Transplant, completed.

Transplant, completed.

"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 and swap my S85-002. Most importantly, I document the S85-EVO high duration camshaft package

In this entry, the S85-002 gets dressed with a few nip and tucks: the Bespoke Valve Covers, the Underdrive Pulley and the Silicone ITB Boots are fitted amongst a few restored and replace BMW parts. 

The chassis then gets lowered onto its new engine and the re-assembly process is nearly completed." 
- Matt 

The swap continues. 

With the S85-001 undressed, it was time to begin the swap process. From here on out, we aimed at time efficiency, and transferring functioning parts that were unaffected by metal shavings. 

To begin this process, the S85-001 was lifted from its subframe and moved to the side. The subframe stayed on the stands in its exact position. 

It would stay here until we'd find time to fully dismantle the block and dive deeper into the probable cause of failure. 

The S85-002 was lifted and positioned onto the front subframe. As a reminder, the chassis will be lowered onto its subframe to be time efficient. 

If you've ever wondered what material the OEM dual mass flywheel was made of, you'll make it out from the surface rust accumulation. 

With the S85-002 sitting on the subframe, the lightweight SMG3 steel flywheel and the OEM twin disc clutch were transferred.

The flywheel was first fitted to the crankshaft. The dowel pins on the flywheel are machined to fit into the OEM clutch assembly. 

Clutch alignment was then performed. 

The V3 long tube headers having already been transferred, the fundamental, external mechanical components were already completed.  

While you're in theres. 

As this was going to be a special engine - I wanted to eliminate additional failure points, maximize performance and add unique styling touches. Prior to fully transferring accessories, we carried out a few upgrades and restorations along the way. 

Parts were everywhere, it's the nature of a swap. 


My S85-001 used a Motoradd 880090 thermostat. It opened at higher temperatures than the original unit to accelerate oil warmup time and slightly increase operating temperatures. 

We pulled the thermostat housing from the 001 engine to transfer over. 

This time around, I opted for a brand new OEM thermostat.

SAP delete.

I first opted to delete a common failure point on the V10, and ever more so on the V8: the Secondary Air Pump system (SAP). 

The SAP is used to heat up the primary catalytic converters during cold start operations. Its purpose is to rapidly increase the converters' efficiency to reduce emissions. 

It's an expensive system to replace in both parts, and labor - most notably on the V8. 

The system itself is a series of hoses, valves and a pump. It will require a DME file modification to eliminate the CEL for increased emissions. 

The valves sit on each side of block, by the exhaust ports. 

On the V10, the pump itself is located by the passenger side bumper, besides the oil filter housing. There was no room in the engine bay. This will be alien to most V8 owners, having both the housing, and the pump on the engine itself. 

To maintain proper functioning of the S85, the SAP's air conduits needed to be blocked off. We opted to quickly fabricate our own. We cut off the OEM valve, and added a sheet metal underneath, re-using the original bolts to complete the installation. 

It isn't fancy, but it works, and it was fast. CNC machined block off plates do exist, and BMW makes their own as well. We ordered the original plates to install them later on. 

ITB Boots. 

The next potential failure point I sought to address were the individual throttle bodies' rubber boots. Being an organic elastomer material, rubber will decay with age: it fades, and loses its elasticity. 

I had never personally experienced failure on any previous boots on the S85-001 beyond my own installation errors, mostly on the V8. I experienced air leaks and intake pressure related codes due to my own mistakes. 

The S85-002's driver side plenum showcased had an obvious ITB boot failure. It was deformed with a protruding section. 

The original boots are designed with a "stopper" for the clamp's bolt. They are at a specific angle for accessibility.  

You can see the obvious deformations from the upper and lower clamps. 

All rubber boots and their clamps were discarded. The upper clamps are one-time use, and the replacement boots came with new worm-style lower clamps. 

Silicone replacement boots. 

I opted for silicone replacement boots. The synthetic make up of silicone makes them a lifetime product. NRW is the only manufacturers of such boots for our S85s, and backs them with a lifetime replacement warranty. 

Silicone boots have been common upgrades for the S54 and their CSL airbox over the years. I expect this upgrade to become widespread amongst V8 and V10 owners considering our plenums are most susceptible to installation errors. 

You can source your S85 set here and your S65 set here.

They are 1:1 replica of the original rubber design, including the stoppers in the proper position.

The CSL plenum's aluminum bungs were greased, and slid into the boots directly. 

The silicone ITB replacement boots kit include worm style clamps. They are the ones bolted to the ITBs.  


The upper clamps were replaced with Genuine BMW units. 

The metal tabs are crushed to complete the clamping process. 

Here's to one less thing to think about. 

Underdrive Crank Pulley. 

Next up on the list was "upgrading" the crank pulley. The principle is relatively simple, reduce the crank pulley's diameter to underdrive the auxiliary accessories. The diameter is selected to retain proper output of each crank driven auxiliaries: the water pump, alternator and power steering pump. 

Similar to a flywheel, the reduced diameter also reduces rotational inertia. Yet the effects are much less drastic. Claims of 15-20 wheel horsepower and torque are made, I doubt those are true. 

I compared the OEM unit to the small diameter unit. It isn't a drastic change. 

You can source the S65 and S85 pulleys here. There are differences over the years and transmission types. 

The pulley is machined from aluminum with similar ridges to the original pulley. It comes with a new set of accessory belt. 

You'll need the right tool for the job. 

New bolts are also provided in the kit, removing another rusted eye sore from the front of the engine. 

Speaking of eyesore, the alternator pulley had me tripping. I couldn't turn a blind eye to it. 

Having transferred the accessories from my S85-001, we were bound to have rusted components. It's my daily driver and it sees the intense, salted Winters in Quebec. 

Tools exist to remove pulleys, but we didn't need it here. It came out with ease. 

We looked into ordering a new one, but with a concern for time, we opted to restore it. 

The pulley got sand blasted down to its raw metal. 

The ridges were then sharpened back to their original shape to avoid slippery belts. 

The bare metal would rust in a few days back out in the salt. We had one more step to perform. 

A few coats of rust-proofing matte black paint were quickly applied. 


Bespoke Valve Covers. 

The S85-002 is a special engine, the world's first fully documented cam'ed V10 deserves a unique touch. I wanted the engine to be easily distinguishable with a Bespoke set of painted S85 valve covers. 

BMW M specified aluminum material for valve covers, as such, they don't degrade nor leak like the S65 magnesium units. The restoration and paint process is far simpler. 

They were sanded down, and sprayed in color matching Sepang Bronze Metallic as a base coat. 

Color matching wouldn't suffice, we opted to recreate the M stripes across the visible outer portion of the valve cover. 

Each stripe was painted, the only sticker were the ///M logos. 

The original colored logo was used, but I felt it was overboard. 

The larger black logo was used instead, and it was off to final clear coat application. 


The valve covers were the missing piece to continue the work. I brought them back to InnovAuto and they went on immediately. 


We re-used the original hardware and begun the installation process. 

New valve cover gaskets were fitted. 

The valve covers have a specific torquing sequence for a proper seal against the heads. 

With the valve covers torqued down, the main engine harness was put back into onto the S85-002 to begin reconnecting all electronic components sitting on top of the engine. 

The ionic modules, spark plugs, ignition coils and various sensors were all installed and reconnected to the engine harness. 

I test fitted the ionic and spark plug covers. It wasn't perfect. 

We would have to trim the plastic on this one. I sent out all 4x covers to create a mold for carbon units. 

Wrapping up the swap. 

With the while-you're-theres completed, we resumed the swap process by doing the final checks before lowering the chassis back onto its subframe. We managed to get bored and temporarily fitted the CSL carbon plenum to grab a few signature pictures. 

How often will I get to see this?

Coolant hoses were refitted and positioned close to the final position inside the engine bay.  

It was time - the plenum got removed, and the chassis lowered. 

Bam - right on the money. 

The subframe got secured and bolted into the chassis. 

The main engine harness was reconnected to the DME. 

It was sealed off with its cap to mark completion of this part of the process. 

The radiator and condenser units were slid back into position. 

Coolant hoses were then reconnected from the radiator to the engine. 

Having worked on the S65 and S54 myself, the S85 is by far the most cramped engine bay of them all. Doing most of the work prior to lowering the chassis made this a whole lot easier. 

With everything reconnected, the chassis was going back up to begin re-assembly of the undersection. 

Reconnecting the steering column with the rack was a painful process. A lot of banging was needed to get it to fit. 

We ultimately noticed a failed seal, and decided to replace the rack with a used unit that was available on the shelf. 

Next up, the SMG3 was going back in. 

Having seen Phil remove and install my SMG3 various times, I remain impress by the speed and muscle memory he showcases every time.  

Aligning the input shaft with the clutch, and flywheel is always a tricky process. 

Having the right tools also helps. 

With the transmission bolted, we proceed with reconnecting all sensors around the headers and transmission. The wideband pre-cat 02s were still in good shape. 

I unfortunately had to leave prior the driveshaft and exhaust going back in. I was back to finalize the front end underbody refit. 

I took the opportunity to showcase the brilliance of the sealed air intake design that BMW M originally designed. Each lower bumper ducts have shaped plastic scoops connecting to the air filter boxes.  

The vertical section have accordions to account for engine movement. I connected the sealed carbon intakes to the ducts to showcase the improvements of its design over the original boxes. 

The ducts were fitted to the chassis. On the driver side, they contour the windshield fluid reservoir whereas the passenger side contours the oil filter housing and secondary air pump. 

The control arms stayed bolted to the spindles throughout the swap. 

The thrust arms, lower control arms and tie rods were bolted and torqued to spec.

This would be one of the last opportunities to catch the engine through the chassis. 

The swap process was now completed. 

It was an extensive, intense process that was performed rapidly thanks to the vast experiences of Phil.

Up next: it's time for pre-flight checks before the first start up. 

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