TDC on an M20/6

[AndyBaur]

I'm trying to find the definitive TDC (i.e. using timing marks rather than 'rocking valves') without removing the top belt cover.

Searches on the net always come up with the injected engines which means the 22mm ring spanner on the crank isn't possible. I have a 1/2 inch drive in the top pulley but I can't find any marks to line up.

Is it just a 10mm & 13mm bolt holding the top cover on?

[jimbob]

Yes its just the two bolts holding the top piece of the timing cover on just had a look on my spare in the shed

[AndyBaur]

Cheers, guess I'll just remove the cover & find tdc that way.

[Duracel79]

It should also be pinched by the alternator mounting lower down.

Also you really should find TDC by turning the crank clockwise from the front. This keeps the tension in the cambelt.
If you can't get a socket on the crank nose then you could try the car in gear (4th?) and rock the whole car forwards (so the engine turns the correct way).
All this is a lot easier with the spark plugs removed as well.

Marks to line up for the camshaft are a dot on the cam sprocket with a line in the head face about 2 to 3 'o' clock.
For the crank there is a line mark towards the inside of the crank damper with a line on the lower timing cover about 1 to 2 'o' clock.

Hope this helps.

Ben

[Jeroen]

Yup, but the alternator pin at the bottom usually is not causing issues. Just make sure when reinstalling that the rubber dust flap is in place correctly or it might rub timing parts or even get in the way!

AFAIK you can turn the crank with a 27mm socket. Turn clockwise with car in neutral en spark plugs removed. I wouldn't turn the cam using the connection at the cam pulley, have the crank drive things.

Cam timing marks see below. Please note the pic is from an E30 Motronic M20 so the pulley is different, the timing marks are similar.

[AndyBaur]

All the guides (which are for E30 versions) say a 22mm ring spanner or socket. ihave the plugs out & it turns ok via the cam. I agree the crank would be better thogh not as accessable.

I'll see if I can find a 27mm socket.

[AndyBaur]

Well I managed by just using a 1/2" drive in the cam sprocket. Despite the special purchase of a 27mm socket I couldn't reach the ratchet to turn the crank.

I've marked the inside of the top cover & cam pulley so I know where tdc is in future.

The rubber cover is a right swine. I messed on for ages & was considering posting here for advice on the knack for fitting it when it just popped on. The engine is much quieter now but there is still some tappet noise.

Spent some time with a Gunson Colour Tune fiddling with the carb. It's now running much much better (& richer!).

I keep having the nagging feeling that converting to a later M20 with Bosch injection would be far preferable (especially if it's a 2.5) than messing on with 20th century technology. AFAIK it's still the original motor with a Weber (DGV?) carb - now with 140k miles on the clock.

The gearbox is a little slow too - it does not appreciate speedy gear changing. I have a new kit of bushes + a Z3 lever to freshen up the change but I think the synchos are getting a bit worn.

Has anyone investigated converting a later E30 box to use the E21's speedo drive? This might be cheaper than rebuilding the E21's box.