A piston consist of;

A top compression ring
A 2nd lower compression ring
An Oil ring expander
And Oil rails that go on both sides top/bottom of the expander

On a stroker piston that has the wristpin moved 6mm up which interferes with the wristpin, you cant install the Oil rings before you have the wristpin through the pistons, because the rings go right across the wristpin opening.

The stroker piston from Wiseco comes with an Oil Rail Support in its own packaging. This is an additional Oil rail, but whats different about it, is it has a dimple in it. This dimple is placed downward and inbetween the wristpin opening. This is to keep the ring from rotating or moving around.

This ring is placed at the bottom under the Oil ring expander and The other two oil rails at the top and bottom of the expander.

Hope that made sense for you.

 

I stopped using 2.4 blocks ten years ago. there were many reasons why but the two biggest were I couldnt keep from blowing head gaskets between the cylinder walls. and I hated to drill the blocks for oil squirters. when I see someone comment oil squirters are not needed I just think those people have very little knowledge of how an engine really works. oil squirters are too control piston temperature. (and also to lube wrist pin which gets no forced oiling) forged pistons expand more than cast. so they need oil cooler more than a cast piston. F1 doesnt eliminate oil squirters. they use like 8-10 oil squirters per piston.

 

Oil squirters are a huge benefit, no doubt. Most manufacturers are using them now for a reason. Along with builders of almost every type of racing engine. Circle track and drag racing guys are installing them in V8's of every type and they're used by F1 and NASCAR. There are no downsides to utilizing oil squirters so I can't understand why anyone would advise against them. The two biggest advantages of the use of oil squirters is more even expansion of the piston which results in less skirt wear, better ring seal and it reduces piston pin galling.

We used to install OEM style squirters on the 4G64 blocks. Because of the core shift and casting inconsistencies there was a better than 50/50 chance that when the hole was drilled, it would intersect too far into the oil galley and block the flow. This rendered the block useless and there was no way to tell until it was too late.

The squirters we use are a derivative of what was used in the 2G 7bolt DSM blocks. The problem with the OEM design, though, is that they use a larger diameter orifice and a check valve. The check valve would stick wide open and the large orifice would steal way too much oil from the mains. Our oiling jets are machined in-house with a much smaller orifice and uses no mechanical valve. They supply a steady stream to the underside of the piston and since the 4G family of engines has a very efficient oiling system, the amount of oil taken from the mains doesn't affect the lower end oil supply in any way.

 

Jam, nice solution to the problem on the squirters.

Your comment that the 4G63 has a capable oil system though, I assume you mean "when the pick up stays covered, the pump is capable of supplying adequate oil volume and pressure?" Because Evos have all kinds of oil supply problems but most is related to the sump and then dumping too much oil into the head.

I've been playing with a spreadsheet I built up on this and it's given a decent amount of insight on to the limits of these motors. As far as keeping the piston connected to the rod at high RPM on the exhaust stroke, piston weight is far more important than rod ratio.

A 4G63 block/100mm stroke/150mm rod can out rev a 4G64 block/100mm stroke/150mm rod motor by about 5%. This is simply because the piston is almost 50g lighter on the 4G63 based motor. Yes the 4G64 has lower side loads and likely has a stronger piston to begin with. But the force on the wrist pin is lower.

Now go to a 156mm rod, but keep the piston weight the same. The change in rod ratio gets you a whole 20rpm more before you reach the same peak wrist pin forces. Rod ratio means almost nothing in its self.

87mm bore vs. 85.5mm bore, the 87mm piston with the same compression height and dish volume will still cost you about 15g. That 15g means the 4G63 based motor still has lower wrist pin forces than the 4G64 with the 1.56:1 rod ratio on the 156mm rod. Again, rod ratio means almost nothing in its self.

Again, I'm not talking about side loads. Side loads will wear a motor out quickly. Wrist pin loads will scatter parts instantly...

 

Thanks! Ok, so there is a rail and a rail support both under the expander. Do they make the oil ring groove wider, to accommodate this? Or maybe they make the expander narrower? Is Wiseco the only one that does it this way? I see that on the list of DSM and Evo pistons from CP-Carrillo, the oil ring thicknesses are all the same 2.8mm wide regardless of compression height.

 

Because the pin bore intersects the third ringland you need the support rail to support the oil ring. The groove is machined wider to accomodate the rail. Without it, there would be a giant gap and oil would get past the ring. Any piston in which the pin bore intersects the ringland will have some form of support like this. The Venolia pistons use a Teflon button which gets placed behind the oil ring and serves the same purpose.

 

oh goodie. mine doesnt have the squirters. i have that kiggley oil pressure regulator but i noticed i have high oil pressure. when i go wot my aem pressure gauge gives me the dashes because its goes out of range.

 

No problem. Looks like Tony answered the question for you.

 

After having read the entire thread I have a curiosity question. Tony, are there any particular years for the 4G64 block that seem to be better than others?

 

Yep, thanks you guys.

I belong to the Phil Hill school of racing, meaning, I get interested in these things from the point of view of robust reliability.
Phil is probably remembered today mostly for his F1 championship. But I remember him most as an incredibly successful driver in the endurance sports car races like LeMans. He knew how to take care of the machinery, make it live to the end of the race. Go fast but not stupid fast. And he would rather drive a reliable Ferrari than a fragile Lotus. That's the Phil Hill school of racing.

 

The headgasket piece is no longer an issue, English probably has gotten that down whch lets them put faith in the 2.4

 

No problem

Everyone uses off the shelf headgaskets. There was an OEM modified evo headgasket, but now they are not available anymore.

Cometic, Power enterprise, Cosworth, are all good HG's for the 4g64.

I know a lot of very high HP 4g64 cars using Orings with good luck.

 

heard nothing but bad things about cometic. i went with a cosworth, but you better get them fast because they are leaving the automotive industry in favor of government contracts

 

No Sir, they all are about the same.

Every engine has its strengths and weaknesses. The goal of an engine builder is to address each weakness and determine a solution. There is more to it than simply ordering up a pile of parts and bolting them all together.

Usually from folks with improperly machined sealing surfaces or the head is lifting. Cometic gaskets have been proven for years.

 

I completely agree, coming from the Mustang world, different years and even different plants had huge differences in the blocks. So that is why I was curious. Thanks for the reply.