What piston rings for S52?

[mcclaskz]

I just picked up a low mile S52 I plan on refreshing for my next race motor. I plan on looking at and replacing the rod and main bearings while I have it out. What piston rings should I use and where should I source them? Why is pelican parts $145 per cylinder for OEM rings? Any others?

[riverrats97]

I just took my S52 apart to do the same, and was pretty shocked to see that $145 price tag per cylinder from Pelican and $135 quoted on RealOEM. ~$870 just for new rings is an absolute joke -- It would be pretty much equivalent in cost to pay for a bore & hone and buy a brand new set of 6 overbore pistons.


From RealOEM.com cross-reference:

REPAIR KIT PISTON RINGS . . . 86,365MM(0) . . . 6 . . . 11251405782 . . . $135.50

Part 11251405782 (REPAIR KIT PISTON RINGS) was found on the following vehicles:
E36 M3 Convertible, S52, AUTO (BK03) : Crankshaft-Pistons
E36 M3 Convertible, S52, MANUAL (BK93) : Crankshaft-Pistons
E36 M3 Coupe, S52, MANUAL (BG93) : Crankshaft-Pistons
E36 M3 Sedan, S52, AUTO (CD03) : Crankshaft-Pistons
E36 M3 Sedan, S52, MANUAL (CD93) : Crankshaft-Pistons
Z3 Z3 M Coupe, S52 (CM93) : Crankshaft-Pistons
Z3 Z3 M Roadster, S52 (CK93) : Crankshaft-Pistons

REPAIR KIT PISTON RINGS . . . 86,415MM(00) . . . 6 . . . 11251405783 . . . $135.50

Part 11251405783 (REPAIR KIT PISTON RINGS) was found on the following vehicles:
E36 M3 Convertible, S52, AUTO (BK03) : Crankshaft-Pistons
E36 M3 Convertible, S52, MANUAL (BK93) : Crankshaft-Pistons
E36 M3 Coupe, S52, MANUAL (BG93) : Crankshaft-Pistons
E36 M3 Sedan, S52, AUTO (CD03) : Crankshaft-Pistons
E36 M3 Sedan, S52, MANUAL (CD93) : Crankshaft-Pistons
Z3 Z3 M Coupe, S52 (CM93) : Crankshaft-Pistons
Z3 Z3 M Roadster, S52 (CK93) : Crankshaft-Pistons


I haven't found an answer yet as to what the reasoning is for the (0) and (00) designations for the 86.365 and 86.415 rings, respectively. The (00) seems to show that it's not an overbore (+0.xx) size and yet is still larger than stock. The 86.415 rings are 0.05mm (1/20th of a mm) larger than stock, whereas the first overbore size is 0.20mm (1/5th of a mm) larger than stock. The guy doing my engine said to get the 86.365 since that's what's stamped on the piston head and was the stock part - but I'm not gonna pay that kind of money for the 86.365 rings. He's not sure what the (00) size is for.


1. '96-'99 M3 search results:

BMW P/N 11 25 1 405 782 (Genuine BMW)
Piston Ring Set, Standard (86.36mm), 1 Set Per Cylinder, M3 (1996-99) with 3.2 Engine, Each

PelicanParts.com . . . . . . . . . . . . $145.25 (x6) = $871.50
TheBMWPartStore.com . . . . . . . $89.42 (x6) = $536.52
AutoHausAZ.com . . . . . . . . . . . . part not found


2. Z3 search results:

BMW P/N 11 25 1 405 783 (Schoettle)
Piston Ring Set, Standard (86.415mm) (6 per car, sold individually), M Roadster/Coupe S52
Piston Ring Set, Standard (86.415mm), 1 Set Per Cylinder, E36 M3 B32, Each

PelicanParts.com . . . . . . . . . . . . $33.25 (x6) = $199.50
TheBMWPartStore.com . . . . . . . $89.42 (x6) = $536.52
AutoHausAZ.com . . . . . . . . . . . . $33.04 (x6) = $198.24

[MasterKwan]

You'd want to check the ring gap and use a ring file if it's too narrow. Otherwise, you might end up with ring ends that butt into each other and break. Last time I re-ringed, I matched the gap to the bores. Basically took all the top rings and trial fitted them till I found the closest tolerance between gap and bore. Then did the other compression rings.


I just picked up a low mile S52 I plan on refreshing for my next race motor.

Thing I'm wondering is why you're doing this. Do you have signs they need to be replaced? These motors seem to go a good long time without having to refurb the bottom ends. You should consider just leaving it alone. Or measure and then reassemble if everything is OK.

[mcclaskz]

You'd want to check the ring gap and use a ring file if it's too narrow. Otherwise, you might end up with ring ends that butt into each other and break. Last time I re-ringed, I matched the gap to the bores. Basically took all the top rings and trial fitted them till I found the closest tolerance between gap and bore. Then did the other compression rings.



Thing I'm wondering is why you're doing this. Do you have signs they need to be replaced? These motors seem to go a good long time without having to refurb the bottom ends. You should consider just leaving it alone. Or measure and then reassemble if everything is OK.

I agree, other than that it is a junkyard motor and I have no idea how or where it was stored. I thought some basic, "while I'm in there" maintenance. It is very dirty on the outside. Pan comes off for oil pump nut and baffles, so I figured I would replace rod and main bearings. The next step is rings.

Both the 86.365mm and 86.415 sets are listed for my S52B32 motor on realoem.:
01 PISTON KIT 86,365MM(0) 1 11251405702 $2,607.18
01 PISTON KIT 86,415MM(00) 1 11251405703 $2,607.18
01 PISTON KIT 86,565MM(+0,20) 1 11251405704 $2,607.18

[riverrats97]

You'd want to check the ring gap and use a ring file if it's too narrow. Otherwise, you might end up with ring ends that butt into each other and break. Last time I re-ringed, I matched the gap to the bores. Basically took all the top rings and trial fitted them till I found the closest tolerance between gap and bore. Then did the other compression rings.

I checked with the guy doing my engine and he said the same as this. Considering the price difference it's well worth it. Was it an S52 that you're referring to re-ringing, and if so do you recall which ring set you used?

[weaksauce]

leave them alone unless they are worn out.

if you must replace them make sure you do your homework on ring gap, make sure you clean the ring grooves well, and make sure you put them on in the correct orientation. Also make sure you know about proper break in for new rings.

Read, read, read my friend. you have lots of homework to do. its not as simple as slapping a new set of rings on and going back in with them.

[riverrats97]

Yeah my cylinder 3 rings needed replacement so they're all getting done. I'm not doing it myself but I'm buying the rings to give to the machine shop so I'm interested in the info regarding these 2 sets.

[MasterKwan]

checked with the guy doing my engine and he said the same as this. Considering the price difference it's well worth it. Was it an S52 that you're referring to re-ringing, and if so do you recall which ring set you used?

In my case it was an Integra R motor and I used OEM rings. On a Honda, nothing can touch OEM rings and bearings. Honestly, they're the best money can buy. That motor was track only and is still going strong after 5 years of 8500 RPM track fun.

[mcclaskz]

Any other sources for rings?

What is the bore, ring groove width and depth of the standard S52 pistons? Total Seal will make any custom ring sets.

[riverrats97]

I ended up getting Grant rings for ~ $175

[mcclaskz]

How did they work? I also heard a friend used Hastings in a race motor w/ success.

[95s52]

Bump. OP, what did you end up going with?

Can anyone comment on this set http://www.ebay.com/itm/Grant-BMW-E36-M3-Z3-M-S52-3-2-Piston-Ring-Set-96-00-/160360443730?pt=Motors_Car_Truck_Parts_Accessories&hash=item25563a2f52&vxp=mtr

Thanks

[purduinaM3]

I bought rings from Hasting's when I did my engine rebuild. Paid $90 through my wholesale account for the ENTIRE SET as compared to the $160 per cylinder from the stealer. No problems getting them to seat and compression is still perfect 3k miles later.

[95s52]

I bought rings from Hasting's when I did my engine rebuild. Paid $90 through my wholesale account for the ENTIRE SET as compared to the $160 per cylinder from the stealer. No problems getting them to seat and compression is still perfect 3k miles later.

I called Hastings, they are unable for find anything for an s52. Can you tell me the part number you used to help them find it?

Thanks

You got a pm