1998 Mercedes C230 Kompressor Sport Manual.

I can understand you being weary but they are really very reliable, most people that are weary haven't owned one - internet whispers and all that.
There's nothing much to go wrong, as you can see from my posts above. The trick like most things is to change the oil.  30- 50k miles is probably ideal not the 100k Merc suggest.  The three bearings and oil seal  should be renewed at 100k  imo, definitely not at 145k miles like I did . Total cost for the overhaul was 70-80 quid
Personally, I wouldn't hesitate to buy another S/C car again.

The M112 you have is a very nice engine (check the crank pulley if you have not done so) but completely different obviously to the M111 Kompressor and their characters are chalk and cheese. One of the advantages of the kompressor engine is there's a fair bit of scope to increase the power with a modest budget, plus they are easy on fuel too which is a nice bonus.
Another reason I bought this car is because it's a manual and that's what I wanted.

If you are looking again at a CLK opt for an early manual model with the M62 Kompressor rather than the later car's with the smaller M45 kompressor.
Of course like all things getting on in age finding really good one's is becoming more difficult.

It's been a while since I updated, a few things have happened and a few things planned.

I booked the car in for an N.C.T. test (MOT) and it passed with flying colours, so happy out there.

As I've took the car off the road for the winter I reckoned it was an ideal time to plan what the next jobs should be. Top of the list was to check for timing chain stretch which it must have some at this stage (150k miles). Now this is actually a big job, to replace the the chain guides the front cover has to come off and that means taking the head off and if I'm doing that I may as well replace the valve stem seals, strip and clean the followers, refresh the cam adjuster with new springs etc, etc. It would turn into a classic case of job creep, the water pump and coolant hoses are original so that's another job.

Anyway pulled the valve cover off and set the timing and to my surprise the timing was off by only 5 degrees, factory spec is 20 degrees after TDC new, max 30 degrees , mine was showing 25 degrees,  not too bad. The exhaust was at 30 degrees, new 25, max allowed 35 degrees. Well it doesn't seem excessive to me? Opinions welcome as I've no experience with t-chains on these engines.

Green spot  20, Red 25 degrees.


After mulling things over I've decided not to change the chain and guides and therefore not pull the cylinder head, maybe next year. What I will do is fit a new chain tensioner (the internal spring can go weak) and since I have to remove the Supercharger to get at the tensioner I'm considering fitting a smaller pulley which will increase the boost pressure from the current 10.5 psi to 12.5 with the aim of 240 bhp/200 bhp @ the wheels. Also I'll  look into a custom intercooler with 50% increase in core size.  New rear tyres are on the cards too and no doubt a few other bits & pieces.     

Ordering parts!

Now being honest I love buying new parts, I suppose who doesn't? But, I'm making this job an international operation, besides buying some here in Ireland I've stuff coming from the U.K., Germany, Latvia and the U.S.. All straight forward or so I reckoned but it's been slow and a bit of work. I reckon too some suppliers are using Covid as an excuse to cover fcuk ups and slow delivery. Anyway, I'm getting there.

List:

Chain Tensioner.
Water Pump.
Coolant Hoses x 4 (the remaining five are Merc only).
Coolant Housing 'O' ring seal.
Cam cover to dipstick tube Breather Hose.    
5L Coolant.
S/C Top Gasket.
S/C Oil.
I.C. Outlet seal.
Front Crank oil seal.
Engine Dipstick used (Merc only at present) and yep I'm the dipstick that broke it!
S/C milled down (in progress locally).
Silver HTP.
Remote Oil hose, Switch and fittings.
27mm Deep Impact socket.
Crank locking tool (flywheel mounted).
 

Since there's not a lot I can do at the moment I decided it would be no harm to clean up the header heat shield. It was looking rather sorry for itself, especially since the engine mount and steering box h/shields were already cleaned and painted.
With shield placed in a large basin of citric acid/water mix over night, then a clean up with brake cleaner, a few coats of HT paint and an hour in the oven I ended up with this. Talk about bling, can't wait for the silver to lose it's shine.




As the heat shield was off I removed all the exhaust manifold nuts, I hate manifold nuts and studs. I've had some bad luck over the years with them being either seized, rounding off or the studs snapping. The key here is to use a quality socket and only turn 1/4 at a time, retighten and repeat while using plenty of spray lubricant. If they're really stuck some heat helps.

Got all eleven of the nuts off, including the curse word of a one at the lower rear. Cleaned the threads and added a smear of copper slip. Guess who was a happy boy... This job should stand to me when the time comes to remove the cylinder head.



I'm almost proud of those nice and clean nuts & studs!








I'm going to fit an oil line for a pressure switch with the option to fit a pressure gauge  - never been comfortable not having such a basic warning light on the dash. This will be plumbed into the redundant port ( M12 x 1.5) behind the supercharger which is clearly visible between #1 & #2 exhaust header (early M111 car cars used this port for a sensor).



The port is located at the rear of the S/C  where space is a little limited. I can't screw in an adapter for both switch and oil feed for a gauge directly thus the remote oil line with a banjo & bolt which should (guesswork by me) sit less pronounced from the block, and not interfering with mounting the S/C back up correctly and then a generic switch can be located nearer the inner wing or somewhere out of the way.

If all goes to plan (famous last words) I could at later date add an oil pressure gauge too or just connect to the adapter to take a pressure reading whenever. I won't be fitting an oil pressure gauge on the dash (there's no room anyway) but at least I'll have a warning light for a little peace of mind. 


Mock up of block connection and switch mounting.







This is what I ended up with.













Oil light

Yep I buy from everywhere while keeping an eye on shipping charges and possible import duties. Just spent 150 with Autodoc, 30 was for delivery. Also spent 67 euro with a Merc main dealer in Germany, 26 euro was delivery charges but still cheaper and very easy to order stuff which is great because I'm no fan of using main dealers here.

Swings and roundabouts, as they say.

Cheers, for the info.
I did use Mister-Auto but generally I found them over priced more recently and lacking in stock. Yes,I keep forgetting about Car-parts.ie, will keep it in mind thanks. As for the U.S. suppliers I've had great success on and off over the years, also I've family there which can help.
I don't travel to the north, well maybe once every few years, there was a great guy in Newry I use to deal with. As for Euro car parts here, they are a joke, well that's my experience anyway.
I do use a local motor factors, family run place and they are great and happy to pay a little over the odds with them but on big ticket items they simply can't compete.

More Boost. Boost is good!

At long last I got my S/C pulley back from the local engineering shop. It's milled down from the stock 94 to 87 mm which should see the car ending up c.240 bhp @ the f/wheel with extra torque, giving a solid 200 bhp @ the wheels. With a max pressure of around 12.5 -13 psi.

Now, all this talk about max power is well and good but I don't run the engine to max rev's or hit the rev limiter that often due to traffic and varying road conditions, what really interests me is mid range punch. Typically, cruising @ 2500 rpm (off boost) and then sudden wide open throttle.
That's were the engine currently sparkles with no lag, hopefully the new increased boost pressure will make it sparkle even more.

Wonder how long the head gasket is going to last now? Answers on a post card please. 😁

When everything is back on the engine I'll need to look into upping the fuel pressure and fitting a larger I.C. too.

Milled pulley.

I sometimes have to visit MSL with cars for work. Service and fuel filter on a 2018 S-Class, €720!

At last refitted everything back on the engine and when for a test drive. Long story short, Wow what a difference the smaller S/C has made.

Cruising in say 5th off boost, then go sudden wide open throttle there's now 9 psi with a the max boost pressure is 13-13.5 psi. Prior to this I had 10.5 psi max , the stock spec is 6.5-7.0 psi max

I think, I've hit the target BHP that I wanted 240 @ fly & 200+ @ the wheels.

To sum up it's a different car to drive, the extra BHP is one thing but the extra torque and spread of the increased torque makes it actually fast. Of course being a car originally introduced in the early 90's it's not heavy which helps.

Now I'm just waiting on higher pressure fuel regulator.

 Stripped and cleaned


Pre porting



Ported