Differences in the 1.8L and 2.0L head...

[Holshot]

Hey guys, starting to do some research on the "best" motor setup and the consensus is the 1.8l head on a 2.0L block. What I was wondering was is why is it better? Now I've read that it bumps up the compression some but is that it? Is the bump in compression all the gains? I guess my question is are there any physical differences that promote better flow, bowl changes, valve changes, ect... I guess I'm asking because ultimately I'll be looking to build a turbo setup and that small bump in compression will be negligible and I don't need to look for a 1.8L head to swap out to have the "best" setup. Just curious and thought someone with first hand knowledge could chime in and school me on the differences.

Thanks,
Giuseppe

[vandor]

The bump in compression is the only gain, so if one is rebuilding the engine with high-compression pistons then it's not the way to go.

[fiatfactory]

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[burgandy81]

Hi Giuseppe, Steve C,

This is on topic so hopefully not a hijack??

If one is trying to improve a US spec 1800 or 2000 head (NOS 2000 in my case). Can you describe the stock fiat inlet and particularly exhaust valves and seat material that are a good upgrade. Can you supply any of these items? I believe they are very difficult to find in North America.

As you describe in your post I am hoping to eventually run forced induction and would appreciate some guidance in a head rebuild. I will be staying with a stock US Spec head although I am happy to look at modifications.

Cheers,

Jordan

[Holshot]

The bump in compression is the only gain, so if one is rebuilding the engine with high-compression pistons then it's not the way to go.

Thank Vandor! That's what I thought but its always nice to here from guys with experience to set your mind at ease.

[Holshot]

Depends on what you mean by "best"??

There are several (non USA spec or delivered) heads that seriously outflow both of these heads without touching them, they use larger 43.5mm intake valves and larger seat throats than anything USA spec. But if you plan on fitting a turbo, inlet flow is a very secondary consideration when compared to exhaust flow and exhaust seat /valve longevity anyway...

There are turbo models (early 8v regular flow models too) that you should consider, if not the entire head then at least the exhaust valves and seat material that the factory used....then there is always the 16v turbo option, again factory specifications of parts like the valves/seats and guides should be researched.

SteveC

Thanks Steve for all the good information! What 8v motors came factory turbo charged that would be different from the US spec 8v motors? Yeah I've heard a few things regarding the 16v heads that will fit our 2.0L blocks but if memory serves me correctly doesn't that reverse the exhaust and intake and make for a very complicated swap? If you have any links as to where I could find some good information on guys who have performed the swap with success I would greatly appreciate it!

[Holshot]

Hi Giuseppe, Steve C,

This is on topic so hopefully not a hijack??

If one is trying to improve a US spec 1800 or 2000 head (NOS 2000 in my case). Can you describe the stock fiat inlet and particularly exhaust valves and seat material that are a good upgrade. Can you supply any of these items? I believe they are very difficult to find in North America.

As you describe in your post I am hoping to eventually run forced induction and would appreciate some guidance in a head rebuild. I will be staying with a stock US Spec head although I am happy to look at modifications.

Cheers,

Jordan

Hey Steve, I wish I could be of better help in answering your questions... While I'm not new to Fiat Spiders' having owned 3 over the years and a few Alfas' I don't know the specifics you've asked for. I'm learning little by little on the swapping and modifying side of these cars. It seems that we are both at the point in our learning curve and it might be a good idea to start a thread addressing those concerns or reach out to one of the guys above who has replied to my original post. Good luck and I look forward to seeing what you have in store for your project!

[PittsburghKevin]

SteveC posted a bit http://www.turbo124.com/forum/viewtopic.php?f=10&t=8261 that might be helpful in going over sizing, customization, and options. There is a lot of information out there and sifting through to find it is tough. SteveC's post here was fairly detailed.

[fiatfactory]

.

[PittsburghKevin]

I just found this from a reference at Turbo124. Giuseppe, had you considered a 16v head? Price seems decent, not great. http://www.deltaintegrale.com/catalogue.php?Clv=2&C1=2