One other thing is the mopar clearance was for two rods on one journal, but the same theory applies.

Kevin

My gut tells me a s/c engine mostly operating at highertorque/lower rpm regimes might want some more oil on the skirts of the thrust side, which is why I voted for rod aquirters. Also, since we aren't talking about as much rod journal sling oil available, and not much open skirt to sling it at, and since I could care less about the undesired (if you're a GREEN) miniscule extra burnt oil, oiling can't hurt. The oil rings will do a real good, but not quite perfect, job of scraping the bore at lower rpms. The steel may be better, and the oil may be better, but until we go to ceramic pistons and bores, I want oil on mine. But I guess I could be convinced...

Frank, if the guy you talked to was worth jack, they would have him doing something besides the phone. Unfortunately, the techs may not be a lot better. I've too often found the tech may know less than I do, or is that just ego talking...

Here's the email reply from 3SX:



That's a little better response, but the question of forced induction in combination with no supplemental lubrication remains. I'll still talk with the machinist about it.

Frank

- enough so that you don't call back and waste our expert time with stuff we never bothered to think about...

I'm assuming the big end bearings are solid/drilled, and not circumferentially grooved? So that the pin oiling/wall squirting port is only lined up once per rev? Is the pin oiled just prior to combustion? or on the compression stroke?

My gut feeling is that the HD rods don't have wall holes because that's one more machining step for what will only show up as a problem well after the warranty period, and which of us would ever muster the resources to prove that you had worn piston skirts on a s/c motor far before you should have expected to, all for the lack of a 1mm hole in the rod? You'll wreck/sell/change/get Toy fever/have a baby/get cancer and probably never even see it happen unless you maintain communications with the new owner...

That's right.



No..... there's only one port in the rod, but the crankshaft rod journal is through-drilled, so the rod port sees 2 supply cycles per crankshaft revolution.



One time just before TDC and one time just before BDC.

In the static view, the BDC squirt is pointed at the sump ceiling and doesn't appear to hit the cylinder wall - but it's anybody's guess where the oil is deposited in a dynamic condition, given variable piston rates that approach near sonic speeds.

Frank

Here's another consideration:

Standard cast piston to cylinder wall clearance is around 0.001", but the forged pistons run about .0035", which allows more piston rock in the bores until the pistons get warm. The short skirts exaggerate the rocking angle. Certainly offset wrist pins help relieve thrust side pressure, but the pistons will still rock and slap until the engine is warm..... even if you can't hear them. The only way to get additional oil to the bores is through the rod squirters..... which might help with cold condition wear and slap noise.

Frank

I have squirters on my 2.6 as well as cold piston slap... Ths piston manufacture may be a good source for a recomendation on how much oil they need.

BTW I dont think the pistons get very close to the speed of sound, although they can help produce the sound of speed.

I may go with some rods similar to yours for my next build, those sure are nice!

Kevin

No - not really the speed of sound - more like 35 mph, but plenty fast enough to shake things up in the sump area.

On the rods, thanks - they are nice, but shop carefully - 3SX won't say who makes them.... only that they're made by a "respected manufacturer". They look suspiciously like Eagle ESP rods to me.

A couple of years ago Eagle offered what looks like these, but all of sudden closed out what was available. Then these showed up at 3SX as a private label rod (at a higher price) and no Eagle rods are now available for the 6G72.

If you look closely at several brands, there is a strong resemblance.

Here's a K1/Carillo:


Here's an Eagle ESP:


Here's a Manley:


Here's a SCAT:


There may be others, but all of these look like the same rod - at least in the pictures. I think all are available for the 2.6L engine. 3SX is the only place I can find this rod style for the 6G72. I really like the ARP bolt style for the cap and the alignment dowels.

Before I install them, I'll weigh them and check the balance and length to see how good they really are out of the box and post the findings.

Frank

The pistons finally arrived. The floating pins are a perfect slip fit for the 3SX rod bushings. <img src="/forums/images/graemlins/kewl.gif" alt="" /> These will put me a little closer to the edge (hopefully not over it) with the same 10cc dish as the last .015" overbore - but these are for an .035" overbore..... SCR should be between 9.1 and 9.2:1 -



The package looks very business-like:




Now all I need is a crankshaft - I can't believe one hasn't turned up here yet.... hopefully it won't be too long.

Frank

Oooooooooooooooooooooooooh lovely <img src="/forums/images/graemlins/kewl.gif" alt="" /> Those rods look really cool Frank <img src="/forums/images/graemlins/cheers.gif" alt="" />