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Advice on piston oil control ring drainage holes?


ProZac

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I'm thinking of giving my engine a little freshen up. I got some pistons in at work from another branch to look at on a hunch they might be suitable. They're low compression pistons for a non-turbo SOHC 4g63 made by Mahle. The tops look bloody identical to the higher compression 'Ts' turbo pistons. I need to measure the dish volume, but I suspect there will be bugger all in it.

As this is a budget build, and will never see super high boost levels, I'm not worried about running cast pistons. One thing I did notice is that there are no holes drilled, or a slot made, for oil return from the oil control ring groove. There are some cut-outs from the groove, on the non-thrust surfaces (in line with the gudgeon pin) that allow drainage back down the bore however.

Can anyone shed any light on what sort of issues I could expect here? A quick google shows plenty of people having oil return holes drilled... Might be an option, if it's even necessary?

Id love to not be such a cheap bugger, but at $165 for a set of pistons, including rings and gudgeon pins... It's mightily tempting. They're on clearance, as Repco wants to sell their existing stock of this item, and just order them from ACL in future if they're required.

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Thats a better thing Zac-san.

I have a new set of E15et pistons here which are the same. It's much stronger not to have any holes in the inside of the ring grooves. It makes the skirt harder to break off. (As I see it)

It'll just mean the oil exits the oil control groove through those slots. Which would probably wind up feeding more oil to the small end. Which can't hurt either.

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