: Help with Timing Chain Removal



Lawrence
02-27-04, 07:22 PM
1994 STS

I have the engine on a stand, valve covers and timing cover off.

Can someone teel me how to loosen/disconnect the timing chains so that I can remove the heads.

I know, I know, service manual. I am waiting on it by mail and was just hoping to get started early.

Thanks Much!
Lawrence

growe3
02-27-04, 08:58 PM
How I did it:

Remove the four large plastic access covers in the front of the heads.

Remove the cam chain tensioners.

Remove the plastic chain guides, CAREFULLY. You will need to just wiggle them around to figure it out.

The chains will now be slack.

I then used a large Crescent wrench to carefully rotate a cam sprocket, while pulling the chain to the edge and rolling it off.

The chains can then just be left in the front cover, no need to remove further.

Do not break the heads down any further than necessary, i.e., do not remove the cams.

When removing the heads have an area cleared, to set them on their side or upside down, so you will not damage any valves. Some valves will be open and can very easily be bent and or get debris trapped under them causing burnt valves later.

-George

BeelzeBob
02-27-04, 10:23 PM
How I did it:

Remove the four large plastic access covers in the front of the heads.

Remove the cam chain tensioners.

Remove the plastic chain guides, CAREFULLY. You will need to just wiggle them around to figure it out.

The chains will now be slack.

I then used a large Crescent wrench to carefully rotate a cam sprocket, while pulling the chain to the edge and rolling it off.

The chains can then just be left in the front cover, no need to remove further.

Do not break the heads down any further than necessary, i.e., do not remove the cams.

When removing the heads have an area cleared, to set them on their side or upside down, so you will not damage any valves. Some valves will be open and can very easily be bent and or get debris trapped under them causing burnt valves later.

-George

George, just to clearify, did you have the front cover off when you pulled the chains off?? I would say that you would have to remove the damper with a puller and then take the front cover off before removing the tensioners and guides to remove the chains.

If you are just in a hurry to get the chains off to get the heads off you can just remove the bolts holding the sprockets onto the cams and slide the sprockets off. You cannot get enough chain slack to get them off any other way anyway so just slip the sprocket off the cam and let the chain fall into the chain cavity. You will have to remove the front cover anyway to retime everything to nothing will be hurt or lost doing this. Just don't trry to turn the engine over with the chains laying loose as they will jam and break something.

I would recommend removing the damper/front cover so that the tensioners and guides can be removed and then the chains can be removed by loosening the sprockets and sliding them off the cams. Remove the chains completely and then the engine can be turned over as much as you want...once the heads are removed. Don't turn the engine over with the heads on and the chains off or you WILL bend valves.

When you are ready to reassemble it is much easier to set the engine at TDC and line up the timing marks on the intermediate sprocket/crank sprocket. Set the cams in the proper TDC timed position on the heads before installing the heads so that the chains can be installed correctly without turning the engine over or the cams in the heads. This will avoid bending any valves or any other problems.

growe3
02-28-04, 12:19 AM
Yes, the timing cover was off, as Lawrence had noted.

With the tensioners and plastic guides removed they slipped off without any problem. I didn't want to remove the cam sprockets if it was avoidable.


Side note:
I have ordered the Arnott replacement struts (4) for my 93' STS. :)

They should be here by 3-5-04. I hope they work as well as indicated.

-George

Lawrence
02-28-04, 12:33 AM
Thanks Growe3 and bbobynski........ I thought perhaps there was something real slick like bleeding off the tensioners and backing them up. Oh well. I think I've got it now though. The tensioners and guides, must come off? And the cam shaft sprockets?

zonie77
02-28-04, 01:38 AM
Once you take the tensioners and guides off you do not have to take off the cam sprockets.

Lawrence
02-28-04, 10:51 AM
Growe3....... These are the passive struts I'm sure. Do you know how you will disable the computer? I'll be watching closely. Mine have the same problem, I suppose, clunk clunk.

Lawrence
02-28-04, 11:00 AM
Growe3......Scratch that. I just checked their website from a link in one of your old posts. Very, very cool! They do all the work for you. All that remains is to see how they ride. For that matter I don't even care how it rides. Anything is better than that damn clunking up there. Please let us know when you get them on.

BeelzeBob
02-28-04, 08:13 PM
Growe3......Scratch that. I just checked their website from a link in one of your old posts. Very, very cool! They do all the work for you. All that remains is to see how they ride. For that matter I don't even care how it rides. Anything is better than that damn clunking up there. Please let us know when you get them on.

You are going to have to reset the tensioners regardless so just take them off the block. They are oil pressure actuated and have an internal mechanical rachet to hold them in position when the engine is off. You will see a little link, like a chain link, on the tensioner that, properly positioned, will allow you to depress the plunger completely. By holding the tensioner plunger depressed fully and wiggling the link you can position it so that it locks the plunger fully retracted.... Stick a golf tee in the hole in the link to lock it there until you get the engine reassembled...then just pull the golf tee like a grenade pin and the tensioner mechanical rachet will zip out and lock it into place. Once the tensioners extend they will not retract unless you go thru this. It is very easy once you get the hang of it.

I find that it is much easier to manipulate the chains for dissassembly/reassembly if the cam sprockets are removed..but I suppose it is possible to not take them off. They are pinned in place so there is no timing measurement or anything to do to reinstall all the chains and stuff....just line up the marks and reassemble.



I think that the Arnott struts come with a high wattage ballast resistor to fool the ride computer from setting codes with the passive struts. That is how to do it on a 93 anyway... The 94 can have the RSS message disabled in the IPC with one of the option messages using the onboard diagnostics.



Clunking from the front end...??? Usually not struts. Most commonly the stab bar bushings and end link isolators. Replace them even if they look good. Those are highly stressed elastomeric isolators and give out and loose the ability to isolate the stab bar with time and miles. Replace the stab bar bushings and isolators. Usually struts will cause codes and/or poor ride as the damping ability fades with miles...but actual clunking from the struts is not too common. It happens...but more often it is the stab bar.

Lawrence
02-28-04, 10:49 PM
bbobynski........Thanks for the tips. And I'll be sure to give those isolators a closer look. I looked at them and they looked good, so I assumed. I'll pull them. It would sure be nice, especially since the head gasket thing, not to need the struts as the car rides fine and there are no error codes.

Good Day to You!