engine timing

[mr rosher]

hi to you all, and i hope one of you guys can help me here, im in the middle of redoing the timing on my e280 1993 straight six, as the idle is rough and when shes at 2500 rpm you get a cam rattle, and then i was asked by someone, are you sure you`ve got ( no one piston on TDC and not no six on TDC ) which got me thinking, theres no distributor so you cant check by this, if anyones done this sort of engine timing before how do you know if its on one or six as both pistons are at TDC at the same time,
thanks for any advice,
rod.

 

[Ultymate]

On a straight six no's 1 and 6 are both at TDC at the same time but only one is on the power stroke the other starting it's induction

 

[mr rosher]

before i restripped her back down, if i turned the crank pulley, to TDC on one turn, both cams were lined up, if i turned it again one turn to TDC both cams were out, the thing is ive had the head of and renewed the head gasket so which is which if you see what i mean,

 

[Ultymate]

It does'nt matter so long as you have pistons1&6 at TDC and the cams lined up your good to go, the cams only line once for every two revolutions of the crank ie your camshafts tun at half engine speed this applies to all four strokes. The only other thing is if you have a distributor then that needs timing also so that If the valves on No1 cylinder are closed the rotor arm in the distributor is pointing to the No1 segment in the Dist.. cap, hope this makes sense

 

[mr rosher]

thanks for your help ultymate, no this engine has no distributor which makes it more difficult, its got hfm ignition,
thanks again rod,

 

[Mikesmerc]

Would a strobe light not check the timing for you?. Mark the specific degrees btdc on the crank pulley and the fixed pointer with tipex of chalk. I presume you can static check it or have her at idle, you would have to refer to a manual for specific degrees or could be on a sticker attached to the cam cover.
Regards
Mike