Crank Pulley Wobble, Normal? (short video)

Of course you don't want any wobble, and if money was no object I would have the shaft balanced and get a flat 6 harmonic pulley. But I am not a race driver, nor is this a race car. Any opinions here, or is this just the normal passenger seat shaking inducing wobble on a 996? Should I just drive the hell out of it and not worry? Or tear into it again. The car is running fantastically after a valve job and lots of other work. Tons of low end torque where it was absent before. At about 1-1.5k rpm the "wobbling" starts to smooth out, barely perceptible - and above that completely imperceptible. But at 680rpm you can certainly feel a little wobbly through the seat. Turning the A/C on to raise the rpm also smooths it out somewhat. Of course the crank pulley wobble is still present. It has fabspeed headers and mufflers as well as an EVOMS warm air intake. I didn't have the special Porsche tool to check the crank bore's concentricity while the engine was out. The RMS I installed about 5k miles and 1 year ago was dry as a bone, so I didn't touch it. Hard to tell from short 20 second the HD video, but my non-scientific eye would say it's about 1-3 mm of wobble. http://www.youtube.com/watch?v=4vq4MWxfHh4

Well, at one time my eyeballs were able to spot a runout of just a couple of thousands of an inch. I don't trust them to this degree anymore. The angle of the view of the pulley is not the best and the resolution of the clip is not the best but I don't see 1 to 3 mm of runout. That's 0.039" to 0.118". That's a lot. If you have access to one mount a dial indicator *securely* to the engine and positioned so its plunger contacts the pulley face then remove the fuel pump fuse and have someone crank the engine while you watch the indicator. Or remove the spark plugs and turn the engine by hand and measure the actual pulley runouts. If you don't have access to a dial indicator setup or don't want to bother then I would say absent any specific callout regarding the amount of axial and radial runout the crankshaft pulley can have and absent anyway to accurately measure this then my assumption would be the runout at the crankshaft pulley should be not more than the runout at any of the the pulleys. You'll have to make this judgement by eye though. Be careful you don't get caught in the belt while you're getting up close to the various pulleys. If the crankshaft pulley runout is more than that of the other pulleys... I think you need to be concerned, at least concerned enough to make a better determination as to what the runout is and to what the limits are. Sincerely, Macster.

I don't think I should be trusting my eyes either for something like this. I'll get a more accurate measurement. Thanks.

I can't see any runout either, are you sure it's not just various size stains on the pulley? For a cheap quick dial indicator hold a popsicle stick/screwdriver just barley against the pulley & see if the contact varies. I'm sure you are overly paranoid during rebuilt engine startup as I am.

watch at the cranking point..it runs out pretty bad IMO...hard to see when running, but whild cranking its easy to see

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Give him some help and hold your hands around the pulley when its running and slowly tighten to see if there are any uneven spots Hey wow where's the fan thats supposed to be attached to it? Everything is an optical illusion when it comes to rotating objects. Even uneven can look even and visa versa. Is it balanced is what makes perfect for the crank.

Hard to believe that you could feel pulley wobble inside of the car. Why do you suspect runout? Did you drop it on it's head while rebuilding? If the crank/block were not concentric it would leak not wobble. Measure it with a dial indicator. If you find runout what are you going to do, remove the pulley and see if it is the crank or just the pulley? I would suspect the vibration is from a slight miss or weak motor mounts.

It's really hard to tell by that video......it sorta looks like how mine was but mine started to leak really bad...I actually had a front main seal leaking a lot of oil and it looked like the pulley was wobbling

Ah the paranoia of a newly fixed engine. I remember when I first had my engine back together after fixing my cracked head. I listened for every little noise, etc. Well after 13,000 miles I now just drive the heck out of it. If there is any wobble I don't think it is the crank, could just be the pulley itself. If you are really worried about it I would try a new pulley and see what happens.

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LOL, no drops, the block was well treated. No leaks. Front or back. I plan on it. LOL. More like feeling an imbalance or perhaps a timing issue. The crank pulley is attached to something last time I checked, right? Lets see, something-or-other shaft right? J/K I think in this case if it was the worst I would probably be looking at a new engine or just drive the crap out of this one until it dies. The nail on the head. I think I might be over it, but I am still going to measure. The thought has crossed my mind. Related or not, the recently installed RMS was bone dry after 5k miles and the pulley end seal dry after 75k miles. Thanks again everyone for the ideas.

Ok, some research while I wait to get some more accurate measurements. Crankshaft axial play wear limit, .28mm (.011") Crankshaft radial play wear limit .15 mm (.0059") (an UN educated guess, could not find any figures anywhere) New stock crankshaft 99610201157 $3300.00 Billet Flat 6 crank shaft $1,000,000 ($5500.00) At those prices and the cost of complete tear down and all the other parts associated (if even salvageable) with that I would probably consider http://www.renegadehybrids.com or perhaps try my luck with a donor M96 engine. I suppose the pulley could be out of true as well? Regarding pulley options: New stock pulley 99610211563 $86.00 New pulley bolt 90008208501 $1.33 Flat 6 harmonic pulley $295.00 RSS 3.8L pulley $329.00 Also, found this post http://www.renntech.org/forums/topic...haft-with-pics "We have a front mounted harmonic damper in testing that should significantly reduce the issues that arise when the dual mass is removed or when some imbalance exists. - Jake Raby" I wonder how much it would compensate for. And this post http://www.renntech.org/forums/topic...armonic-damper "just ordered the RSS 3.8 underdrive pulley, with integral damper...Pulley fits perfectly fine once you give the fixing boss a haircut and add the longer bolt. -Cloudsurfer" And this very sad post https://rennlist.com/forums/996-foru...-centered.html FWIW when my DMF was out of the car I followed TSB 1360 and it could be rotated both left and right by 15mm and then sprung back to original position. I was also very careful to reinstall it and ensuring perfect seating on the flange and each of the flywheel bolts was stretched to 120 degrees after being torqued. Of course, I am not dismissing the possibility that the 75k mile DMF could be not absorbing as much imbalance as it should - perhaps it is "tired". Perhaps the damage is already done and I should just keep driving it and consider myself lucky that the crank seals are not leaking.

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Good eyes. Watching the cranking portion several times and watching the pulley's outer edge relative to various fixed engine components, bolts or other things, there does seem to be some initial radial run out. But if it were me facing this before I pulled the engine I'd like to have confirmation the apparent runout was real, not normal and in fact excessive and needing attention. Sincerely, Macster.

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Yes this might have been poor hindsight on my part. Still getting to know the car. I suppose best case the run out is not excessive and perhaps the addition of a harmonic pulley or new DMF will help longevity. Or perhaps worst case I spent all that time tearing it apart when I really should have cracked the case... oh well. What can you do? For now I am just sorta ignoring that I noticed this potential problem. Had it out for a great drive today and it is performing wonderfully.

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You should still consider getting an accurate measurement of the runout, the amount and direction. If there's more runout than allowed and the pulley is not bent or improperly installed, then the chances another pulley (even a harmonic one) or a new DMF is going to mitigate that run out is slim to none. The runout comes from either the crankshaft bearing or bearings have excessive clearance or the crankshaft cradle is loose, unless you tell me you had the engine cases apart and crank cradle/crankshaft apart in which case ... did you forget a bearing? Sorry. That is I can't think of anything else provided the pulley and its installation have been eliminated. Except... in some cases at least at the rear main seal the standard procedure when replacing a leaking RMS was to check the location/position of the crankshaft seal diameter relative to the seal bore. If the crankshaft was out of position the engine was deemed bad and replaced. The problem was somehow the crank cradle shifted out of position. Now my thinking is if the crank cradle can shift out of position at the back of the engine at the RMS area what's to say it can't shift out of position at the front of the engine, at the front main seal area (FMS)? A bit of question about the above is while the crank was found to be out of position I do not know if the crank remained out of position or was this a dynamic thing? Did the rear of the crank move about and cause the flywheel to exhibit runout? I don't know. Before you go any further I still think you need to accurately assess the crank runout and be sure it is not something else, something less serious. Sincerely, Macster.

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I brought the car to the dealer today and the service manager who has sat in a lot of 911's thought that the slightly seat shake inducing idle was perfectly normal. In fact he said as the used cars manager he would consider it to be running very well (sans a more lengthy inspection). He looked at me funny though when I mentioned a potential crankshaft run-out problem, either bearings or the shaft itself. I have a dial gauge and will be obtaining the measurements of the pulley in the next few days. If it's out of spec I would hope it is just a bent pulley. Unfortunately I can't find the complete specs and the dealer would not provide. I will try to post on Renntech to see if someone might know. All I could locate was the axial play from the work shop manual. Crankshaft axial play wear limit, .28mm (.011") No, I did not take the case apart. I would be surprised if this were true for out of warranty engines on a 12 year old car. The new RMS I installed was BONE dry after about 6-8k miles. The one previous to that installed by the dealer 30k miles previous was also BONE dry. The front main seal is also free of leaks.

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Then the runout was an optical illusion. I'm been on both sides of this question. Make the measurements and know for sure. I hope the runout is an optical illusion. If the seals are dry the crankshaft is not out of position and the runout is most likely not real. No way those seals can compensate for 1mm to 3mm runout. As for a bit of engine/car shaking...I know my Turbo engine at idle sometimes shakes the seats a bit. The engine is a rather high performance engine and this bit of shaking doesn't bother me. My 06 GTO with the 6.0l V8 really rocked at idle. Very cool. The Boxster with its engine is the smoothest engine I've ever had in a car. One guy (a manager where I used to work) who I let drive the car when I needed to pick up another car described the experience of driving the Boxster like driving a sewing machine. Smooth. The only smoother running engine I've ever encountered in one of my vehicles was a 318CI V8 I rebuilt for a Dodge D200 pickup truck I owned for awhile. After the rebuild -- just using off the shelf factory new parts -- that engine ran so smooth that more than once I'd turn the key on to start the engine even though the engine was running. Smooth! Very smooth. And with a 2-bbl carb (which I rebuilt too) no less. Sincerely, Macster.

Not sure about the pulley problem but my impression is a shaking passenger seat is very common on a '99 and less so on newer models. How are your engine mounts and tranmission mount? Tired mounts will contribute to more vibrations too.

Yep there are several threads here and on sixspeed where the shaking passenger seat is perfectly normal. Engine mounts have about 15k on them. New trans mount has about 6-8k on it. First thing is to take the measurement. If the measurements are not within spec then... I would remove the pulley. If the pulley is not true, I'm out a few dollars for a bolt and pulley for $100. If the pulley is true, it's not the end of the world if I have to drop the engine and spend another $1500 to open the case and replace bearings, etc. Worst case and there is something more serious than bearings such as the shaft I'm out an engine. I wouldn't know what to do at that point. I'll have to fab up a tool to counter hold the pulley, I don't trust my $3 harbor freight strap wrench. LOL. 986fix.com...

I'm still working out a way to measure axial play with my inexpensive indicator, but here is a radial measurement. The indicator sweep while cranking for about 2 seconds went from -.006 to .016. A 0.022" difference (0.5588 mm). I am guesstimating a +/- .002 degree of error based on the plungers resting location, since the indicator would give me slightly different readings (about .001 to .002 difference) based on where it rested. In other words when I pulled the plunger up and let it spring back it would read on the 0, sometimes .001, sometimes .002. Also, the outer edge of the pulley had a few imperfections, so that is going to contribute to a degree of error as well. Here is a very short video of the measurement. http://www.youtube.com/watch?v=3XHAc7HHVI0 Before cranking. I couldn't stop the video frame by frame, but this was the best I could get, it might have gone .001 or .002 higher than this. The lowest it reached. Again, it might have gone .001 or .002 higher than this. After cranking. An overall shot of the rig. The plunger was resting on the inside flange of the outer edge of the crank pulley. It was not touching a groove. Let me know if I should try to obtain a different measurement (although might be difficult to do). The indicator was VERY securely mounted to the engine via a pulley bolt, I'm not worried about it having shifted during the test, and repeated the results above a couple times.

good set up...the motor IMO turns faster than the plunger can react...try and hand crank the motor..set the low and read the high....

GOOD call out. After spending some more time with it, the spring was probably causing the plunger to skip a little. Rotating the crank by hand revealed .018" (exactly half way around the pulley from the low point). Three more times around and the same result. The measurement was taken at the farthest point out from the pulley. I will see if I can rig it to measure the inner part of the pulley and also the center in a groove. Edit: measured the center of the pulley. Same results. .018"

thats 0.5 mm not sure its desirable but as long as the center sealing surface isnt doing the same thing inside the case....I think you need a second data point..if that contraption bolts on and off quick, have a friend let you measure theirs 9this is where it gets weird right....the asking.....can I measure yours )

Well no leaks, so if there really is that much radial play going on the seals are doing a great job of soaking it up, because there really isn't a drop of oil coming from either seal. Half a millimeter seems like a lot of play to be going on in the crank case and having the engine seem to run so well. If it is just a warped bolt or pulley, it's an easy fix I guess. But I've never heard of that happening on this car, has anyone? I think I'm going to replace the pulley and bolt or at least pull it off to get a better look at it. That is a good idea to get a second data point, it is extremely easy to bolt on, just remove the one fixed pulley and it bolts right in. Anyhow I gave up trying to get a solid axial play measurement. The best I could come up with was about .001 to .004 ish. It certainly wasn't more than a few thousandths at most. Any other ideas out there? If the crankshaft bearings were that worn or damaged would there be any other symptoms that I could easily check without complete dis-assembly?

are you 100% sure the pulley you're measuring on is perfectly true and centered? I have spent the better part of three years working crankshaft quality control and no crank is ever perfectly straight. that doesn't mean a problem as they are rotated and balanced as long as there is enough clearance in the bearings to cater for the "warpness". i would not worry as long as it runs well, makes normal noises and doesn't cause leaks. crankshafts are STRONG and if warped, likely it was from the factory...

all true but 1/2 mm is a little more than just "not perfectly straight" IMO - and the car runs...but I think he wants to know what the wobble is about and if it will be a long term issue or be OK

The only reason why I saw this. After I raised the engine from recent head rebuild, I had the air box out and someone was cranking it without the fuel pump fuse to prime with oil before first firing. I looked at the pulley and noticed it was not true. My eye thought 1mm or more. That's what prompted measurement, especially considering there is no harmonic damper on this car, just a DMF. I'm glad I measured and found .5 mm, at least I know my eye wasn't playing tricks on me. No, I'm not sure the pulley is true, and I'm probably going to buy another one. I am hoping it is just the pulley or perhaps the way it is installed.

Check the bolt hole in the pulley for wear as well as the crank snout pulley register I.D. & locating pin. I have had 2 engines balanced & both pulleys were out of balance.

0.018" is a lot of crank play. The crank would have to be pretty loose in its bearings, or the crank bent, to manifest that amount runout so I would have to chime in with the others who have cautioned you to be sure the pulley is mounted properly. A pulley that is not centered, or had a ding on the reference diameter that centers the pulley, or if the pulley face is not clean and free of dings/dents and the same goes for the face of teh crank nose to which the pulley bolts this can cause the runout you seek. Sincerely, Macster.

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The axial play you found is probably normal. The crank is allowed some axial play/movement. One thousandths to 4 thousandths of an inch is within some reasonable range based on what I can recall from other engines. If the crankshaft bearings were worn enough that the crank had that much true freeplay I think you'd know it from the engine's bearings knocking. Those are plain bearings that rely upon fluid pressure created by the oil pump *and* the very close fits of the crank main/rod bearing journals and the bearings in which they turn. Enough wear to allow the crank that much freeplay would have the engine facing some serious engine oil presure problems. About all you can do is add a t-fitting where you can get an oil pressure reading at cranking, engine start and idling. If the bearing clearances are real... You'll know it. Sincerely, Macster.

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Short of using an external gauge, for what it's worth I recently replaced the oil pressure sender, both oil scavenge pumps, as well as the hex driver, piston, spring, and all of the gaskets, o-rings, and washers on the oil pump. The pressure reading prior to this work would momentarily dip to 0.8 bar at hot idle and fluctuate a little between 1 +/- 0.2. The pressure was normal at all other times, 5 bar at cold, and in the normal ranges reported while driving. I have a feeling the low pressure problem may have been to a bad spring or possibly a partially binding scavenge pump, but not certain. Because... After the above work, it stays at 1 bar very hot idle dead level with no more fluctuation. All the other readings are still normal. Or perhaps refreshing the oiling system components has masked the problem that you describe with very worn bearings or potentially warped crankshaft and the next step is to crack open the case and then dig a grave for it.

Well, let's not get ahead of things. You first need to be sure that run out is the crank or the pulley. To do this you need to eliminate the pulley from the equation. Can you remove the pulley and then check the radial and axial runout of the crankshaft's nose whe the pulley mounts? At the same time you can evaluate the pulley and its condition both where it mounts to the crank. And you can lay the pulley on something flat (I used to have a shop grade surface plate for this work) to determine if the pulley was bent/warped, shaped like a potato chip, in short in some way not suitable for use. I would consider doing this long before I would consider dropping the engine and opening it up or scraping the engine. Sincerely, Macster.

+1 irst do what Macster suggested "Well, let's not get ahead of things. You first need to be sure that run out is the crank or the pulley." I think that you are just being paranoid... 0,5mm is not that much. Put your dial indicator on the top of the pulley, 12 o'clock, then try to lift the pulley carefully up. Now read the reading, and you have the play that can come from the crank. Is the run out ewen? I mean that when you rotate the pulley, the measure grows stedy when you turn from your zero point to max 0,5mm Is there only radial movement? Or does it "woble" axially allso? Is the reading the same from inner edge and outer edge? if it is the same, it could only come from the pulley. IMO Personally, I would not worry about it.

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Yes, I can cerrtainly do this. I suppose I should be able to reinstall the pulley bolt and rotate by hand without the pulley mounted. It might be a while though because I need to make a proper counter holding tool. I don't trust my $3 harbor freight strap wrench. In addition, I need to have a new crank bolt ready to reinstall since it is a single use stretch item, in the event the play is in the shaft and I resinstall the pulley. As for laying it flat and observing axial play I don't think there is much. As for roundness, I will try to get measurements. Yes, I am not planning to go inside unless there is a real problem. Looking at my other cars with similar mileage, they have no run out that I can see visually. Sure there might be some play in those other cars, but it is probably in the thousandths, not hundreths... Also, with this much play, it is certainly putting more stress on the other accessory drives such as the A/C and water pump, which could lead to premature wear over a crank pulley that does not wobble. Thanks, I will try this. Yes it is even, the high point occurs exactly half way around the pulley and then gradually back down again to the low point at the opposite side. In other words it is slighly oval by .5mm. Whether that runout is observed on the crankshaft is probably a better question. I could not find much more than about .001 to .004 inches of axial play. I measured on the outer edge, and again on three inner grooves from that (more than half way way to the inside). The measurement was identical. I could not rig my indicator to measure the inside flange of the pulley. Half of me is not worrying about it and I have been driving the car. The other half is concerned that if it is abnormal or a condition that is worsening, I might be able to salvage what I've got versus ignoring it until that fateful day when it becomes a big bucket of broken metal.

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Why would it put stress on other parts?? Are you thinking the difference in beltspeed or tension? The tensioner is spring loaded and will absorb the small amount of lenght difference that the pulley causes. Or are you thinking the speed variations? I think that the engine rews fluctuate more than this 0,5mm runout causes... Anyways, check it out. Hope that the cause is the pulley.

Although the spring probably compensates for some for the wobble in the crank pulley, my guess is the proximity the accessories linked to the crank pulley will add more stress to their bearings than if there was no wobble at all. .5 a millimeter though isn't a huge amount, so the belt stretch probably soaks some of it up too. That might be micro-analyzing the situation though. Yep, planning to remove the pulley and measure run out on the shaft end. I am praying it isn't there and is only in the pulley. As well as measure the existing pulley as best I can. It might be a while before I'm able to do these things and I will certainly report back to this thread once those things are done.

Crank pulley removed, indicator fixed to engine and crank shaft radial and axial run out measured. I cheated on removing the pulley, I saw this in a 986 forum as a DIY to change to a harmonic pulley. I used the TDC fixing boss pin to counter hold the pulley whilst removing the bolt. I also had my cheap strap wrench on there for good measure, to counter hold, but I think the pin and boss took most of the pressure. I nearly made a bad oops and re-installed the crank pulley bolt to rotate by hand. While this would have worked to get the measurement, I wouldn't have had a way to counter hold the crank shaft if the bolt was too tight, thus probably requiring removal of the transmission to install the flywheel lock in place. That would have sucked. Anyhow, after pondering (luckily) for a while about this I just decided to remove the spark plug leads, disconnect the fuel pump fuse, and crank the starter motor. Here is the overall rig. Again very secure to the engine with an idler pulley bolt. Here is a short 20 second video of the measurement. http://www.youtube.com/watch?v=ce6RT8RvPf8 MUCH to my delight, radial run out on the crank shaft only measured about .002" or .003 ( +/- .001" ), possibly even a little less. Granted there is going to be some error due to the plunger spring possibly bouncing when the starter cranks, but probably not much because the crank surface is so smooth. Here was the starting point: The high point: And the low point (which also became the resting point, demonstrating the degree of error): NOW here is where I'm a little confused. I tried measuring the pulley but could not find the .5mm I was looking for. Perhaps I just don't have a good way to measure it. Any ideas short of taking/mailing it somewhere where they have a machine to do these sort of things? Perhaps the bolt is bent? Or does anyone think this is enough evidence here to be satisfied that the crankshaft is not bent nor are the bearings excessively worn and buy a new pulley and bolt and be done with it?

well having never measured the crank end before I am actuall pretty shocked it has that much run out. if you look at "bearing specs" whcih this is a bearing they are WAY less than that. did you try and move the crank lattertally by hand and see it the indicator moves? maybe it has to do with no oil pressure which might center the end in the bearing (remember there is clearance between the bearing and the crank for oil....a couple thousants IIRC) 1/2 mm you should ba able to measure from the center of the pulley to the outter lip with calipers but to hit the inner lip you will need some sort of a "standard" I suggest laying a socket or something in the grooves and measure over that to the center...again with a single data point not sure what the "norm" is....

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When I push on the crank in different directions I am about to get it to move about .0006 to .0008. When watching the video a couple times I noticed when I stopped cranking the indicator slowly moved a little, perhaps .0003 to .0005 ish - PERHAPS - indicating that the oil pressure was relieved between the bearing and the shaft and it rested on top of the bearing and whatever oil was left over between those surfaces. Unfortunately without these specifications we are just speculating, this could be perfectly normal. Certainly I could not find the .018" though in the crank end, which is what was previously measured on the pulley (but I can't find a way to accurately measure now with pulley removed from the car). I tried for about 20 minutes with the calipers but couldn't get a reliable measurement on the pulley - it would change every time too much indicating I wasn't resting the points at exactly the same spot. Perhaps the pulley is the red herring and the run out is in a bent bolt or pulley not perfectly mated to the crank end. In addition - as for the potato chip factor, there is very little axial play on the pulley. On several different flat surfaces it did not appear to be curved in any way I could see or feel - which adds some leverage to the axial play measurement of .001 to .003 I got before. Well I'm measuring less than that on the crank shaft itself (no pulley). Only .002 (+/- .001) of radial run out. Which is 1 thousandth or 2 thousandths. Perhaps you meant ten-thousandths? Because I am observing about .0003 to .0007 ish of run out when cranking (indicating oil pressure?) or when pushing on the crank by hand. It's difficult to type these numbers in this post with any kind of seriousness, because I doubt my indicator is that accurate. The degree of error is larger than that with the spring rate in the plunger, it's clearance between it's shaft and tube and the surface it is resting on.

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You should never see the crank move anywhere near the amount of its bearing clearances. Say if the crank bearing clearances are 0.001" (just a number) the crank will not move either sideways or back and forth (back and forth btw is controlled by the thrust bearing/buttons anyway and not by the main bearings) by 0.001". The crank has 7 main bearings and each bearing even when the crank is not turning has an oil film that resists compression and thus the crank is resistent to moving. Remember too the crank has a rod bolted on either side of its main bearings and these rods are attached to pistons and these pistons have some resistence to movement. Besides, to state the obvious the crank is one seriously stiff and strong piece of forged steel. At the forces you're able to put to it the crank should not flex or bend. When you put a dial indicator against a pulley or something similar and turn that pulley at 'high' speed this speed of rotation will magnify the amount the indicator moves. When I checked runout I turned the item by hand or by a wrench and sometimes noted the movement while the part was moving or if the part had say bolt holes or other gaps in the face I was indicating I'd lift the indicator away from the face, turn the part to bring the next flat surface of the face under the indicator then gently lower the indicator back to the surface of the face and take a static reading of the face's runout. Now just to point out this, in case it has not occurred to you, if the crank face where the pulley bolts has a bit of runout this runout will be magnified at the the pulley's outer diameter (assuming the pulley is perfect in every way). There's trig involved and my trig is rusty but as way of some rough example say the crank's face has 0.001 of an inch of runout, the pulley with a diameter of 10" might express a runout several times that 0.001" number. If the crank had that much free play, that much slop, I think the engine would be in pieces by now. Even if it was still together the engine would be making noises and letting you know something was amiss. Without being at the engine, observing your measurement technique, or making my own measurements I can't say for sure with 100% confidence but based on what you post I'd say the crank's ok. Sincerely, Macster.

Logray, just put the car the way it was and drive it. There is nothing wrong in it... Bearing cleraces are usually about 0,005in. (for the engines that I have worked on) If the pin and the bolt centers the pulley, 0,5mm throw out can be easy come from that. You said that the car runs normal and performs well? What's the problem oh, did I mentioned, just drive it....

Thanks everyone again for the input. Macster, yes that is the way I measured with the dial indicator cranking by hand when the pulley was attached, stopping at intervals and resetting the plunger (and got .018"). But you see this was not possible with the pulley removed. So yes, there will be some degree of error when using the starter motor with the shaft surface moving so quickly across the surface of the indicator plunger (as was discovered with the pulley by about .004" of error using this method), however there isn't much I can do about that without removing the transmission (the pulley bolt might get locked into the shaft with no way to counter hold to remove). I would like to think this is a more accurate measurement though because the surface of the crank end was much smoother than the surface of the pulley, so there was probably less "skip". Certainly though it could have reacted more or less than it would whilst turning by hand. So is it .001? or .002? or .003? Not sure. Anyways I'm already happier that it isn't .018" that I measured, THAT certainly would be some cause for concern. Now as to being able to press the shaft in one direction by hand and seeing the indicator move, perhaps that is just the way the indicator is mounted, or perhaps there is a real problem there if I'm able to read ~.0005" of play? I put it all back together and already drove it. No problems, it runs great... seriously. Just not used to seeing a solid pulley wobble "by eye"... that's what threw me off. I might order a new pulley and bolt, then again I might not. I bet it's been like this for 75,000 miles and I, nor any shop or previous owner noticed it. OH, and BTW I do have a "real" issue I've got to address. I've been suspecting my bank 1 variocam solenoid or actuator to be lazy and am kicking myself for not addressing it when the cam covers were off, as it's thrown a few intermittent P1531's in the past that have cleared - or I hadn't been able to activate the bank 1 cam mechanism with PST2 at times, but then other times it would work... anyways now it is solid P1531 and applying 12v manually to the solenoid does not activate the solenoid or actuator (don't hear click or tell tale sign of idle change). Anyhow looks like I'll be tearing off the cam cover for bank 1 to replace that actuator and solenoid...

you might not get a perfect reading with calipers but you should be able to see 0.02 pretty easy on the pulley and when I said there is clearance between the bearing and crank for oil, I was saying a few thousanths but the bearing and the crank should not move more than a few 10ths of thousanths IMO - the reason I stated the oil thing is I was wondering if there was some "normalizing" that the oil does to make the crank concentric with the bearing...but when running, a bearing and its mating part should almost have zero movement esp with a crude indicator...if your wheels had that much your car would hop of the road...even seen the spec for the rotor runnout? it's wicked tight!

Quotes source posts: 8734518, 8734518

I can't, which is what is killing me. I could only reproduce about a .2mm measurement. So as Macster said, perhaps an imperfection in the crank shaft amplifies the .2mm run out in the pulley. I am thinking perhaps the .018" is somewhere else, the bolt, the bolt hole in the crank flange is not centered, or something else. I've put it back together for now. Well perhaps? there is a real problem then with worn bearing(s) and I need to dismantle the bearing carrier and replace them to eliminate the 5 ten-thousandths of an inch I was able to observe on the dial indicator by pressing on the end of the crankshaft by hand and the ~.002" ish that the dial indicator measured on the end of the crank flange.

Come on ivangene, I have seen rims that have 3mm runout, and you cant feel it when you drive... IMO the measurement is correct, and if you want to make it more accurate, lift the rear up put the transmission to 6th. Ask your friend to hold the other wheel while you rotate the other. (works only with manual trans) The movement is so small, that it might be just the engine wibrating when startermotor is running... You can't measure the bearing clearance from the crank, thats true, but it is possible to calculate the movement if you know the lenght of the shaft. (and the right bearing clearace) When you move the shaft when engine is not running, there is no oil pressure and thus you can get the shaft move. The dial indicator that logray has used should be accurate enough to measure this...

Just for fun and some perspective... A standard round toothpick's width in the center is .07" At the tip it is .015". So .001" is REALLY REALLY tiny. and .0005" is even smaller. Human hair's width varies from fine .0006" (0.017 mm) to very coarse .007" (0.181 mm) I'm starting to believe the run out I was seeing was somewhat an optical illusion. In other words when I pressed on the crank shaft, the dial indicator moved the width of a fine piece of human hair. Or the indicator measured the width of the tip of a toothpick's in run out at the crank pulley outer rim. Or this much. Or I measured 2 x to 3 x the width of a fine piece of human hair in crank shaft end radial run out (or less than half that of a very coarse piece of human hair). A dime's width is .05", or about 2.7x the amount of run out I measured on the pulley.

this is what I have tryed to tell you