s52 consuming oil. What to do.

[ZekeTheSneak]

So long story short i bought a used and alledgedly rebuilt s52. Well since is has been put back in it has been burning oil during long periods of decel. I was told the rings we re used and i am assuming the rings are bad. Last winter we did a leakdown and compression test. Number 5 failed and there was oil on top of the valves so off came the head. It was checked and everything passed. I had the valve seals redone.

Fast forward to now and its still burning oil. What should i do? Price of rebuilding is expensive as hell for a s52. I was thinking i could pickup a lower mile m52 and throw the s52 head on and call it a day or should i bite the bullet and re ring it? My budget cap would be 2 large on a rebuild.

Opinions please, thanks guys

Obd1 s52, burning oil on decel

[DesertBMW]

sounds like oil rings are not doing their job. There is no quick fix for that.

[nyChris]

Going to second that your rings are the problem. I have always been told that re-using rings is not an option.

Also, building an s52 bottom end for two grand will be very hard. I priced it out last year.. All the little things add up fast.

[arch4ngel]

I'd rebuild if I could swing it.
Buying an unknown bottom end could land you with the same set of problems.

You already rebuilt the head, the block alone could be within your budget depending on what you want done.

I had my top + bottom end done for under 3k by an experienced race shop, including all labor, bearings and seals, even a set of supertechs for the head.

Shop around and you should be able to find a good shop within your budget.

EDIT: My pricing only includes machine work bearings and valve springs plus a few other bits here and there.
I spent much more on timing components, oil pump, water pump, and all the other little things that add up when you're building everything from the ground up.
So depending on what you're planning on replacing while it's apart your budget will vary greatly.

[ZekeTheSneak]

Yah for me the hard part is where i should take it. I want an expirienced builder that will do it right even with all the bmw quirks.

[THEhomelessONE]

I'm losing a quart every 1000 miles even with 10w60, how often do you have to top off? Thinking about trying a can of restore.

[atldohc]

Let me share my marvel mystery snake oil/semi success story. I have an s52 that I swapped in a couple years ago, that has always run strong but in the past couple months it started smoking profusely on periods of engine braking or sitting at stoplights. And I'm not talking a little fog, this was huge clouds that were making me feel bad for the people behind me. Naturally I thought it could be my valve seals, but I changed them out with no noticeable difference. When I replaced them they were a little hardened, but they had no missing chunks or anything crazy like that. Then I started reading online for stuff to try on the cheap. I'm not usually one to try snake oil products, but I really don't want to have to rebuild this engine yet, it should only have around 130k on it. So basically I did a marvel "piston soak". I pulled the plugs and poured some marvel in to leave overnight. The next day it smoked like crazy for about 15 min of driving. I changed the oil and within a few days I noticed I couldn't see any more smoke on decel. There is still a small cloud I can see when I sit at stoplights for maybe 30 seconds or more and then take off hard. But the smoke and oil smell reduction from before has been dramatic. I'm going to do another soak when it's time for my next oil change. I don't expect much more improvement, as it's already done more than I expected it would, but the marvel is cheap and its pretty easy so I'll give it another shot. It's only been a few hundred miles since I did it, so who knows if the effects will even last. But yeah doesnt really sound exactly like your situation, as my bottom end has never been opened up, but a cheap and easy thing to try if you desire.

[RobertK]

Carbon can build up in the ringlands and cause them to stick and not completely seal.

Many people have had luck with AC Delco Upper Engine & Fuel Injector cleaner using the same overnight method to break down the carbon buildup in the ringlands. You might give that a try.

[atldohc]

Yep I believe I must've had too much buildup in my oil rings. But for the op I would think if they did a "rebuild" on that engine that they would've at least cleaned the gunk out of the rings before putting them in. Maybe they have just lost too much tension

[nando]

if they "rebuilt" it with used rings, they didn't rebuild anything at all.

[Wanganstyle]

if they "rebuilt" it with used rings, they didn't rebuild anything at all.

they also "rebuilt' the gaskets with RTV south of the border style.

That is the hakenttmethod of "re-rebuildinging engines" - with used rings from other engines

[ZekeTheSneak]

Yahi will give the snake oil a shot. Who knows, sad thing is the shops on here but I don't have definitive proof to bash said builder. For all I know the p/o fucked me and not the shop.

[THEhomelessONE]

Shitty, hope the piston soak fixes your problems. Using 8cyl can of restor, motor hasn't blown up yet, been about 300 miles now. Topped off with some MMO.