How to replace timing belt?

davejake

davejake

3 is company too!
OK guys, I'm sure you can point me to a link or cut-n-paste something here. As I am giving my 81 a once over (sat for 20 years) to replace dried out rubber, figured I should put new timing belt as I replace everything else. Midwest sent me a new one.

Any tips and tricks? pictures? Words of caution?

After I sleep off my turkey today, I'm out to the garage to putz!

Jake
 
Some hints

EASY to do with the engine out of the car, but certainly do-able in.

Align the timing mark at the top of the Cam gear with the backplate notch.
Take note of the crank pulley timing mark. Should line up as well with its notch.
Remove the distributor cap and take note of where it's pointing.

Loosen the idler bearing, (I think a 15mm?) remove the belt and replace with a new one.
If you don't accidentally move the cam pulley, simply re-align the distributor to aim to the same place it was before, (this gets you in the ballpark to start your car again later.)
then tighten the nut on the idler bearing while using the spring pressure (only!) of the "snail mount" spring pushing up against the backplate assembly of the idler bearing.
I don't have a picture handy but you'll see these parts when you get there. Do not over-tighten the timing belt! It should be lightly "snug" if that makes any sense. You don't want it flapping loosely OR so tight as to pull tightly against the cam gear.

Once the belt is in place and tightened down, prepare to re-adjust your timing. It usually needs some adjustment. Small arms a must. :wink2:

Hope this helps!
 
As Bob said...

... and if done correctly, there should be NO NEED to readjust the timing. The AUX shaft and the detents on the belt should line back up.

The only reason the timing could be off a bit is if it was adjusted with a severely loose belt prior.

BUT... do recheck the timing anyway. Maybe even BEFORE you remove the belt, just so ya know.

Have fun and Happy Thanksgiving!
 
Also...

The tensioner for the bearing pokes out the side of the snail mount. After you loosen the nut on the bearing, put a pair of vise grips on that tensioner and pull it toward the trunk, then slide an open end wrench between the vise grips and the snail mount to hold it back. It will make it alot easier to get the belt off and back on.

Also, don't be surprised if you drip coolant while the bearing is loose.
 
best way to access?

Am I going to access this through the wheel well? Distributor access panel? Or just top down, bottom up?

I'm guessing it's a good thing I'm a little guy with small arms!

Jake
 
Both, maybe all three

davejake said:
Am I going to access this through the wheel well? Distributor access panel? Or just top down, bottom up?

I'm guessing it's a good thing I'm a little guy with small arms!
Jake
Click to expand...

Mostly from above: belt cover off, smog pump belt off if you have one, alternator/WP belt, timing belt tensioner. Just cut the old timing belt because you're replacing it.

From below: New timing belt over the crank pulley, getting the alternator/WP belt back on its pulley. You might want to replace this belt while you're at it - only a few bucks at the local chain car parts store, and you're taking it off anyways.

My 1974s don't have a distributor access panel, but if they did I'd be using it to reach the distributor.

The first time I did this was thirty years ago, and I was ready to scream with frustration and set the car on fire because I couldn't get the new timing belt to go over the tensioner pulley... not even with the tensioner spring held back as sldsaginaw describes above.... (BTW, don't just count on the wrench to hold it back - tighten the nut down a bit so that if the holding wrench slips out, the tensioner will stay put).

The trick is that once you have the belt on the crank pulley, then you have to pull it TIGHT before you place it around the aux pulley, and then pull TIGHT again before you wrap it around the cam pulley. That way all the slack will be available to sort of twist/slip the edge of the belt over the tensioner. If you don't pull tight you'll end up with one or two too many teeth between crank and cam, and not enough slack to get the belt over the tensioner, and you'll never get the damn thing on.... and a good thing too, because if you did your cam timing would be off. That's why the shop manual says that if the belt doesn't go on easily, check everything again.

This is all way easier than it sounds... One of those things that is hard to explain, but your hands will just feel/know what to do when the time comes.
 
If you do first time ? look for some friend who" do" before to not cry later .Writing is oll possible but not touch if you haven't some "intelligent" help friend .
 
Here's another description of the process for you to peruse: http://www.network54.com/Forum/12159/message/945203222/Tips

Actually, it's not too hard! I had never touched anything mechanical beyond an oil change but I did take a plunge to change the timing belt on my X. I destroyed one tensioner bearing when trying to install a new one and had some difficulty putting the alternator belt back on until I cried for :help:eek:n this site and found out how easy it was! :nod:.

I did not have to remove any pulley but I did pull the distributor for room.
 
Great advice, a little more too

It's correct you want to take out any slop in the belt toward the firewall when you put it on the pulleys.

I've never had a wrench fall out from the vise grip, but it wouldn't be a bad idea to tighten the nut anyway. Then you can remove the wrench/vise grip. If nothing else, the coolant won't be dripping out while you're fighting with the belt. I think I'll do that next time.

One more thing, if you put on a new WP/alternator belt don't be surprised when it appears to be too small. If it's easy to get on then you probably have the wrong belt. Other threads advise getting the belt as far on as possible, then using the starter to pull it the rest of the way on. You can probably do the same thing safer with a socket on the crank pulley bolt. In any case, don't panic because the WP/alternator belt won't slip on easy like most other cars, that is normal.

If you have a car with A/C, that's a whole other monster and you should probably do a search here and on Xweb 1.0 regarding the odd pulley setup with A/C.
 
GOOD ONE Steve...

I remember being SHOCKED when I started leaking coolant about 100 years ago when I last did this! I thought I had really messed up!
 
If you wanna be paranoid about it....

The only thing I would add is when you think you're done, but before buttoning everything up:

A) Rotate the engine 1/2 revolution
B) Loosen the tensioner nut (re-tensioning the belt)
C) Re-torque the tensioner nut

My old mechanic did this and said because you're tensioning a toothed belt at one point only, it's impossible to properly tension the entire belt at once. The teeth prevent the tensioning effects from reaching that portion of the belt that lies opposite the tensioner. He said doing this allowed the "un-tensioned" part of the belt to become properly tensioned. Don't know if he snorted too much Castrol or if it's really necessary but it makes sense and I've always done it...as much out of superstition as anything!
 
Naw... ya missed his point and mine also...

He's definately agreeing with you... from the automotive standpoint I would say. But what he said could affirm what yur Grand-daddy said also!

That's what I found humorous...
 
Hayne's says that too

Let the tensioner tension the belt, tighten up the nut, rotate the crank pulley half a turn clockwise (when you are viewing the crank pulley straight on). DO NOT ROTATE BACKWARDS!. Then loosen the nut on the tensioner pulley and let it tension up the belt again. Re-tighten the nut.
 
Good point flash... and BTW

Flash said:
The only thing I would add is when you think you're done, but before buttoning everything up:

A) Rotate the engine 1/2 revolution
B) Loosen the tensioner nut (re-tensioning the belt)
C) Re-torque the tensioner nut

My old mechanic did this and said because you're tensioning a toothed belt at one point only, it's impossible to properly tension the entire belt at once. The teeth prevent the tensioning effects from reaching that portion of the belt that lies opposite the tensioner. He said doing this allowed the "un-tensioned" part of the belt to become properly tensioned. Don't know if he snorted too much Castrol or if it's really necessary but it makes sense and I've always done it...as much out of superstition as anything!
Click to expand...

Good point flash... and BTW that is part of the procedure in the '74 Fiat shop manual. Oddly, it's not in the later version of the shop manual.
 
Hi your fiend from Macedonia write to not work alone but with company 2 head and 4 eyes is better IF YOU MAKE FIRST TIME !
and company of friend is good for cafe -coke drink talking...
 
This is correct.

I rotate the engine so that the belt makes one revolution. After the belt has come around one revolution, the belt centers itself on all the pulleys and the slack is all on the tensioner side. Let the tensioner take up this slack and your done:dance:
Rolf.
 
Hey Tony..........!!

......you and me and Chris ALL know what Chris's grand-daddy was on about, mate!! :wink2:

Those ol' fellas knew what made young guys "bells" jangle!!!

(And you 'n me are now two of those ol' fellas :shock:)

cheers, Ian - NZ
 
You must log in or register to reply here.
Back
Top