Conversion from 217 to 231 HK
 

Hello forum
I am thinking to Update my 88`carrera to 231hk , 95000 miles
Question is? I allready have my heads off due to High Oil consumption,
So🧐is the only diff between 217 and 231 the pistons? Or do i also have to repl cylinders?dme chip Update ? Cam timing etc.
My cylinders is finde, only needs a light honing,but new ring needed, but still within limit.
In Europe we dont have the low oktane problem goes from 92-100 oktane

Hope you Can help
Reg Jesper

The Mahle 3.2 pistons have the same casting numbers in the pistons.
In comparison of the two, the 10.3 are a couple mm taller on the high lobe piston face.
The cylinders are the same Nikisil.
Bruce

Thanks Bruce 👍
So the only thing i do is to repl pistons with new mahle EU 231hk pistons and rings?
Thats all!,,,

The euro spec engine changes the cam timing, virtually everything else on the long block are identical.
Bruce

Timing
 

Thanks Bruce
Do you know the timing value on EU spec. ?
Acc to waynes book there is only one value 1,1-1,4🤔so i am a little confused
Reg Jesper

Low battery, my teaching moment disappeared.
Youre correct on all carrera cam timing is ideal setting 1.25 with 1.1/1.4 the window.
The carrera and SCs use the same cam and there is different settings for 3.0 US and Euro across the compressions.
Bruce

Make sure your cylinders are nikasil. Some were made by Kolbenschmidt which were Alusils. Those cannot be honed. Check with a little magnet on the cylinder walls and by counting the cooling fins. Magnetic and 11 fins: Nikasil.

Thanks for inf. Both,👍 my cylinders have 10 fins 🤮

Where are you located? I just happen to have a complete set P/C with new Mahle 10.3 pistons and Goetze rings ;)

Hej Martin
Denmark Roskilde
Har skrevet til dig på fb

3.2--3.4
 

You are in luck with Alusil bores.Have them opened up to 98mm with Nicasil and use CP Pistons.Replating the Alusils holds up better than replating Nicasil.CP Piston is also way lighter.Chip will have to be changed but 250 HP for the same amount of money.Lighter flywheel and you are there.Ciao Fred