getting to top dead center...

[bigmuthatrucker]

whats best way to know you are at top dead center.. I was just got to aim the rotor to the #1 plug wire other than that I dont know what else to do I want make sure before I do anything else.. this is my first time changing the timing belt on the m20. Any other tipo would be appreiacted as well
cheers
jim

[Reckless_Kelly]

The best way to find EXACT TDC is complicated, but it goes something like this:
Using a degree wheel and a sparkplug hole "stopper" (threaded rod that goes in the plug hole and stops the piston prior to TDC). Mount the degree wheel and a reference point to the crank and block and thread the stopper down the hole. turn the motor to the stop and mark on the degree wheel where the motor stops. Turn the crank the other way until it stops and mark the degree wheel. TDC will be exactly in the middle of the two marks on the degree wheel. Any questions.

I just noticed that you're changing the timing belt, that's a lot easier, line up the marks on the head and make sure that the crank lines up too. (I like to put a dab of white-out on the marks so they are more visible). Then you just loosen thebelt tensioner, remove the belt, install new belt, make sure that the marks still line up, tension the belt, replace all engine covers, and drive. I haven't done an m20 yet, so I don't know if you have to remove the harmonic balancerto get the old belt off or not, if you do have to remove it, loosn the nut with an air gun BEFORE you remove the belt (this eliminates any chance of the pulleys turning independently of each other).

[bigmuthatrucker]

cool thanks .. I dont have an airgun though any other way to loosen that nut with out turning that bolt?

[winfred]

you don't need to remover the 22mm nut to do a belt just the 6 13mm around it, the upper mark is at about 2:00 on the head and the lower is 11:00-12:00 on the crank and you don't need to worry about the 3rd pulley

[bigmuthatrucker]

ok so there are marks to match up so I really cant screw it up then?? what happened to "Super Mario Jeremy"

[winfred]

becareful and double check by giving it atleast 2 full revolutions by hand to make sure the marks line up, i just rebuilt a head on a 325i where the guy thought he could do his belt and got it wrong then started it, bent 7 valves and cost him over a grand by time i was done.
i recomend a new tensioner and a new water pump, seen more then a few tensioners take a dump and toss the belt, and the water pump (any brand but geba they have shitty bearings, hepu is a good one, laso just changed to plastic impellers so i don't about them now) is about 5 extra minutes of work while the belt is off, vs about a hour. i thought it was time for a change on pic's
http://members.cox.net/kitlou/ronmariochicken.jpg


ok so there are marks to match up so I really cant screw it up then?? what happened to "Super Mario Jeremy"

[bigmuthatrucker]

ok thanks bro I'll let you know how it turns out.. One other thing if I give it a couple of turns and it turns smoothly then it is ok to put it back together and fire it up..right??

[winfred]

yes, check the marks after you turn it if they are still lined up it's good to go, you want to turn it over by hand so that if it's off you feel it and stop before doing damage, the crank makes two turn for one turn of the cam that's why you want to do two revolutions


ok thanks bro I'll let you know how it turns out.. One other thing if I give it a couple of turns and it turns smoothly then it is ok to put it back together and fire it up..right??