Re: 356 Crank in 327/359

Posted by Ross On 2011/8/16 6:54:17

Fascinating stuff. Never had any problem with the aftermarket pistons in the twenty plus sets I've installed, but even when screaming at the top of their lungs piston speed doesn't even approach 3000 fpm in these engines. There is plenty of friction from all that bearing area but the plus side is that it keeps the components from migrating to other parts of the engine compartment.

I am something of a skeptic about the nine-main 51-54 engines; I think it was a sales point more than a genuine quality enhancement. I can not tell the difference between say a 51 300 and a 51 Patrician in driving no matter how carefully I listen. And I would point out far as warming up a 51-54 nine main is concerned that the crank is probably not as torsionaly stiff as a five main as evidenced by the fact that Packard fitted them with much larger vibration dampers than the five mainers got.

Cortcomp is correct to note that these were production engines and subject to casting variations. Did a valve job on a 51 recently where 6 of the 8 intake ports lined up with the valve seats quite well, and two were at least 3/32 off making a big speed bump. This is quite typical and why every engine I do here gets at least a rudimentary porting job. Seems to make a nice difference.


The biggest problem with Packard gas mileage is that the cars are so un-aerodynamic and often at cruising speed the engines are turning faster than they need to because of lack of extra ratios.