Timing chain???

[SW-BIMMER]

Ok i replaced the head gasket on my m42 n i cant get the timing on right cant anyone help me?

[nicknikolovski]

Ok, how far off is your timing?

When you took off the cylinder head did you have the flywheel pinned?

If the crank was pinned at TDC on cyl 1, when you put the head back on the arrows on the cam sprockets should be pointing directly vertical based on the angle of the head when it sits on the block. For cylinder 1, the camshaft lobes should be pointing slightly toward each other and also the square ends on the camshafts should be parallel with the head. Like in these pictures:

http://www.esatclear.ie/~bpurcell/tdccamsup.jpg
http://www.esatclear.ie/~bpurcell/camsinline.jpg
http://www.esatclear.ie/~bpurcell/camgearmark.jpg

Check that this is correct on your engine then get back to me.

[SW-BIMMER]

I didnt pin down the flywheel so i dont know how off it is
i have the cam pointing like the pic
i have the first piston at the top bout i dont know if its at tdc
how cant i check if it is?

[nicknikolovski]

You are either on TDC on compression stroke or you are on TDC on exhaust. You need to be on TDC on compression stroke. When you first removed the cylinder head were the cam lobes on cyl 1 pointing toward each other? Also after you removed the cylinder head, did you at all rotate the crank? If no - you should be all clear.

If you are happy that cyl 1 is TDC and then the camshafts are correctly positioned, re-fit the timing chain and tensioner and then before rotating the crankshaft by hand, mark the current position of the crank and cams at TDC. Then proceed by rotating the crankshaft. Remember 2 rotations of the crank equals 1 rotation of the cams. (NOTE: If while rotating the crank slowly, you feel the engine start to bind or lock-up DO NOT continue turning the engine.) After a few rotations of the crank your marks should be re-aligned and you should be right to start the engine after finishing the job.

Just some advice:
It is difficult to say where the piston positions are as the M42 doesn't have a harmonic balancer timing mark on the timing case. For these types of jobs I would recommend using the correct timing tools. A 8mm drill bit would have been fine as an alternative to the flywheel pin. And also before removing any timing components it is always good to mark the positions of the sprockets or pulleys as a reference otherwise you could end up not knowing where the engine is positioned.

[SW-BIMMER]

I tryed turing it on but it back fired and it will not turn on no more

[RED IS 91]

I tryed turing it on but it back fired and it will not turn on no more

Do you mean that you tried to start it with the starter ? before you turned it over by hand a few revolutions??
Please don't say yes !!!!

[SW-BIMMER]

No i turned it by hand like three time

[nicknikolovski]

I suggest you get the car towed to a independent BMW specialist (not the dealer), and get them to fix this for you. Your timing is way out and now that it doesn't start you have most likely bent valves.

[xwill112x]

fubar'd valve's now.

[Cobra Jet]

I tryed turing it on but it back fired and it will not turn on no more

No i turned it by hand like three time

If you "turned it by hand", once, twice or even three times - there's no way the engine or vehicle would have ever have "backfired"....

Sounds to me (and others) that you tried starting the vehicle w/ the key after you had it all back together... that + engine being out of time = very bad move... especially since you already stated that the timing was off and nothing was lined up properly...

These engines are interference engines - when the timing is off (or if somehow the chain breaks or slips), the valves will crash into the pistons... and that *could* equate to instant head death OR complete engine death (especially if it occured at high rpm or normal driving speed)...  Even if the timing was off and you started the vehicle in your driveway, you're inviting instant valve to piston mashing, which at the miminum leaves you with bent valves...  If the valves met the pistons and you are STILL trying to start the vehicle, you're only causing more damages... STOP.

There are quite a few VERY GOOD tech threads on here as to how to replace an M42 head and/or the timing components - which also includes the do's and don't's ...

I suggest searching for those threads and reading them thoroughly - and if you don't have one already (or a link to it), also follow the Bentley or the E30 repair manual....  Try to get the timing squared up properly, turn the engine over by hand, then once you can confirm you have everything lined up & timed properly, try to start the engine...  If the engine does not start or you cannot turn it over by hand, it's time to pull off the head and check the valves for damages (as well as checking anything else for damages).

[nicknikolovski]

+1

[SW-BIMMER]

Well im going to take off the head to see if non of the valves r bended
ill keep u posted

[SW-BIMMER]

Ok so i took off the head to check the valves n all of them were good
so i bout everything back timed the chain n when i tryd to turn it on it back fired from the intake (?)
SO IDK IF THE TIMING OFF BY A LIL FOR IT TO DO THAT OR WHAT?

[nicknikolovski]

When you removed the cylinder head, were all the valves closed?
I am presuming they were because you said that they were fine. So was there any contact? If no - then thats good.

Before you recheck your timing, have you installed your fuel injector harness correctly, meaning are the connectors on the right fuel injectors? If this is OK, then continue to get your timing correct.

Follow the procedure in the Bentley manual or follow my procedure in this thread. Also you didn't answer some questions from above that would help me, to help you.

Can you post a picture of your cam sprockets? I would like to see how they are positioned when you believe you have TDC.

[SW-BIMMER]