1.9 Mi16/xu7 Blocks With Gti-6 Head

[24seven 104]

ok so I'm told that a GTi-6 head will fit to these blocks (I have a 1.9 Mi16 in my 205 and a 1.8 XU7 16v in my 306). Sounds good, but before I go buying a pair of 6 heads, I need to know a little more on the specifics.

 

How 'well' do they fit? Is it literally just a case of unbolting one, and bolting on the other? What about combustion chamber volumes/diameters, compression ratios, oil/waterways and gasket patterns, cam belt lengths & timing, headbolts etcetc.

 

I don't know a great deal about the specifics of these engines and building them, though I have read a lot of threads on here about various engine builds and have tried to pick up on variables that I could have otherwise completely overlooked. If anyone could answer these questions for me I'd be extremely greatful.

[Sandy 191]

All the oil/water ways line up ok. The Gti6 chamber looks slightly too big on diameter, but it actually clamps the HG fine. The GTi6 chamber is about the same as the XU7J4, but about 5cc smaller than GTi6. Some this raises CR on a standard Mi16 bottom end to about 11.6:1. The inlet patterns are interchangeable (without dowels) but the GTi6/Mi16 exhaust patterns are different, GTi6/XU7J4 are the same though. To fit the GTi6 head on either bottom end,use the XU7J4 belt, idler/adjuster, HG and head bolts.

[pip470 61]

The GTi6 chamber is about the same as the XU7J4, but about 5cc smaller than GTi6

 

Did you mean 5cc smaller than the mi16 head and is it really that much differance?

Edited March 7, 2008 by pip470

[tom_m 0]

The GTi6 chamber is about the same as the XU7J4, but about 5cc smaller than GTi6

 

Did you mean 5cc smaller than the mi16 head and is it really that much differance?

 

enough to raise the compression ratio from 10.4:1 to 11.6:1!

Edited March 7, 2008 by tom_m

[James_R 3]

6 chamber was measured at 36cc's and from a search seems the Mi is 40cc's ish

 

James

[pip470 61]

Sorry i wasnt really questioning sandy, more of a suprised retorical question. Good info as always. Phill

[Sandy 191]

I meant to say, the GTi6 and XU7J4 chambers are both approximately 36cc, the Mi16 is approximately 41cc. It was quite early!

[24seven 104]

Thank you all very much for the info - exactly the answers I was after. is this increase ni CR on the Mi16 bottom end a problem at all? orwould it just be a case of adjusting the ignition/cam timing accordingly?

[Sandy 191]

Tricky with standard management, it would need to be mapped properly.

[24seven 104]

ok cool. Thank you very much .