Anyone want to play virtual Chevy mechanic??

[Jeff K]

Anyone want to play virtual Chevy mechanic??

My neighbor dropped off his 1969 C10 250 straight 6 truck. He has been dinking with it for about a year. throwing parts at it left and right. It still won't run.

It had a no spark issue. I found a damaged rotor, new, but damaged.
I replaced the cap and rotor, again. And now I do have spark but it is very weak and intermittent. tiny yellow spark. And it doesn't even attempt to fire. I checked the static timing and set it to about 10 before TDC.
Compression check was good, all six at 175#

he put a new carb, fuel pump, starter, plugs, cap, rotor, wires, and ignition switch in it. Just throwing parts at it. I have not even looked at the carb except to see that the accelerator pump is pumping fuel.

It's been a long time since I've worked on something like this. It should be simple.
I checked the spark coming out of the coil and it is a lot better than the the spark coming out of the cap. I don't have a bunch of car parts laying around anymore.


Any thoughts?

[YoungPUP]

Weak coil: not enough azz to push the power needed.  Bad coil wire going to the cap.

[Jeff K]

Hmm, it is new, but I may have one laying around

[scoot]

Weak ground to coil, or ground to motor & chassis?

[Joevalk]

Sometimes the the distributor shaft goes bad on the chevys . you can replace the shaft or the whole distributor.

[Jeff K]

Sometimes the the distributor shaft goes bad on the chevys . you can replace the shaft or the whole distributor.

I do believe you are the winner!! I went back out to check the coil wire and did a little test. I put a timing light on it. On wire one it would flash now and then. But when I put it on the coil wire it would flash 4 times then pause then 4 then pause. So I pulled the cap and there is considerable play in the shaft.

 

[hbeck32]

Chect the points and file them and check the Dwell, even with worn shaft it should run, not at its best but still run.

[Brian]

If I remember correctly the dwell is set at 30 degree, that's if you still have a dwell meter on hand. It was either a match book or a dollar bill would set the gap on the points enough to get the motor running. I used to have points and condensors in a box before we moved. I know I still own a dwell meter, if you need it we could work something out.

[Mr.BubblesVRCCDS0008]

About 19 thousands on the point gap on new points or 16-17 on old points. Just make sure key is off before sticking that metal feeler guage in there. Also has the condensor been changed?  Also some of the old chevys ran a resistor on the firewall to limit voltage to 6 volts to the coil. A seperate wire from the solenoid bypassed the resistor when starting to get full 12 volts until engine started and starter disengaged. If it has the resistor just bypass the thing to boost voltage and see what happens.

[John Schmidt]

Jeff, I still have my old dwell/tach meter if you need one. Let me know, I can meet you somewhere on I-4.

[Jeff K]

About 19 thousands on the point gap on new points or 16-17 on old points. Just make sure key is off before sticking that metal feeler guage in there. Also has the condensor been changed?  Also some of the old chevys ran a resistor on the firewall to limit voltage to 6 volts to the coil. A seperate wire from the solenoid bypassed the resistor when starting to get full 12 volts until engine started and starter disengaged. If it has the resistor just bypass the thing to boost voltage and see what happens.

I don't think it has a resistor anymore. It has a "new" wire going from the solenoid to the coil. there is 12 v on the coil. and i did jump it to the battery to be sure.

[flcjr]

I can't remember if that is a 12v system or 6volt for the points but I do know if you run 12 to a 6 system it will run fine but you will burn the points up fairly quick.

[olddog1946]

An HEi distributor from a later model 250 will interchange, should be easy to find in the bone yard, provide a much better spark, with no points to go to S**t.

[Bigwolf]

In the year of 69, chevy ran a resistor between the keyswitch and the coil but it was a resistance wire of certain length.  It was not a resistor mounted on the firewall.  If that wire is replaced with a regular wire and a resistor is not added to the system, it will burn points out quite rapidly.  Also, some coils will break down quickly if ran at a full 12 volts and the result of this is that the engine will run only a few minutes before it starts backfireing and cutting out.  Usually, allowing the coil to cool down will allow it to run well again for a few seconds before cutting out again.  However, continuing to overload the coil this way will (in most cases) eventually destroy the coil completely.  As a side note, aftermarket "high energy coils" are even more sensitive than the stock coils to this abuse.

I believe olddog has the best solution if the dist you have is worn out.  Just be sure to also replace the ignition wire from the keyswitch out to the dist if you install an HEI.

Bigwolf

[Patrick]

If the accelerator pump is pumping then its getting fuel. If your getting a good 1/4" spark from the coil its good. These distributors are know for wearing the bushing, if it isn't really bad then it still should run. Points gap should .018-.20" which gives a 28-32º dwell. Make sure the points contact is 'square' and clean as well as a good ground for the distributor. The coil should have an internal resistor, if not, an external can be added. Points do not like 12 volts and won't last long if thats what they're getting. Voltage to the points will be 12 for a few seconds and should drop to 6-8.

Now, why was there a problem with the new rotor ? Is the shaft causing the rotor to beat the crap of the contacts in the caps ?

[Jeff K]

The top tab of the rotor was bent and dented. I assumed it was from one of the many "mechanics" he had helping him over the last 8-9 months. But there is a LOT of play in the dist shaft, front to back.
I don't know what has been done to it in the past, but I can see there is new wire here and there. There is only one wire going to the Pos side of the coil, and it comes from the starter solenoid. I measure 12v at the coil.

Not sure how easy it will be to find a mid 70's HEI in a yard in Orlando. They scrap them pretty fast around here. I'll have to see if the owner will spring for a new one.

[Joevalk]

As many parts they threw at it, what's one more? Distributor that is

[Blackduck]

Amongst all those parts  I did not see if the condenser had been replace.
If not that would be the first thing I would be changing. You will get a spark but not a good one with a faulty condenser.
With a worn shaft it should still fire at times, you can open the points up and alter the timing to get it to run.
Cheers Steve

[john]

                              new timing chain ?                  
                       new water pump while your there        

[Mr.BubblesVRCCDS0008]

Jeff there is a lot of people who love these old six. Have you search for hotrod sixs on the net. Probably all kinds of parts and imfo out there. These are pretty simple engine and should be easy to trouble shoot. My dad had a 68 chevy stepside when I started driving and even I couldn't kill that thing. Good luck

[Tx Bohemian]

engines 101

Compression
Fire
Fuel

You did a compression check and that looks good.  Don't think it'd be a timing gear issue (these don't have a chain, their gear meshed, right?)
If the owner or one of his buddies changed out the timing gears maybe their off a couple of teeth. But with the compression you say this thing has that would probably be unlikely, however I'm not sure what the compression should be.

You say the carb is pumping fuel, is the fuel good? Are you sure it's gas?
Maybe try some starting fluid just to see.

You say you did a "static check" on the timing.  What is that?
If the distributor has been out are you sure it's on TDC on the "compression stroke" and not 180* off?
Seems like with even a little spark it should at least try to start.

Just throwing out a few ideas.
I'd agree if it is a distributor to go with an HEI.  Way better than what you have there.

[Patrick]

Those points distributors are fine. Depending on where the resistor is located, there should be 12v to the + of the coil. If the resistor is in the coil feed line the voltage should drop. If the coil has an internal resistor the voltage on the - on the coil should drop.
Make sure the points contact are in good shape and changing condensor would be a good idea. Generally a condensor is either good or bad with nothing in between because they'll tend to go open. Coil/points polarity should be the same as the battery.
OH, and, don't go looking for a timing belt, there ain't one.

[Jeff K]

Static timing. I pulled #1 plug, rotated the engine with my manhood over the hole, when I felt pressure i lined up the timing marks on about 10 degrees before TDC, Pulled the cap and marked where the rotor was pointing, then turned the dist to line the #1 tower where the rotor was pointing. That should have gotten it close enough to run.

Since I wasn't sure about the fuel I poured some on my gas in the carb to see if it would fire. Got nothing. Shot a whiff of ether and got nothing.

But again, the timing light rarely flashes so it's not sparking very well.

[Tx Bohemian]

Static timing. I pulled #1 plug, rotated the engine with my manhood over the hole... 

OOOOKKKAY!!  Got it!

Not sure about that "manhood over the hole" thing but I get the gest.


Yeah, looks like it's pointing to the fire thing as your problem. 
And trying to figure out what others have done is part of the trick.  Your not just starting from ground level your in the basement working your way up to ground level!! And electrical issues to boot...

Since there has been sooo much stuff done before you have you tryed to get a wiring diagram to make sure things are hooked up properly?
Probably get one online.

Maybe you stated this but do you know what was the original problem?  Did it just quit on the guy or was there work done and then it had this problem?

Good luck!

[Patrick]

When you mentioned you were getting good spark from the coil, I was thinking that you were holding the coil secondary wire a 1/4" or so from a good ground and breaking the points.
With the points closed there should be no voltage at them, open them and there should be, along with a good spark from the coil wire.

[Challenger]

Just a note also, if he wants to keep the original distributor, Pertronix makes an electronic kit to drop into the distributor, the pickup bolts into the holes where you removed the points, and a magnetic ring drops over the shaft, Even if the bushing is worn, it will not effect the timing, No messing around with resisters or condencers. I have installed many of these and never had a problem. They run around $90.00  Let us know what you find wrong and good luck

[Jeff K]

If the key is on there is 6v at the coil, and cranking there is 12v. So the wire coming from the key to the starter is resistive, and the solenoid over rides that with 12v during cranking.
The spark on cranking out of the coil is weak and yellow it might jump a 1/4" maybe.  but it does spark every time the points open.
I want to see a big fat blue spark! I zapped myself with the coil wire by mistake, I was unimpressed. 

[F6BANGER]

Way back when I was a wrench I saw a bunch of wierd stuff. Especially fixing someone elses screwups.

Ive seen the wrong (too tall) dist caps installed and the rotor doesnt reach.
Wrong rotor inside cap.
wires put backwards in the cap...firing order going clockwise or viseversa that could make your timing 10degrees retarted.
Make sure the coil wire to the dist is good, if its old it may be broken down. Try starting the truck in the dark, you may see a firework dislplay bewteen old wires.

Like others have said, check grounds and/or loose wires.

Good Luck

[Jeff K]

I went and bought a new cap and rotor to be sure it was correct and the wires are new.

He said it had a fuel problem and it progressed into a spark problem. So after I fix this there is still a fuel issue, supposedly.


This is the coil firing a plug directly..

http://s287.photobucket.com/albums/ll126/kozmic1520/?action=view&current=coil.mp4	powered by Aeva

This is the spark coming out of the cap on #1

http://s287.photobucket.com/albums/ll126/kozmic1520/?action=view&current=Plug.mp4	powered by Aeva

[Patrick]

Is the starter motor 'draggy' ? If so, give the end plate a 'rap' and see if it helps. I ask that for a reason. Don't crank the engine over when checking for the spark. Just work the points by hand and see what kind of spark you get. It should be a good spark. If not you could have a bad coil or wiring to the coil. In an old Plymouth Troubleshooting Contest in 1965 the car I drew ended up having a bad primary lead that would show good voltage but not carry any currant. Also, it makes a difference which engine you have. The 250 has a long skinny one piece side cover. The 292 can either be one or two piece but is kinda fat. That makes a difference in the distributor. When you mentioned destroying a rotor it got me to thinking. From what I remember there are 3 different caps and rotors, all different heights.

[Jeff K]

The starter is new
When i cycle the points alone there is very little spark.

[signart]

That is plenty of fire on that plug to start a Chev.  Has the dist. been out? Unless you haven't tried to pour fuel directly in the carb or hooked the fuel ilne to a jug to eliminate fuel issue, I'd say it's out of time.

[F6BANGER]

Just thought of something else.   Pull all plugs and turn engine over while pumping the hell out of the carb. Check to see if the fuel is atomizing out of the holes.  The reason I say this is rediculous. A guy brought his car in and only the right bank was firing. After pulling out my hair and then pulling the intake off, I found out he made homemade gaskets and forgot to cut out the intake holes.  Hopefully there isnt anybody else in the world that bright.....you never know what someone may have done.


Just make sure you are getting fuel into to combustion chambers.....  

[Jeff K]

That is plenty of fire on that plug to start a Chev.  Has the dist. been out? Unless you haven't tried to pour fuel directly in the carb or hooked the fuel ilne to a jug to eliminate fuel issue, I'd say it's out of time.

Out of 20 rotations of the motor the plug sparked maybe twice.

And I did pour new fuel in the carb. It never even attempts to fire.

[hal47]

Distributor bushing is bad,sounds like someone let it go long,usualy the motor will surge going down the road,but sounds like they let it go to the point that it won't start. Have put a lot of them in back in the day. Have a good one.

[john]

                      " OH, and, don't go looking for a timing belt, there ain't one."                       

[Patrick]

                      " OH, and, don't go looking for a timing belt, there ain't one."                       


I only mentioned that because someone responded with that suggestion along with a water pump change. I've never run into an old in-line Chevy with a timing belt I'm pretty sure I never will. I would not have liked to see Jeff remove the front cover for nothing. I've certainly seen the camshaft gear strip many a time, but, I doubt thats the problem.

[Blackduck]

I go back to my earlier post, have you changed the condenser? A weak yellow spark is a sign of a bad condenser though usually you see a fair spark at the points but youhave said there is only a small spark.
Cheers Steve

[Tx Bohemian]

Thought of something else:

You say you poured fuel down the carb.  If the other "mechanics" did this same thing maybe the plugs are gas fouled by now. Maybe  the cylinders too.

Did you try to pull the plugs, stick the wires back on and crank to see if you're getting spark all the way to the plugs. This will help dry everything out too if this is the case.

I've seen this condition a few times with wrecked cars in our bodyshop way back when I used to mechanic (way back when there were still carbs and chokes). A wreckd car, still drivable, would be driven from the outside of the bodyshop inside, ran maybe for two minutes. Sit there for a few days while the damaged sheetmetal was removed then driven on the frame machine, another two minutes. After a day or so there back to the first stall to install the good sheet metal, another two minutes and a couple of days.
In other words the choke was engaged continually and the car would be running rich all this time and gas soaked the plugs. About the time they wanted to drive it to the paintbooth it wouldn't start.
A mechanic would have to come over and remove at least half the plugs (the easy ones to get to), dry em, get it started and let it run to get to normal operating temps which would dry the remaining plugs.  Then it would run good.

Maybe you have new plugs but they could get gasfouled too.

Again, just throwing out ideas.

[signart]

Just for laughs, because I know this never happens, but check firing order 1-5-3-6-2-4. Timing 4 degrees BTDC. After cranking for some period without starting, pull all plugs apply air hose to cylinders and dry it out.