The Stovebolt Site Forums The Shop Area Engine Shop lost fire

Hi, I've been using this forum for help since I got my truck over a year ago. My experience as a mechanic before this was pretty much limited to changing my oil and changing my own flats. I have a 49 3100 that had sat in a barn for at least 15 years. Initially I changed plugs, new wires, cap, rotor, points, coil and put in a new wiring harness removed and emptied the gas tank and put in fresh oil, brake fluid, and master cylinder kit. What a happy day when it actually started and moved and stopped!!! It still had bad tires so I didn't drive it much. It got hard to start so I replaced the starter. Then it started losing power, so after reading alot of posts I replaced the manifold and exchanged the carter carb for a rochester and replaced the vacuum line going to the carb. Now I am stuck! It's not firing at all. What steps do I take now to trouble shoot? I have a new DA fuel pump and glass bowl gas filter to replace the plastic one and want to replace the fuel line from the fuel pump up but am afraid to do these things till I can get it running again. Thanks for all the help past and present!

Well, first check your fire (if you havent done so)by pulling a plug and have someone turn it over while you look for spark on the sparkplug. You will have to ground the sparkplug against something metal to see if it has spark. If there isnt you have to trace back through your ignition, checking wires, checking the power lead to the distributor, the distributor itself (let a mechanic check this out) Then if this is all good it could be your switch in the cab. many possiblities. But first I would rule out the spark question. Thats all I have to say, anyone else?

Pull your distributor cap off.

make sure the points contacts are closed.

Turn the ignition key to the on position.

Take a screwdriver(or your finger if you are brave enough)and manually make the points contacts open.
You should see a spark between the contacts when they open.
If there is spark, next turn the engine so the point contacts are open(rubbing block of the points should be on one of the lobes on the distributor cam.
the point gap should be around 18 to 19 thousandths.

Be sure to not leave the key on too long or it can fry the points contacts.

Michelle, I am assuming that you either have a "helper" or a repair manual. When you changed your plugs and plug wires, you may have erred when installing them (the wires). Check a manual to see that they are correct. If you have neither a "helper" nor a manual contact me via e-mail and I will walk you through this. Also did you get the wires to the coil on their correct sides? Should be labeled. If you check for 'fire" as Mechainiac says and you see a spark, then check your wires to the plugs. These "little" things can be frustrating when you have worked so hard. Sounds like you really, truely, want a "good" truck.

If all of the above are in good order then we move to the fuel situation. Why did you "feel" you were losing power and changed out the carb and manifold?

If you also changed the cap and rotor make sure they are a match. Apparently there is a short and tall version and I am sure it wouldn't start with a short rotor and tall cap.

It is obviously something you did, so trace back your steps. Did it run since you did the wires? Then it has to be the carb work you did. etc etc. If you haven't tried this yet, remove the aircleaner and dump a little gas in the carb. If it starts to skip or run then fuel delivery was your problem.

Michelle, when you replaced the ignition parts, did you also put in a new condenser (capacitor) in the distributor? They go bad with age. Good luck, Jacques.

I am going to change my name to something feminine . . . y'all give a lot better advice without all the bs when it appears a woman is posting! :p

Ken ........There's plenty of GIRLIE stuff goin on here already!
Without a Girl engineer

Hey Guys! I do appreciate the responses. I'll answer a couple of the questions. I do have a shop manual and a "helper", he'll be home tonight so barring freezing cold I "should" be able to get him out there to help tomorrow. (Hmmm might be able to milk the valentines thing ). It did run after changing wires, plugs, coil etc, and did get new condensor too. The reason I changed the manifold was cause the rochester wouldn't fit, I have a 54 235 but the PO must have reused the original 216 manifold. I changed the carb because I couldn't get a rebuild kit for the carter w 1 locally, but could get a rebuilt rochester. For awhile I could drive the truck around the property but when it wouldn't make it up even slight inclines or do much more than creep I figured it might be fuel related and made the carb change. It hasn't run since the new carb, manifold, vacuum line. And then cause it wasn't running I started fiddlin around with everything so I may have undone something that was right!! I didn't notice when it stopped firing may very well have never fired once I made the carb change but don't honestly remember.
So.......hopefully I'll get him out there to help determine if there is still spark and if there is then I'll try pouring the gas down the carb (no gas in the can right now--oops!)then I'll be back asking for more advice. Thanks again!

Let us know, it sounds like some of these guys would be more than willing to drive a few hundred miles to come and help a poor damsel in distress.

My goodness, I am afraid to ask my wife what a condensor is...

Pass me the barf bag.You guys sound like wide eye school boys when there're a women around.

Ok, just came in from the barn, followed the instructions from gearhead56, mechainiac, oly and Tony M.
I have spark at points,

gapped to .0018,

spark at #1 plug, (just to double check, is #1 plug close to radiator or cab?)

checked to see if I had wires correct and secure,

checked to see if wires to coil are right (from dist to - on coil, from ballast resistor to + on coil)

poured gas down throat,

but still not even a sputter. What next?

# 1 plug is at the front of the motor. ( radiator ) .
If your truck has been sitting for 15 yrs , then there is potential for the fibre cam gear to have failed . It may have just slipped a bit on its steel bushing , and be putting your timing irreversably out of kilter .
You can check this by following the timing instructions in the book , and ( with the rocker cover off ) checking the valve opening stages .
Maybe the dist has just moved a bit , you did check to see that it was tightened down ?

Michelle, your repair manual should explain how to check your timing to see if something has slipped like Dusty suggested- if not holler out and someone here can take you through the steps. When you mentioned that it kept loosing power and changed the manifold and carb, it sounded more like the timing going bad. Checking the timing and making sure the plug wires are on the cap correctly should be very easy. then if you have spark and fuel with compression it is go down the road time.

I have a question:::: take your distributor cap off (leave plug wires attached) and have someone watch the distributor while another person cranks the engine.Is the rotor in the distributor turning when the engine is cranked?

If so, do the points make spark when the engine is cranked?

Only had a little bit of time to work on the truck this weekend, I tried to time it by pulling #1 plug and turning it over til finger was pushed away. We could never find the steel ball on the flywheel. Watched the rotor and it did move as the engine cranked but neither of us saw any spark. Went back and just turned the key on and separated the points to see if they would spark and sometimes they would sometimes they wouldn't. I don't know if it was cause we were doing something wrong or if the points are bad. I thought points either work or don't work. What should I do now? Thanks alot!

Since it didnt sputter or start when you put fuel down the carb throat it is electrical related. Since you had ongoing problems it could be an actual problem not related to the things you changed. I would still suspect the timing belt, coil and distributor related pieces. Since you experienced a period of low power I would look real close at the timing gear.

On second thought the carburator could have a problem and maybe should be taken apart and cleaned.

Check to see if you have power to the coil. Also, make sure the wires are not attached backwards on the coil. The coil has a + for positive and a - for the negative. Positive should be connected to the wire from the wiring harness (which goes down to the starter) and the distributor should be connected to the - side of the coil.
Or, you may just have a bad coil .

Hey Michelle

Assuming the engine is in decent shape, it only needs two things to run: fuel and fire. One or both are not working.

Check ignition: Is there spark at plugs? If so, just get the timing close. You may have to get under truck, remove flywheel cover, and clean front of flywheel with a brush until steel ball shows. Line up steel ball on flywheel and pointer in bellhousing. This is TDC. The distributor rotor should be pointing to either #1 or #6 sparkplug wire. Firing order is 1-5-3-6-2-4.

Timing at TDC
Rotor pointing to #1 plug wire
#6 intake valve open.
firing order correct
if its sparking, set it and leave the ignition system alone.

Then proceed to the fuel system. You cannot use a 235 intake on a 216 engine, as the intake port sizes are different. The carbs will interchange tho. Did you remember the intake rings between the intake and head when you changed intakes? Sure no intake leaks?

If everything above checks out, it may be time for a compression test. Screw the parts store tester into the sparkplug hole. Crank engine over until reading on gauge stabilizes. All cylinders should be about the same. If not, you've got a internal engine malfunction.

These engines are very simple. When they won't do anything but spin over, the problem is usually very simple.

good luck
chip

There is a good way to set the timing close with a non running engine. Make a 12v lightbulb attached to a length of wire. It has been 20 years since I used it but I guess, from memory the wire is attached to the small wire from the coil to the distributor? (someone correct me if wrong)

Now, set the engine at TDC with #1 at the rotor and ball on flywheel. Hold the ground part of the lightbulb to something metal. Turn the distributor until the lightbulb comes on. It is now very very close and should start.

It will also prove juice flowing at least to the distributor. Make sure the ignition is on when you do it.

It's been just to cold for me to work on the truck for any length of time and more snow is on the way. 2 questions though; I did not use intake rings when we put the new intake manifold on, I thought these just served as guides, are they a necessity? Could this cause the problem? Also, is the steel ball definately gonna be there? Thanks, once again.

The rings do not seal anyhing,however, they do keep the manifold lined up with the head intake ports.(necessary for proper air/fuel flow into the combustion chamber.
If this truck HAS been sitting for 15 years, it will probably have some stuck open valves and this would cause the engine to not run if there were more than a few stuck!!!
The steel ball will be there,may be covered with crud.Take the inspection cover off and turn the flywheel. use a flashlight or a drop-light.(if the ball is not there, there will be a hole where tha ball was.
Have you done a compression test on the engine?
THREE things need for an engine to run;
1. fuel
2.compression
3.spark
(all three at the proper time and place)

mechano-nut is right.

If an engine won't build decent cylinder pressure, it won't run. The fuel/air mixture must be compressed before it will burn and make the engine run. My post assumed that the engine had compression. Check that first!

A compression tester is available at all auto parts stores for 20 to 30 bucks. It has a high pressure gauge on a 1 foot piece of high pressure hose. The other end of the hose screws into the sparkplug hole of the cyl under test.

To check compression, remove all 6 sparkplugs. Disconnect the wire that goes from the coil to the distributor to prevent sparking during test. Block the throttle wide open. Make sure battery is charged to get good readings. Screw the gauge into each cylinder in turn, and crank the engine over until the gauge reading stops increasing. The pressure difference between the cylinders should be within 10% of each other.

For example, if the highest reading you get out of a cylinder is 130 PSI, the lowest reading in any other cylinder should be

130psi x 10% = 13psi

subtract 10 percent reading from maximum:

130psi - 13psi = 117psi minimum in any other cylinder in a healthy motor.

For a worn motor, the pressure may be much lower. A ballpark figure for a worn motor to run is least 85 PSI to run at all. But the readings should still be within 10 to 15% of each other.

If all but one or two cylinders have good pressure, then the problem is in that one cylinder. It could be stuck valves, weak valvesprings, misadjusted valves, blown head gasket, cracked piston rings, cracked head, etc.

If the motor has good, even compression across all 6 cylinders, go back to troubleshooting the fuel and ignition systems. If the engine has low compression, then you must correct the internal malfunction before it will run.

The reason I asked about intake rings is because if you tried to put the wrong intake on the motor, the intake rings wouldn't let you, cuz they wouldn't line up.

hope this helps

chip

Engine needs 3 things to run - 1. compression 2. fuel 3. ignition

1. This should have been the very first thing you checked when you first got the truck. As stated before, check all cylinders. If compression is down in any cylinder, stop. Engine has internal problems. If compression is down, squirt a bit of oil into the cylinder and retest. If compression improves you need rings, if it doesn't help, you need valve work.

3. If the thing ran before you mucked with it, all you need to do is check for spark at ALL cylinders. Timing hasn't changed and should be fine. If all cylinders are sparking in the correct order we move on to fuel.

2. Since this is what you were mucking with, it is the most likely source of the problem. You have already tried dumping a bit of gas in with no fire. This leaves only a few possibilities. They include a non functional carb (unlikely as you tried the fuel dump), no fuel delivery to carb (again unlikely due to dump trick), or a vacuum leak. Are all intake external holes plugged? are all gaskets covering what they are supposed to? is the intake you are using a good fit for the engine? were all gasket surfaces cleaned shiney with acetone before assembly? etc. gummed up carb? gummed up fuel filter?

The one other thing that comes to mind is temperature. You say that the truck is cold. Was it running well in the summer and got worse as the temperature dropped? What weight is your oil? A heavy oil works great in the summer, but when it gets cold it can slow the speed the engine cranks over and will not start easily. Mine had this problem up here in Canada, a lighter weight oil in the winter perked her right back up again.

The slow decay of performance is a bit puzzling. Also don't forget this truck has been parked for 15 years. An internal problem may have been the reason it was parked in the first place. Start with a compression check, it can be revealling.

good luck, and keep us posted.

Ryan

oh, and thanks from all of us who now have this wonderful mental image of a girl mucking about with a 49 chevy stovebolt! why there aren't more has always been a mystery to me....could be why I'm single!

cheers,

Ryan

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chip

Hey Michelle,
Not sure if I'm much too late but I had an intermittent spark problem which turned out to be plastic insulator and metal washer on field wire on distributor body were assembled incorrectly and spark was earthing out on dissy body.
Regards from down under.
OLD 42