Conrod bearings question

[Pisobiker]

OK guys, I now have to take a decision on whether using the purple shells on both top and bottom of conrod big ends instead of the OEM setup using purple on top and yellow on bottom.

Since it happens I'm hearing people telling using purple ones on both top and bottom, I would like to have some feedback on this.

Thanks

Marco

[RSCoupe]

OK guys, I now have to take a decision on whether using the purple shells on both top and bottom of conrod big ends instead of the OEM setup using purple on top and yellow on bottom.

Since it happens I'm hearing people telling using purple ones on both top and bottom, I would like to have some feedback on this.

Thanks

Marco

I have heard that for very high power applications , you should use the purple on both top and bottom. But as far as I am concerned, the verdict is still out.

[Doug_RS2]

I used the purple and yellow(standard RS2) - not for any reason other than the softer ones had no wear when I took them out of the car.

I have heard you can use the harder on top and bottom as well.

[SteveH]

Marco, I'm sure using harder bottom shells can't do any harm. Does anyone know if the purple shells are three layer, sputter etc? I went for Glyco shells on my rebuild and they appear to be holding up fine. They were more expensive, but I know of a couple of 500 - 600hp S2s that use them without any problems. That was proof enough for me that they'd be man enough for the job.

[Pisobiker]

OK folks, got an answer here....

you see I make questions and then answer myself



I did a quick research at my friend's machine-shop and discovered this interesting sheet in a Glyco catalog:

[Pisobiker]

So it appears the "sputtered" big end shells are the "purple" ones, while the "non-sputtered" are the yellow ones.
In forced induction engines (including later Tdi engines), loads in the power stroke are extremely high therefore producing max load on the upper shell, so the need of using high spec shells on top.

Therefore it seems clear the sputtered ones ARE BETTER/STRONGER, which makes them good for being used at the bottom as well, expecially on high revving engines, where inertial loads put a big load on the bottom shells as well.

Now @ parts guys:

are OEM purple shells "sputtered" type?


Ciao

Marco

[RSCoupe]

Marco, I'm sure using harder bottom shells can't do any harm. Does anyone know if the purple shells are three layer, sputter etc? I went for Glyco shells on my rebuild and they appear to be holding up fine. They were more expensive, but I know of a couple of 500 - 600hp S2s that use them without any problems. That was proof enough for me that they'd be man enough for the job.

How much more expensive are they? Twice as much? Wouldn't you have to buy 2 sets of the Audi bearings to get 2 sets of purple? I thought the part number was for a "set", purple and yelow.

[twoqu]

Marco,
I do remember cross referencing the VAG RS2 top (Violet) with the bearings from the 2.5TDi engine. I believe they have the same part no. I have purchased KS con rod bearings for a TDi and they are definately Sputer. Come to think of it I think I also cross referenced the 20V turbo and they were the same too.

[twoqu]

Marco,

Right, the VAG 034 105 701B top bearing is listed for both the RS2 (ADU) and the 2.5TDi (AAT). Therefore using reverse logic, aftermarket sputter bearings for the 2.5TDi should suit the ADU and other applications sharing the same con rod - basically most of the later 5cyl Audi's.
The KS sputter bearings I have are p/n PL-77 290 600. These appear to also have a Gylcol p/n of 71-3669/5. I have checked the cross referencing and that ties up. So if somebody who has fitted Glycol con rod bearing can tell us the p/n, it should all tie in.

[Martynf]

Marco,

The purple shells are listed in Etka as being sputtered, sorry... you shold of asked me this at the beginning! D'oh.....

Keep your reply polite and dignified

[Pisobiker]

Problem is I didn't have any idea what the "Sputtering" process was.....

Always new things to learn! That's cool


Marco

P.S. Does it sound polite enaugh?

Marco,

The purple shells are listed in Etka as being sputtered, sorry... you shold of asked me this at the beginning! D'oh.....

Keep your reply polite and dignified

[Mark Halligan]

So if somebody who has fitted Glycol con rod bearing can tell us the p/n, it should all tie in.

Glycol con rod bearings part number for our engines is 71-3732/05 the pack comes with five sputter bearings for the top shells and five normal type shells for the lower.

Mark.

[twoqu]

Glycol con rod bearings part number for our engines is 71-3732/05 the pack comes with five sputter bearings for the top shells and five normal type shells for the lower.

Mark.

Thanks Mark.

Strangely that p/n does not appear in the cross reference section of the KS catalogue. In fact neither is there a con rod bearing set listed for the 20V Turbo engines. As I mentioned earlier, on the KS sputter bearings for the 2.5TDi there is a Gylcol number which cross references. Mmmm! Would have thought that as the VAG bearings are the same, probably made by KS or another firm, that aftermarket replacements either by KS or Gylcol would cross reference to each other.