1800 head on 2L Question

[RRoller123]

This should (hopefully) be a simple question, or have a simple answer: I read here constantly that the 1800 head on a 2L block has benefits like raising the US CR, etc. Question: When the 1800 head is installed on a 2L block, can/do the 2L cam boxes get used on the 1800 head or does one need to use 1800 cam boxes as well? And a side question: Does the use of the 1800 head on a 2L block change which timing belt is used? i.e. is the length effected?

Thanks.

Pete

[MrJD]

I think the consensus was to stick with the 2.0 head.

http://www.fiatspider.com/f08/viewtopic.php?f=5&t=25168

[RRoller123]

That hasn't been my read on it. The 1800 head will raise the US CR somewhat.

Pete

[BEEK]

putting a 1800 head on a 2.0 is a direct fit, everything interchanges, timing is not affected. there is a very minor increase in compression, not enough to notice. actually you may hurt the overall performance by the combustion chamber design, and the shrouding of the intake valve. the 2.0 head has a improved combustion chamber.

[bradartigue]

The origins of this were actual chamber measurements (fluid measurements) done way back, you can search Mirafiori if you so desire and you'll find a mountain of information on it. There is a negligable CR increase with the 1800 head. Most of us did it because the 2L Carbureted FIAT head squishes the #1 chamber and has the EGR port running through it. Not that those can't be blocked off, but cosmetically the 1800 head, pre-reed valves (or with them removed) is simply cleaner.

Same could be said for using the 2L FI head on a carbureted engine, it's cleaner looking. I'm not sure the chamber flow factors in unless you've done some other improvements to the breathing of the motor.

The only real CR increase is going to come from replacing those 8.1:1 pistons with something else, my favorite motor being an 1800 head, a 2L block, 8.9:1 CR pistons, the FI exhaust system (or 4-2-1 carbureted if you can find one from a 79), and the 36ADL or 34ADL carburetor. Potent little package that doesn't require significant investment to build.

This should (hopefully) be a simple question, or have a simple answer: I read here constantly that the 1800 head on a 2L block has benefits like raising the US CR, etc. Question: When the 1800 head is installed on a 2L block, can/do the 2L cam boxes get used on the 1800 head or does one need to use 1800 cam boxes as well? And a side question: Does the use of the 1800 head on a 2L block change which timing belt is used? i.e. is the length effected?

Thanks.

Pete

[BEEK]

my favorite setup is

2.0 bottom end, with 9.8-1 pistons, total seal rings
2.0 lancia efi head, with big valves installed, mild port work and bowl opening
42-82 camshafts
uprated valve springs
40dfi single carb on a port mached and worked on 1800 carb manifold
headers, and electronic ignition

this is a real potent engine for use. because i do all the port work myself it doesnt cost much money to build.

fyi, i have taken all the head castings sent to the us from fiat and lancia over the years to a flow bench. the efi lancia casting is the best flowing and had the most raised port location of any head sent to the usa.

[RRoller123]

Thanks, guys. Good helpful info!

Pete

[MrJD]

my favorite setup is
2.0 lancia efi head

Hens teeth in the US though right?

I never realized the 2.0 carb head was different from the EFI head. Interesting...

[bradartigue]

On the Lancia head - the head fitted to the 1800cc Lancias in 1976 was similar to the FI head you're describing (it may have been the same head), somewhere I have a casting number. Port size, chambers, etc., all considerably more performance oriented than the FIAT heads and my other Lancia heads. I have no idea what car it came from, Europe or USA. The only modification was you had to use FIAT cam boxes because of the way the Lancia ones held oil (presumably a horizontally opposed and/or tilted engine).

I never ran 9.8:1 pistons, I wanted to, but "way back when" that was rare air and I could get the 8.9:1 and 9.1:1 pistons from various sources as if they were junk. Given the wholly different feel to the power of the TC with even the bump to 8.9:1 I can imagine the 9.8:1 is a real kick in the ass.

[BEEK]

casting # 4372281

[MrJD]

casting # 4372281

Anyone got some random heads laying around to look at?

[BEEK]

i have a stack of fiat heads, what are you looking for / at