Jump to content


Timing Belt Tension


Exhaustgases
 Share

Recommended Posts

I have a 90 that I checked the TB for condition on, and it seems kinda loose to me. Also I checked the same on a 92 it does have a TB that's high time with micro cracks, and it also seemed a bit loose. I'm reaching in at the top with the covers off. So are the tensioners just a spring? What kind of mess will it be if I pull it off? Are the bolts long enough to reinstall it without putting in some kind of lock on the tensioner? How loose do these belts feel normally?

Thanks.

Link to comment
Share on other sites


Then a person better not remove it without having access to that pin hole. I'm guessing these belts can't tighten up too much then, its a pretty long belt. I know some TB's you use a tensioner to first establish the tension, then you lock down the tensioner pulley with its bolt. Are these the same way?

Link to comment
Share on other sites

Bob,

The TB tension is not a spring. It is a hydraulic unit that is under high pressure. It is not a messy job and you can pull it off by loosening the two screws holding it in place. But do NOT attempt to start the engine or turn the crankshaft while the tensioner is removed. This is one time you definitely want to pull the neg. terminal off the battery.

You can then put a new one on if you suspect that yours is bad. The new ones come already compressed. You screw it onto the engine and then pull the pin to release the rod, which applies tension. Or you could put your old one in a vise and try compressing the rod back in. If it is bad, the pin will move easily. If it is good, it will take some pressure to force the rod back in. You push the rod back in to a certain point where there is a hole thru the rod and body of the tensioner that a retaining pin can be place to hold the rod in. Then when you install back on the engine, you pull the pin to release and apply tension.

There is no way that I know of to test the tension of the belt. It is pretty tight even without the tensioner. I do not believe the tensioner would go bad very easily. Unless you see hydraulic fluid leaked down the side of it, I would just leave it alone and sleep easy.

Link to comment
Share on other sites

landar, is the pin on the side of the tensioner? Or hiding under a cover that has to come off? The belt does feel pretty loose, and looks like it has been changed? Hmm what if they forgot the pin? So to sum it up is the pin or pin hole visible from underneath?

Link to comment
Share on other sites


The pin is used only temporarily on a new or re-compressed tensioner to hod the rod in place. The tensioner is visible from underneath but just the bottom part of it, not the rod which presses against the belt tensioner pulley. You have to remove some parts to see it or remove the tensioner itself.

Since pictures are worth many words, here is a pic of a new tensioner with the pin (round handle for pulling after installation) holding the rod in.

And a pic of a 98 LS400 being removed. It is about the same for the 92 since that part of the design has not changed very much.

The last pic shows the tensioner removed and you can clearly see the rod which presses on the pulley to provide tension on the timing belt.

post-41820-0-80541600-1420549473.jpg

post-41820-0-92747200-1420549542_thumb.j

post-41820-0-34984300-1420549609_thumb.j

Link to comment
Share on other sites

Similar to Subaru, it looks like it could be done without the pin, may need some studs and nuts then remove one at a time when close. If it can be seen with out removing stuff and the bolts loosened a bit at least I could see if it was working some what.

Link to comment
Share on other sites

Similar to Subaru, it looks like it could be done without the pin, may need some studs and nuts then remove one at a time when close. If it can be seen with out removing stuff and the bolts loosened a bit at least I could see if it was working some what.

BOB, why do you have to disagree with every thing we SAY, dont you realize how intelligent all of us are?? my brains just light up my hair

(hehehe)

post-5365-0-93651400-1420645210_thumb.jp

Link to comment
Share on other sites

Similar to Subaru, it looks like it could be done without the pin, may need some studs and nuts then remove one at a time when close. If it can be seen with out removing stuff and the bolts loosened a bit at least I could see if it was working some what.

I suppose it could be done that way, but the pressure one needs to compress the tensioner pin is so substantial I'd be concerned about stripping the threads that the mounting bolts go into. Once the tensioner's compressed in a big bench vise or a hydraulic press (I've done it both ways), slide a small (3mm?) hex key in as the manual says to do, re-install (just make darned sure the timing marks are all lined up) then deploy the tensioner by pulling the hex key. I've not heard of a timing belt tensioner going bad on one of these cars.

Best,

Paul

Link to comment
Share on other sites

Billy not disagreeing with anyone. I'm very appreciative to have the info, and sorry to use the "its not my first rodeo" I did industrial engine and transmission mechanics and on all sorts of rolling stock for about 10 plus years and many more as a machinist. I'm just trying to figure out how check things out with out tearing more down than I need to. I've done the fan bearing bracket before on an LS but not the TB. The TB on this one looks fairly new. And just don't want to do the front of that engine, just too many other things to do for now.

I know how nasty the springs or damper fluid can be, hmm similar to hood struts, and that is why using studs would be better than bolts to start something like that, since studs would have full engagement with the mounting holes, after its in position a person could even use a jack to support the tensioner to get the right bolts in. I guess, I don't know what all is in the way, I do need to check and make sure its okay because the belt seems pretty loose, the engine runs fine and sounds good. I have one more to compare to before considering the next move.

Link to comment
Share on other sites


Bob,

Since you have a 92, the engine will not be damaged even if the belt slips, so that is somewhat comforting. Just because you imagine the belt to be loose, you don't have any imperative measurements, like deflection rate with force. The point being that it is all just a perceived issue at this point.

If you can view the belt with the engine running and the belt is not 'flapping' around, then I think you just leave it alone.

If you still want to check the tensioner, you can pull it very easily. However, you need a vice or small press to compress it again. Oh, and you will need a force gauge to measure the pressure required to compress. Otherwise, it is again, just a guess.

Finally, I 'think' I read that someone put the tensioner back on without compressing it by just inserting the screws and drawing it tight (I am thinking it was sha4000 but not sure). But you might as well compress it and put a pin (allen key) in to hold it since you are going to be checking pressure any way. Or just order a new one and put it on for peace of mind.

Link to comment
Share on other sites

Yes that was me landar but I got the ideal from another post somewhere from another person who was having trouble getting the belt on without the cams moving. I loosened the tensioner until it was hanging on by maybe a thread or two, then lined my belt up and carefully tightened the tensioner back while keeping an eye on the belt to make sure things stayed lined up. That was back in May/June. When I started the TB job and took the original tensioner off I realized that the last guy that changed the belt only put 1 bolt back in the tensioner instead of 2 and we re-used the original tensioner as well as everything else. I only purchased the belt the first time.

Link to comment
Share on other sites

Okay I checked the other 90, that TB has 113044 miles on it and pushing on it the same place as the others it is tight like it should be. The other 90 is loose as a goose, so something is not right, though the TB looks real good and fairly new as compared to the others.

So I got 3 that have TB issues, not fun. The 113044 one is not worth doing the TB on until either another engine is up and ready or that one is overhauled, it has oil consumption issues and has very close to 300k on the clock.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share



×
×
  • Create New...

Forums


News


Membership