Looking closely at the OE rods, it appears that the oil squirter is designed to lubricate the crankshaft backside cylinder wall. I can see that oil can migrate down the oil control ring on the passenger side due to gravity, but that won't happen on the driver side of the block.

I've searched the 3si forum and found some interesting things there. Some say that they completely block off the block oil squirters in an attempt to raise oil pressure to the mains and rod journals. The block-mounted piston squirters in the TT engines open with pressure and there is anecdotal evidence that the balls and springs sometimes find their way into the sump.... causing a loss of oil pressure at lower rpms.

I'm trying to find out if any of the turbo guys have blocked off the piston squirters AND use aftermarket rods, depending completely on crankshaft sling and splash lubrication for the cylinder walls. More than likely splash lubrication is enough, but Mitsubishi drilled the rods for a reason and I notice that GM also uses the method on certain engines.

Frank

So, you are saying that there is a kind of poppet valve for the oil squirters? I don't really like that. Check the MB turbodiesels squirters, I think they are a tapered nozzle type. www.benzworld.org is a wealth of knowledge on that stuff.

Ed

Yes, apparently so. I've never seen one, but from what I've read on 3si, they can be troublesome and most advise either using forged pistons and ditching the squirters - or - replacing them with new ones at every rebuild. They aren't expensive, so I don't know why anyone wouldn't replace them instead of rebuilding and keeping the same ones. Apparently, the only rationale for using them is to cool the crowns on the stock cast pistons.... forged pistons can get by without them.

As low as oil pressure drops at low rpms on our engines, I don't want to add anything that reduces pressure or flow, so I won't use any squirters at all.

What I'm finding so far indicates that the 6G72 block survives nicely with aftermarket rods (no rod squirters) and no block squirters if you use forged pistons. I even saw where one fella's mechanic had used a hammer and punch to close up the rod squirters in a VR4 engine. <img src="/forums/images/graemlins/scared.gif" alt="" />

It seems to me that eliminating the OE rods should raise oil pressure in the engine and benefit the top end oiling - maybe even driving away future lifter tick demons. <img src="/forums/images/graemlins/wink.gif" alt="" />

So, unless I find anecdotal evidence that convinces me otherwise, I'll use the 3sx rods with no squirters and hope I get enough splash and mist to oil the cylinder walls.

Frank

I think I'd rather look for a higher volume oil pump.

The rod squirters hit the thrust side of the bore for a reason. It seems to me that since the bore gets wiped pretty cleam by the scraper rings, it's chancy to depend on splash lubing there, which is probably the highest wear point of the bore and skirt.

If you can keep the squirters, I think I would, even with forged pistons. Tougher is not invulnerable, and it doesn't take much hot spot detonation to ruin your day and your pistons and ring lands and rods. The only path for the heat to leave the piston crown is thru the rings, unless you squirt the bottoms with oil and accept/handle the oil heating.

AFAIK, the only pump that is claimed to be a "high volume" pump for our version of the 6G72 is made by Toga. The 3si folks say the "high-volume" claims aren't true..... but then it could be that the OE pump is already considered to be a high volume pump and perhaps what they mean is that the Toga pump is no better than the OE pump. I don't know what the Toga output for our version is - and don't know the output for our OE pumps, either. It's entirely possible that the Toga pump output exceeds the factory truck pump. Some folks cut new rotors (no thanks), shim the relief valve (no thanks) and/or port polish the pump (no thanks).

I agree with you that the factory rods have squirters for a reason - and I think we agree that the squirters mainly benefit the cylinder wall. Actually, since there are 2 holes in the journal, there's a squirt on the upstroke and one on the downstroke. I'd bet that with piston speed the oil stream that's squirted on the downstroke is intercepted by the piston skirt and ends up in the wrist pin/crown area.... but certainly on the upstroke, the squirt stream lands on the cylinder wall. Whether the downstroke is like a wasted spark ignition and has no value is questionable, but I certainly see the value in the squirt stream to the "hidden" thrust side of the bore on the upstroke.

Maybe before I use those rods I'll have a discussion with the engine builders at 3sx and see if they have experience with using the aftermarket rods and also closing off the block squirters.

These things are sorta mysterious - maybe voodoo - maybe not. It's even possible that they don't do much of anything needed, yet contribute to lifter tick. It wouldn't be the first time engineers have tried a solution in search of a problem that didn't work, but in the doing created a whole new set of problems. I'd sure like to talk with a Mitsu engineer about it.

Frank

I called the 1-800 number for mitsu once and actually got to talk to an engineer when I was figuring out if the KM148 would handle the torque of the 2.6T. I got some nice lady on the first human pickup, and she listened nicely, and then actually transferred me to engineering, albeit an english speaking Eng. Dept., who listened with interest ("Wish we'd done that") and told me that it would handle over 300ftlbs of torque...

If you can to them, betcha they'd like to chat about your question, too.

I have not been here for a bit,


Yes, most all engines with squirters have a valve in them.
In the Mitsus they close the flow about 30psi. I expect they vary from that some.
They are aimed to sweep the underside of the piston dome.
I have seen them in NA engines from Nissan and Mazda too.

As usual, if I stare at a problem long enough, I can find the most complicated way to solve it. <img src="/forums/images/graemlins/lol.gif" alt="" />

I don't see why I can't drill the 3sx rods with the same diameter spray hole and at the same angle as the OE rods, chamfer the hole and regain any lost lubrication benefit to the cylinder walls. The H-beams to the side of the hole might limit the spray pattern width - depending on whether what comes out is a spray or a stream - but the result might be better than nothing and would keep oil pressure the same as the OE design:



Still chewing on this one.

Frank

This morning's call to a 3sx sales guy (I won't name him) went something like this:

Me: The aftermarket rods you sell for the 6G72 don't have oil squirters like the OE rods, so I'm wondering what happens to oiling of the cylinder wall - is it sufficient with these rods and do you have any anecdotal evidence of cylinder wall wear from anyone running no block squirters and using these rods?

Him: I wouldn't worry about it..... just run 'em... they'll be fine.

Me: Well, do you know what happens to oil pressure if these rods are used in place of the OE rods?

Him: Nothing at all.

Me: What do you think would happen if I closed off 6 feed holes in the main oil supply?

Him: Well, oil pressure would go up.

Me: How can that be if nothing happens when I use these rods?

Him: Huh?

Me: Who at 3sx builds your engines?

Him: Whichever tech is available, but they don't take tech questions on the phone - you'll have to send an email.

Me: Thanks and good-bye.

So, I sent an email........... I can't wait to see the answer. <img src="/forums/images/graemlins/lol.gif" alt="" />

Frank

The port is only effective when the hole in the bearing lines up with the drilled hole in the crank. Because the hole is small and goes by pretty fast the amount of oil that that squirter holes consume is tiny compared to the rest of the system.

Basicly, it would be very hard to see a differance in your oil pressure from that small a change in comsumption.

So while he did not present a perfect explanation the message was correct, the change in used oil volume is small enough that it would be difficult to notice.

Kevin