Just thought I would make thread to share this little gem I found a while back.

So whenever talking to people about boosting the RA the argument that the block does not have built in oil squirters always comes up. Well when I took the the rods and pistons out of my block that I am building I noticed a little something.

Standard 4g69 Rod and Piston



Note the oil passage on the bottom of the rod



You can see the hump around the passage in the last picture up diagonally to the left of the "3".



Then the exit of the passage which aims up the the cylinder wall/piston skirt area



These are probably not as effecient as the constant pressure style 4g63 squirters. However I thought this was interesting knowledge worth sharing with you guys.

 

Thank you for sharing, Bakuro. I always enjoy learning these technical tidbits

 

Interesting indeed...now when one is to install aftermarket rods in a 4g69 block, it seems they've eliminated any means of effective piston cooling. How this affects reliability is to my knowledge still unknown, as I have not heard of any failures of built 4g69 bottom ends, but I've always had faith in engineers, and their designs whether they had ease of maintenance in mind or not...so when I see something like oil squirters being employed, I would be wary to omit them especially if my intention was to exceed the intended power output...

 

I actually had the same conversation with an engineer at Manley after I bought my rods and noticed the squirter in the stock rods. I was informed that with a forged bottom end there is no need to worry about having the oil squirters. He basically said, "If you have them great. If not dont worry about it." He made it sound as if manufactures will add oil squirters to assist the longevity of mass produced factory parts. This becomes nearly a non-issue with high quality, high performance forged internals. And I have seen a couple of 4G69 engines without any oil squirters pushing 800+hp in various forms now. These setups have been beat on, and beat on in various motorsports. And I have yet to hear an issue from these guys in regards to the bottom end.

 

nor have I, I just wasn't sure if it was because no one was talking about it, or it actually wasn't happening...

 

sorry but all the turbo motors have these squirters on the rods.. they squirt on the cylinder wall not the bottom of pistons. and forged pistons expand more than factory pistons. so saying forged pistons dont need oil cooling, ehh not so smart if you ask me. they need them more than factory pistons.

 

If that's the case, then there would be zero piston cooling to begin with in the 4g69 as there are no oil squirters in the block.

 

I would like you to understand the difference between cooling and lubrication. The connecting rod has a nozzle for lubricating the cylinder wall. When combining holes of the crankshaft and the connecting rod is injected portions of the oil on the cylinder wall. It has nothing to do with cooling. Exactly the same injector has any connecting rod for Evo.

Now about the cooling. The Evo piston (OEM) has a channel forced cooling.
I noted arrow.

Inside the piston is made channel. It is constantly supplied with oil.

And schematically how it works.


This is a very good decision. This allows to reduce the temperature of the piston and to stabilize expansion of the metal. Therefore, when replace the OEM pistons, it is usually only worsen the situation.

Unfortunately, 4G69 pistons do not have forced cooling. And extra oil injector does not improve the situation.

 

this is some good info...but I feel like it has got to help a little bit, even if aftermarket pistons don't have forced cooling.

 

The essence of the oil cooling of the piston that the stability of expanded metal. We conducted experiments with oil injection. And got interesting results. If the piston is of conventional design (without oil channel). It does not matter, you inject oil from the bottom or not. The extension is the same. Therefore, if the piston has no oil channels for forced cooling, the sense in the oil injector no. You will have to increase the gap between the cylinder wall and piston.

To install injectors, you will need to buy the injectors and valves.


Nozzles and valves are a little away from the oil channel.


You will not be able to make holes in the home. For this we need the machinery of.

 

That is some good info. Thanks Stayer!