Broken Valve Spring

I think the real sticking point a lot of us have is the dearth of bank account friendly options when it comes to major services and honing or reboring the S65. Bore score scares the shit outta me. Having watched the H2 motor sports video on the special honing process used to expose the silica gave me insight as to why so few options are out there.

Thank you for documenting your rebuild process.

spammysammich wrote

I think the real sticking point a lot of us have is the dearth of bank account friendly options when it comes to major services and honing or reboring the S65. Bore score scares the shit outta me. Having watched the H2 motor sports video on the special honing process used to expose the silica gave me insight as to why so few options are out there.

Thank you for documenting your rebuild process.

Funny you mentioned H2. They missed a few steps in re honing an Alusil block. They did not use a torque plate during honing and did not use a profilometer to measure the cylinder surface.
It’s not that complicated to re expose the silica if the machine shop knows a little about what is required. Porsche, Mercedes and most “Crotch Rocket” motorcycles use Alusil cylinders.
Alusil cylinders is almost like Carbon Ceramic Brakes. As long as you don’t let it get physically damaged, it will almost never wear out. Just try to keep everything fresh and in spec and you should be good.

Yeah torque plates are pretty much a standard practice right? Weird. May not be really difficult but the tooling and training still don’t come cheap. I’m always envious of guys that have the space and $$$ to do engine rebuilds on their own. Gonna enjoy living vicariously through you. Sorry you had the problem to begin with.

Looking back through the archives in this site and having had Subarus with valve spring issues in my social circle, I get a little worried.

Sub'd.

How did I miss this thread - interesting, thanks!
(althought sorry that the spring went. Fortunately you're clearly a guy who can sort it...)

Definitely is wear. A little bit above average wear for 130k miles

Time to order new main bearings! Will definitely send it out to WPC.
I believe Main Bearings are definitely a maintenance wear item on these engines.
It seems to wear slightly slower than the RB, but definitely wears.
The front of the engine, at the timing chains, takes most of the fatigue!

130k on MBs
30k on second set of WPC RBs

MBs:
Block Side-All Yellow
Plate Side-GRN, YEL, GRN, GRN, GRN

I don't think the 'mains' look too bad at all for a 130K miles S65, and 8300RPM capable. What does everyone else think?

DrFerry wrote

I don't think the 'mains' look too bad at all for a 130K miles S65, and 8300RPM capable. What does everyone else think?

They’re not terrible but more wear than a typical main bearing at 130k miles. 1st main bearing sure takes a beating. Just like rod bearings, main bearings are definitely a wear item but unfortunately there’s no preventative maintenance for mains. Ay least the main wear rate is considerably lower than the rod wear rate.

DrFerry wrote

I don't think the 'mains' look too bad at all for a 130K miles S65, and 8300RPM capable. What does everyone else think?

There's a bit more wear on the lower thrust bearing than what I'd expect. Pulling the crank was the right move. Visually the wear on #2 lower seems to dispute the theory of excessive chain tension as the actual cause, but we also know nothing about contribution to crank bore concentricity and clearances either.

charliev68 wrote

Time to order new main bearings! Will definitely send it out to WPC.
I believe Main Bearings are definitely a maintenance wear item on these engines.
It seems to wear slightly slower than the RB, but definitely wears.
The front of the engine, at the timing chains, takes most of the fatigue!

Your block shows YYYYY but your crank is GYGGG. Interesting...

Our Main Bearings are made by Glyco.

S85 builder wrote

Your block shows YYYYY but your crank is GYGGG. Interesting...

Curious, what does that mean?

I believe out of three colored bearings, yellow is the thinnest bearing shell. My crank is probably on the thicker side so they decided to loosen the top side to get the optimal oil clearance. Number 2 was most likely real tight, hence the yellow on top and bottom and also the accelerated wear on the number 2 bearing.

S85 builder wrote

Your block shows YYYYY but your crank is GYGGG. Interesting...

How does one tell this intriguing piece of intel from the pics?

DrFerry wrote

How does one tell this intriguing piece of intel from the pics?

Stamp on top of the block, where the head mates. Laser etched on the crank.

DrFerry wrote

How does one tell this intriguing piece of intel from the pics?

Helmsman wrote

Curious, what does that mean?

BMW gauges the crank before install and they laser etch serialize the crank as shown, they print what the bearings should be.

The block is also (supposed to be) engraved with the same information, since a tech needs to know and this is viewable without having to drop the pan.

There are supposed to be 3 different "colors" or sizes for the tolerance band meausred, Red, Yellow, and Green, most are Yellow or Green. I don't know if BMW has ever published the actual tolerance band. dealer service proceedures are to just replace like with like, no measuring, since that actually takes quite a bit of time and skill. This is why blueprinting matters. Also why putting in a differrent used crank isn't ideal, but literally YMMV.

charliev68 wrote

Our Main Bearings are made by Glyco.

what replacement are going with? are you able to measure the main bores in the block? This is quite involved and expensive if you don't have the gauges.

S85 builder wrote

what replacement are going with? are you able to measure the main bores in the block? This is quite involved and expensive if you don't have the gauges.

Can’t find Glyco PNs so I’m just going to order the oem ones from fcp euro. They have lasted me this long with no problems. Another 130k will be fine for me.

Glyco in the US doesn't sell them direct AFAIK, you/d have to get them via BMW OE. King makes a good solution. Only one size there but they are provide a bit more clearance vs OEM as I recall.

If my engine were all GRN, I would consider King. I don’t mind Glyco, it’s an old trusted German manufacturer that Mercedes and Audi uses. I wish I could buy it directly from Glyco because it’s $500 a set from BMW!