Upgrade Euro 3.0 to a 3.2 ????

[targa44]

My '77 Euro Carerra 3.0 engine "restoration" turned south on me with several bad pistons. At this point, I'm thinking why not just stretch to a 3.2. I don't want to build out a monster, so.....

What issues should I be aware of if I only go with the larger bores? i.e. induction - can the C.I.S. handle it - will it run too lean?

any other considerations?

thanks,

kj

[Steve@Rennsport]

Originally Posted by Boxster44

My '77 Euro Carerra 3.0 engine "restoration" turned south on me with several bad pistons. At this point, I'm thinking why not just stretch to a 3.2. I don't want to build out a monster, so.....

What issues should I be aware of if I only go with the larger bores? i.e. induction - can the C.I.S. handle it - will it run too lean?

any other considerations?

thanks,

kj

kj,

You can install the 98mm P/C's (make sure you get the right ones) without an issue. You will need to adjust things to richen things a bit since most Mahle 98mm P/C's have more compression than stock.

[ARCSinAK]

Steve is the Man!

[jsveb]

I would buy Wayne's rebuilding a 911 engine book, if you haven't already. It has also got quite a bit of upgrade combos listed. Then it is easier to discuss what experts like Steve is saying

[targa44]

Thank you Steve....

A new direction - found some very good used US 3.0 pistons and cylinders. However, they are the 9.3/1 compression vs. the old 8.5/1 Euro compression.

You mention with higher compression there will be a need to adjust the fuel richness.

If I don't enlarge the capacity - say from 95mm to 98mm - but increase compression, do I create the same need to adjust fuel mixture?

I'm not the mechanic, but like to be informed and find this interesting.

thanks again,

kj

[Steve@Rennsport]

Originally Posted by Boxster44

Thank you Steve....

A new direction - found some very good used US 3.0 pistons and cylinders. However, they are the 9.3/1 compression vs. the old 8.5/1 Euro compression.

You mention with higher compression there will be a need to adjust the fuel richness.

If I don't enlarge the capacity - say from 95mm to 98mm - but increase compression, do I create the same need to adjust fuel mixture?

I'm not the mechanic, but like to be informed and find this interesting.

thanks again,

kj

You are most welcome,...

The compression ratio increase results in additional heat and pressure inside the combustion chambers. This requires additional fuel to help contain the higher temperatures so some corrections are necessary at the FD.

[targa44]

Steve,

... the engine has a 2.7S CIS that has served this 3.0 well in the past. (prior owner and another vouch for this - I haven't even driven the car yet)

So, out of ignorance I ask, doesn't the CIS system do some of its' own adjusting of fuel delivery? - But its' base point needs a reset to accommodate the higher compression? Am I looking at this correctly?


kj