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piston valve reliefs?

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Old 02-16-2017 | 11:45 PM
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Default piston valve reliefs?

Who's done this on a 944 8v? I know it's been done on the hybrid stroker motors, but what about just normal 2.5L

I know i'll be needing to get new pistons, I'm sure they're damaged.
I'm looking at Wossner pistons probably.

I want to fly cut these so if this ever happens again (1 year old timing belts stuffed), i know i'll be safe and the internals won't be broken. Just a safety measure really.
Old 02-17-2017 | 12:16 AM
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I just read something on here within the last week of someone cutting reliefs to make it non interference. And doing it with the pistons in the block too.
Old 02-17-2017 | 12:29 AM
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There's a few ways to do it. I.e turning the valve into a fly cutter ect.
We've got an engineering shop, so it's not to difficult on a mill.

Just after some exp on it.
Old 02-17-2017 | 11:47 AM
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https://rennlist.com/forums/944-turb...ce-engine.html

Laust offers it as a service for a reasonable price.
You could maybe have your Wossners shipped to him, cut and then shipped off to you?
Although quite frankly for not much more than that, you could just have Wossner design the reliefs into your pistons for you.
Standard 951 Wossner pistons from 100-101mm are about US$650/set...but they will make anything you want for ~$1000/set of 4.
Old 02-17-2017 | 05:05 PM
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Originally Posted by V2Rocket
https://rennlist.com/forums/944-turb...ce-engine.html

Laust offers it as a service for a reasonable price.
You could maybe have your Wossners shipped to him, cut and then shipped off to you?
Although quite frankly for not much more than that, you could just have Wossner design the reliefs into your pistons for you.
Standard 951 Wossner pistons from 100-101mm are about US$650/set...but they will make anything you want for ~$1000/set of 4.
I have no problem doing it. Just after peoples exp doing it/results is all.
Old 02-17-2017 | 05:54 PM
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I'm getting ready to install new wossner pistons in my block, 87 turbo. Before I do how much of a pain would it be to do this mod with larger intake valves?
Old 02-17-2017 | 09:04 PM
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How big are your valves?
I'm not sure how "hard" it would be to be honest. Hence the thread. But i'll be doing it with large intake valves also. 48.2mm valves. I'll be doing it regardless because i don't want to go though this again.

I'll probably use the stock pistons for testing, and use the mill to fly cut them. I also have a much larger lift on my cam also.
Old 02-18-2017 | 03:30 AM
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Originally Posted by Paulyy
How big are your valves?
I'm not sure how "hard" it would be to be honest. Hence the thread. But i'll be doing it with large intake valves also. 48.2mm valves. I'll be doing it regardless because i don't want to go though this again.

I'll probably use the stock pistons for testing, and use the mill to fly cut them. I also have a much larger lift on my cam also.
I'm pretty sure mine are 48mm. I'll have to double check. Built the head some time ago.



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