3.6 vs 3.8

[The Radium King]

hi; looking at 3.6 and 3.8 motors and wondering the differences (beisdes the obvious). the bottom end for both has the same part number, so the only difference should be bore and heads. is there much difference in heads - are they interchangeable? also, lne will take a 3.6 to 3.8, and a 3.8 to 4.0. if the cylinders were the same with just different bore, one would think that lne could take the 3.6 to 4.0, unless i am missing something.

any help with understanding would be great, or a point to a place where perhaps i could find this info.

[ekam]

3.8L came out on 997 and I assume a 3.6L from a 996 is a easier swap without having to rewire everything.

Porsche updates the DME every few years as well.

[BYprodriver]

Originally Posted by The Radium King

hi; looking at 3.6 and 3.8 motors and wondering the differences (beisdes the obvious). the bottom end for both has the same part number, so the only difference should be bore and heads. is there much difference in heads - are they interchangeable? also, lne will take a 3.6 to 3.8, and a 3.8 to 4.0. if the cylinders were the same with just different bore, one would think that lne could take the 3.6 to 4.0, unless i am missing something.

any help with understanding would be great, or a point to a place where perhaps i could find this info.

I believe the cases are basically the same, however some have more "meat" allowing the additional 2mm overbore past the usual 99mm. All LN 99mm bore engines use the OEM 997 3.8 head gasket. I have not built a MKII 3.6 engine yet so I'm not sure about head interchange yet but I would start by comparing part# of heads & valves.

[The Radium King]

well, the heads between the 3.6 and 3.8 are different part numbers, but all the ancilliaries (valves, cam housings, etc.) are the same. Most likely the same head with revised combustion chambers for the different bore sizes (like the 3.2/3.4 heads). so *probably* swappable, although i presume benefits would be minimal.

i guess the reason i was asking was to determine why lne doesn't take the 3.6 to 4.0, like they do the 3.8. if fundamentally the same cylinders between the 3.6 and 3.8 then it should be possible. what does one do for a head gasket on a 4 liter car?