m40 checking timing valves , pistons

[arrisbmw]

Just wanna check my timing is spot on . I understand the cam has a square at the front and needs to be at right angles to the head matting surface of the camshaft cover , which i will be removing . rather than go under the car and push a rod in the hole in the bell housing and finding a hole in the flywheel . My question is . Is it ok to use a tool specially designed to locate t,d,c , its pencil like, screws into the No1 cylinder has a shaft inside , then you connect a dial gauge up in the top . ( i,d load a photo if i knew how too. ) and obviously turn engine until the piston reaches the very highest point of travel on the compression stroke , both valves closed and rotor points to No1 spark plug lead ( as soon as the dial starts to fall back you know you,ve reached t.d.c ) and thoughts , would that be more accurate than sticking metal rod in, well you know what I mean.

thanks in advance Paul

[Brianmoooore]

Dial gauge will be the most accurate, but a locking pin in the flywheel won't be far behind. Why do you think you won't find the hole in the flywheel? No need to go under the car - it can be reached from above.

[arrisbmw]

right ok, didn't realise you can get to it from above . i,ll have to look for it on the inlet side I understand towards the bulk head ? .
is it good enough just to use a 8 mm steel rod. or do i need the special locking tool.

thanks Brian much appreciated. I was hoping you might reply.

[Brianmoooore]

There's a substantial web on the engine block right below the starter motor, and a similar one just above where the sump bolts up to, on the inlet side. There's a small space between these webs, where you will find the hole for the locking pin. There should be a plastic plug with a large tab on it blocking the hole, but this may have gone missing. If it's there, it just pulls out.
A 8mm drill bit is the easiest thing to use as a locking pin, but using a 7mm bit first helps get the flywheel position approximately right, before swapping for a 8mm.
DON'T FORGET TO REMOVE IT AFTERWARDS.

[arrisbmw]

THANKYOU.

[arrisbmw]

updt. yes did check the timing via the hole as mentoned above . timing was spot on , so it seems a bit if a waste of time except ,i took the time to change the spark plugs trying NGK ,S i did notice the ohm reading on the central elctrode was a lot lower 1.40 ish k compared to the bosch 4,8 k I took out.
don,t know if this will make any difference in general running. and cleaned the inside of dizzy cap and rotor too.