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-   -   2001 Boxster S Engine (M96/21) Rebuild (https://dorkiphus.net/porsche/showthread.php?t=33667)

987kmns 12-04-2014 02:40 PM

Honestly, it's just cost. Genuine Porsche rings are about $200+/piston, so a non-negligible cost for me. There are other manufacturers out there for about 1/4 of the cost, but they seem to have poor ratings. I'm still on the fence about this.

Dr K 12-04-2014 05:33 PM

Wow! I had no idea they were that expensive.

N0tt0N 12-04-2014 06:41 PM

Also, new rings in a 100K cylinder = better measure the barreling and hope it is perfect. Dominoes fall....

ausgeflippt951 12-05-2014 09:22 AM

Damn, that's some serious dough for some puny metal rings! ;)

What was your oil consumption like? If well within spec, then I would just say forget it.

987kmns 12-05-2014 11:45 AM

I had almost no oil consumption at all within my 6k miles oil change interval. That's what I'm thinking too.

HughA44s 12-05-2014 02:05 PM

Mihnea, A point or two for your consideration. I have done 3 944s and althought the configuration is obviously different, the materials are not. I am sure Porsche used the same AL/SI Alloy on these engines as the 944 - Ansil?? I think and the rods and piston look exactly like the 944s. So, rings have specs to them which can be measured. I have no idea where to get them for this car but you may. Anyway I would remove (VERY CAREFULLY) a top compression ring from a piston or two and measure the width and compare to the spec. I was surprised by how little wear I saw on the porsche engines I rebuilt. Use a cir-clip pliers and set it to expand rather than contract and put it into the ring gap - carefully remove ring it does take abit to brake them so if your careful it works. Measure the width of the ring and compare to spec. Now with this ring, carefully insert it into the cylinder and about a half inch down from the top - making sure it is level with the top of the housing. As with many things in life use lots of lubrication - in this case engine oil. Measure and record the gap. Do this again half way down the cylinder and measure the gap. Finally do this again at the bottom of the piston. Use feeler gauges and DO NOT nick the cylinder wall. Compare these numbers to the specs for ring gap and you will get your answer on the health of the rings and the extent of the Coke-Bottling that is in the cylinder. I will bet your wear in the cylinders walls is well is spec. Use a can that just fits inside the cylinder work well for pushing the ring down into the cylinders and making sure they are in there square.

Hope that helps.

Hugh

Dr K 12-05-2014 02:31 PM

Some 911 cylinders were either Nikasil (sp?)

987kmns 12-05-2014 03:37 PM

Thanks Hugh! I too believe that it will turn out to be in spec. I got some tools to measure if the cylinders are out of round and I will now add your instructions to my next steps. That way I'll also have an idea about the condition of the rings.

ausgeflippt951 12-05-2014 04:23 PM

Another option is to just assume it's in-spec and then you'll not be proven wrong. Until 2k miles later, the car starts spewing oil.

987kmns 12-05-2014 05:32 PM

That was another option I considered pretty heavily, but was dissuaded by the thought you put in yellow.


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