Camshaft Adjuster vario cam plus.

Hi guys. prepping my engine parts for installation, I disassembled the intake camshaft components. Upon inspection, I noticed that the cam adjuster had some wear on it. To me, it looks like the recessed area next to each bolt had a sharp corner that was worn out by the chain (It looks like the timing chain is riding on that surface). No evidence of cracks beside these corners that look like they broke off slightly. So should I just file them round and carry on, or should I add $800 to my parts list?

From a structural or strength veiw point i cant see how the wear is an issue. But u dont have any experience with the 3.6 adjusters.

Agree. I don�t think it will break but I sure do not want it to keep flacking off.

Hmm that�s interesting. I did not notice anything like that on mine but cannot confirm I looked that closely. The dressing it with a file and see how well it smooths out. May not be an issue.

Surprised Charles or PT3 hasn't chimed in, Thinking with all the m96 engines they've seen,, maybe seen this before. Strange as the only thing moving close enough to do this, maybe, is the chain..? And unless the chain is really flopping around in there, can't even see how it could get there to cause that..?. Unless some chunk of chain roller or debris got caught up in there..? Any 'chunks missing from the old chains..? Like Jandackson & DJ said, that slight wear in that area, probably not a issue at all. But be nice to know what happened....

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I'm no metallurgist, but that's appears to be very minor pitting corrosion of the parent metal. Very early stages IMHO. How are the camshafts? Any pitting? (see attachment) I'd replace it with a new camshaft adjuster.

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camshafts look in good shape, with minimal wear on the lobs. cam deviation was also pretty good before engine disassembly.

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the edge of the chain is riding on that area. I don't think it's slopp related as the cam deviation was close to perfect, and the timing chain guides were also in relatively good shape.

IMO it's not the adjuster, it's wear in the chains.

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possible, but if the chains were stretched, I assume it will show up on the cam deviation. chains will be replaced with new ones, and the sprockets themselves look fine as far as I can tell. looking up the part numbers (different for 1-3 and 4-6) the new parts were revised twice.

The timing chains do not actually stretch, that is a misnomer , they wear.. The timing chains are put together using pins and link plates, the inner link plates have slip fitted holes that the pins go through and oscillate. This oscillating motion wears the link plate holes only on one side and causes an ob-longed hole. This ob-longed hole increases the timing chain length when pulled tight.. The Industry Standard is to replace any roller chain that has lengthened by 3% . ( Quite honestly I replace M96 timing chains at 1-1.5%.....I think many replace then even sooner as a" just because they're in there " ) The chains can be measured by using several methods, one of which is a chain length tester tool. or you can measure from center to center of the pins in a long length of chain and divide by the number of pins.. A wear of only one thousandths per link plate hole over a span of 250 pins would increase the chain length 1/4 " ... Our M96 engines use a 08B or 08B-2 roller chain ...The 08B is the single row chain used in the 5-chain engines from cam to cam. The 08B-2 is the long double row chain in both 3 and 5 chain engines ( just different lengths)....All roller chains are designated by 16ths of an inch. The 08B means it is 8/16ths "pitch" ( center to center of the pins) or 1/2" ( .500) ..The "B" means British Standard ...also conforms to DIN/ISO Standards The rollers and bushings are also wear items although they do not add to length, but they can get worn down or loose and make the link plates ride closer to the center of the sprocket..I would suspect that is what is happening here. With a new chain fitted on the sprocket, I would expect to see at least a few thousands clearance..there is no reason for the link plates to ride on the housing

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thanks for the detailed explanation Skip. I obviously don�t have the tools to conduct this measuring, but will I able to see the difference if I place the old chain next to the new one? I will also appreciate your opinion on if to reuse the old cam adjusters or just bite the bullet and get new ones. thanks in advance.

Hold the chain out flat from one end. If it sags it's worn out.

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I would fit the new chain on the cam adjuster and see how much clearance is there, if not comfortable with the amount of clearance I would chuck the adjuster in a lath ( a brake rotor lath may work fine) and machine a few more thousandths off...then re-use the adjuster if all else is fine.. Yes this is a very quick and easy way to visualize wear, and if you worked with the same length of chain all the time, you could come up with an accurate measurement of "sag to % wear" ..ie 1" sag = 1% wear ...2" sag = 2% wear ect....

PT3, you continue to amaze me with your wealth of specific m96 info/specs, and general mechanical prowess... Thank you.... Are there any High Performance/heavy duty chains available for the m96, like Cloyes or maybe even TRW, they have them for many engines. Does Mountune offer chains for the m96..? Reason I ask,,, seems the m96 chains are another cause of m96 problems that can develop into engine failure in a few different ways. Or is this a waste of time and the m96 oem chains are fine even though they commonly shed pieces of rollers and seem to wear quickly..? jmo

Here is a picture of both old and new chains on the sprocket. I took the picture while putting pressure on the chain from the other side. then I put pressure on one of the links and measured the clearance. I get 0.20" on the new one, and 0.18" on the old. (using filler gauge).

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Thanks for the generous words Allcool, I know you have been around the block a few times in the high performance world so that holds weight with me... The 08B and 08B-2 roller chains that we use are a common pitch ( 1/2" .500) that all the chain manufacturers make, the only thing "special" about the ones we use is the length and that it is a "continuous chain" ie, no master link... I'm sure that any of the dozens of roller chain manufacturers can make this chain with just a little more effort than they are already making the exact same chain in a " cut to length and use a master link" type set-up...I think they all make an econo-grade and a premium grade , and think they can make the "best" roller chain...I have no idea who really is the best... All the ones I have seen had the IWIS name stamped on the link plate... Iwis is a 100 year old German company, I'm sure there may be other brands making them now that they have been around for 20+ years...It would be nice if one of them would step up and make an Ultimate Lifetime Timing Chain ...lol

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With .180" clearance I don't think the chain link plates are hitting the housing, I would come up with another theory...