CAMSAFT SLIPPAGE

[JAMES ADKINS]

My 1.6 N.A. started making a slight noise and loosing power along with noticably more smoke. Yesterday i checked the timing and the crank and I.P. were spot on but the cam off some. I always time with a feeler gauge under each side of my cam locking plate to make sure it's spot on. As i stated it ran fine until it started that poor running problem. I guess my question is this, can a sprocket slip on the taper fit of the cam shaft even if the bolt was tight? My bolt was tight and it's either that or it skipped a tooth or two. Luckily i don't think i caused any damage as it ran fine when shut down other than lack of power. I will replace timing belt and possibly replace the camshaft sprocket just for good measure as i have one on hand, but i swear i don't see a thing wrong with it. Oh yes the belt on the car looked perfect but a few thousang miles ago i got some diesel on it so maybe it was softened? Let me know what you guy's think.

[Vincent Waldon]

I guess the biggest question would be: what did you torque the cam sprocket bolt to when you last had it apart?

[JAMES ADKINS]

Well sir that may be the problem. I did tighten it with a 1/2" ratchet to what felt like a lot, but i will definately torque it to the proper amount this time. Thanks and that's something i had'nt thought of as i've had (3) of these engines and retimed about 5 or 6 times and never used a torque wrench, but rest assured i will now. Thanks again Vincent.

[Vincent Waldon]

Well, the interesting thing is that the stock torque is a pretty low value... 33 fl-lbs rings a bell. Some folks (myself included) take it up a notch to 45 ft-lbs but it's still not as much as you might expect.

I think the real message is that, like the crank sprocket bolt, the cam sprocket bolt is a good one to do scientifically with a torque wrench... if for no other reason than to eliminate it as a suspect if something goes amiss.

[Quantum-man]

The most important point in my experience, is to make sure the mating tapered joint is clean, dry and matched. Standard torque will then suffice, and joint will not slip.

[hagar]

JAMES ADKINS asked : " can a sprocket slip on the taper fit of the cam shaft even if the bolt was tight? "

answer : YES if the tip of shaft hits the heavy washer. check with "Plastigauge" .

For torque all us Oldies use 45 foot pounds..

hagar.:

[JAMES ADKINS]

Ok i set it at 36# but will up it to 45 if you guy's say thats not going to strip it. By the way she'such happier now.

[Fatmobile]

What are you holding the sprocket with,
while torqueing?

Hope it's not the cam locker, in the slot.

[JAMES ADKINS]

Yes i did use locker plate. I guess by your asking i'm lucky not to have broken the cam slot? Anyways will continue torqueing to 45lbs. and will put tranny in gear for this one. Thanks for some more good advise that i had'nt realized could be a prob. One things for sure after you've owned one of these things awhile you'll either be a better mechanic or die tryin. Later dudes and thanks.

[82vdub]

When I loosen or tighten the cam sprocket, I use the timing belt to hold everything tight. I lock the IP, loosen the cam sprocket, then set TDC for the crank, then install the cam lock plate. I don't knock the cam pully loose from the cam until after all this is set. Installation is reverse - after the timing belt has been adjusted/tensioned/replaced etc, I snug up the cam pully bolt, remove the cam lock plate (IP is still locked) and then tighten the cam pully. Don't have any idea how the Bentley says to do it, but that's how I do it. You won't damage anything by locking the IP and using the belt to hold tension to tighten the cam pully.

[hagar]

J A . said : " I will replace timing belt and possibly replace the camshaft sprocket just for good measure as i have one on hand,"

Here at hagar's we have many spare sprockets , BUT we consider the tapers as a mated pair. Yes we use steel blue and lap in with valve lapping compound if needed. .. As a bonus we make alignment marks on the end of shaft and mark on sprocket.

Then an application of nail slick ,that will show if it ever slipped. (never had one slip here).

Thank you Val Christian he taught me.

hagar.

[VW cat]

I always give the socket a light rap with a small hammer, on any taper, after torquing. Always requires a re-torque, sometimes I do it twice. Phil