IMSB - Did I Dodge A Bullet

[Tarek307]

Forget the IMS, my engine just pretty much got destroyed because of the camshaft/lifters

"The piece of cam cover was ejected after the lifter failed and was shot through the cam cover."

i guess this is another very common problem with them...makes me now agree they are POSs , mine had RMS & IMS done before

[thom4782]

Jake - there was oil in the IMS tube.

[Jake Raby]

Originally Posted by thom4782

Jake - there was oil in the IMS tub

e.

Then you were at Stage II bearing failure, at least. Period.

Youch! the groove cut down the side of the key at the highest stress concentration screams, "break me!", and where does the punched out piece from the solid end of the IMS go? Through the new bearing if it's not retrieved. The concept is outstanding, but the execution leaves me cold

Attend my class and you'll learn all about this. See that broken factory oil pump drive key? That cost me 25K back in 2009, I'd never even consider milling a pathway down the edge of one of these units. All that does is create one continuous, longitudinal, stress riser. I also have another pic that I won't post in public, at least not yet.

Punching a hole in the center of the aluminum end plug within the IMS shaft also compromises the press fit of this component. Anyone who has seen mode of failure #8, (where the aluminum plug dislodges and allows the oil pump drive to fall into the IMS tube during operation) would also never consider doing this.

[Smallblock454]

Originally Posted by Tarek307

Forget the IMS, my engine just pretty much got destroyed because of the camshaft/lifters

"The piece of cam cover was ejected after the lifter failed and was shot through the cam cover."

i guess this is another very common problem with them...makes me now agree they are POSs , mine had RMS & IMS done before

This can be caused by a broken slide rail. If the part comes between chain and chain wheel and is big enough and is not crunched the engine housing can burst. In general this is not a common problem with 986/996 engines, but we had this problem over here in germany 2 times.

Earlier 944/968 englines have broken chain rails as a common problem. But maybe it can be a 986/996 problem in the future. The plastic of the slide rails will not last forever and they definetely will get worn.

[Giller]

Originally Posted by Tarek307

Forget the IMS, my engine just pretty much got destroyed because of the camshaft/lifters

"The piece of cam cover was ejected after the lifter failed and was shot through the cam cover."

i guess this is another very common problem with them...makes me now agree they are POSs , mine had RMS & IMS done before

They definitely aren't POSs. The plastic rails will deteriorate over time (like most parts) and need to be checked now and again. Keep an eye out during oil changes - not unlike the ims - but instead of metal, you may see little bits of plastic. If this continues, take a close look at the rails.
But certainly not "a common problem".