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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHIMS Tube Totally Misaligned
Leading reported evidence
Use genuine porsche chain
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Performed · outcome unconfirmed · Original poster
I actually used a genuine porsche chain that was black in color.
Leading evidence: 'Use genuine porsche chain' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace rod bolts, and the cooling passage seals' (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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Suggestion
You will need to replace the rod bolts, and the cooling passage seals.
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Suggestion
This will keep the change taut and will keep this from recurring, as it can happen after assembly.
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Suggestion
I did a dry run on fitting my bearing carrier to the case half and before I did, I decided to use a zip tie to simulate the function of the chain tensioner.
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Suggestion
In my classes I generally set people up to create this issue, then just before we seal the case up I ask them what's wrong with the picture, and after they look for 15 minutes and don't find it, I'll point it out.
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Suggestion
I did a dry run on fitting my bearing carrier to the case half and before I did, I decided to use a zip tie to simulate the function of the chain tensioner.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
In my classes I generally set people up to create this issue, then just before we seal the case up I ask them what's wrong with the picture, and after they look for 15 minutes and don't find it, I'll point it out.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I did a dry run on fitting my bearing carrier to the case half and before I did, I decided to use a zip tie to simulate the function of the chain tensioner.
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28 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261026T112012Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Put the engine case together today with Loctite 5900... My IMS tube is way off center. Obviously no tensioners on, heck, I haven't even installed pistons 4, 5 and 6 yet.Anyone got any ideas how to get this corrected? Looks almost as if the new IMS to crank chain is a little short. I measured the new chain with the old one and they were the same length (I purchased part # 996-105-171-58 for the 2001 996 C4).
I am at the same stage as you. Can you move the IMS sideways to align it correctly by very careful leverage? Or is it rock-solid in the offset position your photo shows?
If you temporarily fit the flange only by the center nut (but not torqued down!) does that enable you to get a better grip to correctly align/position the IMS ?
Good to hear from you again Schnell. I can move it side to side without any issues, it just wont go down. I can fit the flange on, but don't know if I want to push down too hard with it? I saw another thread where someone advised a vise grip grab along the flange and case, but I have what seems like a quarter inch of a gap and am reluctant to risk it...
Well it looks like we're going to have to muddle through this together :-).
Is there a chance that the chain is not laying correctly on the sprockets? I mean the chain is heaped up slightly on a sprocket?
No Vise grips/hammers or brute force until/unless someone knowledgeable(not me !!) comes to your rescue.
Jake had mentioned a problem with IWIS chains.I think(??) they were too stiff in some positions . For that reason I 'cooked' all my new chains in new engine oil to 180 degrees .I used a hot plate and an old hot plate.
I know you do not want to hear this but you may need to dismantle a little to discover the problem.Better to find out now than when you turn the key for the first time on your labor-of-love rebuild !
I bet this engine has the early duplex style IMS drive chain? The only time this issue ends up occurring is when the early duplex chain skips a tooth on the crankshaft drive, lifting the IMS assembly up and out of alignment.
This is the reason why I always install the IMS flange as soon as the block halves are together. This way you know you have the issue before you get things further assembled. Too late for that now, BUT there';s a good chance it'll have to come back apart.
In my classes I generally set people up to create this issue, then just before we seal the case up I ask them what's wrong with the picture, and after they look for 15 minutes and don't find it, I'll point it out. With early drive chains, this is a big assembly glitch, and I take time to address it in the classes. This early chain issue has bitten every one of us here at my place at one time or another, but you'll only make the mistake one time.
Also, was the chain that you used shiny silver, or was it black? That also makes for a huge difference, too.
Thanks for chiming in Jake. I really appreciate it. I actually used a genuine porsche chain that was black in color. Fwiw, the old chain was also black. I measured the length of chains against one another and compared the links, and they seemed identical.
Should I be taking it apart again and reusing the old chain?
Okay, thats good.. The OE chains are black and made by Renold, these aren't as strong as the Iwis chains, BUT they also don't have the fitment problems that the IWIS chains have, either.
Since you have the Renold chain, I'll bet that if you take it apart you'll find one link of the chain rolled out of the sprocket. As you turn the sprocket the chain will stay out of place because the next link just feeds right back into the same place. Look carefully to find this, and you'll be able to move forward again.
You may have to pull the carrier back out, so you can remove the IMS tensioner paddle to address the issue. Once the issue is addressed, and you have the block half back together, do NOT turn the engine over at all until you can fit the IMS flange and the IMS tensioner paddle. This will keep the change taut and will keep this from recurring, as it can happen after assembly.
OUCH!!! While I am ultra pissed that I have to separate the case again, I am really grateful for your expert advise as you just saved me a lot of time and further frustration. You simply must publish your engine building book....it would be worth its weight in gold. Thanks for bailing me out Jake.
Wonderful -this is Rennlist at it's best.
It is quite funny - two bungling enthusiastic diy-ers rescued from their mess by Jake -in minutes.The U.S. cavalry was never this good in the movies.
But please don't mention
the
book while things are going so well :-).We're on eggshells here.
Quick question for Jake as I have to take apart the case again and lift the carrier out:
1. Can I reuse the brand new connecting rod bolts on rods 1,2, and 3 or should I replace them again?
2. Should I buy 2 new water passage gaskets (the little square ones inside of the case)?
3. Should I use Loctite 5900 or 574? It took me about 10 minutes to lay down 5900 at 1.5 mm, and that was 5 minutes too long according to the WSM.
Thanks
Use Dreibond, forget the 5900 and certainly not 574.. Its good for aircooled engines, horrible for these.
You will need to replace the rod bolts, and the cooling passage seals.
yes THE BOOK covers this chain mistake, in fact theres a whole page about it.
You'll get it... This HAS to be the issue, its the only thing that will shift the IMS assembly up, toward the crank.
Take pics and post them when you find it! This is so easy to screw up.
Interesting phenomenon. I would have pictured the chain sorting itself out as you rotated it, but now I see that it would just keep a hump in it while it spun. Great tip from Jake as usual (I'm apparently also sitting on a tube of 5900 I won't be using).
I bought an IWIS chain before I saw Jakes comments a while back. I checked my chain and it is 0.020" shorter than the old one. Wondering if I should cut bait and get a different chain.
Tough to take good pictures, but the first one is of the chain not sitting properly on top of the sprocket due to several links on the bottom (not pictured) climbing on top.
The 2nd picture is of the chain seated properly inside the sprocket.
After the readjustment, I noticed that the IMS tensioner paddle loosened up, and the distance between IMS sprocket and crank sprocket increased by 7 MM or so.
Will have to wait for parts to come in from pelican to put it back together again, so I won't know until the weekend if everything is ok. As Jake stated, I noticed how easily it can pop out on its own, so I will definitely fasten the IMS flange as soon as possible after dropping the crank carrier back in.
There ya go… Thats the late drive, its much more difficult to goof this up with the late drive, but it is possible.
Its almost like I've done this a couple times :-)
As I recall it was a little bit of a struggle for me to seat the crank carrier on its dowels...I am guessing the chain must have shifted during that process???
That would be an easy time for that to happen. I did a dry run on fitting my bearing carrier to the case half and before I did, I decided to use a zip tie to simulate the function of the chain tensioner. It takes up all the slack, keeping the chain snug against all the teeth.
Once it's in place and the carrier is attached to the case half I can snip the zip tie and begin the process of installing pistons 1-3.
This pic may help show what I'm talking about.
There's no danger of forgetting the zip tie because I can't rotate the crank to install the pistons with this in place.
