Speed Sensor Gapping (Thoughts on Physical Properties)

[Blondie]

I was just wondering how much these 944 engines expand when hot. I'm gapping the reference/speed sensors and I paused for a second when I thought about the temperature of the air/motor during the initial gapping.

Ie. If you gap the sensors in the middle of a really hot day, will they be too far from the engine when operating temperature is reached? (Due to the expanding metals around it.)

Any thoughts on this? (And really, how much does the engine expand under heat??)

[fast924S]

Thats a good question, But Im sure Porsche figured that into the tolerance for the measurment, But then again I could be wrong

[DanAllen944]

The heat of the day is not going to effect the thermal expansion of the metal enough to make a diffrence. I would not however use a blowtorch and then gap

[Blondie]

So then I should be able to gap at any time of day...ok thats fair. The engine should probably be stone cold, I would think. Hmmm..the questions we ask ourselves while deep in that engine bay lol

..probably my favourite place to think

[bholmes]

I'd try to install it on a day that's temperature is the average of the highs and lows at which it opertates. Say you use it typically drive on 50deg to 100deg days, so your average is 75, I'd install is when it is 75 degrees out with the engine cold that way you optimize the car for your operating spectrum. That said I really don't think it'll make much difference at all. in my opinion that would be like gapping them differently if you install a low temp thermostat and low temp fan switch...hmmm maybe I should regap mine now...but really I think we are over thinking it.

[Blondie]

Seeing as I live in Canada, I wonder (theres that word again lol) if I'll end up re-gapping twice a year: once in the summer months and again in the winter months. Although you'd think in the winter that the sensors would merely end up closer to the flywheel, if anything...

My thinking was that gapping the sensors when the engine was nice and hot would have them operating at the perfect gap when the engine is hot...never pulling them too far away from the flywheel as opposed to gapping when everything is cold, which I thought might pull them too far from the flywheel under hot conditions.

Maybe we are overthinking this lol

[Aufenbahn]

What about at high RPMs when the flywheel expands from centrifugal force? Just kidding

[blown 944]

There is some merit to this IMO

I have found that on a hot day that the sensors can cuse startingn issues whereas it doesn't happen on cold evenings.

[Blondie]

Originally Posted by blown 944

I have found that on a hot day that the sensors can cuse startingn issues whereas it doesn't happen on cold evenings.

As have I..