8v Head On 16v Block

[andy0075 9 1 Cars]

Hello!

 

1.)

 

My XU9JA head is allready scimmed 0,8mm.

 

Does anyone know what cr i will get from this combination when

i bolt the head straight on the 16V block ?

 

What cr is possible in an 8V race engine ? How much more to skim ?

 

2.)

 

I was on a rolling road session last month and the results are as follows.

What do you think about that ? Is it to less power for an XU9JA ?

 

I use 45er Weber, 300° cam, 12,50mm max. lift,

head and valves are optimised, full race exhaust.

 

PDF of the rolling road result

 

Andy

[vern 0]

The 16v block is the same as the 8v block except for a few minor differences, (spray bars, and power steering mounting points), at least that is what I found when I put the 8v head on 16v block. It should not change the CR.

[cybernck 402 1 Cars]

perhaps by "block" he meant the whole bottom end?

 

that wouldn't be a good combination really.

[andy0075 9 1 Cars]

Yes, i mean the whole bottom end, but with the pistons from the XU9JA engine.

 

Why isn't that a good idea ?

 

 

If i stay with the original bottom end and the original head,

what cr should i go with my race engine ?

Edited September 16, 2008 by andy0075

[pug_ham 244 3 Cars]

If you are just asking about bolting your current head onto a 16v block but with your XU9JA pistons in then the compression ration shouldn't change from what it is at present.

 

I think cybernck mean't using the 16v bottom end complete with pistons but as you aren't doing this it shldn't matter. Although the under piston spray bars wouldn't be needed so you could remove them / blank them off & you'd be better to swap the whole 8vinternals over to the 16v block imo.

 

The 16v blocks are virtually the same as the 8v ones except for the internal oil spray bars on the Mi.

 

Graham.

[cybernck 402 1 Cars]

yeah that's what i meant and why i said it wouldn't be a good idea.

 

what about crank though, 1.9 crank is lighter but obviously less suitable to increased revs.