[Lemming]

Started the car this morning to get it ready for the dyno at 1pm. Listening to the engine, I noticed a slight knock that I have not heard before. I put my thumb on the spark plugs and sure enough I can feel a slight bump on the number 2 with all others feeling fine. I'm guessing that the bearing is bad, am I correct?



This is the track car, not my DD.



<img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" />

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[whakiewes]

Symptoms I have heard on 951's, not 968's. May not have any bearing (no pun), but I would assume they are similar -



First symptom was a 2800-3100 knock, almost like bad fuel. Very faint, growing louder.

Second was it start to grow from 2000 to 4500.

Then the bearing gave up, and sounded like a spun bearing, knocking from idle to redline.



In any experience I have had, if you suspect it, don't drive it. As soon as it goes completely round, you can end up with a $5k dollar rebuild quickly...ask me how I know <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> . At this point, you could probably get away with just changing them and your crank should be fine. In the 951 we just had blow, it spun to the point where there weren't large enough OS bearings to use the crank...had to buy another crank.



Whats your mileage? Oil type/mileage? Engine warm/cold when it started? Under load? I ask as I am trying to compile information as to try to prevent it on my car!



Wes

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[Lemming]

[quote name='whakiewes' date='May 6 2006, 10:38 AM']Whats your mileage? Oil type/mileage?  Engine warm/cold when it started?  Under load?  I ask as I am trying to compile information as to try to prevent it on my car!



Wes

[right][post="20538"]<{POST_SNAPBACK}>[/post][/right][/quote]



<70K. I have used a mix of oils, 10W40 in winter, 20W50 in summer. Car was cold, I heard it at startup.

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[Dave]

My symptoms in my '88 NA 944 were on the magnetic oil drain plug. I grouping of very skinny metal shavings about 1/8" or so long, forming a little X-Mas tree shape on the drain plug.



I saw these twice in that car. Both times, #2 bearing was visibly worn. Modified the pan and pick-up during the second rod bearing change. I never had a knock.

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[whakiewes]

So what is the fix? If I am going to replace my bearings, I would like to take the precautions in order to not have it happen again? As with anyone, I am just trying to prevent a big bill!



Wes

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[Etnier]

Didn't Porsche do something about this in the design of the later cars?

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[Lemming]

[quote name='Etnier' date='May 6 2006, 02:14 PM']Didn't Porsche do something about this in the design of the later cars?

[right][post="20551"]<{POST_SNAPBACK}>[/post][/right][/quote]



I believe that '87s and up had a better baffle but the problem still occurs.



I've gone ahead and cancelled my DE for Tuesday, that way they have time to find me a replacement. I'll pull the pan tomorrow and assess the damage, will shoot some pics.



Someone on rennlist suggested that it might just be a lifter pumping up, any quick ways to check this?

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[Dave]

Consensus I have heard is that 968's are less prone to the #2 rod bearing problem. That said, I've seen a nice '95 M030 spin one big at the track and grenade pretty good.



I would consider rod bearings to be a PM item on any 968 north of 120k miles. For a track car/race car... PM regardless of mileage.



I did mine when I bought the car (leaking oil pan gasket anyway) and will likely check/replace them at about 50 hours of track time going forward.

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[968gene]

I had the oil pan off of my soon to be track car yesterday. The car is a 944 S with 90k on the clock. The ALL of the rod bearings looked great. All of the internals looked very clean as well. However. and this is the reason for this post, Porsche specifies that NEW rod nuts be used for reassembly. I ordered a set last night. Don't overlook this on assembly.

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[Lemming]

First the good news. I warmed the engine and checked the oil with no apparent metal. However, since I changed the oil after my last DE, I was not convinced. So, I dropped the oil pan and everything appears to be normal. I'll order new bearings and rod nuts tomorrow and I should be ready to go before next weekend.



Now the bad news - I think I know what was making the noise. After pulling the pan I remembered that I need to remove the spark plugs in order to easily rotate the crank. GUESS WHAT, #2 spark plug was loose <img src="/forum/images/smilies/968/blink.gif" class="smilie" alt="" /> I'm thinking that was my problem all along and would explain why the spark plug cap was thumping in the first place. Don't I feel like an idiot <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />



At any rate, changing the bearings is a good preventive measure. In addition the oil pick tube appears to be in good shape, so that's a plus.



Live and learn <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />

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[Eric_K]

If you didn't open it up and look, you would not have been able to get the thought of impending disaster off your mind.

Now, you are just being proactive in your maintenance. <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[968bill]

[quote name='Lemming' date='May 7 2006, 12:41 PM']Now the bad news - I think I know what was making the noise.  After pulling the pan I remembered that I need to remove the spark plugs in order to easily rotate the crank.  GUESS WHAT, #2 spark plug was loose  <img src="/forum/images/smilies/968/blink.gif" class="smilie" alt="" />    I'm thinking that was my problem all along and would explain why the spark plug cap was thumping in the first place.  Don't I feel like an idiot  <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" /> 



Live and learn  <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />

[right][post="20593"]<{POST_SNAPBACK}>[/post][/right][/quote]

We've all done something like that, some of us more times than we care to keep track of. Hey, we're only human.



I admire your aggression at getting in there to fix it, I'm still putting off an intake manifold gasket replacement project on my 911 that I should have done last year!

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[Lemming]

[quote name='968bill' date='May 8 2006, 09:42 AM']We've all done something like that, some of us more times than we care to keep track of. Hey, we're only human.



I admire your aggression at getting in there to fix it, I'm still putting off an intake manifold gasket replacement project on my 911 that I should have done last year!

[right][post="20638"]<{POST_SNAPBACK}>[/post][/right][/quote]



I have a 3-day DE at Barber in three weeks, hence the hurry. If there had been major damage, getting started last weekend would have given me time to work on my spare engine (belts, etc) and get in put into the car.

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[GuardsRedCoupe]

Lemming - I admire your ability to pick out sounds. Always better to be safe than sorry.



There has been developing a slight sound in my car as well, but I can't put my finger on it. It started around the time I took out my rear seats, so I don't know if it was actually there all along. I plan on getting the experts to listen to it at the 968 celebration.

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[Lemming]

[quote name='GuardsRedCoupe' date='May 8 2006, 12:18 PM']Lemming -  I admire your ability to pick out sounds.  Always better to be safe than sorry.



There has been developing a slight sound in my car as well, but I can't put my finger on it.  It started around the time I took out my rear seats, so I don't know if it was actually there all along.  I plan on getting the experts to listen to it at the 968 celebration.

[right][post="20662"]<{POST_SNAPBACK}>[/post][/right][/quote]



I have my head under the hood alot <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" />



Once you start removing materials from your car (sound deadening), it's scary what you begin to hear.

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[Lemming]

Rod bearings came in tonight and they are installed. Car is back and running but I still need another evening to get the steering/front end back together. The rod bearings did show a little grooving but were in pretty good condition. Actually replacing the bearings was easy, it's all the "stuff" that has to be moved to get in there.



Idled the car for about 25 minutes to "break them in", everything seemed fine <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />

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[JakeS2]

Good to hear! Did you replace the nuts on the rods too? Porsche says they should be changed when opening them rod nuts. But usually it's the 951s which suffer from the rod#2 bearing problem as the oil for turbocharger is retrieved near that rod. That said my friends S2 broke that bearing... So, it's question of luck more likely <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />



--Jake

Porsche 944 S3 M030 'CS'

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[RS Barn]

This is a bit off topic and may seem like a product plug but I haven't gotten the message out there about the lack of antifriction additives in current oils. The feds made them take out additives that were in oil for 75 years

This is especially important to DE guys who run the ---- out of their engine and withstand high heat levels.

I'm starting to see cams and rod bearings with unusual wear.

Look at ZDDP info on my site to read more

Pete

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[bob blackwell]

Goog point Pete, since reading about the reduced amount of ZDDP in many of the oils I have switched to Shell Rotella T in both my 968 and my 356. There is a good article about this in last month's Panorama. Never can be too careful, good luck, Bob Blackwell.

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