The Stovebolt Site Forums The Shop Area Engine Shop engine that ran fine will no longer start

Provided you have the points properly adjusted and still no spark you may want to consider the condenser you installed was defective. It happens.

A defective condenser would short the voltage to zero, not allow it to remain at battery voltage with the points closed. I'm guessing the points are adjusted too wide, and are never closing to allow current flow through the coil primary winding. A wrong connection at the inside of the distributor housing that insulates the point spring from the stud can cause the same problem.
Jerry

Per the OP's original post " I was revving the engine and then it sputtered and stalled.
have not been able to start it since."

It would seem something broke as opposed to being a faulty part or missed adjustment.
Unless it ran out of gas... Isn't there a ceramic resistance block (Brain fart, what DO you call that thing on the firewall again?) that can crap out?

Since then he's thrown every part but the kitchen sink at it, and if he was able to figure a way to install that, I'm sure it would be on there too. He has battery voltage at the side terminal of the distributor, indicating a complete circuit to that point. The only thing left in the circuit to ground is the point set- - - -they've got to be open circuited for some reason- - - -out of adjustment or defective. "I have not set up points in 40+ years" tells me just about all I need to know about this situation.
Jerry

As usual your deductive reasoning is Holmesian and I've always thought it was inside the dizzy, but you didn't answer my pressing question about the name of that ceramic block on the firewall... Hmm the firewall.

Hplace:
Do you have a white ceramic 3-4" long block on your firewall or anywhere under the hood?
Does your new coil say internal or external resistance printed on it?

You are at this point now.
1. Setting points correctly.
2. Getting a test light.
3. Doing this Jerry advise:

With the points open and the ignition switch on, you should see battery voltage on the terminal on the side of the distributor. With the points closed, you should see NO voltage there, since the points are grounding the terminal and the (-) side of the coil. An ice pick type test light with the lead grounded and the probe touching the distributor side terminal should flash as the engine is cranked. If the test light flashes, you should also get a spark at the center terminal of the coil by holding the wire near a ground while cranking.

Caso: Bypass resistor/ballast resistor/ceramic block.
As said, you don't need it to fire, you do need it to run. I advised a temp wire from batt pos to coil pos so as to bypass the bypass.
Like you I was thinking something busted, like a timing gear or ?. But no indication of backfire or carb blowing. An electrical component can terminate that fast. Revving may have just been enough more juice/stress to blow an electrical part. So we'll see.
Last time this happened to me they had to call Father Flaherty with his bull horn to call me down off the ledge.

Ballast... that was it.
One of my first lessons in Experience (circa 1970) was helping a friend install a T-bird engine (with a high compression oil pump)in his Edsel.
Fired up and ran 20 or 30 seconds then stopped.
After a search of all the likely culprits lasting hours and hours it turned out to be a fully twisted off dizzy shaft.
Replaced dizzy, fired up, ran 20 or thirty and snapped another one off. We were kids and the junk yard was close by
Replaced the dizzy, removed the engine pulled the pan, cleaned the tiny little piece of crud out of the oil pump and put it all back.
started it up, ran a min or two and snapped another one... we didn't clean the crud in the pick up screen good enough. a spec the size of a comma did the deed.
Finally got it going and took it for a spin.
He started bragging about how his 'new' engine and tranny were all done and before he could get another word out the rear end took a dump.
We walked away and never looked back.

He has already eliminated the possibility of a bad ballast resistor by measuring voltage at the:

Coil (+) terminal
Coil (-) terminal
Distributor side terminal

An open circuited ballast resistor would have stopped the voltage prior to reaching the upstream (+) side of the coil. It would have had battery voltage at that terminal during cranking, assuming the ballast resistor bypass circuit is intact and hasn't been disabled by someone who fantasizes that he's smarter than the engineers who designed the GM 12 volt ignition system. A burned out ballast results in an engine that runs as long as the starter switch is engaged, and stalls as soon as the switch is returned to the "run" position or the stomp switch is released, eliminating the resistor bypass.
Jerry

lol

"...Houston...... we have ignition..."

it started. hooray!

I ran it for 30 seconds, it ran a bit rough, but I shut it off for the night and will continue tomorrow. sweating bullets outside tonight.... I will report back tomorrow, but until then:



thanks to all who provided advice, suggestions, recommendations and shared personal experience.
'collectively' you got me to where I am now.

I still do not know what happened to prevent it from starting in the first place (after it had started months just fine),
but i do know what i did since then,
so it must be something i did that got it going.

the only thing different the day it would no longer start was me revving the engine higher than ever before....

So, here is what I did today:

(1)
took everything apart that i had worked on or replaced; put it all back together (never know....).


(2)
several comments about maybe having the wrong part or a defective part (the new ones i put in) got me thinking....

when I ordered the new coil i also ordered 2 sets of points and condensors (why not; not a lot of money).

so, i changed out the previously installed points and condenser for the new parts i got with the coil.

(3)
set the points again (on the new points) using the valuable advice and hints from several replies (the same as i did with the other set of points)

(4)
turned the key and it started.



I will continue tomorrow and report back.

indeed, the degree of frustration caused by this is of biblical proportions...

I would expect with all the fidgeting around in the distributor, you may have moved it a little causing the timing to be a little off. Just loosen the vac advance collar enough so the distributor turns just easy enough to play with the timing. No need to loosen the bolt. Start it, listen to the engine and it will tell you when you are close to the sweet spot. lower rpm and crappier running to the left AND to the right is the sweet spot. Then later you can check it with a timing light and vac gauge. Good luck! We have some amazing talent here.

New points today very often have something on the contact surfaces preventing them to spark when opening and closing them.
This is easy to check by turning the engine over until the point are closed and then manually open the points with a screw driver while the ignition switch is on. You should see a bright spark there. If not, clean them up with fine emery cloth and wipe clean with whatever denomination of paper money that you have left after pouring all your money after things which are not defective. Then don't forget to turn off the ignition.
(I can jest about this stuff, as I am as guilty of overlooking the easy stuff as the next guy.)
Carl

Something that works a lot better than emery cloth for burnishing points is a clean pencil eraser. There's just enough abrasive mixed into the rubber to remove any anti-oxidizing coating, followed by a cleanup with a solvent that doesn't leave an oily residue like 90% rubbing alcohol or lacquer thinner.
Jerry

C'mon Jerry, match book striker. You know that's the best. You can't get an eraser in between those contacts.

Hplace: glad you got it running. It's got to make you feel good.
Moral support is what this place is all about.
Points are one of those items that are often Chinese bad. They come out of the package without the pads matching or as Carl says "dirty". I guess we should always buy the known brand name ones. (I.E. AC Delco). Now-a-days you can't find out where anything is made even though it's the law to give country of origin. That is fuzzed out by integral parts of an assembly being made in 4 countries and assembled in a fifth. Finding the words "made in America" is impossible anymore.

Basically you did a complete "tune up". nothing wrong with that.

Not counting this year, I adjusted points for someone else about 25 years ago. Though when I changed my son's points this year it felt like old times right away. Jeffrey

I've got enough Briggs & Stratton, Tecumseh, and Kohler engines around the farm that point cleaning is a regular chore. The little bit of time spent in removing the points so the eraser can be used is time well spent, particularly when all the primary current available to generate the spark is coming from a magneto.
Jerry

I use an old Telco burnishing tool with great results. like Jerry I have several old kohler and B&S engines that sit idle over the long winter months and sometimes won't fire come spring.

I like to leave the points in their spots but turn the engine until they close, the spring tension is all I need to get both contacts cleaned up. A couple swipes with the tool then a couple swipes with a clean piece of paper and they're usually GTG.

Dave

SUCCESS !


an update.

the reason it was running rough yesterday was that,
though I had thought that I set the gap as documented,
the 'way that I did it' actually set the gap too small.

Yesterday I had inserted the gap gauge,
used the adjustment screw to close/tighten down on the gap gauge,
tightened the other screw that holds it all in place,
and then removed the gap gauge.
I turned the key, it started, and I said hooray for now, and shut it off.


Today, checking the points gap again, I found that the points gap had actually closed behind me when I removed the gap gauge - so I had inadvertently set the gap too small. it was enough to start the engine, but not enough to run well.

I adjusted the gap today so that the gap gauge would slide in and out of the gap freely when set (compared to 'tightening down' onto the gap gauge),
and then tightened the hold down screw.

it is now running much smoother.
I high revved it and it is very smooth and powerful. in fact, I cannot believe how good it runs now. smokes some (as before), but smooth running - idling and at high revs.
still some more work to do in the way of timing, etc, but that can be another thread

after having changed out all of the parts, and finally getting it to the point where it would start again and run well, I realized that it had actually been running really bad before all of this happened.

I will try to post some pics tomorrow to help anyone who might fall over this thread in the future.


Thanks Again !

What's all this high revving about? Cool it, dude.

DITTO- - - -or at least keep a big basket around to carry the pieces home. These old engines live very comfortably below 3K RPM- - - - - UNDER LOAD!

Free-revving one is a really good way to scatter it all over the neighborhood.
Jerry

let me restate - medium revving.

like if you were driving down the road around 40mph - more than just idling or tapping the gas.

but you are right; good advice. true high revving is bad.

thanks

Understood. Just got scared from the first time you did it. You know what you are doing. Glad it got figured out. Those idiots on TV rebuild a motor, finally get it to start, and rev it right away and laugh. It's not their money.

I use a test engine with no load (just the flywheel) a lot. I am very careful to not do that. If I had the cash for a dyno, I wouldn't be doing 6 cylinder engines! But, with the flywheel and HB balanced, you can run it safely with no problems as long as you do it understanding high rpms under no load is bad.

You can tell when you are going overboard if you understand these engines. Sounds like New Jersey knows. yeah, TV is like another universe. I watch alot of Powerblock TV and even Velocity Channel. With money not being a factor, the very best Dyno equipment, the very best parts. I want to see a real life TV show where money is a very serious factor (believable).

Can one of you experts put down 3 or 4 lines on why no load revving is bad for an engine...that is what is happening to the bearings, etc. vs. loaded.

1. Cooling by forward motion is not present.
2. The revving was after initial start up, in old motors it takes time to build oil press and delivery.
3. No load means it's not producing any torque, some say it will spin beyond safe when gas is let off. I don't want to see if that's true, if anyone does, go for it.
4. We all rev, just don't rev high or long to be on the safe side.
5. Some, so called, mechanical engineers say no load/no torque will cause parts to "stretch" during high revving and pistons, for example, can get beyond the ring ridges.
6. Old motors are designed for clearances at operating temps. So during cold motor revving, clearances are at max loose.

Good stuff Bart, thanks, that wasn't as bad as I imagined. I thought you were going to wax philosophic about bearing clearances and rotational moments, and internal centrifugal forces, etc.

That's funny, I did add #6 just now while you posted, See if you are still OK with it. In general, a modern motor does not care if it is loaded or not. Bearings and clearances are much better. Forces are equal at load and no load. Compression is compression. (red line must be respected). The feeling some of us older car nuts have when hearing high revving in neutral is not a good feeling. That's most of it. Racers have no problem with that. Euro's do it right away on high performance cars.

They sound reasonable to me Bart, thanks for taking the time. Just wondering how design engineers would have allowed for these engines being loaded 99% of the time, and if it really made a difference once at op temps.

OK, just to muddy the waters a bit- - - -the most dangerous point in a 4-stroke cycle is the top of the exhaust stroke. The piston and rod assembly is heading up the cylinder with virtually no opposition. The exhaust valve is open, the exhaust charge is leaving the cylinder, and if the pipes are designed right there's a little vacuum being developed to help scavenge the cylinder. Centrifugal force on the connecting rod and rod bearing is maxed out, and as the speed is increased, the rod can actually stretch. No such problem on compression, as the gases in the combustion chamber are exerting a push force on the rod and bearing.

Add a somewhat long-duration camshaft, and the intake valve will be in the process of opening toward the upcoming, no-load piston at the top of the exhaust stroke. A little high-RPM valve float- - - -a little rod stretch, a slightly loose rod bearing- - - -crash time!
Jerry

BTW: I did not answer under the disguise of an expert. But you probably were tongue-in-cheek.

It's all good Bart, between you and the Professor I think we got it done. No time for slamming BS here, it's about sharing and passing knowledge between bolters. Knowing what not to do is one thing, knowing why is another.