moonbase1

I got a code 52 on my 91 3.0 runner so I’m replacing the knock sensor and wire. Before I did anything, I made marks on both upper gears and corresponding marks on the belt. However, i forgot to mark the lower gear.

I proceeded to take the tensioner pulley off, but didn’t rotate everything to top dead center. I didn’t realize the valve gears would be pre-tensioned, and they rotated away from the marks on the belt. As it sits, I don’t think the belt moved from the position it was on the lower gear, but I’m not sure.

I’m wondering if there’s a reset point where I can turn all 3 gears to line everything up correctly. If not, I’ll just trust that the belt hasn’t moved on the lower gear and line things up on the top using the marks I made on the belt and gears?

Any thoughts???

Thanks for any help you can offer!!

24Runna

Don't worry about the marks on the belt. They literally mean nothing and just confuse people. Make sure Cyl. No. 1 is at compression, and the cams are lined up. Then pull the belt as tight as you can to the right, rotate the right cam (drivers side) slightly to the right, put the belt on, release. Go under the idler pulley pull as hard as you can, rotate the cam slightly to the right, put belt on. The goal is to put all the slack where the tensioner is.

Ok I just reread your post. First rotate the crank to No. 1 Compression. If the cams line up after 3 or 4 revolutions you're fine. If they don't remove the tensioner, and reset the timing belt like I said above. Please just don't trust that nothing has moved better safe than sorry.

moonbase1

I'm a bit confused, but i'll try that out. If i understand right, the 3.0 is a non interference engine so the worst that could happen is i'd have to try again if it runs crappy.

On that note, can i get a good enough test of the engine running properly without installing the belt cover, radiator, fan belts and such? Lots of work just to take it off again and adjust the belt..........

putneysmachine

If you look at the lower (crankshaft timing gear) there is a mark on it that will line up with a mark on the oil pump (the aluminum piece behind the gear), that is TDC for the crank. Like 24Runna said, ignore ANY marks on the belt. There are also timing marks on BOTH cam pulleys too. Make sure all 3 line up with the belt installed.

I wouldn't recommend starting it without the lower cover / front pulley installed. the belt can walk off of the lower pulley and make things un-fun.

Check one of the online manuals for proper timing marks for all pullies (just do a search, they are easy to find)

OutlawMike

If the marks all line up after three rotations, you won't be back in there to adjust it. Just make sure that the marks on each cam pulley and the mark on the lower pulley line up with their reference marks, and you are good to go.

You don't even really have to worry about which top dead center the piston is at, since, the valves dictate compression and exhaust strokes, not the crankshaft. With the belt removed, you just need to make sure the lower pulley is pointing to the reference mark, then, that is a done deal. The cam pulleys will try to move on you, due to forces on the cam lobes from the valve springs. Putting the belt back on is a two person job, best case, so that the other guy can make sure the cam pulleys do not move.

Lots of posts on the aboard to reference.

Good luck.

moonbase1

Thanks for the advice everyone! So i understand:
1. align the lower timing pulley with the reference mark
2. Align both cam pulleys with their reference marks
3. Have a beer buddy hold both cam pulleys in place on their marks (yellow dots..... from the factory i'm assuming)
4. install the timing belt so all the slack is on the tensioner side
5. install spring, and allow it to tension the belt

Do i let the belt get only as tight as the spring makes it before i tighten the bolt in the center?? That seems lika alot of slack..... how do i know when the belt is tight enough?

Thanks again!!

24Runna

ALL the slack needs to be where the tensioner is. There can't be any slack anywhere else, otherwise you'll skip a tooth somewhere and it won't line up.

eugenedbrooksiii

I just completed my belt change for the fourth time this weekend,
practice makes perfect...

You have 1 and 2 right. With the crank on its mark, install the belt around the crank. Then have a friend hold the passengers side of the belt tight while you route the belt around the water pump and then around the drivers side cam sprocket. The cams stay on their marks in my truck, but you can use a wrench to rotate the cam into place as you fit the belt. Route it under the idler pulley on the water outlet and then around the other cam sprocket, again with the marks lined up and no slack in the belt. Once done, have your friend hold the slack in while you install the idler, taking up most of the slack, tightening the bolt just snugly. After this, install the spring. Once you install the spring you can loosen the bolt that holds the idler in place to allow the spring to establish tension on it. Once this is done, rotate the crank at least two turns in the direction of engine rotation to allow the belt to settle into its proper place on all of the pulleys. I do four turns... Finally, apply tension on the wrench that you have been turning the crank with while you tighten the tension pulley where the spring is. This is to make sure that the belt is tight everywhere except the slack side where the tensioner is. When you do this you want to be at a place in the rotation where the cams are also doing their part to tension the tight side of the belt, pulling the slack through to the tensioner. Be sure to use a torque wrench on the tensioner pulley bolt to bring it to proper torque after snugging it down while tensioning the belt via the crank bolt. This bolt stretches a bit as you tighten it and you want to get the stretch just right. You can bump the tensioner a little with your hand to make sure the spring is pulling the tensioner in properly just before you tighten it, but the spring (in good condition) establishes the tension. Before you do all of this, make sure that the spring is in good condition. Its coils should be tight against each other while it is out of the engine. If they are not, replace the spring with a new one. After you are done, rotate the crank to confirm that the marks on the cam and crank sprockets line up at the same time. If you are off by one tooth somewhere it will be easy to see.

moonbase1

I finally finished the knock sensor repair! What a PITA! There was something weird that happened when I put the timing belt back on:

I aligned both cam pulleys and the crank pulley to top dead center, and installed the belt, and noticed the marks I put on the belt before I started are one tooth off from the marks I put on the cam pulleys!?!? It runs fine, so I’m sure it’s lined up correctly, but it makes me wonder why I didn’t run like crap before!

Any ideas???

There was a lot of slack on the non-tensioner side of the belt, probably from the mec who did the belt change, and didn’t install it properly.

I also had to re-do the timing, it was set around 20 deg BTDC!! I had to adjust the distributor cap from wayyyy right of the center mark, to slightly left of the center mark to get the required 10 deg BTDC.

Like I said, it runs great now, and seems to have more power in the low end than it did before!! Maybe that’s all in my head though

Thanks everyone for all your help!!

94-4-NUBORN

I don't mean to hijack, but I am doing the same thing.... but my timing belt broke... actually the tensioner or spring did, I haven't taken off the lower cover yet. But will as soon as I have the answer to this question.
The crankshaft and driver side cam are lined up the the match marks, but the passenger's side cam is not.
This might be a stupid question, but can I turn just that one cam to the match mark? Or do I have a much bigger problem?
Thanks in advance.

moonbase1

From what i understand, yes you can. You'll have to hold it in place though...... the springs on the cams try to move it away from TDC.

OutlawMike

Yes, just rotate it over to the mark. Once the belt is removed the crank and two camshafts are completely independant of eachother, you can rotate them with no issue. The trick is getting those cam sprockets to stay lined up with their mark, as they like to move on their own due to the valve springs. An extra pair of hands is almost a must.

Good luck.

94-4-NUBORN

thank you very much fellas... I'll let you know how it turns out.

MJ

818 AV8R

i just did my timing belt and didnt have any trouble with the cams trying to move on their own...infact they seemed hard to turn....???? 95 V6 3.slow 4x4 5 speed