I'm about to send the V5 off to advise of the engine change that happened many years ago and noticed a slight difference in the numbers; the original has an 'A' suffix (8S068105SA) and the replacement has a 'B' suffix (8S074445SB).
What is the difference between the A and the B if any?

 

Steve
According to Sean Straw's engine number decoder, these are both HE engines; the penultimate S means standard compression ratio (ie 11.5:1) so not the normal UK ratio of 12.5:1 which is designated H instead of S.

The final letter indicates whether A or B pistons were used. This is nothing to do with the compression ratio, I believe (not 100% sure) that pistons and liners were sorted into sets that most closely resembled each end of the tolerance spectrum. So slightly higher end of the production tolerance pistons and liners went together as (eg A) and lower ones (eg) B.

Greg

 

Damn, I ended up with a B, story of my life all over, slack tolerances.
Thanks Greg.
Mind you the whole thing is more of a D at the moment, could do better.

 

No, no, B is good, It just means, I think, that (eg) the plus 10 thou pistons went with the plus 10 thou liners. Actual net clearances unaffected. Mine is a B, too.

What I want to know is how much faster that XJRS is than a standard car?

Greg

 

I don't objectively think that it is faster than a standard car. At least until the 6 litre ones came along I think that the engine was standard although I have seen air boxes with modified intake trumpets (have some myself ready to fit).
Most of the difference is cosmetic with the body kit plus uprated suspension and revalved steering rack. I think the whole theory was to make it dynamically tauter without increasing the power and make it visually different to the standard one.
I'll let you know how it goes when I get it back in a couple of weeks with replaced front subframe and new radius arm bushes at the back.
It should go significantly faster because I will have lost a lot of weight out of my wallet!

 

from BB on the JEC website;
Reading up on this it is indeed the matched piston grade mark , A or B , as a matched set to the liners.
So that explains that then.

 

just research ,


BB

 

It helps if you have access to the right tools and places to research