"In this new Special Series named “S85-002”, I earn a badge of honour: I blew up my V10.
I document the service history of my original S85 engine and diagnose its failure. I go through the process to source, refresh, cam and refit the replacement V10 into the E60.
In this entry, the dishes get pulled. The nearly complete OEM valvetrain gets removed: cams, followers, collets, retainers, springs, seals and seats.
I take detours to discuss technicalities of hydraulic lifters, and the mechanism of a valve assembly."
Heads on work.
Our framework to fitting the Schrick cams package was to remove close to the entirety of the original valvetrain to be replaced with uprated springs, retainers, collets and replace seals and lower seats.
As a reminder on our intentions, we aim to document whether cams upgrade are an alternative to strokers for similar power. I also needed a car to Winter drive and I hate beaters - I needed my E60 back pronto.
We gave thought to removing the heads but decided against it. We didn't feel the need considering the overall engine's health upon inspecting pistons with bore scope.
The heads stayed on and aimed high. With the connecting rod bearings service completed, the engine was turned over once more.
I filmed and edited a first reel here with a voiceover commentary. Feel free to drop comments and questions on IG!
This is not a DIY.
As with the previous entry, this will be a series of pictures running through the process.
We're about to undo 24x cam blocks, 48x cam block bolts, remove 4x camshafts, 40x followers, 80x collets, 40x valve springs, 40x retainers, 40x valve seals, 40x lower spring seats [...] and then do it all over again, along with timing the infamous S85 VANOS.
If you'll take on this work, you should know what you're doing.
Having done various S85s in the past, we had most of the tools already, but we did have to buy a few new ones for intricate work.
Original Cams Removal.
To remove the camshafts, you first need to remove the VANOS cam gear units. They are held by the cam bolts. These are torque to yield, and require 180 degrees to put in. They're one time use and will be included in future S85 cam packages on EuroConnex.
They bolt through the VANOS units, into the camshafts.
You'll notice we left the intake gears in the engine. We did so to avoid having to reset the complete VANOS system.
S85 VANOS timing can be a pretty simple affair - or an abyss. The less you can undo, the better.
The exhaust VANOS gears were bolted through the timing tool and left on the shelf. This will reduce errors and time spent to re-install the VANOS later on.
One tool we did miss was the cam removal tool. It allows you to remove the cam blocks in a single bolt removal pass. Instead, we proceeded to slowly undo the bolts one by one, starting with manually ratcheting the torque off the bolts.
If this is rushed, you risk breaking the original cams as they are manufactured to reduce weight with a hollow design.
There are 12x cam blocks per bank, 24x bols total - and 3x passes were performed. That's 72 opportunities to mess it up.
The intake cam is loose.
Cam blocks were aligned. You'll notice the cam block nearest to the VANOS gears is a single piece.
The process was redone completely for the exhaust cam.
Ah - the right tools: they not only save time, but reduce risks. We'll probably purchase it in time for the V8 cams installation.
Still, with patience - anything that can happen. Both cams were off bank 2.
The Genuine BMW cams are markings that match their timing blocks and position.
The Schrick cams did not. We marked them ourselves.
AH! Time to fit the Schrick cams am I right?
Original valvetrain disassembly.
Patience! We still have everything but the valves to take out, starting with the hydraulic lifters. I filmed and edited a reel with voiceover commentary on this part of the work here.
Feel free to drop comments on IG!
Lifters, followers - I like calling them "tappets". They get tapped on quite a lot.
If you hate yourself, you can pry them off with your fingers. We used a magnet.
A chat on lifters.
Let's put some context to lifter technologies in M engines by comparing hydraulic versus solid lifters - and what makes each tick. The S65 and S85 engines marked the first time BMW M used hydraulic lifter technology in an S series engine.
The hydraulic lifters are a fundamental of the high revving magic and overall reliability of the S85 and S65 valvetrain. Their design allows higher engine speeds, and less servicing over the previous BMW M counterparts.
They are commonly called "tappets", and this picture is self-explanatory. These get beat on.
What makes them maintenance free - in theory, is the self-adjust mechanism. What makes them hydraulic is how the self-adjustments are done.
The tappets are hollow, leaving space for oil to be pumped into the lifter while the engine is running to push the lifter, leaving no play between the camshaft and valve.
The tappets were designed as a compromise for performance and servicing. I've never heard of failures related to lifters on these engines.
The lifter "tick".
We often hear of complaints about "ticking" valvetrains on the S65 and S85 - with the S85 being notoriously louder, often compared to a diesel at idle.
It's in part due to a unique combination of the S85. The hydraulic lifter technology BMW M used on the S85 and S65 is a culprit, along with the high pressure VANOS system making its share of a racket.
The tappets will tick when something causes them to lose their internal oil pressure.
Wrong oil weight.
Too light of an oil weigh can have oil bleed out of the tappet when the engine is turned off, creating a delay in lubricating the lifters when turned on.
Not all 10W60 is made equal, it's why some will report lower valvetrain "ticking" when using certain oils. Always be mindful of online oil recommendations, learn the metrics, and research the data by yourself - or trust someone that can explain it all to you.
Letting it sit makes it worse.
We often hear how a rarely ran engine is less reliable than a properly whipped one. Here's a reason why: when an engine stops, at least one valve inside of it will be open. When an S85 is shut off, somewhere - a few valves stay open and tappets get squeezed.
If a tapper is not sufficiently pressurized when a motor turns off, it loses its pressure more easily and ticks more readily when the engine turns on. This can be avoided by priming the engine oil system if a car as sat for an extended period of time.
Please, don't get paranoid about it. It's a trade off.
Lifters are defined as solid when they have no moving parts. There are solid lifters available for the S65 and S85. They retain the cylinder shape of the hydraulic tapper, without the hollow internals. A frequency of adjustments will be required - as such, they are most useful in race engines.
All previous S engines, including the S54, excluding the S50, made use of solid lifters. However they used a classic "rocker arm" design.
You can read my entry "CAPS OFF" for the S54 Schrick cam installation to learn more.
They are dimensionally bigger than tappets - as such, they are heavier. This is a major limiting factor to higher revs on the S54.
They also require adjustment shims to retain their position relative to the camshafts. It's an expensive, mandatory process.
Additionally, Diamond Like Coated rocker arms are required on the biggest duration Schrick cams that remain VANOS compatible. They are +/- 100$ a piece an 24 are needed.
Properly adjusted rocker arms may be quieter - but the S54 had it's share of issues the S85 didn't, such as the self-destructive dual VANOS system.
Getting to the rest of the dishes.
Removing the lifters was easy, here comes the more difficult part of getting the dishes out completely. We'll now tackle the removal of retainers, collets, springs, seals and lower spring seats.
In order to perform this work, we needed a new set of tools. We ordered a new set to start fresh as some pieces were lost from the previous kit.
These are universal valvetrain tools - they are fine for this level of work.
A bridge is created across the head by bolting it on, and sliding the rod through. Nothing locks in the rod, which can surprise you at times.
The "pillars" have slotted holes to allow adjustment depending on the depth of the head.
A lever is then fitted underneath the rod, and cylinder'ed tool fits on top of the retainer.
Valve Assembly 101
Before we get start pushing on the lever, we need to understand the concepts of what we're up against. In the Schrick cams unboxing "Same same but different", I touched on the theory with the original BMW diagrams of the valve assembly.
The valves have a rod that goes through the assembly and locks into the retainer with a mechanically activated locking design on the valve's rod itself.
#4 to 11 are what interests us.
It takes shape in practice a bit differently. Here's a valve assembly laid out on the table.
Here's a random valve we had laying around. See the notches? The lockets are designed to slide into the retainers to fit into the notches, locking the valve assembly together.
You'll notice the lockets have a conic design: the lower section has an ever slightly smaller diameter than the upper section.
The retainer is designed and manufactured to match this decreasing overall diameter of the collet.
Here's the underside view of the retainer, with the lockets fitted.
There's a seal in the middle of it all, and the spring seat sits at the bottom of the assembly.
Ready, set - wait! Last, it needs oxygen. As the lockets are removed, gravity would do its thing. The valves would drop into the cylinder head.
To avoid this, air needs to be fed into the cylinder to keep the valves closed. This is a quirk to doing this work with heads on.
It's like playing "Operation": you need to carefully remove the collets, retainers, springs, seals and lower seats one by one.
80x collets are coming out - one by one.
The seals get pinched and removed.
The valve and its rod remains, and we gain access to the lower seats.
These steps need to be repeated for the 40x valves.
It's a long, painstaking process requiring focus and dexterity. Forget the air pressure once, and you'll hate yourself.
Up next: we repeat this entire process with fresh and uprated hardware.
Finally, we'll get to cams, and timing the VANOS.