jshalomo

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).

Schnell Gelb

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 ?

jshalomo

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...

Schnell Gelb

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 !

jshalomo

I didn't know that about Iwis chains...I would really hate to take it apart again.

Jake Raby

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.

Schnell Gelb

Jshalomo, the Cavalry just came over the hill and rescued you. Hug the next Marine you see.

jshalomo

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?

jshalomo

You said it man!

Jake Raby

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.

jshalomo

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.

Schnell Gelb

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.

jshalomo

LOL

jshalomo

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

Jake Raby

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.