Packard Forum Index » Post-War (1946-54)

I'm not familiar with the 327 but my 1948 288 is very sensitive about sparking plug tip length and thread length. I had the same problem with ground tang of sparking plug mashed against electrode. I got the rite plugs and all is well.

NUmber of plug is meaningless on most brand of plugs except AC's. WHATEVER u choose be sure the thread length and extension of electrode tip is correct and NOT TOO LONG!!!!

What year is the 327 and i'll try to look it up in my plug book.

28 does sound more correct... Easy enough to change! I'll give it a Gio and see what happens. I'm planning on driving it to school tomorrow, so effectively it will be her first long-distance trip...about 20 miles or so one way.

PackardV8- the Auotlite 86 I'm running is 3/8" (.375") reach, which is correct as far as I know.... It seems odd that only two cylinders had this problem and the rest were all fine...

3/8" of plug reach is correct. The proper plugs back in the day were Autolite A7 or Champion J8 according to the 1953 A.E.A. Tune-up chart. The Champions are hard to find these days, and if you want the Autolite plugs, you have to remember that thanks to Ford's purchase of most of the Autolite branding, those plugs happen to now be called MOTORCRAFT A7, which are still available in some places.

The plugs you are using should work, but I've always preferred to go with tried-and-true (and cheap). Autolite 308's work great in my '52 9-main 327, and they're $1.41 each from RockAuto. Champion J12's will work as well, but I've had trouble finding them. I've heard rave reviews on Bosch Super Plus 7915's, mostly because they seem to last longer and they come right out of the box consistently gapped to the proper setting, but I have not tried them myself. Resistor plugs suppress ignition noise, so I recommend them if you have a radio in the car.

The gap spec for 1953 is .023-.028, which the factory put more precisely at .025, and that happens to be the approximate setting of the plugs I mentioned above. Erring on the wider side (closer to .028) may be preferable as it will result in a smoother idle; I wouldn't go any narrower than .025.

Your timing may be retarded a bit, by the way. At 600 RPM, the centrifugal advance may already be coming into play. The idle speed when setting the timing should be under 450 RPM and above 390 RPM (do not idle the engine below 390 RPM).

You can easily check your plug wires with a multimeter. A bad wire will have wildly higher resistance than the rest.

Wow, I had no idea on the 450 idle... that seems low compared to the V8s I'm used to (namely FE Fords, and Buick 300-340s)That makes sense though, because the motor does shake considerably at idle, as if it was running retarded.. I'll drop the idle down and reset it. Thanks for that info!!!!!

For plugs, I called my girlfriend's brother who manages a Napa back home, and is coincidentally the best dang parts guy west of the Pecos (I call him for numbers all the time.. he actually has a bunch of parts books from the 70s, and can cross reference just about anything to their new numbers. I got all my brake parts that way for this car. You'd be surprised what they still make, and whats on the shelf at Napas all over the country). Anyways, he carries Champion J8C's (now called 841), which are the exact same as the old J8's but with a copper core instead of nickle. I'm picking them up from my local Napa tomorrow, and getting some wires from Sac Vintage Ford as well.. I'll let you all know how it goes!

Dwell is a function of the point gap, wear block and points cam. If you set the points to specs but the dwell is off, there is something wrong.

First, see if there is any wiggle to the distributor shaft. If there is, you need new bushings. You will never get a good running engine with an ignition system that is bouncing all over the place.

Second, take a good look at the points cam. The points wear block of the points isn't full width of the cam. So it wears in the middle.

If those look good, put in a new set of points. 5000 miles is enough to wear down the wear block. It's called a wear block for a reason.

The dwell reading is more important than the points gap.

Take a look thru this thread:
https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=11455&forum=2&post_id=119022#forumpost119022

I checked my 1948 2262 with 288 engine. Recently installed a set of Autolite 3136. It's a 10 mm plug and thread length is 1/4 inch long. Not sure how that mite relate to the 327, maybe no relationship at all. But as DrewLA points out above in his post then a 3/8 thread length mite be too long.

There is an Exhaust valve under the spark plug????? The valve mite have raised up hitting the plugs that had the ground tang mashed against the electrode.

The AL 3136 plugs i have came in a box with a website adress printed on it so the plugs can not be more than 20 years old stock at the max.

The AL 3136 plugs i have came in a box with a website adress printed on it so the plugs can not be more than 20 years old stock at the max.

The 10 mm AL 3136 plug is still in current production.

The AL 308 plug which DrewLA mentioned is a good choice for any flathead Packard engine with 14mm plugs between the early 30s and 1954.

I can envision a situation which could lead to the plug side electrode could be struck by a valve and the gap closed or narrowed. If a cylinder head which originally had 10mm plugs (thus a 1/4 inch thick web between the base of the plug well and the underside of the combustion chamber) was subsequently drilled and tapped for a 14mm plug (a lousy practice but common enough in the day) with it's 3/8 reach, then a portion of the plug and threads would protrude into the combustion chamber further than the original 10mm plug. If the head had been resurfaced once or twice, you could run out of clearance.

I'm running AC-45R's with out any issues. For wires I am using Packard 440 solid core wires.

A major problem (long term) using a spark plug with thread length longer than thread length in the head is that the threads on the end of the plug will carbon up over time. Making removeal of the plug very difficult if not impossible without damaging threads in both the head.