Magnetic Cam

Michael Diagnostician Irving, Texas Posted   Latest   Edited  
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2016 Jeep Wrangler Unlimited Sport 3.6L (G ERB) 5-spd (W5A580)—1C4BJWDG3GL251507

Working on a Jeep Wrangler and remember a discussion about the magnetic cam. I figure I share some pictures from a rebuild I'm working on.

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Mike Technician
Atlanta, Georgia
Mike Default
 

I got bit by one of those. We'd sent the head off to the machine shop with the cams and all still on it. When it came back, I put everything together and got a cmp code from that bank. Scoped all 4 cmp signals and found that one cam's pattern was missing some activity. There was no getting the machine shop to own up to anything so we ate it. Lesson learned. When AllData has warnings about those…

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Michael Diagnostician
Irving, Texas
Michael Default
 

So,as I disassembled the engine and laid the cams down, they touch each other. I wondered if this would damage them. As this was a donor engine for the block I'm not to concerned about them Now that I learned from others, I will make sure the ones in the other engine will never touch or get near anything.

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Matthew Mobile Technician
Bartlett, Illinois
Matthew Default
 

There have been a lot of issues with them de-magnetizing. They cannot touch each other or be set on a metal work bench during service.

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Michael Diagnostician
Irving, Texas
Michael Default
 

...and I have the old ones setting on a metal bench. I wonder how new ones are shipped.

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Matthew Mobile Technician
Bartlett, Illinois
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The dealers are told to store them on a wooden bench... told being the key word there lol.

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Jaxon Technical Support Specialist
Stafford Heights, Australia
Jaxon Default
 

Hello. Could you supply the vehicle's details, please?

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Michael Diagnostician
Irving, Texas
Michael Default
 

This engine was purchased from a junk yard for the block for a flood damage Jeep Wrangler. Air filter box had a clamp installed incorrectly and sucked water in.

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Tom Engineer
Claremont, California
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I've updated your original message to include this vin/vehicle, which may come in handy later.

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Jaxon Technical Support Specialist
Stafford Heights, Australia
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Hi Tom, thank you.

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Olle Instructor
Albert Lea, Minnesota
Olle Default
 

Could the cam be degaussed?

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Michael Diagnostician
Irving, Texas
Michael Default
 

I wondered if they could be cleaned off and still be good, but with the amount off work it takes to install them I wouldn't use them again. All that metal is from the timing chain.

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Matthew Mobile Technician
Bartlett, Illinois
Matthew Default
 

Yep, and those reluctors are notorious for slipping on the cam. If a dealer tech has a correlation code step 1 is to tear it apart and install timing tools. Super efficient, right? LOL FCA had to redesign the timing tools to fit into the reluctor in addition to timing the engine. The techs would tear it apart and confirm timing chains were good. Then it would get a PCM, then it would get torn…

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Rudy Technician
Montebello, California
Rudy Default
 

Link to the previous discussion?

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Justin Mobile Technician
Herriman, Utah
Justin Default
 

I believe its this one. diag​.​net/msg/m2u07ro3qw…

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Bob Owner/Technician
East Longmeadow, Massachusetts
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That seems like a really unnecessarily fragile system. Whatever happened to trying to build Robust components?

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Martin Diagnostician
Burleson, Texas
Martin Default
 

Well, we'd all be out of work if they actually built them to last!

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Matthew Mobile Technician
Bartlett, Illinois
Matthew Default
 

They are using a magneto resistive sensor, no chunk of actual metal needed, just a magnetic strip. They are more accurate when they work, but reluctors can be an issue. The reluctor losing magnetic properties is a service issue only, far as I know. The real issue is engines that use a reluctor that looks like a seal, the 3.0 FCA diesel CKP for instance. The material is falling apart and the…

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Michael Diagnostician
Irving, Texas
Michael Default
 

I completed the rebuild and have to say the engine with 30,000 miles had a good amount of metal stuck the the cams too. I didn't get picture of it as I already had wiped them off and hope they are still good. To prevent any damage to them I used the valve cover as trays and avoided a metal table. I wonder how this will effect motors with high mileage when it comes to sensor reading. I attached…

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