06-09-2013, 09:57 PM #1
Measureing Axial Play In Your Turbos
I've been plagued with oil consumption issues and smoking with catalyst free down pipes. I plan on buying some upgraded turbos (see last paragraph), but wanted to be sure this would fix the problem. I figured if I could measure the axial play in the turbo shafts, this should be the smoking gun I need.
I noticed when I bought the car it ate a quart of oil every 1500-2000 miles. I was told this is normal and these cars just use oil. Bull$#@!. Once I put on the FMIC and downpipes sans catalysts, I noticed smoking issues that I originally attributed to PCV problems. After re-engineering the PCV system to actually catch oil vapor instead of making a mess of the inside of my intake ports, I still had problems. The main one was my denial that the turbos were not bad.
I also noticed I burned more oil the higher I had the boost. For this reason I have been running Cobb Stage 0 and my oil consumption dropped from a quart ever 250-500 miles with Stage 2 + FMIC to 1800 miles as of the last quart added running Stage 0.
I borrowed a dial indicator and holder with various arms from work.
I removed the downpipes. I had switched back to the stock downpipes because people were literally flagging me down to let me know the car was smoking. How they thought I could drive around and not notice the smell and associated cloud behind my car in traffic and when coming to a stop was beyond me. At least they seemed like nice people concerned about my car and possibly my safety, but I digress. I found by pulling the exhaust rearward with a ratchet strap, I was more easily able to remove/reinstall the stock DPs and gaskets because they use studs instead of bolts.
I started with the front turbo. Noting a distinct lack of ferro-magnetic material on that side of the engine, I used a c-clamp the secure the base of the dial indicator holder to the subframe. The following image was taking from directly below the turbo, with the steering rack removed and pushed forward for additional arm room.
This image was taken from the spot where the pre-cats usually are, somewhere under the rear turbo, looking forward to the front turbo. Note the tip of the dial indicator on the end of the shaft.
To take the measurement, I positioned the tip of the indicator on the top portion of the end of the shaft, and got a pair of needle nose pliers in there to push and pull the shaft through it's range of motion. It was tricky because you have to get a good grip on the shaft and pull it straight in and out, without disturbing the indicator. This image is of the rear turbo, but it was done the same way for the front. I put heat shrink tubing on the tips of the jaws of the pliers to create a surface with more friction compared to the metal jaws on the metal shaft. You are not going to get a picture of that, sorry. Electrical tape would also work I just happen to have a lot of heat shrink tubing. Another way to take the measurement is to remove the air intake tube to gain access to the other end of the shaft from the compressor side.
Next I moved to the rear turbo. You can get an idea of how I positioned the arms of the holder from the image below. I kept the base in the same spot, but repositioned the arms, which was tedious due to lack of room.
Over all the front turbo had 0.0085" of axial play and the rear turbo had 0.006" of axial play. The best information on the internet I can find states the play should be between 0.0015" and 0.003". Both my turbos are out of specification, which is not surprising due to my oil burning issue. At least I can point to a cause now instead of guessing.
Sources for axial play specification:
The Suburu document is for a TD04 I believe, but I figured at the very least the TD03 would have the same if not slightly tighter tolerances.
Not everyone may have access to a dial indicator and holder, but McMaster-Carr carries a wide selection, with less expensive setups running around $50 for everything (magnetic base holder and 0-1" indicator with 0.0005" accuracy). They are very useful tools to have. If you can change downpipes, you can do this. Just be careful with your turbine wheels.
I did this in my driveway, laying on a piece of cardboard using Harbor Freight tools. Note: my driveway is not an approved installation center. Tony, I want my warranty.Eppur si muove.
06-09-2013, 10:02 PM #2
06-09-2013, 10:13 PM #3
No. I suspect I would only notice this if there was a problem with the journal bearings causing excessive radial play and not the thrust bearing which causes excessive axial play. I mean the turbos do make noise, but it doesn't sound like the fins from the compressor or turbine wheels are touching the inside of the housings. It just sounds like a set of tiny turbos spooling.Eppur si muove.
06-09-2013, 10:14 PM #4
Cool. Thread title spelling fail.Eppur si muove.
06-09-2013, 10:26 PM #5
06-09-2013, 10:30 PM #6
06-09-2013, 10:37 PM #7
06-11-2013, 01:15 AM #8
I like learning things.
Those two avatars still bother me. I don't know why I just feel like that guy just talked to himself.Chrome Space Bar Issue: http://www.boostaddict.com/showthrea...338#post738338
06-11-2013, 01:54 AM #9SOLD --'07 E90 335i, PTF COBB E50, HFS4, ER CP, ETS 7", AA DP, Vishnu Exhaust, DCI, ACT, Nitto Nt555
'10 E92 335i M, 6MT COBB v3, ER IC, ER CP, VRSF DP, Fuel-it st2
installing soon: Mfactory LSD, , powerflex subrframe bushings