91' Code 41 - Cam Sensor

[cerjzc]

I have been following the excellent instructions on the web site located here:

http://bellsouthpwp.net/p/a/padgett46/cammag.htm

and have indeed found that the magnet is missing. I have a question for someone that has done this in the past. It shows in Figure 5 the picture of the brim still located in the hole. It mentions that you must clean out all broken and excess plastic, but does not mention if that includes removing the brim and there is not a picture of what it looks like afterwards.

Is the brim left in place as a backstop for the new magnet or is it removed? If it is removed I am concerned that I would insert the new magnet too far as it shows in figure 4b that you remove part of the bottom of the new one.

Your help is appreciated.

Thanks,
Jeff Calvin

[HotZ28]

If you will re-read the following two paragraphs of the instructions and especially the bold, Italics and underlined portion of the sentences, you should be able to answer your own questions.

Using an awl or small screwdriver clean all of the excess/broken plastic & gunk out of the hole (this is the most time consuming part. Use a mirror so you are sure to get all of it removed. This is critical. Will be able to see cam through hole when done. Then clean thoughly with carb cleaner or something similar that won't leave a residue.

Once started in the hole, remove the socket and push it in with your finger until you feel the arms bottom in the recess (will see what I mean when cleaning the hole). Make certain it is in far enough to clear the timing cover (not by much) when the cam rotates. When seated all the way, it will be.

Step by step replacement

1) Start as if you were going to replace the water pump except do not take any water pump bolts out.
- remove serpentine belt, water pump pulley, and any resovoirs that block access.
2) Disconnect wire from cam sensor
3) Remove cam sensor bolt
4) Remove can sensor - Will probably need a mirror to see in hole
5) Rotate engine until either interrupter or hole where interrupter once was in cam sprocket is visible
- rotate either with key off and out with breaker bar on crank bolt (easier with plugs removed)
- or by bumping starter with plug wires disconnected (hard to stop in right place)
6) If interrupter is missing then continue else check sensor for continuity
7) Remove any remnants (can use an awl) and clean the hole in the sprocket and surrounding area *thoroughly*
8) Proceed as in article to modify new interrupter and JB Weld in place
9) Allow to dry overnight before replacing sensor
10) Replace everything you took off

BTW: Welcome to AF

[cerjzc]

Thanks for the quick response. I did see those sections that you mention I guess I was just wanting to double check with someone that had already done it. If you look in figure 5 I think you can see the cam through the hole in the bottom of the old brim and I was not sure if that is what they meant or that you needed to remove the old brim completlely. From your response I am guessing that the whole thing should be removed.

As for the second issue with installing the new one I was not sure that the notches would catch once they were covered with JB Weld.

I guess I am also a bit confused on why I need to trim the bottom of the brim if I am going to be removing the old brim from the socket. I understand I need to remove the edges to get it to go in but I don't know why it would need to be shorter.

So to confirm the old brim needs to be removed completely and the tabs should catch once the new one is installed.

Thanks,
Jeff

[HotZ28]

Some very good questions and observations! I hope I can clarify this, if not, keep asking!

Normally, if you were installing a new cam gear & magnet, the magnet would be installed from the “back side” of the cam gear. The purpose of the “brim” is to stop the unit from going too far forward. If you install it from the front, only the larger portion of the brim needs to be trimmed for it to fit in the hole of the cam gear. The overall length of the interrupter will not be altered. (You will only need to reduce the O.D. of the brim to match the size of the rest of the unit). Also, the “tabs” are like spring loaded fingers, that catch in the groove in the cam gear. The JB Weld will still be in a paste form when you install it and would have no effect on the tabs working as designed.

[cerjzc]

Very good information thank you. I will work to get the rements of the brim out of the sprocket and then get started with a good cleaning.

I think answers all of my questions so thanks again.

Jeff

[DioGreer]

I went the expensive route when my magnet broke. I had them take off the front cover and replace it. while they were in there I got them to replace the timing gears/chain and the water pump too

[HotZ28]

Originally Posted by DioGreer

I went the expensive route when my magnet broke. I had them take off the front cover and replace it. while they were in there I got them to replace the timing gears/chain and the water pump too

Yes, normally it is better to pull the front cover and replace everything at the same time, especially if the car has over 100K on the clock! I had to do that on my Ultra @ approximately 140K!
(Don't forget the tensioner)!

I did help a friend replace the magnet only, since he could not pass emission inspection with the SES codes and had a tight budget. He drove the car another year without any recurring problems, then traded it for another car. If you plan to keep the car, you do not need to perform “shortcuts” when doing maintenance. My philosophy is; “Spend some now, or spend more later”!

[Alibi]

My 3800 threw its cam magnet at 50k miles (although I had the code 41 at 33k), and I am a poor student so I had to cheat and take the shortcut. The hardest part that I ran into was getting all the bits of the old magnet cage out. I ended up having to use a soldering iron to melt the plastic base in half so I could remove it. I didn't have JB weld either so I used a combination of 2 part epoxy and gorrilla glue. 5k miles later, its still holding so I must have done something right

This took me an afternoon to do, with most of the time being drying of the adhesives. Just be sure to not run the engine and leave the cam sensor off overnight to allow all the adhesives time to properly cure.

[cerjzc]

I just want to thank everyone that responded. I have completed the work and so far so good.

Thanks again,
Jeff