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Engine Rebuilt..but won't start


Daniel L

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Hey guys, I bought a 47' P15 about 3 years ago and the engine (218 flathead 6) was seized up. I had a machine shop machine the engine and ensure that it was ready to be put together and runnable. I took the engine in pieces home and put it back together, while following the manual step by step. So here comes my problems, the engine turnsover, backfires, and spits from the carburetor. I put a new carburetor on it since the original was too far gone (Rebuilt it but it was leaking from everywhere). The following is what I checked and did on the engine to get me to this point. 

 

- Have the right spark plugs for the car and they are a tannish brown when I pulled them out from trying to get it to run for almost 2 months. 

- Carburetor is jetting gas after I put some directly into it (I do not think the fuel pump is pumping gas into the carb)

- Rebuilt the fuel pump.

- Put a timing light and have everything TDC but the distributor seems a little finicky. 

- Backfires from the exhaust, which has no muffler and is about 1 foot away from the engine.

- Spark plug wires are off of a 1972 Ford F100 and unknown about the time the distributor was rebuilt.

- Engine has compression in all cylinders. 

 

If you guys have any tips or guides for troubleshooting, that would be great!

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Backfiring and spitting from the carburetor very likely points to a timing issue - particularly given your comment that the distributor is "a little finicky".   Take your cap off and make certain that the distributor adjustment (you should have two: one on the bottom side of the dizzy that allows for a fair amount of movement and the other at the point where it mounts to the block.  Make sure that the available movement allows you to point the rotor at the wire leading to the number one spark plug.  I've seen it where there isn't enough adjust-ability to do that.  If that's the case, try moving each plug wire one position (in whichever direction necessary) so that the rotor points at the no. 1 plug wire.  The entire process should take no more than about five minutes.

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25 minutes ago, Hamilton said:

Backfiring and spitting from the carburetor very likely points to a timing issue - particularly given your comment that the distributor is "a little finicky".   Take your cap off and make certain that the distributor adjustment (you should have two: one on the bottom side of the dizzy that allows for a fair amount of movement and the other at the point where it mounts to the block.  Make sure that the available movement allows you to point the rotor at the wire leading to the number one spark plug.  I've seen it where there isn't enough adjust-ability to do that.  If that's the case, try moving each plug wire one position (in whichever direction necessary) so that the rotor points at the no. 1 plug wire.  The entire process should take no more than about five minutes.

Just did that and the engine continued to do the same thing. I just want to make sure that I am using the right firing order (1-5-3-6-2-4). I have the rotor pointing at the lead wire. My next course of action is continue to move the disturber around until it fires up. Also might be thinking for a new distributor. 

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this happened to me. rebuilt a buick straight eight. a friend wanted to help, so I let him put the timing chain on. the block was sitting on a cart  upside down to its position in the car. the timing chain went on perfect, but 180 out because of the position of the block. when I tried to start the engine it did exactly what yours is doing. corrected the timing chain and all was well.    

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24 minutes ago, Daniel L said:

Just did that and the engine continued to do the same thing. I just want to make sure that I am using the right firing order (1-5-3-6-2-4). I have the rotor pointing at the lead wire. My next course of action is continue to move the disturber around until it fires up. Also might be thinking for a new distributor. 

By lead wire, you mean the one that leads to the number one plug (front of engine), right?  Might be a silly question but I'll ask anyway: is no. 5 clockwise of no. 1, no. 3 clockwise of no. 3, etc.?  Want to make sure you're not wired backwards before moving forward.

 

If rotating the distributor a couple of degrees at a time (trying both directions, of course) doesn't bring success then you need to consider what was mentioned earlier - that you're 180 degrees off.  Time to ask how you confirmed TDC, as both no.1 and no. 6 are reach TDC at the same time, but on different strokes.   A very simple method on these in-line flatheads is to pull the number one plug and place a ping pong ball over the hole.  Turn the engine over (either by bumping it with the starter or rotating it manually) slowly until you see the ping pong ball begin to move so you know you're on the compression stroke of no. 1 cylinder, and exhaust on no. 6.

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Same thing happened to me on the third static timing procedure, I discovered the spark plugs leads were correct for the firing order but I had them off by one position.  Do another static timing procedure and assure you have number one lead indexed to the rotor position.  The stock rotor position for number one cylinder is 7 o'clock.  This assumes the oil pump which drives the distributor is indexed correctly to the cam.  If you got this correct during assembly you should be good to go.  If you didn't, it's just a matter of adjusting the wires to where the rotor is pointing with number one at tdc on compression stroke.  If this is the situation, make sure you document it for future reference.

 

When I got mine sorted, it started so quickly it scared me... Good luck!

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Your firing order is right.  That order follows clockwise around the cap . The other thing to consider is your point gap as your dwell affects timing.  Double check that. I am not sure what it should be, but it is in your manual.  The dwell for mine should be about 36 - 38 degrees. Manual for mine says .020 gap. If your are backfiring , then you are getting spark.  Once you make sure your timing and point gap are good, manually prime the engine just to rule out starving on start up and try to start the car.  If it actually starts and then dies, you might look at carburation or fuel pump.  If it just continues to sputter and backfire, timing sounds like the issue. You do need to insure that your calves have been properly adjusted. there is a procedure (I think on this site) to do that with the engine cold. Hopefully, when this was assembled, the timing chain was properly installed to line up the cam and the crank. Most everything else revolving around timing on a properly assembled engine should be fixable from outside the block.

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I think you know this already, when you assemble the engine, and install the oil pump, There is a procedure to follow. You need to be TDC when dropping it in. The distributor is ran off the oil pump.

On my truck, the oil pump was not installed correct, From past owner. I had to rotate the plug wires to accommodate it.

 

Because I do not know, I would like to toss the idea out there ... Is it possible to install the oil pump so far out of time that it is hard to install distributor correct now?

Mine is like one tooth off and had to change my wires one position, what if it was 3 or 5 teeth off, then trying to use distributor adjustment to correct?

Just a idea.

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2 hours ago, Los_Control said:

I think you know this already, when you assemble the engine, and install the oil pump, There is a procedure to follow. You need to be TDC when dropping it in. The distributor is ran off the oil pump.

On my truck, the oil pump was not installed correct, From past owner. I had to rotate the plug wires to accommodate it.

 

Because I do not know, I would like to toss the idea out there ... Is it possible to install the oil pump so far out of time that it is hard to install distributor correct now?

Mine is like one tooth off and had to change my wires one position, what if it was 3 or 5 teeth off, then trying to use distributor adjustment to correct?

Just a idea.

You can get the timing right no matter where the oil pump is installed, but you would need to figure out which contact the distributor is pointing at when you are at TDC. There is plenty of adjustment as long as you plug your wires in appropriately. 

Best practice is to bolt on the oil pump (and roughly time the distributor) while the head is off so TDC is very obvious, but it is never too late and there is no way to put it together where it can't work - you just need to start the wires in the right spot. 

Assuming you have the timing gears and chain in correctly (and it sounds like you do since you say the compression is good) then you just need to get the distributor timing right. Do double check that your 153624 is going clockwise.

Of course "a little finicky" might be a fatal issue. If the bushings are too worn (or many other issues) then your distributor will not put out a dependable spark.

It should be relatively easy to get your distributor working well, but if you want to do a little upgrade Langdon's sells a really nice HEI distributor that will fit right in. You'll still need to time it right though (and you'll need to be running 12 volts).

http://www.langdonsstovebolt.com/store/online-catalog/#!/Stovebolt-Mopar-Mini-HEI/p/1222043/category=18665979

 

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3 hours ago, Tooljunkie said:

My vote is 180 out. 


I had the same issue with the same symptoms mentioned in the initial post on a rebuilt motor in my ‘51 Dodge business coupe. Rebuilder swore he had set it to TDC but it was 180 out. Fired immediately once the necessary changes were made. 

Edited by RobertKB
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Great! Even us old timers get it wrong sometimes. I once put plug wires on in reverse order on my Landy after drying it out after a creek crossing. Started but didnt have enough power to pull the skin off a rice pudding, took a while to figure why.

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