Packard Forum Index » Pre-War (1899-1942)

I am having trouble getting the timing to fall into specs on my '38 Eight. I am sure that the procedure of using the light etc. is correct and that I'm shooting for the correct marks. When I turn the distributer I can only get to about TDC. I can retard the spark easily but that's it. The vacuum advance is working too as when I rev the engine the timing advances. The big issue is the advance diaphragm is hitting the oil filler tube when I try to advance the spark any more to get 7 degrees BTDC.

My thoughts are that when I rebuilt the engine many years ago, the oil pump was installed possibly incorrectly. Could the pump be off by a tooth where it meshes with the camshaft creating the timing issue? I understand the distributer can only go in two ways, correct and 180 off. Also I know about the witness mark going up or down for the Six or Eight.

The dwell/points are fine. The engine runs fairly well timed at TDC but I am still trying to get it in spec. I'm looking for advice, photos and help to solve this issue.

David

Hi David,
I am thinking out loud here, but perhaps the wires are one position off on the cap? Also, are you using a timing light with any kind of timing read adjustment? I know it sounds odd, but from your post you have all the bases covered, and you should be able to time the engine per specs otherwise.

I have a 37 120, and I will gladly take pictures of distributor or wires if it is applicable to your situation.

Please let us know how it turns out.

Rich

Thanks for helping.
The plug wires are totally correct in their position. Have done the one spot out of order before... Know all about that. Quite embarrassing too. That's a different story for another post.

The engine starts okay, runs fairly well and the firing order is totally on. No doubt on that one.

What experience do you have regarding the timing of the oil pump gears?

What do you mean by "timing read adjustment"? The timing light I am using is the typical inductance style that I have used many times before.

David

Sure, you can remove the oil pump and play trial and error until you get the original positioning. But as long as the distributor hold-down plate grips the base like a clamp ring and isn't bolted directly to the distributor body, it really isn't necessary as the distributor can function properly with any engagement of the oil pump and in any number of positions. It's just a matter of going back to the basics of ignition timing, after all, all the rotor cares about is what plug wire is above it - it could care less where the body of the distributor is positioned. Put #1 cylinder on TDC on the compression stroke. Remove the distributor and temporarily loosen the hold-down/retaining plate. Reinsert the distributor and rotate to a convenient position where the vacuum advance has plenty of room to accommodate whatever slight positioning might be required for final timing. Then rotate it slightly if needed one way or the other (doesn't matter) until the rotor tip is just approaching ANY post on the distributor cap; Snug up the distributor hold-down plate. That post beneath the rotor then becomes plug #1, and then just follow the rotation with the other wires in the timing order.

Note you can't use this technique if your distributor hold down plate is the type with a slot and bolt that goes directly into the body of the distributor - you need the complete freedom that the lock-ring type hold down gives. I've done this dozens and dozens of times.

From the Packard Manual:

Install the oil pump with driving slot parallel to the camshaft when cylinder one is at top dead center.

So remove the starter and use the timing marks to get the motor at TDC and install the oil pump.

Hope this helps

Well thanks to all that wrote in... As usual, I over thought the issue. That's typical for me! I should have figured this out myself, oh well.

This morning I set the octane adjuster at zero, set #1 at TDC, loosened the base plate then rotated the distributer about one cam lobe CCW and readjusted the wires to their new home position... Retimed number one and rechecked dwell. Easily got the engine to specs. Awesome. The only issues are the new position of the distributer places the grease cup almost against the block. Also I had to cut the solid vacuum advance tube because it wouldn't reach the diaphragm in its new position. Simple rubber vacuum line solved that easily.

I now have better mid to high rpm power and real decent acceleration.

Again thanks for the help.

I owe you all a beer.

David