budgerian
Member
As I was trying to find some suitable oversize pistons for my 3.0Si E3 I found a set that at first seemed suitable but wasn't.
They were for a 3.0S, which had 9.0:1 compression, whereas the 3.0Si has 9.5:1, presumably because the d-jetronic system needs the extra bump in compression.
I was about to let it go, but crossreferenced Realoem and to my surprise found out the following:
Later 3.0Si models between 73-77(L-jetronic) used the very same pistons as the 3.0S, despite still being advertised as respectively 9.5:1 and 9:0:1, both using identical headgaskets. What gives?
Should I worry much about this half percent loss in compression (although we could consider decking the block slightly to make it even less of a problem) with regard to using a fully rebuild d-jet system?
And did BMW fool us in advertising later 3.0Si as 9.5:1 when in effect they were only 9.0:1?
Interested as always in anyones thoughts on this.
They were for a 3.0S, which had 9.0:1 compression, whereas the 3.0Si has 9.5:1, presumably because the d-jetronic system needs the extra bump in compression.
I was about to let it go, but crossreferenced Realoem and to my surprise found out the following:
Later 3.0Si models between 73-77(L-jetronic) used the very same pistons as the 3.0S, despite still being advertised as respectively 9.5:1 and 9:0:1, both using identical headgaskets. What gives?
Should I worry much about this half percent loss in compression (although we could consider decking the block slightly to make it even less of a problem) with regard to using a fully rebuild d-jet system?
And did BMW fool us in advertising later 3.0Si as 9.5:1 when in effect they were only 9.0:1?
Interested as always in anyones thoughts on this.