PDA

View Full Version : new problem with t-belt


davericher20
06-24-2009, 12:40 AM
so got the new timing belt on with the help of jays325is but there was too much slack on the right side....from the power steering side to the crankshaft.....if that makes sense.

there's alot of tension from the bottom of the crankshaft to the tensioner, but too much slack on the other side........need the slack to be on the other side where the tensioner is.

When we started (before the removal) the lines didn't match up perfectly even after like 5 revolutions we did it, but said f-it because they weren't gonna match up. it looks like we need 1 more tooth somewhere and it will give us what we need.........

need alot of help. I want this done and over with.

anyone?

juzer
06-24-2009, 01:47 AM
take it out and do it again, untill it match . what kind of belt you got, conti?

juzer
06-24-2009, 01:51 AM
This may help if you dont allready have it:

http://www.pelicanparts.com/bmw/techarticles/101-Projects-20-E30-Timing-Belt/101-Projects-20-E30-Timing-Belt.htm

Ceeker
06-24-2009, 07:15 AM
Timing marks should line up no matter what. it recommends that you rotate the crankshaft 2 complete revolutions to make sure you have true top dead center on cyl 1. Then rotate the cam shaft to match the timing mark on the crank. I had the same problem with the timing belt. You may have put the timing belt around the wrong side this is why it was taught at one end and loose on the other. Hard to explain but the diagrams provided by the previous gentleman should show clearly how the belt loops. Also make sure you have the tensioner adjusted correctly. You should be able to turn the belt approx 90 degrees to either side once everything is set. Don't over tighten or your likely to prematurely wear it out and you'll get a whining noise from it telling you it's too tight. if I find anything on it I'll add the link.

http://www.angelfire.com/blues2/bimmer/maint/tbelt/timingbelt.html

Check here to see if this helps.

supernaught
06-24-2009, 08:31 AM
the links are pretty thorough, but to answer the slack question more directly, you will need to put your 22mm wrench or socket on the crank and carefully rotate it CCW until the slack appears on the tensioner side. But you should only be doing this in order to re-line up the timing marks(move the belt a couple teeth on the cam pulley).

e30jones
06-24-2009, 06:50 PM
Did you count the number of teeth on your old belt and new belt to make sure they are identical? IIRC, there are two different ones, some have one more tooth than the others.

BmW1819
06-24-2009, 08:07 PM
send me a pm

Ceeker
06-24-2009, 08:57 PM
If you got the correct belt which there is only one for the M20 then it should fit.
it's next to impossible to fit a shorter belt on even 1 tooth off. it's a very very tight fit to get it on. Even if you a belt with one extra tooth shouldn't matter this is why we have the belt tensioner. once the belt is on - you should rotate the crankshaft two complete revolutions to make sure the marks line up. Otherwise you may have put the belt on but with a tooth off. that could happen. shorter or longer belt? no difference.

Red_Rocket
06-24-2009, 09:50 PM
Start at the crank and route the belt around counter clockwise (the side without the tensioner) and the teeth might be off a hair but as long as it doesnt get any worse u should be good. I think my car got a bit more power because my timing was advanced a hair by doing my timing belt.

echo
06-25-2009, 01:29 AM
Do more or less what all of the above people say.

In summary:

1/ There are 2 belts - a 126-tooth, and a 127-tooth. I'm pretty sure you can't buy the 126 anymore.

2/ It's good practive to change the tensioner for a new one when you do the belt. The new tensioner should have 127 stamped into it, and is the correct tensioner for the 127-tooth belt.

3/ Line the marks up with the belt off, but don't turn either the crank or the cam more than necessary to line them up - otherwise you can be a full turn out which would be catastrophic.

4/ As stated, tuck the belt under neath the crank first, and get it sitting on the teeth, then holding it in place pull it up and over the cam gear at the correct tension. it sounds as though at the moment you are at least a tooth out. then with the tensioner pushed back as far as it goes (ie loosened) and it's lock nut tightened to hold it there, thread the belt past the tensioner.
Everything should now be in place.

5/ Now loosen the lock nut on the tensioner and let it spring into place on its own. Rotate the crank by hand through two full revolutions and check the timeing marks. They should be exact. If you are a tooth out your can will run like a sack of shit. More than a tooth or two can cause damage from the valves hitting the pistons so DO NOT LEAVE IT LIKE THIS!

6/ now the belt is correctly fitted and the marks line up, tighten the lock nut on the tensioner. Do not push the tensioner in further - it is self adjusting. You should not manually set the tension. Tighten the pivot bolt on the tensioner.

7/ double check the timing marks are lined up and reassemble the distributor and covers etc.

Done.

davericher20
06-30-2009, 07:22 PM
k, went on e30tech and I followed a dudes advice word for word and it worked.
move the crank pulley 1/4" before the mark, set the belt on the cam, move the crank back to the line, and that did it.

except when I went to turn it (I wanted to do a couple cycles just for fun) it gave me a little resistance about 2-3 inches into the turn............I'm paranoid now, all the lines match up and everything but.........paranoia.

should I just crank it? or be worried?

supernaught
06-30-2009, 07:32 PM
it will be tight in some spots as the cam pushes on different combinations of valves. But make sure you turn it by hand. Do not use the starter until you know everything is clear.
Also, if you want to make it easier to turn, pull out the spark plugs, then you won't be fighting compression. Thats probably all it is.

davericher20
06-30-2009, 07:35 PM
spark plugs are out,

turn it by hand? that seems hard to do, I've been using the socket wrench the whole time........

supernaught
06-30-2009, 07:40 PM
haha, ya, well thats what i mean
rock it back CCW a bit, the CW again and try to feel if its hitting solid or just a bit tough.

davericher20
06-30-2009, 07:49 PM
If it is off would I have enough strength to bend valves if they were hitting?

davericher20
06-30-2009, 09:33 PM
ok, it cranks fine, I was paranoid. The lines match up and that bitch is duuuunnnnn!!!!!!!!

thanks guys