Re: [ihc] RE: Knurling slugs

[bearbvd@xxxxxxxxxxxxxx (Greg Hermann)]

At 2:41 PM 8/17/04, Jim Grammer wrote:
>>Date: Tue, 17 Aug 2004 10:19:03 -0700
>>From: John Hofstetter <hofs@domain.elided>
>>Subject: Re: [ihc] Re: David's "diesel" 258
>
>>Is anyone else on the digest old enough to have pulled out pistons and
>>knurled them, put new rings on them and stuck them back in ?

BT,DT. It WORKS. BUT--be sure to check the side clearance in the top ring
groove. If it's pounded out too wide, you either need to cut them wider (to
get a good fit with thicker rings) or toss the pistons.
>
>Not exactly, but my B-102 pickup has 5 knurled pistons. When I brought it
>home and fired it up, there was a death rattle in #4 hole. ID was by
>stethoscope and then pulling the plug wire. Pretty sure that's what got it
>parked in the walnut orchard. Yanked the piston, knurled it was. Used to be
>a 'quick' fix for a bad overheat that collapsed the piston skirts a bit.
>Stuck a new standard bore piston and rings in, and it's been going strong
>ever since. The new piston weighed something like 6 grams more than the old
>one. That sounded like a lot, so I called my motor machinist. He said 'In
>one of those engines? Just run it'. He was right.

MATCHING the weight of the pistons (to one another) is important to the
balance of ANY engine. The more accurately you match them, the smoother the
engine will be (assuming that you have also matched (independently) the big
and small end weights of the con rods to a similar tolerance).

The actual weight of the pistons in an I-4, an I-6, an I-8, a V-12, a flat
12, or a V-16 is irrelevant to the balance of the engine.

With a V-8 (with a 900 , NOT a flat, crank) , on the other hand, the actual
weight of the pistons (which are also, hopefully, of equal weight) IS
critical to the rotating balance (crank bob weight) of the engine----

Greg
>
>Jim