hi I got a 1981 B310 A12 and everytime I start the engine it makes a lot of noise pitchy loud cranking noise. Anyone have an idea whats wrong with my engine?

sounds like your big end bearing is stuffed, is it really really really really really really really really really really loud?

it is quite loud, whenever I start it if I'm outside people just look straight away looking where the sound came from. It's really embarassing sound, its like I'm starting the engine twice. Is it gonna be a big job or is it easy to change? you know how much its gonna cost me?
thanks for quick reply

Hi Razor,
While it is very hard to diagnose noises via the internet I will give you a possibility that may help you out.
You say in your second post that:

"its like I'm starting the engine twice."

If this is the best way to describe the noise then it is possible that the starter motor pinion gear is not disengaging properly from the flywheel after you start up the motor therefore causing clatter and noise between the starter and flywheel.
Does the noise go away?
Does the noise increase or decrease with engine speed?
If it turns out to be the starter, then it's no big deal really, so long as you fix it before it gets worse and maybe damages the flywheel.
I wouldn't be concerned about big ends and things YET.
Always start with the basics and work your way up.
Hope this helps. I'll check back on this post to see if you add any more details of the noise.

the noise is only when you start the engine, it doesnt make the noise when its running or idling or anything. Only when you turn the ignition key and start the engine.

I'd be definately getting the starter motor off then and checking it out.
Have a good luck at the pinion teeth.
Put the starter in a vice or something and check its operation with a set of jumper leads.
There is a fair chance that the teeth on the starter pinion will be stuffed and / or the flywheel teeth.

Start with the starter.

That last comment was a beauty

ive had a problem like that befor, my stater motor wasn't disengaging after the engine started. my problem was a short circut and after i fixed that it hasn't done it since.

is there an article regarding this topic so I can go through it and fix the problem myself.

Hi Razor, there's no article here, but your basic repair book (Gregory's?) should have it -- check the library perhaps.

If it makes exactly the same sound AS IF engine is running and you put the key to "start", then the teeth on the starter and/or flywheel are bad.

If it starts but makes a loud "whiz" sound, the starter gear clutch is worn. Take the starter off and rotate the starter gear by hand. It should turn one direction but not the other. If it turns both directions, the gear needs replacing. Most people just change the entire starter.

I havent had a chance to fix this car been really busy but I finally replaced the starter motor with a reconditioned one and still the same problem
must be the flywheel then?
the noise only occurs when starting