1947 flathead will not start

[Dexfoster]

Looking for some insight or ideas. Just  finished rebuilding a 1947 flathead Cadillac 346. We have good spark at plugs. Timing is set correct fuel pump is working. 750 cold crank on battery. Put a 12v starter on it. Put a little gas directly in the carb still wont start. Coil works, points working and gap right, spark plug gap is right,new wires. Got a new battery as of last night. Turns over no problem but won't start. It seems to have a slight puff out of Carb as if its backfiring. Any ideas would be greatly appreciated!

[harry s]

John,  Bring #1 cylinder to TDC with pointer on timing cover aligned with timing mark on damper and check where the rotor is pointing. Start you firing order from that point if different from the picture in the shop manual. The symptoms you describe sound like the distributor mount may be off. Hope it is this simple.  Good Luck,    Harry
PS Nice looking engine and stand.

[LaSalle5019]

A problem I just recently encountered was with a new set of points.  The spring force was too light.  This was for my flathead '39 LaSalle engine.  I ordered points from NAPA and noticed the spring pressure was a lot lighter than my original set.  I installed them, set gap but couldn't get the engine to start....it would only fire once or twice.  I had done a total tune up so I started with the basics of voltage at the coil and continuity through the point set.  I wasn't getting continuity from the coil through the points.  I verified the issue was at the point contacts and no where else....just a little extra pressure on the contacts and I would get continuity.  I thought maybe they were dirty so I cleaned them....still intermittent.  So I thought maybe there was some type of coating on them so I ran some 400 grit paper between them.  It helped, but still intermittent. 

I replaced a lot of point sets in my life but never had this problem! I'm thinking: "Really?? Two metal contacts that open and close. They can't not work".  I rechecked the gap, pulled them out and reinstalled them but could not get them to work....just too light of spring pressure. I ended up filing and polishing my old set for now and running them.  In the engine specifications there is a specific call out for spring force on those points and it is pretty high on this engine.  May not be your problem but I thought I would mention it.
Scott

[Dexfoster]

Thanks for the response guys!!! Just getting off work. Heading to motor now to look into your suggestions. Ill let you know how it goes.
Dex foster

[Classic]

Is it my imagination or is the fan on backwards?

Gene

[Dexfoster]

harry s you called it bud! Fixed wires fired right up! Thanks!!!

As for the fan being on wrong i don't think it is? When it turned on it was blowing at the motor i didn't feel it in the front blowing out.

[Steve Passmore]

Just as a point of interest, it's not possible to have the fan turned around. If you turn them, they are exactly the same.

[Dexfoster]

Thanks  steve was about to pull it this morning and flip it....
DeX foster

[savemy67]

Hello all,

I am confused.  The photo shows a fan with blades that have a concave surface facing the front of the car.  If the fan is installed turned around, won't the concave surfaces of the blades face the engine?  And won't that alter the airflow?

Respectfully befuddled,

Christopher Winter

[Steve Passmore]

Turn your fan around yourself and you will see it makes no difference. You would have to bend the blades differently.

[35-709]

Hello all,

I am confused.  The photo shows a fan with blades that have a concave surface facing the front of the car.  If the fan is installed turned around, won't the concave surfaces of the blades face the engine?  And won't that alter the airflow?

Respectfully befuddled,

Christopher Winter

Agree.  SOMETHING is not right with that fan!

[Steve Passmore]

Respectfully, George you can't compare a flathead fan to a modern one. The one on the OP car is identical to all the fans I have here except where they have an extra blade.

[35-709]

   Steve, with the greatest respect back to you --- I still submit that fan is wrong, how about these on 3 different flathead engines?  How a cooling fan works hasn't changed THAT much.
Geoff N.

[Dexfoster]

I just looked at those same pics on google. It does appear to be on wrong. Either way works but if its producing the correct amount of airflow backwards well..... dont want to take a chance of cracking the block  to find out 😁. Thanks to all for your input.

[V63]

I JUST had this discussion with a 47 flathead owner and a persistent heating issue...he reported the fix was correcting the reversed fan with immediate results.  😳

[Roger Zimmermann]

Respectfully, George you can't compare a flathead fan to a modern one. The one on the OP car is identical to all the fans I have here except where they have an extra blade.

When I first saw the picture, I felt that something was strange. If you are turning the fan the other side, the angle will be the same, but the curve of the blades will be the other side. The first picture from Dexfoster is showing it very well.

[Steve Passmore]

The curve of the blade may change slightly but the argument here is it will still not blow air forward as many people seem to think.

[Roger Zimmermann]

The curve of the blade may change slightly but the argument here is it will still not blow air forward as many people seem to think.

Correct, Steve: the leading edge is in front and, with the rotation it will push air towards the engine. However, the efficiency will be less.

[35-709]

Right.

[Steve Passmore]

Granted, but I have lost count of the discussions over the past 50 years I have had with those that think if you turn the fan around, it will blow forward.  We are a little off topic here anyway as overheating is not an issue for the OP.