First Start A Wipe-Out

[Bingster]

Well, a friend and I tried to start my '47 DeSoto and all we got were smoky pops from the carb and even one flame. We reasoned it was the timing so we rechecked all of the plug wires and still loud bangs. The coil is new. Points and rotor new. Rebuilt starter works. I think I got it TDC.

I'm sure you guys (and gal) will know instantly what could be the cause.  I'll have to go over the posts last year about distributor plug wires and rotor direction. In all of the "will it run?" videos that I've seen I never saw a carb do that.

 

What say you?

[Merle Coggins]

Anytime I’ve experienced backfiring out of the carb after distributor work, I found that the distributor was installed 180 degrees off. Double check #1 TDC on the Compression stroke. Then recheck your plug wire placement. Also, extremely retarded timing could be firing the spark plugs on the intake stroke, causing backfire in the carb. Either way, double check the timing. 

[Bingster]

Thanks!

[keithb7]

I just posted timing instructions here:

 

https://p15-d24.com/topic/61588-reviving-my-p18-after-po-gave-up/?do=findComment&comment=662050

[Bingster]

Thanks so much Keith for taking the time to lay that all out. I thought I had it nailed last year with all the advice I got about the distributor and the TDC.  I'll try and get things straightened out. At least the starter and the fuel pump I rebuilt worked.

[Bingster]

The top of the coil got hot when we tried to start it before

[Los_Control]

I'm with Merle, it is 180 out assuming the plug wires are correctly installed.

Simply removing the cap and see where rotor is pointing. Then lift the distributor up and rotate it 1/2 a turn and drop it back down into the slot where rotor is pointing to other side.

 

The 4 stroke engine pistons are at TDC twice, once for compression stroke and once for exhaust.

It is fairly simple to get it to TDC on the wrong stroke.

You are getting fire to the cylinder when the intake is opening so it coughs out the carb instead of the exhaust.

This is actually pretty promising .... it is a actual ooops moment of slight embarrassment .... I have done it a few times over the years, SBC were the same way.

 Is a simple 2 minute fix to lift the distributor and rotate it and do not move the plug wires.

 

If you did everything right it will now fire on compression stroke and should run. ..... If not then you need to start over from scratch.

[Bingster]

Thanks. That seems a bit more doable so I'll try that first. I'm gonna stick my neck out a bit here but the compression stroke is when #1 cylinder is up?

[Veemoney]

19 minutes ago, Bingster said:

I'm gonna stick my neck out a bit here but the compression stroke is when #1 cylinder is up?

The #1 piston is up once on the compression stoke with both the exhaust and intake valve closed. This is the compression stroke where the air/fuel mixture gets compressed and the ignition sparks. The #1 piston comes up to the top again with the exhaust valve open to let out the burned gas out the exhaust. You need to make sure you are on the compression stroke when the piston is up (both valves closed) when checking the rotor position of the distributor.

 

[soth122003]

Easy to do since the spark plug hole is right above the valves. Just look and make sure both valve are closed when you get a puff of air on #1.

 

Joe Lee

[Los_Control]

I think people sometimes makes things more complicated then it needs to be. If you understand that #1 and #6 pistons are at TDC at the same time.

The difference is one is on compression stroke, the other is on exhaust stroke.

 

I simply use the pipe plug over #6 and lay a small piece of toilette paper over the pipe plug hole.

Then I rotate the engine by hand with the spark plugs installed .... when #6 comes up on compression stroke you will see the paper move or blow off the hole.

Now you know that piston is coming up on compression .... Now take a long wire over 6" long and insert in the hole and continue rotating the engine and watch where it gets to the top. .... when it starts to go down then stop and rotate the engine the opposite direction to bring it back to top.

 

Now look at the rotor on your distributor .... install the cap, the plug hole on the cap the rotor is pointing at is where #6 wire goes. ..... Thats all you need to know to install plug wires.

The firing order is 153624 ..... you install #6 wire, then going clockwise you install #2, #4, #1 .... This is how I wired my truck.

 

If you truly want to do it by the book and start with #1 ..... When you get #6 at TDC compression stroke and the wire starts to go down, just keep turning the engine around 1 full turn and when the wire comes back up to TDC ...... Now #6 is on exhaust stroke and #1 is at TDC compression stroke and look at the rotor and that is where you install #1 wire ....

 

To me that is just one extra step that is not needed ..... we only need to know 1 cylinder that is ready to fire, since we are working with the pipe plug over #6 why not just start there?

 

Technically by the book, #1 is at 7 O'clock and #6 would be about 2 O'clock ...... you can raise the distributor before installing plug wires and rotate it .... then install the #6 wire on its own side of the cap ...... It will run the same any way you go it just makes no difference ..... simply gets confusing when someone else comes along in the future and gets confused.

 

My #1 is at 6:00 because the guy who installed the oil pump installed it a tooth off .... no big deal .... just find where #6 is ready to fire and install the wires and it will work.

 

[Bingster]

I'll give it another go at my next opportunity. Thanks.

[Bingster]

A question: When you say "you can raise the distributor before installing plug wires and rotate it"  do you mean the metal housing underneath cap? Cause mine is like welded on there.

 

I believe that #6 cylinder is at compression TDC. I  say believe because I'd like to believe it.

But my rotor is at 5:00 o'clock. The pointer on the crankshaft pulley seems to be at TDC if the raised line on the pulley indicates TDC.  So am I supposed to shoot for #1 spark plug wire being at 7:00 o'clock or 2:00?

 

Also, there is a tiny hole at the top of the distributor cap which I think indicates is supposed to line up with one of the snap levers to secure the cap.

 

 

[Sniper]

If number six is on the compression stroke and you are at TDC then put the number six plug wire in the cap tower that is lined up with the rotor. 

 

DO NOT get hung up on where the rotor is supposed to be pointing, it's obvious someone did not reinstall the oil pump properly. 

 

At this point you can either roll with the way it is or try to R&R the oil pump to sort out your rotor position. 

 

 

[Los_Control]

I agree 100% with Sniper. Do not get hung up on that point. .... If you lift the distributor up and rotate it it would not help .... just connect #6 wire there and carry on.

 

On these engines with this firing order it just does not matter .... They run the same as long as you place #6 wire and follow order.

 

The oil pump is geared and it is close but 2 teeth off when last mechanic installed it.

 

In the past I have ran into 4cyl and 8cyl engines where the distributor was installed 1 or 2 teeth off and they never ran right .... it was my lob to figure out why and properly placed the distributor in to correct it.

 

Our 6 cylinder engines do not care and will run fine anywhere you install the oil pump ..... As long as you match the plug wires to where the rotor is pointing it will run fine.

Mine is wrong also, I would fix it lickety split if I thought it mattered ..... our engines just do not care and will run no better if you change it.

I will fix it someday when I actually remove my motor and reassemble it .... just a waste of time today to worry about it.

[Dave72dt]

Your primary concern is to get it running.  Use a paint marker after to mark # 1 position on the cap for your own reference later.  The next owner can worry about changing it.  As long as you know where it is it isn't a problem.

[Bingster]

Okay. So leave the rotor at five o'clock and put #6 spark plug wire there, then follow the plug wire sequence around the cap clockwise?

[Hickory]

Correct