way it won't run.With it compensated it runs,ok. Something seem a little off.


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## Uncle John (Jan 11, 2013)

Both positions were wrong.
The vacuum advance should point a little towards the right fender from straight forward.
Find TDC. With distributor out, check position of the tongue (couldnt think of a better word)
on the bottom of the distributor shaft.
That fits into a groove on the oil pump shaft.
Use a long screwdriver to turn the oil pump into proper position.
Install distributor with rotor pointing to #1 wire terminal and vacuum advance pointed where it should be.It probably wont fall right in. 
You might have to barely bump the starter till it drops in. You might have to repeat several times.


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## Overtrained (Jan 11, 2013)

Pull the #1 plug out, ball up a paper towel or rag and stuff it in the spark plug hole. Pull off the coil wire or the 12V power wire(HEI) going to the distributor so no spark will be present, bump engine over with the keyed ignition.....bump.... bump.... bump

you will here POOOFF!! and the paper towel will blow out on the compression stroke. Now you are near TDC on the compression stroke.

Check your balancer and move the line on the balancer to "zero", you can do this with a breaker bar on the crank pulley. 

Once its on zero you can drop your distributor in, follow this diagram for the correct placement of the rotor on #1 on the cap. Mark the cap and run your wires from there in the following sequence....


*1 8 4 3 6 5 7 2 in CLOCKWISE order*

Note: As long as you route this order on the cap after you find TDC on #1 cylinder you can make any terminal on the cap #1


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## Cedar Ed (Jan 11, 2013)

I have the HEI,but didn't remove the wire.And haven't used the breaker bar to turn it yet,first thing tomorrow,will give it a try,and compare to diagram. Working on it in the driveway,20 degrees outside.


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## Cedar Ed (Jan 11, 2013)

So if I am off by a tooth,or off by 180 degees ,just take it out and start over by going to TDC then reinstall,and check plug/wire fireing order,and turn oil pump,if needed,just about got it I think.


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## Cedar Ed (Jan 12, 2013)

*rotor question*

Should the rotor point to the#1 cylinder,or the #1 plug in the cap?


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## Uncle John (Jan 12, 2013)

Cedar Ed said:


> Should the rotor point to the#1 cylinder,or the #1 plug in the cap?



#1 Wire in cap


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## Uncle John (Jan 12, 2013)

When you install the dist. the rotor will move a little. 
You can see why by looking at the gear on the dist. bottom.


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## Overtrained (Jan 12, 2013)

Cedar Ed said:


> Should the rotor point to the#1 cylinder,or the #1 plug in the cap?



The rotor should sit under the #1 in the cap. As mentioned, you may try and drop the distributor/rotor in near the #1 in the cap and the oil pump shaft wont be lined up.

Try and wiggle the distributor, it may drop in.

If it doesnt, bump the key once and it will drop in.

Once its dropped in it wont be in the #1 position because you cranked it over a bit, put the towel back in the cylinder and repeat the process.

Bring #1 cylinder back up to TDC and check the position of the rotor. If it looks good, put the cap on and mark which terminal is going to be your #1 and run your wires from there clockwise around the cap.

1 8 4 3 6 5 7 2


Let me know how it goes.....


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## Overtrained (Jan 12, 2013)

NOTE: If the dist doesnt drop in on the first ignition bump hit it again until it does.


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## Uncle John (Jan 12, 2013)

Overtrained said:


> NOTE: If the dist doesnt drop in on the first ignition bump hit it again until it does.




True

And you might be 180 degrees off.

Try again!


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## Overtrained (Jan 12, 2013)

Uncle John said:


> True
> 
> And you might be 180 degrees off.
> 
> Try again!



You get a pretty good pop using the "towel" method to find TDC, its less noticeable on the exhaust stroke which would put you 180 degrees out. 

Either way , OP check it after the dist drops in.


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## Cedar Ed (Jan 12, 2013)

Thanks alot I am out working on it,have a friend helping,so I'll get back here later and let you know how it's going.
I think the rotor was pointing the opposite way.


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## Cedar Ed (Jan 12, 2013)

Cedar Ed said:


> Thanks alot I am out working on it,have a friend helping,so I'll get back here later and let you know how it's going.
> I think the rotor was pointing the opposite way.



I'll keep trying!


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## Overtrained (Jan 13, 2013)

Cedar Ed said:


> I'll keep trying!



Get it squared away?


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## Cedar Ed (Jan 13, 2013)

*Squared away !*



Overtrained said:


> Get it squared away?



I know it's late, but got it all squared away with all of your help.Thanks.


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## Cedar Ed (Jan 13, 2013)

*To:Uncle John, ft.churchill ,and Overtrained,Thanks for your help.*

Well, after a friend came by and all of the great advise,my truck is on the road,again!
It took a little while,by 3:00 pm we were on the road,had a few tense moments ,cranking the engine,with no start
and almost draining the battery,trying to just getting her to start.After a while and some fussing,got it to idle,although a
bit rough.Got snow and ice,on the ground here,so she was very cold to start.
Now,hours later we are ready to test drive,and the whole while my friend and I were working on the old Chevy,his wife and kid were 
loading up a cord of wood,dry seasoned N.W. mix of firewood,for the grandma who only has wood heat,at this time.
The grandma lives 50 or more miles awat,so this is no aROUND THE BLOK,oops.. type of move,we decided just to go for it,
because we were running out of daylight.
The checking of differential and transfer case fluids,was a game changer since the truck had been sitting for 9 months,and
they were both empty,would not have been good,on an old school full time 4wd.So after checking everything twice,with a cord 
of wood,made the journey.
So granmas house is way out in south prairie up a sttep ass hill.and I wasn't sure if something was gonna blow,with
such an incline,and so much weight,not to mention I don't even think the timing was on,after all we were road timing her my ear.


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## Cedar Ed (Jan 13, 2013)

*Pt. Two.*

And then ,there was the second hill coming up,so I pulled over to let some of the vehicles fly by,as we wern't making such
good progress uphill.And we continued on.So this time I said ,come on Betsy,and passenger and I patted dashboard,as I downshifted the 
auto trans into 2nd and stepped on the gas 3/4 throttle,we proceeded up the second (smaller hill) what a relief ,we made it over,
and coasting down the other side,what happened ,then? 
Oh no,loosing power steering,brakes,what the heck is going on?Uh oh she is dying,as I pull to the side with headlights on ,as it is
now dusk,the engine no longer revs.


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## Cedar Ed (Jan 13, 2013)

*Won't start*

Only a quarter mile to grandmas and what could it be? To make the long story short,pulled the starter out,to it to the autoparts store,and oh,yeah.The starter went out,how did it cause the truck to die, I don't know,but that's what happened,and the nice thing about about old truck like this is the starter was around 40 bucks,and lifetime warranty ,so yeah! I can do that,dropped it in,and good to go!


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## Uncle John (Jan 13, 2013)

So why did it die in the first place?

Old gas? Fuel filter? Fuel pump?


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## Cedar Ed (Jan 15, 2013)

Uncle John said:


> So why did it die in the first place?
> 
> Old gas? Fuel filter? Fuel pump?
> 
> ...


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## Uncle John (Jan 16, 2013)

Does it seem to be ok now?


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## Cedar Ed (Jan 17, 2013)

Uncle John said:


> Does it seem to be ok now?



IT starts easy,but then idles high,and a little rough when driving at low speed,and it had a little backfire through the carb.


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## Uncle John (Jan 18, 2013)

Cedar Ed said:


> IT starts easy,but then idles high,and a little rough when driving at low speed,and it had a little backfire through the carb.



If its idling faster than it was could be the timing is better. Could also be a vacuum leak. 
Backfire through carb could be a cracked distributor cap. 

How did it run before you started working on the distributor?


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## Cedar Ed (Jan 18, 2013)

Uncle John said:


> If its idling faster than it was could be the timing is better. Could also be a vacuum leak.
> Backfire through carb could be a cracked distributor cap.
> 
> How did it run before you started working on the distributor?



The idling is getting smoother,and no more backfiring,after a 15 mile test drive after a warm up,and then it wanted to die,and did start dying at low speeds,example:when it was at a stop sign,it died,but when running at 35 ran normal,then turned into driveway ,it died before I could park,then had to give extra gas to keep running,let of gas then would die while in nuetral,and in drive.
It ran good before the distributor was replaced,although it didn't like to start on cold days.After I got a different distributor ,it started alot easier,then the auto parts store had a brand new one one sale,it was a MSD Streetfire distributor,a complete HEI style with cap and rotor,so I got it,but still have the spare,and they took the bad one as a core.
Now I am guessing it may have some other issues,because of the engine dying,perhaps just a fuel filter I am hoping.


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## echoshawn (Jan 18, 2013)

High idle and backfiring could be timing too advanced as well. After sitting for that long, most likely with e10 gas, probably have plenty of water in the tank. Those old 350s are pretty damn bulletproof though, so some fresh gas, fuel filter, etc should help out. A can of carb cleaner works great for checking for vacuum leaks around the carb base gasket and intake. Just going to take some tinkering.


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## Cedar Ed (Jan 18, 2013)

echoshawn said:


> High idle and backfiring could be timing too advanced as well. After sitting for that long, most likely with e10 gas, probably have plenty of water in the tank. Those old 350s are pretty damn bulletproof though, so some fresh gas, fuel filter, etc should help out. A can of carb cleaner works great for checking for vacuum leaks around the carb base gasket and intake. Just going to take some tinkering.



I am going to try spraying some carb cleaner on there,and check for some leaks!I got some fresh gas,but after sitting for 9 months I guess some stuff can get stirred up,maybe have a clogged fuel filter,hope it is something simple.Someone once told me to "make sure all the bolts and things are tight"on old trucks.


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## knothole (Jan 19, 2013)

Don't laugh and if it's already been mentioned, sorry, but also try running some Startron (heavy mix) in the next couple tanks of fuel. Stuff seems to do a good job of getting rid of the ethanol gunk that builds up.


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## Uncle John (Jan 19, 2013)

Definitely change fuel filter!


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