Right, I've finally been encouraged to learn something...

Had an interesting Thermodynamics lecture this morning, in which the lecturer was showing off a sports clyinder head for a old Vauxshed that effectively doubled its power (from 42 to 82BHp, 1600cc engine).

Im interested to know how I could make my Sporting faster by playing with the cylinder head, eg: camshafts, port + polish...

Or even better, are the 1242cc 16v and 8v heads interchangeable?

I know one's MPi and the other is SPi, but there must be a way around that!

--Updated--

Parts CD shows same inlet manifold, but MPi has injectors in bit on that as far as I can see... and a pressure regulator!



Tom (AofB)

Snapped exhaust flexipipe becoming GrpN ASAP!

16v problems mainly centre around bulkhead and exhaust manifold clearance.

8v and 16v heads should fit the same block, I think.

You could skim it to up the compression, port and polish it but you're talking cash. Fast road cam will help too but you will lose out a little on low end torque.

Pete.
1242cc cinq,turbo cinq,Cinqs&Seis Yahoo group,Clubcento

Hmm, im thinking that skimming wouldnt be that costly, and I could to the Port+ polish myself...i'm sure I could get advice on that from somewhere

Tom (AofB)

Snapped exhaust flexipipe becoming GrpN ASAP!

Sticking to the 8V head, it can be ported fairly easily and skimmed. Most will have been skimmed at some point due to head gasket failure so careful measurement needed before breaking out the skimming axe.

While the engine is in bits look at the pistons and bores very carefully. If the engine has been at all over heated the bores can be barrelled. There is no point in upping the CR if its just going to blow past the rings.

MPi heads are different to SPi heads, the ports are in different places. SPi also works at a lower pressure than MPi so it is more than just the head, manifold and ECU that need changing.

16V heads are completely different and, I believe, there are clearance issues, although I have never fitted one myself.

cheers

D

Grumpy old git going fast downhill rather than downhill fast!!

Skimming axe? Thats a bit arcane isnt it?

Couldnt I try a Punto 60 (1242 SPi) Throttle Body and camshaft?

Or could I try and source larger valves from somewhere?

Tom (AofB)

Snapped exhaust flexipipe becoming GrpN ASAP!

You could try lots of things. The Punto 60 throttle boddy is a good idea, remember you also need the black plastic block that locates it to the manifold as well. Don't know whether there is much difference in the cam, maybe someone with a parts CD could tell if its different, but I wouldn't have thought there was much in it if an extra 134cc can't give the extra 5bhp with the same cam then wjats the point of 1242.

Cheers

D

Grumpy old git going fast downhill rather than downhill fast!!

Yep same cam. Hmm, so thats just a bore out for an extra 5 BHp?
I take it I could find a hotter cam without that much difficulty?

Tom (AofB)

Snapped exhaust flexipipe becoming GrpN ASAP!

No, quite easy to find, just slightly more difficult to fund.

If your credit card balance is ok, speak to Avanti.

Cheers

D

Grumpy old git going fast downhill rather than downhill fast!!

Well, just taken a battering from my local parts hole.

Might be an eventual....

Tom (AofB)

Snapped exhaust flexipipe becoming GrpN ASAP!

Take a Punto 75 throttle something and the Punto 75 cam (which is hotter).
Just started a new topic on the trottle body.