Shimmed my cam sensor last night

[VadersV6]

There wasnt any free slop in it, but there was alot of movement that was kept under tension by the wave spring. The shaft would move like 1/8 inch up and down. Someone had already shimmed it before with the wrong shim (I.D. too big), but it was the same thickness as the Delco shims I have. I pulled that one out, and ended up with 2 of the right shims. Now there is only about .020" of movement in it, but its under so much spring pressure from that wave spring, thats its hard to move. I didnt have any issues lining up the oil pump drive shaft. The biggest PITA was getting the lock screw back in. My engine is way quieter now. All that noise that was coming from my oil pump area...well most of it, is gone. Now I have a bunch of other noises I have to track down. There is some loud buzzing like rattle that happens at about 2000rpm when Im driving. Doesnt happen in Park.
First off, you dont need a voltmeter or special tool to set the cam sensor. GM designed it with alignment marks that line up when you have the motor at 25* ATDC. This is a little trick that Lou Czarnota showed me.
Another problem was, that there is lot of rotational slop in the cam sensor ring. Neither drive gear is worn out, so thats not it. I think its just a basic alignment issue when the hole was bored on the block. Removing the up and down movement with shims reduces this rotational play some. I can see why advancing the cam sensor helps alot of people overcome stumbling problems. When the engine is shut off, the window in the ring isnt in the same place as it is when things are more dynamic, and the engine is running....because of all this rotational slop Im assuming.
Bottom line, my engine doesnt sound like its about to blow up anymore. I cant believe what a simple cam sensor can do.

 

[pacecarta]

i shimmed mine before these new sensors surfaced
through GM the sensor is over 200 but that sensor can be had new , standard parts # pc 16 , its a brand new gm part with gm apart# (not a repop or a rebuilt) in a standard motors box and its the complete sensor and best news is its around 45.00 retail


as to dropping it in and not having to set it , i know the marks are there thats for general positioning for consistant wire locations , you still need to set it .

 

[VadersV6]

Wow, 45 bucks is very reasonable!
All i know is, before I pulled it out, I set the engine to 25ATDC, and took the cap off the sensor. The marks lined up perfectly. I dropped it back in and adjusted it the same way, and the car fired right up and ran great. Like they say, the cam sensor doesnt have to be set perfectly. Either it will run in batch fuel mode, or it wont. It would be interesting though, to stick a voltmeter on there and see how close it really is.

 

[pacecarta]

biggest problems with the cam sensor is most dont understand TDC they just set it at 25A the timing mark with no regard for TDC which has a 50/50 chance of putting the sensor in 180 degrees out , and even if you set it with the meter or easier with the casper tool youll think all is good , but it will be wrong and run in batch mode.

as long as its on the #1 compression stoke 25A and you point the dot on the gear toward the passenger fender which puts the window toward the alternator parallel with the engine , it will be close and the wires fro the cap will be toward the alternator once its put back

the whole procedure with pics is at
http://www.vortexbuicks-etc.com/

 

[VadersV6]

Well, I put it to TDC on the compression stroke, then 25 degrees after. After all was said and done, the window on the ring was pointing toward the alternator, while the little black marker, 180 degrees around from the window, was pointing directly at the mark on the cam sensor housing, which is obviously pointing 180 degrees opposite of the alternator. The hall sensor wires were also pointing toward the alternator.
Did i get it right? I would definetely not want to be in batch fueling mode.

 

[VadersV6]

This is what it says on the site-"Top view of drive assembly. The wheel must be pinned into place so that it cannot rotate versus the drive gear. If the wheel moves, it will screw up the fuel timing and the car may not start, or, it will run very badly."

Thing is, the wheel/shaft assembly does rotate back and forth maybe 3/32", as if there is too much play between the drive gears. The wear marks on the cam sensor gear look fine though.
When everyone refers to "the window", are they referring to the window on the vertical part of the wheel, or the little mark 180 degrees opposite on the horizontal part of the wheel?
I have some off idle stumbling that I cleared up once by turning the sensor a little clockwise. I need to try that again. It doesnt always work. There seems to be a sweet spot that can only be found by playing with it.
Off Topic note- I hooked my wastegate line back up to the factory wastegate solenoid. I cant believe what a dog it is compared to my pressure regulator. The spoolup is aweful. As far as I can tell, I do have it hooked up right.

 

[pacecarta]

yep thats right , now set it , you will be very close but it only takes a little more time to check it with a meter or the caspers tool .
i marked all points before yanking mine so i knew it went in as it came out but the chain can stretch and the gears wear (i replaced the timing chain ) so it should be set
with the key out , rotate the crank backwards about an inch then bring it back clockwise to the 25ATDC mark to eliminate the slack in the chain
then set the cam sensor

one thing i noticed when i shimmed mine was the roll pin fell apart (cracked right down the center from end to end) , I had to put a new one in. glad i caught that because it wouldnt have lasted long with that pin . as it was my nylon timing gear was just getting ready to become a multi peice unit , dodged two that day

 

[pacecarta]

that info on there about pinning is for the metal window plate where it is attached to the top of the shaft ,theres just a screw and a tab in a notch , if that scew comes loose it can wear out that retainer tab and it wont stay in line with where you had set it , the shaft will spin but the window plate will be out of position and cause poblems , lots have had that problem for something that simple and its not the easist to catch unless you know to look because it will usually move enough pass the visual test

 

[VadersV6]

I checked the screw to make sure the wheel was on tight, and it was. That little slot 180 off from the window is there for locating? I dont recall it locating anything.
Im really glad you mentioned the slack in the chain. I didnt even think of that. Before I got started, I rotated to 25 ATDC, but I went a little too far, and then went CClockwise till I got to my mark. Odds are Im out of adjustment cause of this.
Thanks!

 

[Lee Thompson]

pacecarta

I like the way you post your replys. I can understand what you are saying. Some post ---I don/t have a clue as to what people are trying to say or ask. Its as if they skipped ENGISH class. I would like more info on this new sensor and where to get one. Is this a complete sensor and is it a better design than the original? Thank you for your time.

 

[pacecarta]

thanks lee ,
i used to field questions on the second gen TAs . sometimes it seems i step off subject with all the brackets and run ons and i tend to bracket out a lot of things to clarify or support . sort of scatterbrained . I suppose there are better ways to write things out but I see the reader getting lost mid way and like to keep them on track.

the sensor isnt "close" or "just like" , IT IS the complete GM sensor , driveshaft with cap part # 25516915 (not shouting just stating it as a fact) .
ask you local parts guys or advance for standard motors parts # PC16 average retail was $45 , since this news even kirban dropped his price on the sensor to 70 ,

heres a long thread on the subject

http://www.turbobuickX.com/forums/showthread.php?t=32667
the site wont allow the name so just substitute s for the X

 

[Gary Wells]

The complete cam sensor, as being sold by some places for as little as $ 50.00 or so, such as standard manufactured/outsourced part) is no more. When everybody heard about it, everybody bought out all of the sources that were selling it. Kirban's bought up some/all and is selling it for either $ 59.00 or 69.00. The places that were selling it for about $ 50.00 sold out and supposedly raised their prices drastically of can not get any more from their supplier. There is a good thread over on TBS regarding this, about 6 or 7 pages worth. Might be benificial to do a search. GM list is about $ 416 or so, GM parts Direct shows it for about $ 216 or so, plus postage. Try Kirban's for the current least inexpensive price available now.

 

[Lee Thompson]

?

Are these a better design then the original? I have a few originals that I can shim. Would it be worth my time to purchase an after market one?

 

[pacecarta]

they are in everyway the same as the originals that were installed in 87

the shim fixes the wear to the 4 lands at the base of the cam body , when new they are about 1/8 long but wear down with mileage and that allows the shaft to be driven up by the cam gear and then the disc under the cap can contact the cap (that ticking tapping noise you may hear at the cap ) and then eventaually cracks the cap or knocks the ring out of whack and makes contact with the sensor magnets and ruins the cap sensor . replacing just the cap would only be a short time fix without shimming
. the shimming makes up for this wear to a point . the shim will fix up- down play . there is supposed to be some slack thats held by a wave washer but if the body wears too much at the bottom and those lands are gone shimming will tighten it up but the shaft wont recieve any oil splash and probably wont be long before its wobbling.
if you have any side wobble then the new one would be better.

advance still shows it ontheir site , best way is to go to the store and see of they can get it under part pc 16 ,
i got one from discountauto.com because they are right around the block from me .
its possible dennis made a few calls and bought up all that was in stock, if any one could do it he could .
advance still shows it at 54

 

[Gary Wells]

FWIW & IMHO:
http://www.turbo*****s.com/forums/showthread.php?t=32667
Worth your reading if you are considering ordering any of the lowball priced cam sensors.

 

[scottyb]

Regarding your buzzing sound, I had one at ~1600 rpm under load only. It turned out to be the EGR valve/solenoid.

 

[VinsGN]

Looked up part number “pc 16” on the Advanced Auto site. “pc 16” states that it replaces 84-85 GN cam sensors. Are 84-85 cam sensors are the same as 86-87 cam sensors?

 

[mcroz3]

I also have a tapping sound that happens at about 2000rpm top of first gear.. only happens in drive under load cant dupicate it in park Help

Curt
87 GN

 

[VadersV6]

I made this thread over a year ago. Why not make a new one? Ive made a more recent cam sensor thread as well that may be more relevant to you.

 

[mcroz3]

I made this thread over a year ago. Why not make a new one? Ive made a more recent cam sensor thread as well that may be more relevant to you.

Didn't notice the date when I replied. So what was the solution?