Packard Forum Index » V-8 (1955-56)

OK. i remebered the following from the "Packard V8 Engine Size " thread Posted on: 7/17 15:26:51 .

Parts Wizard wrote:

"Everyone seems to have a problem "not trusting" Egge pistons. And later noted that they would have to be fit with .003 to .0035 clearance. Egge recommends a clearance of .0025 to .003 on their V8 pistons. Why would someone install pistons with a different clearance than what the manufacturer reccomends? I would like to here why Egge pistons can not be "trusted"."

Posted on: 7/17 15:26:51.

I doubt that the extra .0005 (1/2 of 1/1000, NOT .005) of clearence would cause any problems. That's setting them up LOOSER not tighter. But i won't argue the point.

I'm wondering if some of the piston failure that has been cited is due to trying to fit an aftermarket piston to an EXISTING bore that is too tight.

Of course that certainly does not explain a wrist pin piston boss .006 out of parallel with crank.

It is not uncommon to replace ONE piston without pulling engine. If this is the case then one must tread easy with aftermarket pistons for the V8.

And maybe this one flew over everybody's head but i remember it from page one of thuis thread:

Wiz wrote:
"All of Egge's pistons for the 3 1/2 bore 282 and 327 engines are of the steel strutted design. Kanter does buy both the 3 1/2 and the Packard V8 pistons from Egge. If anyone has had problems with Egge pistons I would love to hear about it. The only way problems can be fixed is to know what the problems are."

Posted on: 7/17 15:15:28


NOTE that the streight 8 pistons mentioned are STEEL STRUT. But the V8 piston is mentioned seperatley of having any steel strut.

SO, that somewhat begs the question as to why the V8 pistons are not steel strutted too??????

SEE page 14 and 15 of the Engine section of the 55-56 Packard factory service manual. Heading "PISTON" at bottom of page 14 continueing top of page 15. MY manual indicates the factory V8 pistons are steel struted to control expansion.

Wow, this has been a very informative thread, and I hope others keep chiming in with their experience.

I never would have learned so much about a product/vendor at any other site.

I'm wondering about Scot726's problem. If the wrist pin was off by .006: then i am amazed that the rod was ever successfuly bolted to the crank. The wrist pin bushings and rod bearings should show significant tapered wear.

Scot726. HANG ON to that piston!!!! Don't let anyone "throw it away".

Scot726.
If all of the other piston and rod assemblies look ok then use one of them withOUT rings to double check the machinsists findings. Use some palstigauge at the rod journal. If the plastigauge is tapered then it is possible that the BORE is not streight.

If it were my engine and before i expended any more resources on it i would do A LOT of double checking use two or more different methods.

"Yeah. ok. THE QUESTION IS WHAT is properly installed supposed to mean????"

Although I'd have liked to have been able to afford custom forged pistons for the Pat, I'm a long way from that financial condition. I do not remember where the information came from at the time my engine was rebuilt as do not believe that I discovered this forum until sometime after the rebuild.

We weighed the individual pistons and determined that they were within balancing tolerances (I do not recall the exact figures but engine did not require re-balancing) and allowed an extra .0035" clearance on the bore. Again, I do not know where the advice to do this came from. I had never been inside one of these engines before, hadn't had any experience with Egge pistons (or any other kind) since the mid-1960s. I do recall that I thought that the extra clearance made sense at the time because of the different expansion rates of the materials used in the originals and the Egge pistons, the machinist and mechanic agreed and I have had no problems with the engine. It used a little oil for about the first 500 to about 750 miles but that has ceased, the engine is quiet and, for the past 5000 miles, has given trouble-free service in daily use.

V8,

My next door neighbor is a cracker jack machinist. He put the piston on a surface block, skirt down and measured around the top. It was six thousandths off. Then he shimmed it at the skirt until the top was level with the block all the way around. He verified that the ring grooves were level as well. Then he touched off on both sides of the wrist pin hole, it was off six thousandths. The rod bearings weren't tapered, I already plastigaged them. To be fair, the engine had other issues; a bit of bad babbitt which I caught before it screwed anything up (on a different rod/piston) and some blow by between #2 and #3 cyl at the head gasket. Maybe a thrust bearing issue too, not too sure about that yet.

You don't have to worry about me getting rid of the piston, I am going to frame it...

Scott

Does Egge do all their own casting & individual machine work on the low volume stuff? There was an episode of "How It's Made" on TV in last week or so showing how pistons are made. After seeing that and the mass production process, am actually surprised there are so few issues in modern stuff as the process & machining is so fast. From time the automated machines grab the rough shape, clamp, machine & kick it out and start next one is very little, and they just spot check. Was thinking if they used an automated process, would be easy to see how .006 could slip through.

Yes, Egge Machine does cast and machine all of their pistons. A piston made by Egge in the 80's I could see how a piston with .006 runout from wrist pin to top could have gotten through inspection as back in the 80's Egge did not realy have a quality inspection. Every piston that Egge makes today has to make it through a quality inspection. The tolerance for the wrist pin paralelism has to be less than .002 or the piston is rejected.Every step in the manufacturing of a piston is inspected and must meet all tolernces or they are rejected. All of the materials & machines used to make a piston today are better than anything Egge had back in the 80's. The reason the V8 Packard pistons do not have a steel strut is that the mold used for this piston can not use a steel strut. As long as you used Egge's recommended clearance (.0025 to .003)you will not have problems.