Is the 3.4 and 3.6 based of the 3.2?

[insite]

Originally Posted by Paul

All I can say for sure is a 2002 996 3.6 bolts right up to a 1998 5 speed tranny in a 1998 Boxster.

correct; all of the M96 variants have the same bell housing pattern. the GT2, 3 and turbo all mate up to the split case trannys.

[blue2000s]

The cylinder heads changed twice on the 3.2, twice on the 996, and once on the 997 and they were all different part numbers.. That's not counting the high power packages. There are many different heads for these engines.

[pk2]

If the blocks are all the same, why was is it that the lowly little 2.5L 98/99 Boxsters are the only ones that catastrophically crack their little cylinder walls? If anything I’d think they’d have thickest cylinder walls.

Regards. PK

[blue2000s]

Originally Posted by pk2

If the blocks are all the same, why was is it that the lowly little 2.5L 98/99 Boxsters are the only ones that catastrophically crack their little cylinder walls? If anything I’d think they’d have thickest cylinder walls.

Regards. PK

A couple of misconceptions here. The castings for the 2.5 and 2.7 are not the same as the 3.2 and 3.4. So the outer cylinder wall diameter is not the same. Also, cylinder wall cracking is a BIG issue on the 3.4. Cylinder sleeve slipping is the more common issue on the 2.5. It's a different failure mode.

[pk2]

Originally Posted by blue2000s

A couple of misconceptions here. The castings for the 2.5 and 2.7 are not the same as the 3.2 and 3.4. So the outer cylinder wall diameter is not the same. Also, cylinder wall cracking is a BIG issue on the 3.4. Cylinder sleeve slipping is the more common issue on the 2.5. It's a different failure mode.

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Thanks for the reply.

My mistake, some post here implys that the blocks were all the same.

I read a couple extensive and contradictory descriptions of sequence of events that result in catastrophic failure the 2.5. The net result though seemed to end up with a chunk out of your cylinder wall flopping around.

I wasn’t aware that the 2.7 suffered the same fate as so many 2.5’s. Just plain was not aware of 3.4 problems at all.

You seem to be implying then that a 3.6. is the only worthwhile upgrade. (not much more point or bang for the buck with a 2.7 or 3.2 swap)

Regards, PK

[blue2000s]

I think cylinder walls have cracked on every engine, but it seems to be the biggest problem on the 3.4. There's no statistical info on any of this. Is a 3.4 a worthwile upgrade for the risk? It all depends on the individual.

[pk2]

Originally Posted by blue2000s

I think cylinder walls have cracked on every engine, but it seems to be the biggest problem on the 3.4. There's no statistical info on any of this. Is a 3.4 a worthwile upgrade for the risk? It all depends on the individual.

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Mmm, All I’ve ever heard about here and elsewhere is the 2,5’s. “LN engineering” (Nickes) and” Flat 6..” (our sponsor) dosn’t seem to discriminate though, so I guess your right.

I does seem 98/99 2.5L’s were particularly vulnerable. I had read some where that after some year they had sorted it out though. I’m just doing advance reconnaissance. I have 35k mi. and am pushing it pretty hard.. I’ll be amazed if dosn’t become another ugly statistic before long.

Regards, PK