Ed Hughes

What am I missing on "adjustable cam sprockets"?

dshepp806

Expound, Sir Rusnak.

Doyle

dshepp806

I think you can look at that parts list and tell we were after whatever we could get to....even if it wasn't leaking!!!!!!!!

No "pair" here to do that either.......that's why I brought to the guys with a pair! !!!!!!!!!!!!!!

Best to you Ice.

rusnak

I figured you guys already saw this.

https://rennlist.com/forums/911-foru...in-wheels.html
Check the link on post #3.

I think they're from JB Racing or some such? In concept they look simple to use, and if proven could take a lot of the worry out of re-timing the cams. I might add that there are empirical ways to check TDC, such as the Stomski Racing TDC finder.

Ed Hughes

Interesting. But then again, once you jump into timing cams, it is pretty straight forward. If I had a racing motor that I tore down a lot, it may be worth the $400 for these sprockets. But for a one time deal or once in a blue moon-timing using stock sprockets ain't that tough.

whalebird

Shepp, How's it coming? Any developments? I looked at the list you posted and I think it looks plausible. The discussion here concerning cam-timing can be a little murky, but I would not think that is a problem. You know the doctor's analogy...if you hear hoofbeats, don't look for zebras. Your guy's just disassembled the one side, resealed the chain-box, and set it back up to where it was upon disassembly. This, with the flywheel locked. It's a normal procedure. Now changing the cam timing (left and right) requires retiming both banks. But, they didn't "change" the cam timing, they just retimed the offending bank back to where it was. I suspect, based on the info you posted, that they may have worded it on the invoice in a way that has raised a bit of concern here. Your posting reads like a repair invoice and every step is listed, which is a bit of an art in a shop. A shop has to list everything that can have a labor charge associated with it. The cam timing vernacular used could have been worded a hundred different ways, but they just put it back where it was for that side.
I like this thread...lots of PPI's going on elsewhere on Rennlist. Everybody thinking about owning a 911 should read this thread.

All my best
Scott

dshepp806

Nope,..was told they retimed the cams (that would mean both sides, no?) Unless, of course, I misunderstood........

Not sure about "putting it were it was",..as I would assume you'd time the cams with a procedural effort, aside from wherever it was, no? Am I missing something here? I ask this quite honestly...

I mean, isn't there a difference between "retiming the cams" vs; "putting it back to where it was"? What if "where it was" was not right to begin with? Isn't there a right or wrong here? (or better: correct vs. incorrect?) .

I'll have to doublecheck with the wrench on this notion....

As always, Whalebird,..appreciate the input !!!!!!!!!!

My best,

Doyle

dshepp806

In fact, he mentioned the tediousness of checking, double-checking,..triple checking the procedure...a bit time consuming to ensure you're ON with the adjustment.....

Doyle

whalebird

You're right Shepp. I cought up on this thread this morning and am just getting around to replying (long day). So yes, what you are putting forth is right on. If they did, in fact, retime the cams(plural) then that is one thing and would require the removal of the right(passenger)side chain box cover. If the driver's side cam was disassembled as discussed, it would have to be put back where it was. If it were wrong upon disassembly, then the only action would be to set up both cams. "wrong" is a moving target here. 911 Cams can be adjusted infinitly for different performance. In any case they have to be set evenly, both sides. I may be stating the obvious here, I think you have a good grasp of whats going on. So, is she running better? have the lumpy idle symptoms changed at all? I hope your feeling ok with the neck stuff you have going on.

whalebird

It is time consuming...you don't want it to be off. There are different methods for getting it on, they all involve several micrometers and copius engine turning. But, no magic if you know what I mean.

dshepp806

Thanks for the reply....Whalebird. Trust me,..YOU guys have it down better than I do. I just read and try to learn more. The statement about both sides requiring a matching is intriguing.......I'll have to check with the wrench about the other side.......as you stated, they must "match".......geeze,..you've opened up another vein of assessment for me........

The idle is still lumpy (if you ask me)....haven't had a chance yet to R/R and clean the ICV. As stated, she's due back in shortly for the followup........I will do this BEFORE the followup....as well as take a look at the idle setting.

She's revving (seemingly) VERY easily........and smooth....much more power.

As always, I continue to welcome all of you guys' inputs.

Bird: you wrench for a living? Sure sounds like it...............

My best to you (your fellow RUSH FAN!),

Doyle

whalebird

The cams can be set "advanced" - both cams (evenly) ahead of the crank or TDC, or retarded behind the crank TDC. I am still not sure that this has any forbearance on your loopey idle, but very worthy of discussion regardless. If the IACV is "dirty" or slow to react, Turn on the A/C, see how prompt the engine is in correcting for the added load of the compressor. This may give you an idea...you know a kinda field test. I am "retired" after 23 years Porsche and Benz (factory trained) tech with a strong focus on motorsports and restoration of older, air cooled Porsche. My wife and I sort-of dropped our lives to continue a family business, a really cool one at that. I get my Porsche fix, which has been such a major part of my life, here on Rennlist (as well as in my shop in my spare time).

rusnak

Well, a well recognized Porsche shop just closed here in Fresno, and the owner took a job maintaining classic cars for some collection.

An enterprising wrench might look at that as an opportunity.

Ed Hughes

That would be a cool gig though-steady income, playing with cars and someone else footing the bill.

dshepp806

Thanks for the info, Bird. I figured you were a P-wrench...the info's too good.

!!!!!!!!!!!!!!!!!!!!!!!!!!!

Best,

Doyle