IMS cover seal replacement.

[DeanP]

Hi i recently bought a 1997 boxster with issues .
One of the issues was a leaky IMS cover . I mistakingly thought i could take the cover off and replace the seals and put it back on. I have since read about the locking of the cams and rotation to TDC.
My question is , Is this neccessary if i am not removing the bearings ?
Obviously the whole assembly is resting off ctr now , which is common anyway i understand.
Can i just release tension on the chain tensioners a couple of turns and refit the cover again.
Cheers for your comments .

DP

[JFP in PA]

Originally Posted by DeanP

Hi i recently bought a 1997 boxster with issues .
One of the issues was a leaky IMS cover . I mistakingly thought i could take the cover off and replace the seals and put it back on. I have since read about the locking of the cams and rotation to TDC.
My question is , Is this neccessary if i am not removing the bearings ?
Obviously the whole assembly is resting off ctr now , which is common anyway i understand.
Can i just release tension on the chain tensioners a couple of turns and refit the cover again.
Cheers for your comments .

DP

You may already be in trouble. Anytime the IMS flange cover is removed, the engine has to be rotated to TDC and locked in place; then on your engine because it is a five chain version, you needed to lock the exhaust cam on the passenger's side before removing the shaft tensioners and the flange cover. If this had been done, the shaft would have remained centered. As yours is now off center, the engine may or may not have jumped time.

You can try totally removing the three accessible tensioners to see if the shaft re-centers itself, but even if it does and you get the cover back on, you need to check the cam positions before starting or even rotating the engine,

Good luck..................

[Jamesp]

If you heard a ripping metallic snap from the engine as you took off your IMS cover, that was the engine losing timing, and that's bad, meaning a lot of work. The valve springs are trying to rotate the camshafts if the engine is not set to zero timing. When the timing chains get loose, the cams can rotate their sprockets under the chains making that terrible noise and you've lost valve timing (ask me how I know).

If the engine has not made that terrible noise I'd go with your plan of loosening the tensioners a little and trying to get the cover back on. Once the cover is back on, tighten the tensioners then rotate to zero timing. If your going to mess with the IMS bearing it's best to lock the camshafts and the crankshaft, just remember to remove the locks before rotatiing the engine. The engine "locks" are really just rotation stops, you don't want to use them to resist you trying to turn the engine over, they can break.

+1 on what JFP said, you'll want to check, and possibly adjust your valve timing after this little adventure as well.

[Jamesp]

One other item, don't decide to just pop off the valve covers, you can break your camshafts.

Crazy as it sounds the valve covers are half valve cover/half camshaft journal. The valve covers hold only the end of the camshaft opposite the chain sprocket down. You need a special tool to hold that end of the camshaft down while you take off the valve cover or the valve springs will try to snap the camshaft in two.

There are additional bearing journals under the valve cover that are not part of the valve cover that hold the chain driven end of the camshaft to the head. If you remove the valve cover without the special tool holding the "free end" of the camshaft against the valve springs tension, they will try to snap the camshaft in two.

This engine can be a bit of a minefield to work on.

[DeanP]

Thanks guys.
I didnt hear any strange noises when i took it off. It was a little tough though . What a mess up!

DP

[JFP in PA]

Originally Posted by DeanP

What a mess up!

DP

You are not the first, and I am sure you won't be the last..............