Warm idle too slow - occasionally stalls 300E

[fredfloggle]

An update. Over the last couple of days the car has worsened, it will definitely cut out if I don't right foot accellerate and left foot brake. I decided to buy a cylinder compression tester. The procedure I followed was remove all spark plugs, coil lead and fuel plug relay, then screw in and test cylinder compressions.
The results surprised me as I expected low cylinder compressions. The specced cylinder compression for my engine is 10.1:1 up from the 300's 9.2:1. The actual compressions I read from cylinders 1-6 were: 12.5, 13, 12, 11.5, 12, 10.75. So hopefully Ian was correct when he mentioned the valve clearances as excessive clearences will give higher compression. After the valve's were re-seated the all the clearances became too small so I had to loosen all of them, perhaps all too much. I'll re-check them tomorrow. I would have thought if the valve clearances were out the engine would be noisy though as remember this happening on the M110 engines, my 103 runs fairly quietly. Does anybody know of a site that explains clearly how to get valve clearances 100%?!
I have attached a picture of a spark plug that just came out. Unfortunately the picture isn't great but the plug tips look fine however the base of the plug, bottom of the thread is blackened, its smell I cannot make out. Could be carbon or oil fouling. The valves have just been re-seated etc. so I guess it's either incorrect valve clearences or an overly rich mixture?
Thanks & enjoy yourselves tomorrow night!

i think you may mean either BarG or kg/CM2 , the gauge won't read ratio directly - and it is a bum to calculate - you need to know the top ring to piston head volume for a start - it is not just chamber capacity/(sweptVol+Chamber capacity )

Excessive valve clearances won't give high compression ! because of overlap etc and scavenging , peak BMEP is seen higher up the rev range . Try it if you like , screw down a tappet - watch the gauge , and as you start to hold the valve open , the you will loose compression - wind it back the other way , and you will get quite a big valve clearance before you loose compression - all to do with the cam geometry , and air dynamics . Valve clearances would have to be wide open to give the situation you mention , not to mention the God awful noise .

Alternator load - an alternator charging flat out at maximum turbo would draw a couple of HP , but this wouldn't be at idle . The engine is seriously lacking grunt not to be able to turn over the alterator .

Re-Reading this - I am going to take a flyer that when it cooked - you broke at least one ring - yes , it might give a reasonable compression test , but as soon as the ring has combustion gas pressure on it , it can go all over the place . Symptons would be about right - oil passes the control ring and sits in the ring grooves - on the over run it passes into the bores and chamber . On a six pot , one or two pots waffling wouldn't necessarily cause it to shake all over the place - it would tend to pick up when worked as well , but loose loads of power at low revs .

If it is this , get the bores scoped right away - for the cost , send in an oil sample - they can tell you what it had for breakfast . What you don't want is to have a heavy rebore (assuming not linered) because a ring goes to town on the bore .

 

[fredfloggle]

I have the M103 engined 12V variant which I do believe shares the same bottom end. I can only say ensure all Brabus specific items are working. It may have the Brabus Tempamatik system allowing oil or outside temperature to be viewed. If this is innoperative I know first hand that just the oil temperatue sensing bolt is over £130!
The biggie to watch out for is the head gasket. At 155,000km it may have already been done but if not it's only a matter of time. While the heads off you'd be mad not to do stem seals and valve guides. If you do your own work be prepared to be set back around £1,000 as just the head gasket is £440, valve guide work is expensive too as it's best left to the engineers. If you don't I wouldn't like to estimate the cost involved in doing this.
My experience with the car, having clocked up over 30,000 miles on it doing a water pump and a couple of head gaskets plus much more along the way is that provided you don't abuse it, it's little more trouble than a standard Merc. There is a dude on this forum and others with a Brabus 190E who has I believe, your engine. He would be better informed about your particular M104.

With regards to my problem last year of the dash lights not coming on it was because I had the wrong alternator. I had one from a 2003 car which used a new style voltage regulator incompatable with these cars. I swapped it for another 150A one from a C43 which has the single bolt VR and all is fine. I also managed to cut back down to one battery. The massive 975CCA optima can be doused (just!) in the original battery position of the 124 with slight modification (read - smashing) of the battery tray.

A water pump and two head gasket ? I can see the first one going if you had a water pump failure , but the second one ? something isn't right .
How much has this thing cost in 30,000 miles ? sounds like a fortune . yes , it has a few horses , but it hardly wild . For the life of me , I can't work out why you would buy a Brabus and not abuse it ? isn't that what it is for ? you should kill yourself before you blow it up surely !!

 

[Brabus 300E 3.6]

you misread the post

fredfloggle vbmenu_register("postmenu_308813", true);

Im not the same Brabus3.6 who posted this threat, im the Brabus 300E 3.6

I never change the water pump. i have been told that the head gasket has been changed before but i think who ever did the job didn´t do it right.

i had my car checked at a mercedes shop and they told me the compresion was 13.5 on all 6 cyl wich is a litle rare, normal they will differ i litle so i think thats a good sign.

But the engine only gives a big cloud of smoke when i comes from speeds at 80Km/t and higher and letting the gas off and just letting the car doing the braking without using the brakes and when im at stop and starting to accelerate away the car lets out a huge cloud of blue smoke but only the 2 first seconds after that it stops smoking even if im still on accelerating.

That tells me that the valve guides and/or the stem seals is to blame.

But what surprices me is when the repair place did a bore scop look inside the cylinder with a cammera they could see fresh oil comming from ALL the 6 cylinders valves so the oil is deffently comming from the valves but then, why from all the cylinders? i would have thought that it was only from one bad or something like that.

They also told me that cylinder number 6 had a lot of black slack on the piston top and on the valves after burning a lot oil i think.
He told me it could be because the engine type M104 has a weekness at cylinder 6 for cooling more than the others so acturely not all cylinders get the same amount of cooling and he see that on almost every M103 and M104 engines.
He wouldn´t worry about that, he would worry a lot more for the oil he could see comming from the valves.

HAW can i check it it´s my stem seals or its the valve guides that need to be changed?
Can enyone tell me the bore and stroke for the brabus engine and the org. 300E-24?

 

[Brabus 300E 3.6]

Hi again.

A litle update.

My car is still using a lot of oil, but know im suing the sales man for saling me a car with a serious error that couldn´t be found for the regular man.

I will post here as soon as i get tha case closed.
But for now it seems like he is going to pay all the cost for a rebuilt of the top or what ever that needs to be done.