Boxster piston ring end gaps?

[356Guy]

Originally Posted by marsheng

...Hasting Rings says 0.014 " per inch of bore...

Are you sure they don't say 0.004" per inch of bore? I think 0.014" would be the total end gap

[marsheng]

Originally Posted by 356Guy

Are you sure they don't say 0.004" per inch of bore? I think 0.014" would be the total end gap

Sorry you are correct, from the web Example: 4" (bore) x .0035 = .0 14 minimum gap. I work in mm so I didn't click that .014 was wrong figure.

I understand the 2.5 and 2.7 are basically the same motor. The 2.7 has a 6 mm longer stroke and the pistons are 3mm lower to fit.

My guess is the rings are the same if you can get 2.7s.

I'm sure there are aftermarket ones available for a few $100. Rings aren't rocket science.

[Homeoboxter]

Originally Posted by marsheng

Sorry you are correct, from the web Example: 4" (bore) x .0035 = .0 14 minimum gap. I work in mm so I didn't click that .014 was wrong figure.

I understand the 2.5 and 2.7 are basically the same motor. The 2.7 has a 6 mm longer stroke and the pistons are 3mm lower to fit.

My guess is the rings are the same if you can get 2.7s.

I'm sure there are aftermarket ones available for a few $100. Rings aren't rocket science.

I`m not sure about the bore, the ring sets for the 2.7 are listed as 86.5 mm standard size. In my 2.5 I measured roughly 85 mm. But here for instance they claim the two engines are the same bore-wise:
https://www.auto-data.net/en/porsche-boxster-986-2.7-boxter-24v-228hp-6710
I`ll check what the manual says about this.

[Homeoboxter]

Originally Posted by Homeoboxter

I`m not sure about the bore, the ring sets for the 2.7 are listed as 86.5 mm standard size. In my 2.5 I measured roughly 85 mm. But here for instance they claim the two engines are the same bore-wise:
https://www.auto-data.net/en/porsche-boxster-986-2.7-boxter-24v-228hp-6710
I`ll check what the manual says about this.

Yes, the bore size both for the 2.7 and the 2.5 should be 85.5 mm, so rings listed for the 2.7L should be ok for the 2.5L, unless I`m missing something else.

[BYprodriver]

Originally Posted by Homeoboxter

Yes, the bore size both for the 2.7 and the 2.5 should be 85.5 mm, so rings listed for the 2.7L should be ok for the 2.5L, unless I`m missing something else.

You should measure the cylinder bore's for wear, if they are worn beyond spec you should probably reinstall the original conforming rings in their original positions.

[Homeoboxter]

Originally Posted by BYprodriver

You should measure the cylinder bore's for wear, if they are worn beyond spec you should probably reinstall the original conforming rings in their original positions.

Well, I don`t know the specs and I don`t have precise tools to measure the wear. The bores show no sign of wear by feel and the ring gaps do not change much when I slide the ring all the way down the bore, and there`s no difference if I place the ring to the top of the bore (the area that the ring normally does not reach) vs. if I slide it down. So I assume the wear is not substantial. I think the compression rings could be reused, my worry is about the oil rings, the side rails seem deteriorated, I can see through between the cylinder wall and the side rail when I place them into the bore.

[maytag]

Originally Posted by Homeoboxter

Well, I don`t know the specs and I don`t have precise tools to measure the wear. The bores show no sign of wear by feel and the ring gaps do not change much when I slide the ring all the way down the bore, and there`s no difference if I place the ring to the top of the bore (the area that the ring normally does not reach) vs. if I slide it down. So I assume the wear is not substantial. I think the compression rings could be reused, my worry is about the oil rings, the side rails seem deteriorated, I can see through between the cylinder wall and the side rail when I place them into the bore.

Ohhh.... i'd probably back the bus up abit, if I were you. At least lay on the brake some...
If you're trying to do this even partially "right", you shouldn't be letting $100 worth of snap gauges and a caliper stop you. Take your time, do it right. You'll be glad you did.

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