1242 16v or 8v?

[gopp]

Hi,

My first post here.

From what I read on forums and articles, I get the impression that the MPI 1242 8v is the way to go for tuning. Why not the 1242 16v?

I understand that the lower end will take more load, and that the 16v head usually flows better. The 8v may be ported to flow almost as good as the 16v, but I guess that a lot of work and knowledge must be used to get this result.

It's harder to find cam shafts to 16v, and the hydraulic valve pushers must be converted to use a wild cam. The 16v also weight more.

I'm not talking about a comparison of mildly tuned street engines, but very hot street engines or full race. No remapped EFI, but throttle bodies and full EMS.

I'm just collecting information now, as I already have a tuned 1050 Abarth engine in my A112 racer, but for the 2009 season a F.I.R.E is the way to go.

Any comments and links to full race tuning of 1242 are most welcome.

Best regards Gopp

[oldschool]

Hi and welcome.

The first question is what the race ragulations allow for.

One of the problems with the 16v is that it is so difficult to shim because it is hardly possible to get the clearances measured. And it would be necessary to use top hat shims for reasons of size.

I wouldn't underestimate the 8v engines. The Panda cup engine is 1368 8v engine pushing out 157bhp.

[gopp]

oldschool said:

Hi and welcome.

Thanks!

The first question is what the race ragulations allow for.

The regulations are very liberal. Fiat engine in Fiat, Alfa engine in Alfa, and so on. Gearbox must be at the same location as original. The bearing parts of the body must be original, but brakes and suspension is free. The outer body parts may be in fiberglass.

That means that it´s possible to use a A112 with a Fiat 20v Turbo, if it´s mounted up front, and you manage to do this without alter the bearing part of the body (not very likely).

One of the other members at this forum will start in a A112 with a 8v FIRE this spring.

Racing is not very big in Norway yet, but growing. This series started last year, and some video and pictures from the last season can be found on the Norwegian website www.corsaitaliana.no/

One of the problems with the 16v is that it is so difficult to shim because it is hardly possible to get the clearances measured. And it would be necessary to use top hat shims for reasons of size.

OK! This is just that kind of information I was looking for. That probably means that shimming must be done with the head off.

Are the pushers modified standard parts, or custom made, and from witch engine do they find the shims?

I wouldn't underestimate the 8v engines. The Panda cup engine is 1368 8v engine pushing out 157bhp.

Yes I know. The 8v is probably one of the best 8v engines around.

The questions is; will the "problems" with the valve system on the 16v be less than the cost of a first class porting job of the 8v? As I understand that it´s not a great deal of porting that needs to be done on the 16v.

And witch one will be the best racing engine (not only max power)?

Thanks!

-- Gopp

[oldschool]

One of the problems with shimming the 16v is that the head is split in the actual head and the cam housing. To shim it you need to take the cam housing off. Between the cam housing and the head is a gasket. This already creates a tolerance problem.

The lifters are standard parts and the top hat shims are readily available with tuners. If you can't find them I can help you getting them from here.

I currently prepare a 1368 16v for whatever power I can get out without remortgaging my house. The conrods are the weakest point and they do not look too promising for the power I would like to extract, which is in excess of 140bhp.

The 16v head naturally flows better than the 8v. But the 8v can be made quite good too. Whether thwe flow on the 16v is so much superior over the 8v that the 8v can't make up in terms of rpm I have not been able to establish yet. I am working also on a 8v conversion and will see when playing with it in the crucial stages.

Anyway, if I can be of any further help, let me know and feel free to ask any questions on the worlds best FIRE engine site.

[gopp]

Thanks oldschool!

I´ll do some more research and try to ask clever questions her later.

Maybe I buy a cheep 1242 16v to investigate, the 1368 will be too big, as I would like to start in the class below 1300 cc.

[oldschool]

You can bore it out from 70.8mm to 72mm. 1242 and 1368 use the same block. You could possibly use the 1368 pistons or find some proper pistons or have them made.

This should leave you still under 1300cc.