Minor loss of power

Since having my tennsioner upgrade,cam timing and major service completed my car seems to have lost just a little UMPH. It does rum smoother but just seems to not be quite as responsive. Any ideas?

Drew Reed
79 911SC

Can you give us more detail on the cam timing? Did you alter it from stock or just fine tune it to exact factory specs? Did they mess with fuel mixture settings? Ignition timing settings? Need more info.

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Tyson Schmidt
72 911 cabriolet (964 bodywork)

I'll have to call mechanic Mon. As far as I know he set the cam timming to factory specs. Don't know how it was set up be fore I brought it in.

On another note. Is their an optimal allignment setting that I should go with. Just had some new Yok AVS sports put on yesturday, but my old tires had alot of outer edge wear.

Drew

It sounds as if your mechanic went with the retarded setting to get a little more top-end! I think the advanced setting would have been better for low-end torque, as flogging the CIS at the top-end is pointless, kind of like getting the last 5 mph out of a 'stock' VW Beetle!!!

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Warren Hall
1973 911S Targa

Sometimes I am flattered into imagining I think like Warren. I also first thought of ignition timing and I'll bet it's backed off. I've found that I can surely get away with the FULL 5 degrees BTDC. Spec says plus or minus one or two additonal degrees and since I use super unleaded, I may try just a hair more advance. Sure makes a difference. check it.

But don't get it too advanced or you will have detonation (knocking or pinging) which is very bad.

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'83 SC

Hey Superman, hate to burst your bubble but you don't think like Warren. He's talking about CAM timing. Oh well, you're still the man of steel.

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Tyson Schmidt
72 911 cabriolet (964 bodywork)

Since we're all guessing right now anyway, I thought I'd put in my 2c.

I bet your wrench advanced your cams, setting them at more than 1mm at overlap.

Curious to see what he says on Monday.

Cheers,

Joe

[This message has been edited by stlrj (edited 12-03-2000).]

Drew,

The three cam timing settings used by the factory with SC cams are as follows:

Retarded: 0.9 to 1.1 mm ... 1.0 mm ideal -- Top-end power emphasis!

Middle-of-the-road: 1.1 to 1.4 mm -- 1.25 mm ideal -- Bruce Anderson recommennded!

Advanced: 1.4 to 1.7mm ... 1.55 mm ideal -- Bottom-end torque emphasis!

The above settings and their history of use beginning with Carrera 3.0 model of 1976 are discussed on page 125 of the 2nd edition of Bruce Anderson's Porsche 911 Performance Hanbook.

It was my presumption that thr mechanic had encountered either the middle setting or the advanced setting, and for some reason decided to change to the retarded setting, causing a slight reduction in bottom-end power/torque that you noticed as 'sluggishness.'
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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 12-03-2000).]

Thanks all

the info will give me some good questions to ask. E-S Man thanks for the specs

Drew

Warren was right. He did set it to the most retarded setting. The good new s is he's happy to adjust it for me and was suprised that I was unhappy with the power. It does have very good top end power but the roads I like are not all 6000 rpm turns. So I think the mid to advanced set up might work best for me.
I'll report soon

Drew

According to the spec book, a 79 SC is factory set to....0.9 to 1.1 mm ... 1.0 mm ideal.

Did someone advance it previously?

Joe

Just got the car back and what an improvement. I had him set it to the middle setting 1.1-1.4mm 1.25 ideal

Works great and best part NO CHARGE

Drew