8n wont start after engine rebuild

[Luke 8n]

Hey guys, I'm a little stumped on my Ford 8n no start. I rebuilt the engine last month, and after getting everything back together I only get an occasional backfire with starting fluid. During the rebuild, I marked the crank and camshaft to make sure they went together correctly, and they seem to be timed because when the number one cylinder is at TDC both valves are closed, and I can turn the engine over and see that the valves are moving as they should. I also set the distributor timing to point at the number one cylinder spark wire at TDC. The tractor is getting a strong blue spark, so I don't think it's a spark issue. I'm not sure what else the issue could be. The only other thing I may do is adjust the valves, but other than that I'm not sure.

 

[olddavid]

Are you getting gas at the carburetor?

 

[Jim L WA]

Double check the firing order. 1,2,4,3 C.C.W. The no start and back firing is typical of wrong firing order.

 

[Luke 8n]

For now, I'm just spraying starting fluid directly into the carb to see if it will fire off.

Yep, the firing order is correct

 

[Jim L WA]

Don't take this as an insult, but I have to ask. The number one cylinder you are referring to is the one in front of the engine, correct?
Unless the valves are way out of adjustment and not closing it sure sounds like a timing issue to me. Either firing order of 180 degrees out. Can you do a compression test?

 

[Luke 8n]

Yes sir, the cylinder closest to the radiator. the tractor is disassembled for paint, so I just pulled the head off and all of the valves are opening and closing when they should. It feels like strong compression with my thumb over the spark plug hole, but I can get my tester out later to check the exact amount.

 

[soaked]

For reference--- this sidemount has rotor pointing to #1 terminal, and 0°mark is in the timing window. Its at the end of its compression stroke. Its in running condition.
If yours is in time, it should look the same.

Remember static timing is 4°
If the carb bowl is full of gas, it should start and run long enough to see oil pressure.

 

[Hobo,NC]

Hey guys, I'm a little stumped on my Ford 8n no start. I rebuilt the engine last month, and after getting everything back together I only get an occasional backfire with starting fluid. During the rebuild, I marked the crank and camshaft to make sure they went together correctly, and they seem to be timed because when the number one cylinder is at TDC both valves are closed, and I can turn the engine over and see that the valves are moving as they should. I also set the distributor timing to point at the number one cylinder spark wire at TDC. The tractor is getting a strong blue spark, so I don't think it's a spark issue. I'm not sure what else the issue could be. The only other thing I may do is adjust the valves, but other than that I'm not sure.

Is the head still off.

 

[Luke 8n]

Thanks for the help guys. I must of not put the flywheel on correctly after the engine rebuild, because the marks on it were not even close to top dead center. I pulled the head off and re-timed the distributor, then it fired up! Now it and my Massey 1080 are getting painted which will be an even bigger project

 

[KCTractors]

I think that the flywheel can only go on one way. The bolts are off-set, if I remember right.

 

[olddavid]

I think that the flywheel can only go on one way. The bolts are off-set, if I remember right.

Pretty standard to offset one of the bolts but I don't know if Ford did it on the 8n.

 

[Luke 8n]

Yea, I'm not sure if it had an aftermarket flywheel or what, but there were no markings through the inspection hole when the engine was at TDC. The flywheel was installed correctly though.

 

[soaked]

Yea, I'm not sure if it had an aftermarket flywheel or what, but there were no markings through the inspection hole when the engine was at TDC. The flywheel was installed correctly though.

The 8n flywheel will fit on the crank in one position,, and then can be lifted off and rotated 180° and fit on a second time.

If you used to have marks visable through the timing window when #1 was TDC, the marks are now showing TDC for #2 and #3.
4° BTDC static timing is about 7/16 up from 0° TDC. Put your timing lite on either 2 or 3 plug wire to time it.

Front mount N flywheels didnt have the stamped set of timing marks so that may be what you have.

 

[Jim L WA]

Good news that you got it running. That was a lot of work, re-splitting the tractor and correcting the flywheel.

 

[Luke 8n]

yep, luckily it's being painted and everything was easy to get to. Thanks everyone for the help

 

[JMOR]

Do you have the two dowels shown in SOAKED picture in place?

 

[soaked]

Hi JMOR,

You post an excellent question!

If no pins, there are 4 posible flywheel mountings. 90° apart. The two possibles where dowel holes are not 12, and 6 oclock, would put the pistons all even at mid stroke, and no marks in the window to use any plug wire.
(Im looking at a sidemount 8n with a flywheel, mounted on a stand, head off)

Thank you!

 

[used red MN]

Oops, invalid reply

 

[used red MN]

Oops, invalid reply