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1.7 8v heads

 
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Bobkelso
Alfa Sprint


Joined: 09 Aug 2011
Posts: 190
Location: Milan - Italy

PostPosted: Fri Mar 06, 2015 4:54 pm    Post subject: 1.7 8v heads Reply with quote

Hi,
I'm trying to understand if there are
more type of 1,7 8v heads/pistons or only one:

1987: 1.7 8v twin carbs mechanical tappets 118 PS (116HP)
1988-89: 1.7 8v twin carbs hydraulic tappets 114 PS
1988-89: 1.7 8v I.E. normal/ecologic/cat hydraulic tappets 110-105 PS
1990-94: 1.7 8v I.E. normal/cat 107-105 PS

What it seams from manual and Eper (but it don't cover 1987 year):

- versions with mechanical tappets have the old type camshaft support
- carbs versions have a specific camshaft more aggressive
- ecologic version was a pre-cat experiment with some ecologic
devise in the exaust tubes and special pistons, may be only for U.S.

But (except the exotic ecologic version),
all these boxer alfa 33 (and alfa sprint) have same identical heads and pistons? Question

In particular I have some doubt about 1987 version with mechanical
tappets..if they had heads/pistons different in some details or not
because 4PS less power passing from mechanical to hydraulic tappets
and maybe adding power steering losses (considered in 1988 DIN
Power measurement if power steering was present in the 1988 version)
seams a bit too much..
..or from 87 to 88 they have adjusted some other details
in carbs or advance timing so the slight less power?
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Bellamachinna
Alfa 33


Joined: 12 May 2003
Posts: 352
Location: Lisbon-Portugal

PostPosted: Thu Apr 02, 2015 10:17 pm    Post subject: Reply with quote

Quote:
1987: 1.7 8v twin carbs mechanical tappets 118 PS (116HP)
1988-89: 1.7 8v twin carbs hydraulic tappets 114 PS
1988-89: 1.7 8v I.E. normal/ecologic/cat hydraulic tappets 110-105 PS


Hi

I had several 1.7 8v cars, (4 to be correct), and i never saw one fitted with mechanical tappets. One of the cars that i had was from 1987, had the webber carbs, but it was fitted with hydraulic tappets, just like the 1989 model that i also had, although this one had dellorto carbs.
Both cars feelled equal. Both were quotted at 118 hp

Quote:
- carbs versions have a specific camshaft more aggressive


I disagee... Sad
One of the cars that i had was a series 2 1.7 IE. This car was significantly slower than the carbed cars, feeling like a 1.5 TI altough with better in gear pick up.
However, this engine was reused in a series 3 sportwagon, that i bought with a blown 1.3 engine.
The injection sytem was removed, and in its place i fitted the carbs from a 1.7 car. The engine was transformed.
I didn`t used the 1.3 gearbox (that has lower ratios), opting for a 16v gearbox.
The sportwagon could stay with a standard 16v until 140-150 km/h in accelaration, so i don`t believe that these engines had a softer cam profile.
Pistons and heads were similar in all my 1.7 engines.

Quote:
ecologic version was a pre-cat experiment with some ecologic
devise in the exaust tubes and special pistons, may be only for U.S

Catalitic cars were selled in Europe northern markets (Sweden, Norway, Germany, Switzerland, etc...) Those were quotted at 105 hp (or 107 hp in series 3 cars) and had some modifications in the induction system that included a very crude EGR system.
The diference in hp between series 2 e 3, is due to better callibration of the injection system.
Also in some of this countries, the QV version (that was a carbed car here), was sold with the IE engine and catalitic converter, altough with all QV "extras"
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paulhide
P4


Joined: 20 Dec 2003
Posts: 1607
Location: Oh Beautiful Billingham

PostPosted: Sat Apr 04, 2015 3:54 pm    Post subject: Reply with quote

A few series two 1.7 cars did have mechanical tappets (John Haynes' car has one of these engines) though the power was unchanged from the hydraulic tappets.
Carbs give more power, but are less efficient/use more fuel.
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http://www.alfa-pages.co.uk/viewtopic.php?t=5188
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ZeNiTh-PbArM
Alfa 33


Joined: 14 Mar 2003
Posts: 388
Location: Paris, France

PostPosted: Fri Apr 17, 2015 8:10 pm    Post subject: Reply with quote

Yes a few early 1.7 have been sold with mechanical tappets. If I remember correctly they were advertised at 114hp rather than the 118hp which was quoted for the hydraulic version.
I'm not so sure whether the power difference was related to the tappet/camshaft or carb settings. I didn't notice any significant difference between the two (and i've driven both over quite a distance)

regards,
zp
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