Can anyone enlighten me on the differences b/w the 2.7L NA block and the 3.0L S2 block? I tried a search and know the ins and outs of the head, pistons, etc. but I am wondering about the block differences themselves. Are they the same minus the crank and other components?

Thanks.

 

I think they are the same.

 

i think the 3.0 block might have a little more clearence for a longer crank

 

^ I think so as well but don't know for sure.

I have heard 2.7L blocks lack the coolant drain bolt on the passenger side of the block, near cylinder 4. I don't know if S2s and 968s got these or not.

 

I think if you get the 968 block you get piston squirters

 

different crank. I believe the flywheel etc is different so the back of the block may be slightly different as well. 2.7 has the same crank as the 2.5

 

What about the cylinders? The 2.5ltr is open for 360o around the whole way. The 3.0ltr has 'siamesed' cylinders which some say can create hot spots as the water can't get completely around it, others say that increases the strength.
Plus different water jacket.

 

The 2.7 block is not the same as the 2.5, just the crank is.

 

2.7L bare block is the same as the S2.

 

John was is the going rate for an s2 block? What would you pay for a 2.7 complete motor?

 

Thanks for the help, John. Always coming through for the list!

 

I have no idea on the pricing today. I have 4 or 5 3L blocks with various 2.7L heads, I've had them for over 10 years. So I haven't kept up with the market. I hope they go for lots of $

I think a good 2.7L engine will be around $1500-2000 (I might be way off). Of course the condition will be a key factor here.

 

Hmm anyone interested in a complete 2.7 with 97k miles?? :P

 

In addition to the cylinders being connected(or siamesed) the base of the coolant cavity is moved up a little over a third of the distance up the cylinders as compared to the 2.5. This is all aluminum so there is definitely more aluminum mass and on the surface it appears the 2.7, S2 and 968 blocks are structually stiffer. As for the cooling aspects the bottom third of the piston travel has less heat to transfer to the walls than the top 2/3. I guess the question is whether there are any indications in the racing world that the S2 and 968 suffer from heat related failures due to these changes relatively more than comparable HP 2.5 cars or even the stock 2.5 turbo class cars.

 

Yes well I guess that's the question. It seem to be the preferred option of engine builders to go with the 3.0ltr blocks though doesn't it? So I guess they're going for strength over any cooling/heating issues. The main issue with failure is probably still the oiling, which can be affected by heat in some cases too.