Hard Calculations for Strokers

[TunaTalon]

After years of reading about the “conventional wisdom” of stroking the 4G63 engine I have drafted a white paper as my contribution to the DSM community. The white paper presents a mathematical analysis of the piston dynamics of three popular versions of the Mitsubishi 4G63 engine, the stock 2.0L, the 2.1L destroked version with an 88mm crankshaft in a 4G64 block, and the stroker with a 100 mm crankshaft in a 4G63 block. Where applicable, charts are included to show the differences between the versions at different RPM’s or different crank angles.

The paper has been posted on http://www.kidzuku.com/StrokeOrNot.pdf. All equations used to generate the charts in the white paper are listed and the Excel Worksheet used is also available for download as referenced in the paper.

 

[TunaTalon]

Do you know anything about the issue of having the oil rings located in the top of the rod pin for the 2.3Lstroker pistons vs the 2.4L pistons the Oil rings are located above the rod pin location on the pistons because of the block being 5.9-6mm higher than the 2.0L block...????(these are aftermarket pistons im talking about) I heard that oil consumption on a stroker is minimal but still a higher % than the stock 2.0L? Thats the main reason why I went with the G4CS block vs the 4g63 stroker

The entire 6mm does not have to come from compromising the oil ring. The top ring can be moved up and the ring pack can be reduced (which compromises the maximum power).
The image below is of a 4G63 stroker piston clearing showing the extent of interference between the oil ring and the pin.


Moving the pin up has the added advantage of increasing piston stability which is more important in the stroker with the higher side loading. I opted for the 2.3L version to keep it simple and reduce side loading effects.

“A high pin location adds to piston stability and reduces thrust on the piston skirt. “(Stroker Engine Kit Basics: Bigger Really is Better, Len Emanuelson, Engine Builder, March 2007)

 

[Bender]

Oops. Sorry, it was late last night and I was tired. I thought you were talking about oil squirters. .

Anyways back on track, I see what your saying about having the oil rings up further. But if you order a complete stroker kit, (or the pistons for that matter) wont the manufacturer have already cut the reliefs in the right spot?

This is the kit I was planning on getting <a href=http://cgi.ebay.com/ebaymotors/Eagle-Stroker-Kit-Arias-Evo-Eclipse-4G63-4G64-7Bolt-2G_W0QQcmdZViewItemQQcategoryZ33616QQihZ016QQitemZ260190737133QQrdZ1QQsspagenameZWDVW> Click Here </a> And I was just going to put all the rings in the reliefs that were already machined in the piston.