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M156 Rebuild due to bad fuel injector! Follow my progress!
2008 S63 AMG with 115K miles. Got it for a steal. Tons of leaks including ABC pump. Replaced ABC pump and all seals with engine still in but then fuel injector got stuck on and filled the cylinder with fuel. Metal in oil pan upon examination and hard start... So what are we going to do? Rebuild the motor! The good ole' AMG way.
Parked up the car in my garage and got it on some 2 ton jack stands. Removed a bunch of stuff including torque convertor bolts and bell housing bolts. Fairly easy to remove all that. AC compressor bolt (3) came out so the compressor can stay with the frame. Not into evac-ing and refilling AC so this will make it a breeze. Radiator lines, exhaust manifold bolts, wiring harness at ECU, starter cables that run to the starter battery, ABC pump ground, radiator fan housing, transmission oil cooler lines, ABC pump lines, rear hose for heater, motor mounts (only the 2 bolts from the bottom), and probably some other stuff im forgetting...
Hooked up my good ole' cherry picker to the handy 3 hoist locations using 750lbs tie straps from HF. And out came the engine!!!!
Alright, now that the engine is out. I tried to put it on this cheap **** 1 ton engine stand from harbor freight. STAY AWAY FROM THAT. It is garbage, the engine almost toppled over and could have caused serious damage. I returned that SOB asap and picked up a heavy duty 2 ton with more support. Engine was stripped down before putting on stand. All the accessories, misc oil cooler lines, intake manifolds, vaccum lines etc all came off.
Now the engine is on my sturdy engine stand, the fun began! Started by taking the heads off, you need special tools!!!!! Once heads came off, took off the crank pulley and took out the timing cover. lower oil pan and upper oil pan both came out. After that the crank cover came out. Here's what we have now!
Took off all the other junk and flipped the engine upside down (pee'd oil allllllll over my floors haha.) But after removing the crank cover, the crank and pistons were visible... Look at this dissapointment!!!!! Luckily its only 1 piston, but I will remove both from that chamber and inspect the walls. But plan is to remove and replace the damage piston and rod, all bearings, all seals, etc. The car was leaking oil from the rear main seal so I will be addressing all seals. New timing chain guides and timing chain. New tensioner, new this new that. Everything will be new. Heads will go to AFM machining to be pressure tested and cleaned. Straightness will be checked too. Crank may or may not come out for inspection for straightness and balance. But honestly the crank is beefy as heck. The weak point is really the piston/rod so I don't think the crank needs anything but a polish. All bearings will be replaced. New water pump, abc pump, thermostat, mounts, intake camshafts, SLS black series tappets/valve lifters, and 4 new camshaft adjusters will be put in. It sucks you can't buy piston rings anymore or else those would have been replaced also. This motor will be like new once I'm done with it. Stay tuned for updates!
Here is the damage! Bent con rod and cracked piston bottom. Cylinder walls are not scored as far as I can tell, looks like the damage fell striaght down into the oil pan. Will be checking the oil pump for debris etc. Also will remove pistons tomorrow to inspect block etc.
Anyways, stay tuned. This will be a slow pace project as I am a medical student and get busy here and there. But I will order up more parts (pistons/bearings etc) tomorrow and hopefully make progress on it soon! I thought about going aftermarket conrods (Italian RP) or weistec but 5000 for some rods is nutz. Especially since I don't plan on supercharging it. Maybe a nice tune after its all 100% and it should suffice. The S class is massive and makes no sense on supercharging it. It's fast enough for the weight you are pushing.
Alrighty! Got out the suspect piston and the other one within the same chamber and look at this! I now have to make a decision if I will replace all pistons and rods with weistec ($$$) or just replace this piston and do all the crank bearings etc. It sucks they don't sell piston rings anymore or i'd do all the rings too... Anyone know where I can get piston rings without buying all the pistons? If I go weistec, it will come with all new piston rings... Hmmmmmmm.
heads and crank are off to a machine shop for cleaning, valve job, and micropolishing! The owner worked for Mercedes for 20 years and has rebuilt these motors before. He is going to contact his piston source and see if they can make forged custom pistons and rods for this motor! He said my camshafts are toast and will need replace. So time to look for those. He will be cleaning all my parts in his big **** hydro cleaner! This is going to turn out neat!
Engine block, heads, etc are at the machine shop getting cleaned. heads are getting re-valved with new valve stems! Figured we'd go ahead and do that to avoid issues in the future.
Intake manifold was refurbed. Opened up to look for corrosion. Believe it or not, zero corrosion. So I cleaned it really good (throttle bodies also) and gave it a nice coat of engine paint (VHT high temp). Used Shin-Etsu Silicone (the best stuff ever) on all the rubber and plastic areas where there is rotation. So everything will move nice and smoothly! Looking sharp!
Ordered all new camshafts, bearings (main and rod) (becareful when ordering these, they are color coded to the color sequence on the crank snout), and a million other bolts and stuff. These bolts are mainly all one time use so theyre quite pricey. Probably estimate 600$ just in bolts LOL! AutohausAZ has the best prices. SLS buckets will be ordered shortly. Oil pump was dissassembled and cleaned and checked for any debris. Only the screen has some debris. Otherwise perfect condition. Tons of little rubber seals here and there you must replace! It's a real bummer Benz doesnt sell piston rings... you have to buy all 8 pistons to get the rings. So I am using old rings as they didn't have any issues prior.
Update!! Got all the parts back from the machine shop all clean and polished! Heads got a valve job with new valve seals. Cleaned all the pistons by soaking them in chemical dip carb cleaner for 2 days and all the carbon just melted off. Cleaned all the ring grooves. Of course I used a replacement pistons for the piston/conrod that was damaged. Brand new main bearings and put the pistons in one by one. After the pistons, put a new rear main seal. Sealed up the upper main cap girdle. Bolts are one time use and have a 9 stage torque procedure. Replaced the 2 o rings on the block. Next was upper oil pan and oil pump. New oil pump chain guides and chain. New timing chain guides and chain. New tensioner. Lots of new stuff lol. New oil level sensor etc etc. Put all that together and let the sealant dry before flipping engine over. Timing cover seals replaced, sealant path followed per WIS. Replaced rubber seal on the timing cover, on went the timing cover. Heads and all that went on after. Brand new camshafts and tappets (INA) etc. Rebuild the camshaft adjusters using 63motorsport stage 1 kit with new springs and pins etc. Titanium camshaft adjuster bolts used to close them up (18nm torque, any more and you will damage them. Next was a bunch of accessories and intake manifold, fuel rail with new injectors (bosch), tensioners, alternator, knock sensors, oil filter housing with new gasket etc. Gotta make sure you time it properly, after you think you are done timing it, spin the engine 2 whole turns and if everything lines up per the tool, you are set.
Should be fully done by tomorrow, waiting on a water pump gasket and EGR pipe gaskets from dealer and its a go! Will try to get it in by Friday! Stay tuned! I will probably record the first start and post on youtube. Enjoy the pics below!
cannibalism? new chain guides/chain etc. Yes I know this is not the final orientation of the chain, this was before I properly set the chain. squeaky clean pistons! cmon mercedes, use better material. 63 motorsport is legit!!! New cams, don't get them mixed up! 98% done!
All done! Went in smoothly, got everything bolted up and filled with fluids. Did the transmission service and differential service also! I need to buy a new lower oil pan, I think this one is bent out of shape from previous owner and it is dribbling from the oil pan seal. Will buy a new oil pan, reseal and we will be ready to roll. Engine runs and drives so smooth and quietly. I might remove the resonators for a louder exhaust. For some reason, it isn't as loud as an AMG should be. After that, its time for a detail with new floor mats and steering wheel cover!! The thing has so many new parts I can't even list them all! Not a single check engine light on, not bad for my first engine overhaul... I think any other engine will be a breeze moving forward, although it was a time consuming and costly process. I think I am nearly 4-6K deep in parts. Will have to tally it all up later and see where we stand. Either way, this S63 M156 is back to life and ready for another 150K miles!
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