about ready to start the IMS project
 

I'm about ready to start the IMS replacement project. I'm doing all of these things at the same time:

RMS
Luc Clutch kit
dual mass Flywheel
Manzo Exhaust/TopSpeed test pipes
AOS
serpentine belt
spark plugs

I think I have all the parts and tools to finish everything.

Tonyhttp://986forum.com/forums/uploads01...1435278757.jpg

Wish me luck.

Tony

Good Luc. :)

Go for it Tony

Crossing my fingers!

OK. I need advice. I'm at the point where I have the transmission out and I need to put the cam lock (LN engineering) for a 2003, 3 chain engine. I'm putting the cam lock into the cams on bank one behind the passenger seat (right side of vehicle for the RHD folks), but I can't seem to get it to go in. It fits in the bank to cams but not in bank one. This tells me that one of the cams on bank one is out of timing. It's only out by lest than one degree. is there ant way to fix this without having to put the whole thing back together?

Please help.

Tony

Try rotating the engine (by hand, clockwise direction only) another lap or two and see if the cam lines up then. What ever you do, do not attempt to rotate the engine counter clockwise.

OK. Thanks Jeff. I got the cam lock in, but now the special tool TDC lock won't slip into the hole. Is it OK to do the bearing change if I lock the engine from the flywheel (without the special locking tool)?

Tony

No, because you will need to remove the flywheel to do either the IMS or RMS. You need to find out why the cam tool will not go in with the crank pin in place.

My bad. I meant the rear crank (after the the flywheel has been removed). The reason the tool won't go in is that with the cam lock in, it's ever so slightly out of TDC. Here is what I was thinking:

http://986forum.com/forums/uploads01/1721435531131.jpg

My Indy just did my 996 last week and we went through this. Everything at tdc. Cams have to be locked on bank 1-3. Crank lock tool needs to be inserted. 1-3 chain tensioner removed and ims chain tensioner removed. On 3 chain motors you also have to lock bank 4-6 cam (intake iirc) to keep it from moving with the slackness of the chain. You can then remove the ims but you have to note if there is any side movement if the ims shaft. If there is then you have to also take out the bank 4-6 tensioner (hence the locking of the cams on that bank as well). I will,try to have my Indy post tomorrow for you. I am sure that jfp can guide you better, but thought I would try to help as the 3chain motors are a bit more involved than the five chain motors.

My thought is that the locking tool is to lock the motor by locking the crank shaft. The tool locks the crank shaft in front. The picture above locks the crank from the rear. The cam lock is to keep the spring load in the head from moving the cams when there is slack in the chain (tensioner removed for that bank). Is that not correct? Or, is there another reason for having the engine at TDC?

Tony

The engine has to be a TDC, as that is the only rotational position where all of the valves are close and the cams are unloaded (spring pressure is what causes these engines to jump time). Any other position and at least one or more valves are partially open and under spring loads.

If the cams do not sit in the correct position at TDC, something is wrong and needs to be corrected before moving forward. Did you check the cam deviation values before you started this project?

Yes. Using Durametric. I wrote the numbers down, but I can't find the sheet right now. It was only a few degrees. Neither bank went passed -3. When I say not at TDC, it's REALLY REALLY close. It's off just enough to not let the locking tool slip into the boss. Using a mirror I can see the hole in the boss through the hole in the main pulley, but it's slightly off.

3 degrees isn't close, its a mile...

If you're not already done, locking the crank at zero degrees is what is important because that unloads all of the valve springs so the cannot physically push the cams to change the valve timing. Locking the cams with the cam locking tool is not necessary for an IMSB replacement. The durametric is giving you valve deviation while running, which is all about the chain ramps, chain tensioners, and timing chain stretch. There are quite a few threads on adjusting the cams to try to compensate for the deviation due to wear.

You have got to be kidding...............

And you work on these cars? Not mine if you don't even know that at TDC the lifters are sitting on the Cam circles and it is physically impossible for the valve springs to move the cams. I suppose you use two cam locking tools and the crankshaft zero lock along with bolting the flywheel end of the crankshaft to the block before changing an IMS? :D

I just had the IMS bearing replaced in my '99 986 base. the clutch was getting a little spongy and some ever so slight slip (I really took it to my indie because of a really bad clatter that started quite suddenly). any way, clatter was from the water pump deciding to retire.
so anyway, clutch need changing so might as well do IMS too.

I wish I had taken pix of the operation to change the IMS. my mech didn't lock down the crank, just the cam shafts. He has done a bunch of boxsters and made the job look easy.

my indie mech is a little ocd. I don't know if it's because he's a retired navy fighter jock and a top gun grad, but the guy is better than most dealer mechs.

everything went fine and the old IHS was starting to stick instead of spinning freely. good call on his part. he said there was no deviation in the cams which surprised him as the car has 94K on the clock...

tim

Yes, I do work on these cars, and have been called upon to reset the cam timing on more than one three chain motor that jumped time when the owner removed the tensioners without locking the cams while the engine was at TDC. You should never pull the tensioners on the three chain motors unless the engine is locked at TDC, and the cam lock is in place. To do so is inviting a disaster.

Well then you should be using 2 cam locks, not a cam lock. It would be interesting to understand what would you think could drive the cams to move independent of the chains as there is no driving force to rotate them at TDC to lose timing. I've had my 3 chain apart and set the timing without the cams locked, all that was needed was TDC as there is nothing to cause the cams to rotate independent of the chains. Tearing the engine down for the first time after an IMSB failure, I made the choice not to be at TDC because I thought I might have valve to piston interference if I rotated it. A poor choice as I can confirm through personal experience the valve springs will rotate the cam independent of the chain if not at TDC, and they will not, and indeed can not if the engine is at TDC. I prefer to complete jobs without unnecessary parts (cam plugs) and time (messing with the cam locking tool).

As I have always been brought into the issue after it has already happened, I can only surmise what is causing it. That said, I would put my money on the removal of the tensioners, and perhaps the order in which that is done. Removing the tensioners has a similar effect as valve spring tension would, only to a lesser degree. When one tensioner is removed, the load on the chains is asymmetric due to the released tension. I have discussed this problem with other shop owners that have encountered it, and that seems to be the general consensus of what happens.

You also have to ask yourself why Jake even developed and LN produced three chain cam locks at all if they are not required during an IMS retrofit.

My experience has been that tensioners in or out, or going in or out, won't make the chains jump timing on the cam sprockets. I messed with the tensioners with the engine out on a stand, they do tend to rotate the cams a little but don't cause the chain to jump teeth on the cam sprocket. Not sure what the folks did who brought you their cars, but it would not surprise me if they fibbed a little to save face.

The Cam locks are used in disassembly, assembly and final adjustment. The factory tools are pretty basic. Why Jake developed his is a good question, they may be superior in some manner to the factory tools.

Well, I can tell you the others, including some shops that have gotten themselves into trouble not using them, would not agree with your assessment. After you hear the same scenario for the third or fourth time, particularly from someone you know fairly well, you have to consider it as a potential fact. We have never encountered this issue in my shop, but my guys always use the cam locks, regardless of how many chains the engine carries.

My amateur observation is that you can only be at zero valve spring load on one cylinder head at a time. If you've assembled the M96 you may recall two TDC locations. You install one bank, rotate the engine 360 degrees then install the chain for the other bank.

While you're on that second bank the valves for that head are unloaded, but at that moment there IS spring pressure on the first bank. In short, there is no position of zero valve spring pressure. A five chain motor, set correctly, will lock the head with valve spring pressure, allowing removal of all three chain tensioners

OK. First I'd like put a damper on the tech battle brewing. I respect everyone's opinion, but I know that Jeff has done a LOT of work on P cars. I trust his judgement. As I understand it, the only time you don't need to use the cam lock is if you're not removing the tensioner for that bank. Even at tdc, there may some tension in the valve train. It's always better to be safe than sorry.

More importantly; I found the spreadsheet where I saved the cam deviation values. It was .3(8) not 3 deg of deviation on bank 1. I was able to get the cam lock on, but the front crank lock wouldn't wiggle into place. I ended up locking the crank from the rear. Everything came apart and went back together easily from there (with the exception of the transmission not wanting to go in...that's another story). I fired it up for the first time this afternoon. Everything seems to be running perfectly. I rechecked the cam deviation again. Bank 1: .38 (again) bank 2: .22.

I'm going to call it a success for now.

Thank all.
Tony

Good on you for getting it done. Glad it seemed relatively drama free.

Fan-frickin-tastic! :cool:

Do you have a lift, or did you do it shadetree style with jacks and stands?

Jack and jackstands, baby!

Sent from my SM-T800 using Tapatalk

Congratulations on a job well done.

A bit of an update. I just finished changing my IMS over the weekend. My 03 S had 55300 miles on it. I ran into a couple of glitches, but for the most part, it went well. The old bearing was in good shape, but I'm not sure it was original (is there a way to tell?). In any event, there were a few things that needed to be done on it anyways. There was an oil leak. I thought it was the RMS, but in the end, it looked like more oil was coming out of the IMS flange than the RMS. Since the oil was out of the car, I decided to add the LN oil filter spin on adapter.
It also needed a new clutch. Although the clutch wasn't slipping yet, it was really rather stiff. It was still the original clutch I believe and at almost 60k I figured it was time for a new one. I also installed a new dual mass flywheel. The feel on the new clutch is SOOO much lighter. Compared to the old clutch, it now feels like it's not even connected. While the transmission was out, I decided to change it's oil as well. I decided to go with Royal Purple 75W-90. It feels a little smoother, but that could be the clutch.
Since I had to remove the exhaust to get to everything, I replaced it with a Manzo muffler/TopSpeed test pipe system. All I can say is....WOW. The sound is so fantastic. At 5K RPM, it sounds like a supercar. It's really incredible. There is fiberglass all over the car though. I'll have to hose the car off sometime this week.
I'm so happy to have all of this done. It's like having the car make it though a successful open heart surgery.

The next project will be the brakes and repainting the calipers.

Tony

Congratulations! :cheers:

Tony, what is your hourly rate. Ill bring my car to you for a new clutch and IMSB

No way. man! There is no way I want to do this on a regular basis. The most nerve racking part is hammering the new IMS bearing home. Get it wrong and kiss the bearing good-bye. It was hard as hell getting the extra 120 deg onto the flywheel bolts as well.

LOL :cheers: