Rebuilt engine it ran for about five minutes backfired and shut off

Hello and thank you for using 2CarPros. Here is a link to troubleshoot this. Just follow it and we can narrow this down and got it fix for you.

https://www.2carpros.com/articles/car-cranks-but-wont-start

If you have any questions or need help let me know.

Rich.

On a side note. Backfiring is caused from a lean fuel mixture. I am not sure which carburetor you have on that, I believe a Holley was stock on those, but a backfire will blow out the power valve in those which in turn causes a lean mixture. You can also check for a weak fuel pump (flow and or pressure) and a plugged fuel filter. Also confirm your timing is set right.

Let us know what you find out.

Thanks, Rich.

Turns over but doesn’t seem to be firing. Looks like a fuel spot under the fuel pump.To be honest,the mechanic that was to have rebuilt the engine called my car his project,smarted out at $3,600.00 and 3 weeks turned out to go to 9 weeks and $5,000.00 and he was adding things I didn’t want at this time.Wires loose,from battery on .fitting on carburetor has no line going to it. Picked up car ran for 5-7 minutes backfired cut off. had it towed home. got it restarted 2 days later seemed good.Drove about 5 minutes backfired cut off has not restarted.looks like fuel getting into carburetor.but like I said turning over but no firing. Distributor was loose turn by hand, tightened bolt. that was when it ran in garage.was told by someone else that is suing him he has a thing of keeping cars doing what he wants to it run up bill until bill is more than car is worth.So this really does sound like a rat trap.telling you this so you might have an idea of what we are facing. Carburetor is a hell if I know.He bought a new Chinese made one then charged for a rebuilt twice the amount he said he paid.he put an electric choke on it I didn’t want, put a fan on it, I did not want. when he clipped onto wire it cut through all but 2. It is a 1965 Ford Falcon station wagon, v8/289.

I am so sorry. Sadly people like that are everywhere. He has left you with quite a mess.

I am more than happy to walk you through this step by step. Is this something you can or want to tackle? The good news is due to the age of the vehicle everything will be fairly simple but there will be a good bit of testing and we have several issues it sounds like.

Also the open vacuum port you mentioned can cause the backfiring.

Rich.

I am willing to tackle it. Caution,I am blind in one eye decent vision in other eye. may have to wait for wife to get home to help look at things.

Did you get picture or video?

Manually pumped fuel into carburetor. Tried to start,turned,fired acted like it wanted to start backfired and quit. wont fire now just turns ,like no spark or fuel.

Starter solenoid is hot as heck from trying to start car.

Battery,12.6 volts solenoid volts coil 6.5 volts.turn key on electric choke sounds like it’s running constant.

Turning the distributor it’s sputtering like it wants to start.not sure of dead center and cap.?

Okay then lets get his thing running.

Lets make sure we have not only spark, but good spark. I need you to pull all the spark plugs. Keep them in order as you pull them so you know which one came from each cylinder. Once you have done that I need you to look at each of them and note what color the porcelain is on each plug. Take notes so you can tell me if they are all the same color, If some or even one is a different color take a close up picture of it and tell me which cylinder it came from. A normal plug should be tan to medium brown.

Once you have that done, plug one of the spark plugs into a plug wire and hold the threads on the plug to the engine block and crank it over with the key. (This will take 2 people) I suggest your wife hold the plug and you crank the motor because I need you to tell me if you have spark at the plug and what color the spark is. Is it blue, yellow, orange or white?

Also I would hold the spark plug with a pair of pliers that have a rubber handle in case your wires are leaking voltage and you wont get zapped using pliers to hold it.

Let me know what you find and we will move on. If you have any trouble let me know and we can straighten it out.

Rich.

Plugs are new. this is plug number one:

2,3,4,5,6,7,8.

Spark appears to be white.

Rod fell off of distributor fell into hole fell out of end but into correct hole.

Got it.

Good work. Can you please shoot a quick video with your phone of the engine cranking over so we can see what's going on? that would be great. You can upload it here with your response. I will be able to tell if the engine is okay from the video.

Okay, so put everything back in,what about the rod that fell off of distributor, just stick it back in bottom the into engine?Do I need to turn balancer to TDC or TDC plus degree.

That rod runs your distributor and the oil pump so it is critical it goes back in correctly.

First you need to set the motor to top dead center on the compression stroke on the #1 cylinder. The easiest way to do this is to pull the #1 spark plug. Put your finger over the plug hole. Not in the hole but over it. Then crank to motor until you feel the pressure blow your finger off the hole. Then put a ratchet on the crank bolt that holds the harmonic balancer on and line up the notch on the balancer with the TDC mark on the timing chain cover. That will be TDC top dead center.

Then put the rod back in the hole. Note:
Both ends of the rod should be keyed. Make sure the end that was down goes back in down and engages the oil pump.

Now comes the fun part. The distributor is run by the end of the cam shaft. You will notice the worm gear on the end of the distributor. As you drop the distributor back in the hole the rotor will turn as the worm gear engages. Here is what needs to happen all at once. The slot in the rod has to line up with the slot in the bottom of the distributor shaft when the distributor drops all the way down you need the rotor pointing at the #8 spark plug so that it is pointing at #1 on the distributor cap. See image below.

In order to do this you need to line up the rod with the slot on the bottom of the distributor shaft and because it will turn as you put it in you need the rotor pointing at the #4 cylinder so that as it rotates on the way in it ends up pointing at #8 when its all the way down.

You will find you will need to turn that rod just a bit again and again until it lines up.

If this is not put in correctly, the car will not run.

Also note.. when the distributor is installed the shoulder at the bottom of it should be all the way down to the motor with no gap. If you have a gap it is not all the way down and is probably hanging up on the rod.

Here is a video to help you get an idea of what to do:

https://youtu.be/mZ17tftzkeo

Once you get this back in let me know and we can set the timing.

Let me know how it goes, Rich

Okay, so now I have created a bigger headache for myself.As I was putting things back in the oil pump rod fell off the distributor and kept going, I’m guessing into the oil pan? I am guessing I will have to drop oil pan? Be patient with me, I’m blind in one eye and not great in other.But I’m not giving up on this.Thanks for all the help.Am I right on oil pan?

Yep in the oil pan, there are two ways to go either the rod is stuck somewhere up in the engine or it is laying in the oil pan which is fine and you can simply get another rod use a flashlight to see if you can see it and try to turn the engine over by hand to see if the rod is stuck somewhere. Let us know.

I agree, If you are lucky it got hung up in there. Unless you heard the thump when it hit the pan. If you did then you can drop the pan to get it or leave it in there and get another one. Unless you go 4 wheeling in this it should be okay to leave in there. Get a light and look down the hole and see if you can see it. If you can you may be able to get it out with a telescoping magnet. Its your option to drop the oil pan.

Rich

We looked and don't see it in area so think it fell all the way. I did notice while looking for a new one the retainer/washer was no where to be found or seen. Tried to fish it out of pan which a telescope magnet but no luck doesn’t seem to be getting a connection,except for some metal shavings,not a lot but a little piece. would it be safer to drop pan and check oil? it looks clean on magnate,but wondering if not safer to pull it and check everything.like I know what I’m looking at or for.do I need the washer to stop rod from coming out?

I would be wondering where a metal shaving came from in a new motor. Did this same guy do the motor too?

Rich

Yes he did,as far as I know.That is one of the reasons I’m wondering if I should drop pan and see if the few pieces we found was a fluke,from magnet cover or more of his mess up.One second,I think he took engine apart sent it out to get bored out etc.

I was hoping you would say no. I am not saying this is your issue but it is a possibility. When you build a motor you need proper oil clearance on all the bearings. If the main bearing clearance is too tight on just one main bearing as the motor heats up everything expands from the heat. When a bearing is too tight the oil clearance becomes too small and the bearing over heats and starts dragging on the crank. If it is bad enough it can drag enough to stall the motor. The bad thing here is, it would take about five minutes of running for this to happen. That is the amount of time you have said it has run before shutting down. When the motor cools down the clearances open up again and it will start and run for another five minutes. The more this process happens the more bearing damage happens each time until eventually the bearing will melt down and weld its self to the crank, thus ruining the crank in the process. Eventually it will not start because there is so much load on the crank when turning over it cant get enough cranking speed to start.

Two questions.

Does it sound normal when cranking? Or does it sound slow and labored?

When it did run, did it run okay and at the end of the five minutes did the motor seem to lose RPM and just slowly shut off?

If you have a main bearing issue these are the only symptoms you will get other than a loss of power. They make no noise at all as they fail. They will also give you metal shavings in the oil pan as the bearing is torn apart.

Rich.