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Camshafts give me headaches

Posted by Carl S 
Parry
Dave Maxwell
Senior Moderator
Location: secoast NH
Join Date: 02/17/2006
Age: Settling Down
Posts: 97


Re: Camshafts give me headaches
April 10, 2006 10:08PM
Carl S Wrote:
-------------------------------------------------------
> I'm gonna. Though from measuring the cam, putting
> it in directly without any modification its still
> about 10* retarted from ideal. So its not worth
> it to put it in unless you do time it right, which
> I'm going to do.

Well, obviously you need it modified into an intake cam. That's a given.


> 1.8 head on the 2 liter being a benefit is an
> urban myth. I havnt had a chance to measure the
> combustion chambers on any of my 1.8 heads, but
> from other people that have they come out just
> about the same as 2.0 heads.

Not true in my own personal experiance. Motors I have driven with the 1.8 head and the 2.0 bottom have had more pop up top then my 2.0/2.0. I ran a 2.0 head on a 1.8 block on my old car and picked up mid range but lost top end. I will be trying a 1.8 head with this motor once I get some sort of numbers for my carb setup, but I was planning on shaving the 1.8 head a bit before putting it on which would void the comparison.

Try it yourself. Your milage may vary.

I've read different things in terms of effects of cutting the two different heads. I have no real good proof either way, not having checked both myself. The most definitive information I read on that subject indicated slightly higher compression ratio with the 1.8 head on the 2.0 block.


Here, this goes into more specific detail regarding the flow rates of the intake and exhaust ports:

http://www.scirocco16v.com/tech/faq_18v20.htm


As that mentions, if you are going to work the heads it's a different story, but I assumed you were using a stock head (other then having it cut).

> I didnt think it was that much, but I'm not really
> concerned in any case.

I wouldn't be either.

> Well considering brospeed is crap I'm not
> surprised it didnt do you any good. My street car
> saw a decent gain from the race downpipe, and I've
> got one kicking around here so I figure why not.
> Of course in a perfect world we'd all be running
> the techtonics race header, or those swedish
> things jvl is always pushing.

Junk perhaps, but I dont't think i would rate it as worse then a stock manifold + race downpipe. EDIT: actualy, come to think of it I might. I bought the header, a big hollow cat, and the techtonics cat back for under 150 bucks, so it wasn't a big deal.


> The chipped motronic is another case of why not.
> I've got the whole setup in a box, chipped ecus
> can be had for $50 used. And the cis-e motronic
> is a better system than the jetronic. Sure its no
> efi, but hell, I cant afford megasquirt either, so
> I'm making due with what I have.

My MS box is going onto another more involved powerplant, but I have thought about it. Experimentation with carburation (rhymes with orange?) is more interesting anyway, as I have really no experiance with it. I have enough overly complex vehicles, I don't really feel the need to add complexity to this one.



Edited 1 time(s). Last edit at 04/10/2006 10:20PM by Parry.
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