Hello,

I am new here and a new M-B owner. I picked up a 1972 280SE 4.5 that had been sitting for 14 years in a garage. My hope is to get it up and running and use it just to cruise around in.

I'm in the process of getting the engine to function again. After dripping oil down the spark plug holes and valve covers I want to try turning the engine by hand. Since the crankshaft bolt is pretty well-recessed in the pulley/balancer can someone tell me what size the bolt is? Will I have to remove the radiator, fan and shroud to really get access to it? Or will a deep impact and a breaker bar, hopefully, be sufficient?

EDIT - I did a search on these forums and the diesel engines list a 27mm bolt. But I wasn't sure if it would be the same configuration as on my gas V8.

Thanks in advance,

Doug
Massachusetts

My M117 5.0 V8 out of a 1990 500se is also a 27mm bolt.

HTH, Martin

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1990 420SEL 217k Miles
1975 Chevy K10 400ci SBC power!
1995 Jeep Cherokee 4.0 Limited
1997 Suzuki GSXR750 SRAD
1989 Kawasaki GT550G4

be frozen in the cams.

and it might be worth trying to breakit loose with the starter for a while.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Sure. Frying the starter is preferable to fitting a socket to the crank bolt and being careful.

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1989 300 SEL that mostly works, but needs TLC

Well, you could carefully bump it with the starter, and I mean carefully and bump: one to three very short bumps to see what it does. Lube it up really, really, well first. Remove the cam covers and see what it looks like up top: be sure a valve is not stuck in the guide, etc. before. You may break a ring or two; typically the rings are the single greatest source of friction in an engine anyway, much more if rusted. Either warm the coolant and pour it backin the engine, or heat some water and put it in. Heats up the cylinder bores and expands them, maybe enough to get things loosened up. whichever cylinders have open valves could be the culprits.
I reinterate: proceed with caution.
Better yet, I take it back: don't do this. I might try it on my own in special circumstances,like if I knew I was going into it anyway, but it would be with thought.

As for the car: this could be a nice car, if you repair it properly. Have you seen the credit card (I think) ad on TV, where the answer was to throw money at the problem? I saw one of these pass through the local U-Pull salvage yard a couple of years ago; did not have a dent on it, no broken glass, and had all the wheel covers. I could not rescue it at the time; so sad.

Hi, thanks for the Replies. The heated fluid is a good idea and one I hadn't seen yet. Formula 1 and Indycar engineers used to do this when priming their engines (may still do it).

I may just bite the bullet and pull the radiator, shroud, and fan and get better access to the crank bolt. I feel a whole lot more comfortable turning this by hand rather than troubleshooting the electrical system if the starter doesn't spin (no battery at the moment).

Thanks again,

Doug

P.S. -- it may not be frozen. there was still a good amount of oil in the top of the valve covers and I may get lucky. I'd love to be wrong on calling it 'frozen'.

If you get it running it will be a nice car. It is my understandings that these engines are virtually bulletproof.

Yeah, it should make for a great cruiser or maybe even a sleeper. A V8-engined W108 has always been one of the top two or three cars that I ever wanted to own. And for the price that I bought it for I really couldn't lose [price left out on purpose].

The car is very complete (only missing the battery and the radio, which I have from a 1969 280SL). My mechanic friends groan when they hear it has fuel injection. I guess it's pretty finnicky but what the heck.

If you guys want pics or to follow along, I have pictures here: http://douging.smugmug.com/gallery/1090938

Best regards,

Doug

Leave the plugs out, especially if you pour oil into it, when you first turn it a few rounds. you don't want hydraulic lock.
I bet its not even stuck. Try it.
Get all the old gas out of it, it will really mess things up.
Best luck to you. Wish I could be there to help.

with caution, you won't fry the starter. i have tried this several times. it has worked for me at least once. persoanally i dont think that thee is really much danger to the starter at all. and as far as breaking the rings, well, if it doesnt work you have to tear it down anyway.

if it is just stuck with dry oil, there is not much danger, i dont think. and if it is really rusty and stuck, well there is a big problem anyway.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I don't care what you do personally, but offering bad advice to folks who know no better is downright malicious. What possible advantage is there from using the starter on a potentially seized engine that would trump the potential damage from trying the same?

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1989 300 SEL that mostly works, but needs TLC

i have never been all that fond of trying to break loose a stuck engine with the crank bolt. the problems of a broken crank bolt seem a lot more seriuos to me than using the starter to bump the motor.

why are you so upset about this?

accusing me of being malicious is just ridiculous.

so, do you know someone who has actually fried a starter doing this? i am sensitive to the concept of frying starters, and i dont think there is much danger here. what WILL fry a starter is cranking and cranking and cranking on an engine that isnt going to start because of a problem that is going unfixed.

i am speaking from personal experience. are you?

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I once tried to break loose an engine that had been sitting for some time, using the crank bolt. The head snapped off although I used very little torque. Sad part is, just out of curiosity we turned the key in the car and the engine turned over with the starter. We ended up scrapping the engine anyway because it was too cost prohibitive to remove the sheared stud from the end of the crank.

I'm with whoever said to use the starter. If it has been sitting that long you may end up needing a new starter anyway. Solenoids and bearings can go south sitting too long in a damp climate.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

I've been focusing on the crank bolt method because I didn't have a battery for the car. I have now and might give it a shot. Mice were in the trunk and I'm 'afraid' they might have gotten to the engine compartment too. For some reason, mice like to chew on wires and troubleshooting the electrical system is not something I look forward to. On the other hand, you're right about the despair of a broken crank bolt.

Everyone is giving their opinions and advice and I'm taking each in stride. I have my own ideas and the guys I work with at a BMW specialty shop will help me along the way. There's nothing wrong with someone offering up advice that they have seen first-hand or even heard from other sources. The listener(s) has to decide what to do with that information. For me, I feel more comfortable turning it by hand, hence, my original question was what size was the crank bolt... 27mm seems to be the answer, maybe I'll find out tonight.

Hard-won advice, right there.

This is what I will do (different than 2 mins ago). Install the battery that someone just gave me and turn the key. At least this way I will get to see what powers up and or what is dead. If there is juice to the starter... I'll cross that bridge when I come to it.