New engine on the horizon

[Snakebit]

I respect your opinions, but placing the wrist pin in the oil ring groove just isn't natural. As far as using a 5.315 rod vs a 5.4 rod, you are talking .085" difference. Just one more thing to help me sleep better at night knowing that the engine will not turn into an oil burner.

[blykins]

It wouldn't.

But peace of mind is a wonderful thing.

Think about how many fox mustangs there are across the us running 347's with 1.090" pistons. They are not rolling smoke shows. This is extremely common and even the 4.300" stroke bbf pistons come this way.

Once upon a time, I think someone jacked up the ring install or got the hone job wrong on a build and contributed it to the piston design. As you know, there are lots of bench racers on the Internet, so the idea stuck. :-)

[Barry_R]

Originally Posted by blykins

Once upon a time, I think someone jacked up the ring install or got the hone job wrong on a build and contributed it to the piston design. As you know, there are lots of bench racers on the Internet, so the idea stuck. :-)

While I generally agree on it not being a huge deal, I will only pierce the oil ring groove on a race or performance package if it's the only way to satisfy other limitations - such as pulling the pin out of the bore or banging the counterweights on the pin boss. Or a checkbook limitation.

But if there is any other way I will avoid it. A narrower ring pack (.043-.043-3.0mm) coupled with reduced crevice volume can get you some good usable real estate up there (over .100") for modest cost and you end up with a nicer package as a result.

Consider the development budgets in the OE world and list the number of engines built with pin/ring groove intercepts.

That 5.315 rod ain't a bad deal either - it just never caught on with the bigger is better crowd. I do like the short CD for keeping the roll couple of the piston small - keep the ring pack squared to the bore and stable - don't need a long heavy piston since the working part of the skirt is all below the pin.

[blykins]

I don't know of many Cobra/Galaxie/Mustang engines trying to hit the 200k mark though...

OEM and what we deal with is certainly a good distance from each other.

With that being said, we may all have our theories/preferences, but again, I've never really seen any oil consumption or wear issues because of the oil ring placement. Most of my engines fall into the street/strip category, with some a little more strip than others. I do dabble with the LS crowd, BBF, FE, and SBF stuff, and it's not uncommon to see the oil rail support in the piston box.

While each point has its own merit, I do believe that the wrist pin/oil ring fiasco has really had its own evolution, carried on by most of the guys on The Corral and www.yellowbullet.com.