Carb Backfire

[Ric0126]

The '51 8n is backfiring thru the carb. I have replaced dist. cap, plugs, condinsor, wires and set the points at .025. It is a side mount dist and converted to 12v. I was careful to replace the wires and cap to maintain the proper order. earlier I read that the firing order was 1243 with the cylinders 1 in front and 4 in the rear. If that's correct how do I get TDC on 1 in order to double check the rotation order around the cap. The next suggestion was a stuck intake which I assume will require a compression check?

 

[Dell (WA)]

Ric......you do know you don't need sparkies to check the compression, don't you? 90psi min dry. Iff'n you have a stuck valve, it should be intuitively obvious by LOW compression. New engine compression is about 125psi, good engines about 110psi.

As fer yer 5-nipple firing order 1,2,4,3 CCW, most people determine TDC by the timing mark under the teardrop coverplate. Others, use their thumb on the #1 sparkie hole next to the radiator. When it blows off, guess what??? TDC or close to it.

Since the 5-nipple dizzy is 360deg rotatable, #1 can be ennywharr the rotor points, but generally its about 9-10 o'clock, then #2 would be about 6pm etc. I know digital watches.......Dell

 

[Bruce (VA)]

After you find #1, set the timing. If you don't know how to do that, just ask.
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[Ric0126]

I have identified the order, checked the compression by "thumb" method and stiil backfires. I am now wondering if I am only getting inconsistant fire perhaps due to coil issues. The points just don"t seem to being firing consistantly? The thing is that she ran briefly on starting fluid the very first time i brought her home from the farm and had done nothing?

 

[G6 at Snook, TX]

Ric,

Have you recently pulled the distributor? I ask to see if your ignition timing is off.

NDG

 

[Bruce (VA)]

" I am now wondering if I am only getting inconsistant fire perhaps due to coil issues."

No, that's not the problem.

Re-check the point gap. Then, check the timing.

Have you fooled w/ the distributor hold-down bolt? Is the distributor loose?
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