[RichardGoller]

So I bought this car last year, and at first I found bits of rubber under the valve cover. Now I'm doing a full re-ringing of the pistons and I see more of the same rubber in the sump, and a lot of it baked on the engine block under the vibration dampener and inside the block on the same area, so I assume it did swallow a belt at some point. Now the car ran fine other than low compression in one cylinder which came back up when doing a wet compression test. Im in the middle of reringing it and I had plans of refreshing the suspension, maybe an upgraded radiator, etc. thinking someday their prices might go up because it's a manual N52, kind of rare. What do you think? Is there a chance all is good I just need to clean it out as best as I can?

[hassmaschine]

I don't know about in London, but here, you can buy a good used N52B30 all day long for under $1000. I wouldn't mess with rebuilding one in that case.. but you guys got way more variants than we did.

[Noir]

+1 ^
If you can get another ones, just do that and recycle the old block. Good luck!

[E92_William]

Well you won't know how bad it is until you drop the pan and see if any of that belt material is on the oil pickup screen. If there wasn't any and the bearings looked healthy you could opt to keep it. My 335 was cleaned internally for belt material and was okay with that after

[RichardGoller]

Originally Posted by E92_William

Well you won't know how bad it is until you drop the pan and see if any of that belt material is on the oil pickup screen. If there wasn't any and the bearings looked healthy you could opt to keep it. My 335 was cleaned internally for belt material and was okay with that after

I dropped the sump, thats how I know. The screen wasn't full of it, it had like 2 specs on there, the bottom of the pan had some chunks. But that is why I'm asking, everything else looks fine

[E92_William]

That'd be a lot of money to spend on a new engine if this one ran alright. I'd triple check every corner to get rid of all the belt material in there and it should be good. You said you had a rough idle prior to doing this. I would check the chain timing while you're in there to make sure a piece of belt maybe didn't make the chain jump a tooth or so that could be the cause aswell.

[RichardGoller]

Originally Posted by E92_William

That'd be a lot of money to spend on a new engine if this one ran alright. I'd triple check every corner to get rid of all the belt material in there and it should be good. You said you had a rough idle prior to doing this. I would check the chain timing while you're in there to make sure a piece of belt maybe didn't make the chain jump a tooth or so that could be the cause aswell.

I don't think it's the timing, ISTA says a cylinder needs to be corrected over a critical value. Now this cylinder is said to be 5 and sometimes 4 in ISTA but cylinder 4 has about 80% compression of that of the other cylinders, at 200psi compared to 250 on others. A squirt of oil into the cylinder bought this back up to 250, so the whole reason I'm tearing down the engine is to replace piston rings on all 6

[CTinline-six]

I guess the question I would be asking is what caused the piston rings to have the issue? Is there a piece of belt fragment somewhere blocking an oil passage which lead to the rings being cooked? It would suck to do the rings and then a few thousand KM later the engine is trash again.

[E92_William]

I guess he's gonna have to remove the oil squirters and blow air through to see what happens and if maybe one of them is indeed blocked. The pickup screen should theoretically prevent this but maybe it's small fragments

[Fritzer]

Kind of off-topic but I have to ask. If someone had to re-ring the pistons on a N52 in the states, the car would be practically totaled. All the freakin' time I see people in the UK with E9x cars and they are having relatively expensive and large engine work done. Is it just much more affordable to do things like this in the UK? I feel like I see an inordinate amount of people from the UK having large jobs done on their cars.

[RichardGoller]

Originally Posted by Fritzer

Kind of off-topic but I have to ask. If someone had to re-ring the pistons on a N52 in the states, the car would be practically totaled. All the freakin' time I see people in the UK with E9x cars and they are having relatively expensive and large engine work done. Is it just much more affordable to do things like this in the UK? I feel like I see an inordinate amount of people from the UK having large jobs done on their cars.

I'm not really educated on this topic, but it's a good question. I'm not sure about the cost of service in the US, but I think it's fairly similar to here in the UK. It could simply be a matter of attitude towards fixing things instead of replacing them. What I do know in regards to N52s is that all 328s, 330is and even in other series cars with a 3 litre displacement, it is going to be an N52 because you didn't get the N53. In the UK I think it's much harder to find a car with an N52 because they substituted it very quick with the N53 so someone looking specifically for an N52 will have a much harder time finding it here than there, which probably also explains why it costs double the price for a used N52. So the reason I'm doing it is because I want an N52 powered car(until I have money for a B58 powered one) and at the cost of buying a used N52 I might as well just "rebuild" mine at home using genuine BMW or OEM parts and have a better, more reliable engine(in my head at least). But for the US and UK difference between E9X cars, I really don't know, I think service is just as expensive, so it could just be "bonding" to the car(?)