Cylinder Head rebuilt recommendations

[PSU_Crash]

There is definitely a learning curve to using the scraper. I use a steel bladed scraper. It's a little more forgiving than the carbide and even that can get you in trouble if you aren't careful. If you can run your fingernail across and feel anything, it isn't good enough for me.

[danmartinic]

A machinist friend taught me about stones.. no idea why so few mention this

Spray with WD40, keep flat across surfaces, and hone in a circular motion. Quick, flat, and clean as a whistle. I have a couple now but keep going to a little 4" one that sales guys give for free as ads to machine shops

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[libarra82]

Head almost ready

All is well, just needed a new intake valve and seals.

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[libarra82]

Installing a new water pump and thermostat but not sure it’s fitting correctly. I have two seals, thin one is not snug, I can easily rotate the thermostat. With thick seal the snap ring doesn't go into the grove, even without the spacer. Any suggestions would be appreciated.

[danmartinic]

Take a small punch and tap the ring & thermostat in

[libarra82]

Thanks, will pickup a set and give it a try. This is definitely a job done with the water pump out. I would not do this correctly with it on the car.

[libarra82]

I have two thermostats made by Wahler, one OEM purchased from my local porsche dealer with about 200 miles on it, and one brand new aftermarket version. They’re essentially identical in design, but there are some noticeable differences, so I decided to compare them.

The OEM thermostat is manufactured in Germany and has a richer brass color. The stamping is cleaner, the springs appear visibly thicker, and it takes more effort to press down and open.

The aftermarket unit is made in Brazil. It feels a bit flimsier even though the weight is similar. It also has some minor staining and small nicks despite being new out of the box. It opens with noticeably less force compared to the OEM.

It makes me wonder: is there an advantage to the OEM’s stiffer springs over the aftermarket version?

Aftermarket on the Left, Porsche Right

Aftermarket on the Left, Porsche Right

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Aftermarket on the Left, Porsche Right

Aftermarket on the Left, Porsche Right

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Aftermarket on the Left, Porsche Right

Aftermarket on the Left, Porsche Right

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Aftermarket on the Left, Porsche Right

Aftermarket on the Left, Porsche Right

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[danmartinic]

I would use the OEM

For kicks, suspend each in water with a thermometer and bring to temp to see when each opens

[libarra82]

My test wasn’t the most scientific, but it should serve as a good reference point. I submerged both in hot water and observed their performance. As expected, the Porsche performed better, it opened and closed more quickly and had a larger, more even opening.

Edit: I believe they started opening and closing at the same temp. OEM opened and closed almost instant, aftermarket was gradual, took a minute or so to fully open and close after the OEM.

Porsche
Open: 210f
Close: 170f

Aftermarket:
Open: 220f
Close: 160f

Porsche top, aftermarket bottom

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[danmartinic]

Sometimes it's worth ordering from the dealer