Austarion

Hi

I was told by the previous owner that he had put in higher compression pistons when he decided to permanently remove his damaged turbo.

I have my doubts that he actually did this but as I am looking to refit the turbo I need to check -Any ideas??

Does anyone know the compression figures for the 4G63 in turbo and normally aspirated, although this could be influenced by other compession problems.

Does anyone know the hight from the centre of the gudgeon pin to crown for both or either.

Thanks and Regards

Steve Irwin

Cape Town
South Africa

I believe if you have a pressure of around 152psi per cylinder your running around 7.6:1 compression, maybe this will help?

Crikey

If you have the head off you could see if it has higher compression pistons. Standard ones have a slight dish, so you may have flat top ones instead. I doubt it would make a big difference and would only be a problem if you plan to run huge boost. But they will still need the valve relief cut into them to avoid damage if the cambelt lets go. Then again, if this guy went to the trouble of getting different compression pistons and rebuilding the engine just to avoid rebuilding a turbo, who knows what's in there.