Refreshing my M52B28

[Aatos]

A while ago I bought an euro Al M52B28 of unknown mileage for my project. The engine ran when I removed it from the donor so it isn't completely bad. I finally started dismantling it to check the bores and bearings and so far so good.

This is my first BMW engine job, so I made a thread wherein n00b Aatos asks things he doesn't know ;). Here's first two:

I haven't ever had chain engine before, so how worn these cam sprockets look? I think the vanos intake sprocket is definitely in need of replacement:


The photo's a bit crappy, but can anyone say whether this is the original head gasket or not?:

[318isbmw]

The vanos gears look fine to me. But for me its just standard proceedure to do the timing setup when I build it all on my american motors just a while your there type of idea cuz it'll cost a lot more to fix it if it breaks than to buy new parts now. That being said, these are a lot more expensive, and those look a lot better than the setups I've seen on my chevy motors, so I'd leave it unless their cheap to replace, which I doubt.

Headgasket, I don't think it matters really whether its original or not, either way you should have the head surfaced since those heads are notorious for becoming not straight anymore after some heat goes through them.

[Aatos]

I'm interested about the gasket because I'd like to know if the head has been worked before. The gasket looks too good to be 12 years old IMO. Once I'll figure out how to remove the cams, I'll remove the valves and have them and the guides checked out in the shop while it's surfaced.

I removed couple connecting rods today. The old bearings don't look bad, but there's interesting pitting on them. Here's a pic of lower halves:

[318isbmw]

I'm interested about the gasket because I'd like to know if the head has been worked before. The gasket looks too good to be 12 years old IMO. Once I'll figure out how to remove the cams, I'll remove the valves and have them and the guides checked out in the shop while it's surfaced.

The shop can measure the depths I know. They should be able to see how much is left and therefore know how much has been removed before they do it for you. Either way it doesn't matter IMO.

[Jean]

Subscribed.

[PiercedE30]

Bearings look fine. The pitting you see is from the motor sitting. I know it sounds weird, but it is. The water/fuel that is collected in the oil on the bearing will pit them just like that. They look like little nicks on the surface.

[Aatos]

Thanks Pierced, that makes sense.

Some progress today:



Removed cams and stuff and found this on the exhaust cam.



I'm assuming the grooves are due metal in circulation. All other bearing surfaces are fine and there's no sign of any damage elsewhere though, sort of interesting. Need to check if there's a cheap cam available.

If I have time on the weekend, I'll remove the valves and then it's shop time :).

[e30serg]

How deep are those score marks? If you're not sure, have the shop take a look. How is the bearing ledge looking? You may get away with polishing that bearing surface and using the cam.

[PiercedE30]

Run your finger nail across the scratches. If they feel pronounced, toss the cam.

[Aatos]

They are pretty deep on the cam. On the bearing cap not so much. Seems like the exhaust cam is the same on most M52 engines so hopefully it'll be easy to find.

[PiercedE30]

Now is a good time to get a set of S52 cams since you have to replace one anyways.

[Aatos]

Not a bad idea, but they're not readily available here and I'm trying to maintain an illusion of a budget. I scored a new M52 cam plus bearing ledge for not much money.

Anyway, removed the valves today. I got lucky and got access to a bench drill. Marvel the high-tech wood plate I made for the job:


The valves. Intake ones look clean so I don't think the valve seals were leaking at all:


The rest I'll leave to the machine shop. Time to start hunting seals and other stuff for the head. I've decided to get new secondary chain and gears for it plus new upper and lower tensioner.

[Aatos]

In honor of one year anniversary of my last update I actually dropped the engine to car :p. The engine is actually a 1995 alloy M52 with OBD1'ish electronics. I don't think any of these ever made it to the US.

Some pics from along the way:

Installed new rod bearings, modified windage tray and swapped pickup:




Head was worked at the shop and I installed the cams with replacement exhaust cam.




Tools I acquired for assembling the timing.




Chain stuff assembled with relevant new parts and Vanos unit refreshed with new seals.




Custom flywheel with M52 starter ring and e28 535 clutch set.




New seals everywhere, everything ready for installation.




There it goes...




..and there it is!




And I think that concludes my refreshing project. Now the only thing that remains is finishing the actual swap :D.

[evil_twin]

:)

[Jean]

I am curious why e28 535i clutch?