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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHAdvice/Opinion on 996 IMS to Cam Chains by IWIS
Leading reported evidence
Inspect sprockets and don't see any wear
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
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0
Unsuccessful attempts
1
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Read evidence and context
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Performed · outcome unconfirmed · Original poster
I inspected the sprockets and don't see any wear on them so I will stick with them as well.
Leading evidence: 'Inspect sprockets and don't see any wear' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Inspect sprockets and don't see any wear' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed
I didn't see any on the last couple of sets of chains I've installed from IWIS, but it doesn't hurt to look.
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Performed · outcome unconfirmed
All the engine rebuilds I participated in and the several I did on my own I replaced the cam chain and related sprockets with new ones purchased at the parts department of the dealer.
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Performed · outcome unconfirmed
As I mentioned above with car engines during a rebuild I just replaced the cam chain and the sprockets.
Replace sprockets/chains i just bought factory new ones
Performed · outcome unconfirmed
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Unsuccessful attempts
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Read evidence and context
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Performed · outcome unconfirmed
Still, as I mentioned before when I replaced sprockets/chains I just bought factory new ones from the dealer's parts department.
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Performed · outcome unconfirmed
All the engine rebuilds I participated in and the several I did on my own I replaced the cam chain and related sprockets with new ones purchased at the parts department of the dealer.
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Suggestion
Say if you measured 300mm of chain and found the first and last pin of the worn chain further apart by 3mm (1%) compared to a new chain this would be sufficient to justify replacing the chain.
Replace chain and sprockets if there condition warranted it
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Suggestion
Primarily my interest in chains was from when I had a bicycle or a motorcycle and then if there was any doubt I just replaced the chain and sprockets if there condition warranted it.
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Suggestion · Original poster
The 2 JWIS chains I purchased that run from the IMS to the Exhaust Cam (99610517752) appear to be inferior to the existing chains that have 100k miles on them:
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12 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261027T042512Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I am doing an engine rebuild and part of my plan is to replace all 5 chains. The 2 JWIS chains I purchased that run from the IMS to the Exhaust Cam (99610517752) appear to be inferior to the existing chains that have 100k miles on them:
1.The chain link pin ends (or rivets) are very jagged and not smooth like on the original chain.
2. The rollers also appear to have a wider gap where the 2 ends meet.
Should I just keep my existing 100k chains and sell the new IWIS/JWIS chains on Ebay, or am I being too picky? Any opinions, experiences...?
Reads like the new chains you have are not very good quality. They may be ok though, but if they prove not to be there goes your engine.
All the engine rebuilds I participated in and the several I did on my own I replaced the cam chain and related sprockets with new ones purchased at the parts department of the dealer.
In your car's case, unless the chains (or sprockets) show damage to the rollers, visible sprocket teeth wear, the original chains at 100K miles are probably ok but I'd be tempted to replace them with new ones.
I am trying to remember how to test a chain to see if it has excessive wear. I can't recall exactly but I seem to remember it involved with the chain stretched out how much arc one could get out of the chain. But I do not recall how much was too much.
Another possible way is to measure the chain over a length and see how much the roller pins are separated by their nominal pitch. But I can offer just some WAG as to what amount of 'growth' would be considered too much and this would be around 1%. Say if you measured 300mm of chain and found the first and last pin of the worn chain further apart by 3mm (1%) compared to a new chain this would be sufficient to justify replacing the chain.
Also, if the sprocket teeth show signs of wear the sprockets get replaced along with the chain.
Primarily my interest in chains was from when I had a bicycle or a motorcycle and then if there was any doubt I just replaced the chain and sprockets if there condition warranted it.
As I mentioned above with car engines during a rebuild I just replaced the cam chain and the sprockets. I never bothered trying to determine if they were worn enough to replace, even if at the time I would have known how to do this.
Wow that's a tough one. I believe Iwis made all the oem chains. Did you buy the chains from a reputable source? I bought those same chains from "Discount Auto Parts" on E-bay. When I got them I think they had the correct part# on the boxes but the chains were short 4 or 5 links. It was a major hassle to return them & get a refund for the chains. Gave up on a refund for the shipping.
I would buy 2 more from a more reputable source. Try Circle Porsche's online parts site. Great prices, but frustrating site!
Thanks Macster. Very informative... I measured the chains and they were identical in length to the originals...I am going to take a few pics later and post them...maybe I am over reacting.
Here are some pictures of the chains side by side. JWIS on the left...
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While the old and new chains look different, and I like to say different means they are not same, I am not convinced the new chains are sub-standard. Granted the pin ends are a bit less smooth but they are consistent in their appearance compared to each other though obviously not to pins of the other chain.
Still, as I mentioned before when I replaced sprockets/chains I just bought factory new ones from the dealer's parts department. I probably compared the new and the old chains and sprockets but I can't recall now if I spotted any real differences. I do recall I never had a replacement chain or sprocket fail.
I agree with you Macster. I think i am over reacting...I will use the new chains. I inspected the sprockets and don't see any wear on them so I will stick with them as well.
Every company makes good, great and crappy parts. It's the nature of the beast when it comes to mass manufacturing and while two sets of IWIS chains might bear the same name and part number, they might be made to different tolerances. If you bought the parts from a reputable source, don't worry about it. If you bought them from bestcarparts4u.com, stay away from diy repairs please.
Thanks? My mother named me.
I think you'll be fine then with your chains. Be sure that if there is a directionality mark that you follow it. Just look at every link to be sure. I didn't see any on the last couple of sets of chains I've installed from IWIS, but it doesn't hurt to look. Just be happy you don't have a master link you need to use.
