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The only difference is that porsche bearings are measured by hand at porsche and confirmed they are ok. Glycos often come with manufacturing defects.
Porsche ones often have visual lines caused by thickness measuring. Line positions vary so it is obvious that they measure each shell at 4 different spots by hand. That is probably why the price is as it is.
On the other hand Goetze rings are POS, stay as far away as possible. OE rings are TRW-Thompson and Mahle.
In the 911 world properly installed Glyco branded bearings have recently been shown to sometimes last less than 1k miles. The trouble seemed to be connected to parts with "made in Poland" on the box. I got a set of made in Poland 944 turbo Glyco bearings from LR a few months ago, and there were a couple manufacturing defects. Ended up buying a set of Porshe bearings, also from LR, that came in boxed marked "Made in Germany" and looked MUCH better. For me it was worth the extra hundred something dollars.
For what it's worth porsche branded bearings for the 911 are OUTRAGEOUSLY priced!! something like $1500 for a set of engine bearings.
It's a bit of a gamble. I have rebuilt several 911 engines over last years and two 944 engines, all of the bearings I bought have been Glycos. I have never had any issues with them, but I was alert and checked each one of them before putting into engine. For reference I have a perfect sets of STD 911 (one for 2.2 and one for 2.7) and 944 rod bearings. Note that there have never been issues with main bearings.
For 3.0 and up 911's, GT3 bearings are also an option.
Regarding Goetze rings, used them many times, never seen any problems. Though they do not require 99% cases to be gapped, in fact they could use a bit less of a gap but they have been in tolerances.
The big problem with the Porsche bearings is the packaging, unless they changed it over the past few years. I had to buy and return a few from LR before i was able to get a set of 4 that were undamaged. The way the bearings are packaged from Porsche i had a bunch of nicks in the bearing surface from them moving around. No fault of LR, just really poor packaging from Porsche.
Most important thing is that the end gap is within spec when installed into specific cylinder. It does not matter if it is less or more in uninstalled state.
I have used them, guess I am not a serious builder too. And I used Goetze rings in my 2.5 16v turbo build too, seem to work so far.
Goetze are garbage rings and if you are happy that the most important friction element in your engine is garbage, I won't argue.
The point I was making is that these POS rings don't even meet basic dimensions of original ring and are made of inferior material, seal less and are not even close to porsche OE part. (as it is often claimed they are OEM supplier)
You can claim whatever you want but as usual, your mileage may wary and when doing engine one has to take into account the installed dimensions.
FYI, my 2.5 16v has no noticeable and no measurable blow-by with your cursed Goetze rings even at maximum power, seem to work for me. And yes, I have measured crankcase pressure during full boost. That forms the next question to you: how you have determined that they have worse seal? You claimed in all honesty that all 4valve heads will crack immediately too and now you build 16v engine. Isn't it possible that you may be wrong sometimes?
I never claimed that, I did claim 16v heads in general like to crack, and they do. However rennlist collectively convinced me that porsche heads are better and I got one. Performance wise things are clear and since I am aiming over 500whp extra volumetric efficiency is more than welcome.
Originally Posted by Raceboy
how you have determined that they have worse seal?
pre set end gaps
weaker spring load compared to Mahle or T-T
more space behind the ring in piston groove
= worse seal.
However I have to admit the rings I took a picture of are for BMW nikasil engine.
You are getting it wrong regarding seal. First off, spring load does nothing to seal, rings only seal when load is applied to the piston, that pushes rings against cylinder walls.
Regarding end gaps, as I already said it does not matter what the end gap is in uncompressed state. Each engine has its own end gap tolerances in installed state and as long as the ring meets these the end gap is in spec, that's it. Yes, it may be in the either side of the tolerance, but if it is within limits, it is ok.
Wrong, spring load does seal. Without it, pressure would not trap behind rings and push them to the cyl. wall, but would just escape past ring.
What makes you think I meant end gap is important in uncompressed state? The point of the picture I posted is not end gap in uncompressed state but thickness of both new goetze and Mahle.
Goetze very often is gapped in a way it falls outside of limits and the gap is too big. (in compressed state)
Do you happen to sell these? If not, I cant really understand this; it took you over seven years to complete this engine, you spent what, 10, 15K€ on it and at the heart of the matter you put $10 per set piston rings made in china (or turkey), Why?
No, I don't sell any engine parts, I am just telling you my experiences, that's all. And no, I have not put 10 000 euros on the engine, it's much less. The time it took long was because I happen to have 4 Porsches (race car, and two 911's) and I just completed several of them in the mean time.
What makes you think that material spring pressure is the main factory regarding sealing piston ring? Sorry, I will not go further into this. It falls into the same category as babying the engine for first 1000 or even more km's after rebuild lol.
Why are you using BMW rings as a reference? I have always measured each critical dimension on parts when rebuilding and I have not seen anything like this on Goetze rings. Gaps are within spec.
I have also used Mahle rings, same goes there.
I owned 4 porsches one audi and bmw at one time. Boy was I happy when I got rid of most of these.
Its not main factor but it is important part of the seal. Also sealing is needed on the sucking stroke and there is no considerable pressure in the crankcase.
Nobody except few of us worldwide ever rebuilds porsche 4 banger engines. BMWs are current cars, and I occasionally deal with disaster cases of BMW engines.
Thickness of the ring compared to OE alone (picture) is good enough reason for me to throw these rings in the garbage and never look back. But I also run-in new builds by not exceeding ~3-4k rpm for first 1000 kilometers.
07-10-2015, 06:39 AM
Sorry, I will not go further into this. It falls into the same category as babying the engine for first 1000 or even more km's after rebuild lol.