I am new to this forum. And looking for advice. In regards to finding TDC I believe #1 piston is up to head and both valves are closed on comp. I have been trying to set this 1948 truck flathead for a week now. I attempted to start but backfires only and out of carb. That seems to point to off of TDC. I do have #1 at 9 o'clock position on distributor.

 

First of all, welcome to FTE! We really want to see pics of your truck. Now that I got that out of the way, I just looked at my truck. My #1 is at 12:00 on the distributor. That might be your problem...

And just in case you want to show us some pictures, we'd be glad to help with that if you need it.

Others will chime in I'm sure, but they're going to want to see your truck too!

 

Greetings!

You might be best served by getting your hands on a timing light. Would make shorter work of your task. There are timing marks on the lower pulley.

Good luck

DW

 

Hum yours is at 12 position? I would think the 226 tdc is same mine is a 1948. Heading to garage will let you know progress. Thnx.

 

Yes it's at 12:00 and runs great. And the firing order is 1-5-3-6-2-4.

 

yep got the firing order stuck in my head 15 too young 36 too old 24 just right thanks Joe put my flathead as avatar. Got to pick up another solenoid in am then will attempt to start.

 

ROTFLMAO!! I've never heard that one before, but I'll remember it! I had to share that firing order mnemonic with my wife. She cracked up too!

But I do remember an old one from the Air Force for remembering the color codes on resistors. Not PC now, but we thought nothing of that at the time... back in the 60's.
Bad black
Boys brown
Rape red
Our orange
Young yellow
Girls green
But blue
Violet violet
Gives gray
Willingly white

 

I changed the distr plug wires to #1 at 12 o'clock but unfortunately just backfired when attempted to start. I pulled holly carb to clean but wondering if wiring is good. Any help would be good.

 

Maybe it's timing?

This is from my build thread. I got it from another member on here (38 coupe), and it worked great.

"I set the timing at TDC (0 degrees) with the engine off. Turn the engine by hand until the pointer is aimed at the "bump". Pull the distributor cap. Loosen the distributor. Turn the ignition on. Start with the distributor at full retarded and slowly advance it. When the points spark, stop turning the distributor and lock it down. No timing light needed."

I made sure the rotor was pointing at #1 plug ( it can point 180 out with the timing marks lined up) although I doubt it makes a difference, and followed these instructions. The truck starts easier and runs smoother than it has since I got it.

And rather than turning the engine by hand, I used the button on the starter relay to crank the starter. If you do use this method, make sure the ignition key is OFF and the truck is in neutral before pushing that little button.

 

I will look at that idea tomorrow I just went out took plug #1 out again manually turned engine until both valves closed its now 180 degrees from where it was now 6 oclock looking at dist from drivers fender... Can a guy pm on this forum or email instead of putting here.

 

I believe you need 25 posts to be able to use the private message function here.

It really doesn't matter where the rotor points in relation to the clock, as long as your plug wires are in the correct order from where number one is sitting in the distributor. Either way, it still sounds to me like you're 180 out. It sounds like you just did what I was going to suggest, and that was rechecking your TDC setting, and found you were 180 out. Reset your plug wires from there and it should work better.

 

A picture is worth a thousand words some times....



At the left center (just above the alternator) you see the timing pip (little circle) marked with paint on mine pointed directly at the timing indicator. At the bottom right you see the tang of the rotor is pointed directly at the casting seam (I marked the seam with a red marker) & oiler on the distributor... that is TDC and "good enough to get it to start and run rough"

Because of camera angle things look just a little off, but line them up as directly as possible and unless something is screwy with your plug wires or internally that will get it running.

Note on plug wires, the rotor on mine is pointed directly at what should be your #1 plug wire... so when you put the cap on #1 should be right over the tang of your rotor setup like that, then clockwise 1-5-3-6-2-4.

As mentioned you have two timing pips on the front dampner - one of em is 180 degrees off.

On the 6's you can't take a plug out and use the dowel method of finding TDC, spark plugs sit over the top of the valves not over the pistons.

 

I'll chime in. I don't have a flathead 6, so I'm not 100% sure on how the distributor drive is set-up. That being said, it doesn't matter where the distributor rotor points.

Generally speaking, you put the engine at Top Dead Center (TDC) for the #1 cylinder. You should pull the spark plug, and put your thumb over the hole while you crank the engine in the right direction with a wrench. You'll feel the pressure pulse when it is actually on the compression stroke. When you feel the pressure, start paying attention to the timing marks on the lower pulley. Turn until you are at TDC or better yet, a couple of degrees before TDC.

Now...install your distributor. It doesn't matter which way the rotor points, unless the dist. cap is marked with a reference "#1". If that is the case, then you want to install the dist so that the rotor points in that direction. Some engines have a dist drive that is a slot drive, so it will only go in two ways, and some are gear driven, and there are 12 or so teeth on the gear, so it will go in 12 ways....again, it doesn't matter at this point.

With the engine still positioned in the slightly before TDC position, and the distributor installed, put on the rotor and note which way it is pointing. At this point, you can either visually or by using the Ohm function on a multi meter, rotate the distributor until the points have just opened...do it a few times, rotate it back, then forward until the cam in the distributor that opens the points has just barely opened the points...then snug the distributor down with the hold-down clamp so it won't turn. The ignition fires when the points open, so this is your rough initial timing setting.

Now...figure out which spark plug wire connector the rotor is pointing towards...that is the spark plug wire to hook to the #1 spark plug (which you can re-install and hook up the wire). Figure out which way the rotor turns when the engine is turning. In that direction, the next spark plug wire connection on the dist cap will go to #5, the next to #3, the next to #6 until you have all of them connected in the 153624 firing order.

It should start....now you'll need either a timing light, or a vacuum gauge to to the precise timing setting, but you should be pretty close.

Dan

 

Yea you can see the exhaust and intake valve through the plug hole. Nothing to lose I will set the distr. to the position you have and see that valves are closed. Finishing up the carb cleaning Thx

 

Both valves will be closed for most of the compression stroke and most of the power stroke (maybe 300 degree of crankshaft rotation). You need to use the timing marks on the pulley to determine that you are somewhere near the position were you want it to fire.