Same same but different.

Same same but different.

"In this Special Series, we fit the biggest duration V10 Schrick cams compatible with the high pressure VANOS system in the S85B50.

I document the theory & unboxing, the installation with the help of InnovAuto, break-in procedures, tuning, and real world results on the dyno and the street. 

On this entry, I finally received the 296/284 Schrick V10 cams from Germany along with auxiliary hardware. I chat S85 differences, the theory and specs.

-Matt 

The V10 is just different

As I set out to cam the S54 and the S65, I couldn't leave the S85 without cams. I pulled the trigger on a set of cam earlier in August '23 directly with Schrick AVL in Germany. 

The S54 cam upgrade is already well documented amongst the community, and the S65 292 cam duration has been done before by a few race teams and enthusiasts. 

Although little has been publicly documented on the V8, if you poke around and talk to the right people, you will find the information you need for a proper package.

I touch on this dynamic in my original entry "Barbies & Unicorns" to the Special Series on S65 cams. .

The V10 is different: a forum dive in the 2000s won't net you anything worthwhile except a few one liners about how it's not worth it from guys running stock DME calibrations. 

Beyond forums, you aren't going to find anything outside of a few flashy YouTube videos, notably the race stroker engine Dinan built way back. 

A little more different. 

The S85 was the first on its kind for BMW M: the large bore, short stroke, large displacement, high cylinder count engine were all something new for these engineers.

It was a stop along way of their legendary naturally aspirated engines' evolution, topped by the S65's further development of the dual VANOS system, mastery of intake and exhaust tract along with further refined engine mapping protocols. 

The S85 was fitted with hydraulic "tappers" that sit over the retainers and springs. These allowed operations at higher RPMs over rocker arms of the S54.

Below is an official BMW M document taken from the S65 & S85 engine technical literature used for workshop training. The graph shown is for the S65.

It's unfortunately missing the S54 CSL engine, which featured 268/264 cams as I documented here.

The max duration. 

With the S65, we step up from a 256/256 cam to fit a 292/292 set of cams. On the S85, it's again a bit different.

We gain +28 on the intake cam, and +24 on the exhaust cam. It's a lesser duration increase than on the V8, but a larger gain than the S54's 288/280 - at least on the exhaust cam. 

On the intake tract, I moved up to a 296, the maximum duration suitable for the dual VANOS system. Schrick's complete technical specifications for this duration are here

On the exhaust tract, I moved up to a 284. Once more, this is the maximum duration suitable for the dual VANOS system. Schrick's complete technical specifications for this duration are here

Unboxing. 

I received the set of cams from Schrick in late August '23. The cams came in a shipment of 292 cams for a member of EuroConnex. 

The boxes were massive, taken up the entire width of the single large package. The smaller boxes are the 292 S65 cams. Everything is bigger with a V10 :)

As with the S65 cams, the first thing I did was validate I received the correct SKUs. It checked out. 

The intake and exhaust cams can be differentiated by their length - and most easily by the VANOS compatible section at the front of the engine. They are positioned as they will be in the engine. 

The outer left camshaft is a S65 292 unit. You can immediately discern the much different VANOS compatibility section. The S65 got rid of the high pressure oil system and made way for a low pressure system that is bolted onto the camshaft. 

For once, V10 owners will be saving some dollars relative to their cylinder count. The S85 camshafts are the same price as the S65 cams, for 2 more cylinders. 

This is most likely because they necessitate less machining work after the casting process. 

The camshafts are made from a hollow, chilled cast iron construction. It mimics the Genuine BMW M manufacturing process. 

Each camshafts have machined gears to integrate with the S85's head. Technically, it's still a bolt-on - albeit a very expensive one.

As I unboxed the S85 camshafts, my feelings resembled those I felt unboxing the S65's. 

There's something special about improving upon BMW M's best naturally aspirated engines ever made. 

I also received 64x Schrick springs and titanium retainers for the S65 cams.

I took the opportunity to shoot videos and photos to document the process. I will be document the S65 springs & retainer options shortly. 

Schrick does not specify new valve spring and retainers for any of their S85 duration. 

Whether this is technically correct, or comes from a lack of documentation - I am unsure. 

I won't be following Schrick's lack of advice on this one.

Up next: we chat springs & retainers specific to the S85

[...] because yes, it had a little something different.

In the mean time, get on the waiting list for the upcoming social buy on cams for the S65, S54 and S85


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