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Why are the exhaust ports so big? They look bigger than the valves themselves. Ports should be no bigger than 85% of the valve head diameter, tho if the port ends up being oval or square shaped, the port should only have 85% the cross sectional area of the valve(s). Any larger just slows down gas speed and pushes the boost threshold further up the rev range and typically with a power drop.............

Usually the tubing used for turbos usually are thicker and maybe that makes it look big bore? Doesn't look too large in my opinion.

I'm looking at this pic, rather than that of the manifold.
Maybe its a bit 'force perspective', but the port at the the manifold flange, looks bigger than the valve head.

Some more pics of the heads . I will ask nick when he comes over this weekend about the specs .

looks like he tried to match the ex- ports with the header pipes geometry ...

Alfa sacrificed services for wear and tear by not installing a harmonic balancer originally. A good engine deserves a harmonic balancer.

OK, I see what you mean now... HUGE ports!

Harmonic balancer? The engines already outlive the rest of the car 2:1 ratio, you really think a harmonic balancer is needed?
I guess they removed i on the TS due to the trigger on the pulley.

Mats wrote:OK, I see what you mean now... HUGE ports!

Harmonic balancer? The engines already outlive the rest of the car 2:1 ratio, you really think a harmonic balancer is needed?
I guess they removed i on the TS due to the trigger on the pulley.

actually there are ts's with rubber vulcanized into this front pulley and I know the spider IV woth the 2[L] motronic engine have these.
And they are as good as impossible to find as they all fail/come apart around the inner bushing which clamps around the crank.

This one is a ROMAC and does not fail. It's built different. Here is one with an aftermarket trigger wheel attached to it.
My current racer has a trigger wheel and supercharger pulley attached to it as well and the whole assembly balanced as a unit.
Race motors get a bigger pounding than street engines and usually the low mass flywheels do not absorb much vibration and so some harmonic dampening is useful.

On the transaxles would the front rubber coupling bolted to the flywheel not absorb those vibrations . On the front wheel drive cars I can understand as their is no ' barrier ' beween clutch and drive unless it has a dual mass rubber inserted flywheel .

Kevin that is not a yes /no question and whatever the answer is would need some hard data before it is worth anything.

The fact is, Alfa decided to fit harmonic balancers to the transaxles when making the Alfettas. Factory beancounters are reluctant to increase the price of a car by 1 cent if they can so why would they fit an expensive harmonic balancer instead of a cheap pulley? The sound assumption is they tried to minimise the harmonic vibrations in the engine.

(The fact that the original balancer has a short useful life maybe due to its quality of construction, a result of sacrificial energy absortion thereby proving its usefulness, neither or both)

If anything, the shaft vibrations would be simply adding to the engines vibrations issues compounding the problem. Who knows !

Rest assured that dampening the engine harmonic vibratrions is not going to do it any harm and can only improve things. It should be considered part of best practice when building these 4 cylinder engines .

Check out this link for the basics :http://en.wikipedia.org/wiki/Harmonic_balancer

The fact is that the engines never fail so why bother? Over engineering doesn't help anybody.

HI,

What oil are u guys using for 1.8t?

10w60 Selenia racing breaks down quite fast on hard use.

Don't know about 15w50 mobil v300 or TITAN SUPERSYN SAE 10W60 still havent tried those, any experience?

also, spark plugs in summer are an issue. i got b9evx ngk now will try in few days.

and yes, this motor is standard, 165hp, qv version.

Why the special sparkplugs? B8ES should do it?

Oil, there are probably a lot of info on the site... I have had bad experience with Mobil 1, good with Selenia but Motul has been the cure-all oil for me. Expensive but excellent.

I am using Motul 15/50 with no apparent problems, since it holds up pretty well in the track too. Surely there are better oils out there but if I,m satisfied now with Greek summer being what it is, there's no urge to look for something else.
Re. plugs, I use cheap Champion N2C all year round BUT, if you burn oil and you don't have a good ignition DON'T use them.
Jim K.