Manual transmission causes crankshaft wear!
 

I have very recently found out something about early crankshaft wear that is caused, believe it or not, by starting the engine with the clutch depressed.
Wheather you have a push or pull clutch, depressing the clutch while starting a cold engine causes wear on the crankshaft journal that keeps the crankshaft from walking.
I will now ONLY START THE ENGINE in neutral.
Once the engine is running there is oil pressure and minimal wear is experienced.
More on this later.
Tom

Re: Manual transmission causes crankshaft wear!
 

Now that I think about it, I have always put my cars and bikes in neutral when starting. It's just the way I've always done it. On a 2 stroke dirt bike you can feel the extra force necessary to kick it over in gear.

Re: Manual transmission causes crankshaft wear!
 

I believe that the engine that I just took apart has less than 7000 miles on it since I built it using the best of everything. The walk on the crankshaft was 0.032". It should be no more that 0.0045". I installed a new bearing to recheck it and the walk was 0.020''-0.018". The wear was only on one side of crankshaft, on the side that the crankshaft gets pushed to when the clutch is depressed.
I have to replace the crankshaft, or find thicker bearings for it in terms of width, to compensate for the crankshaft wear.
Note, I would only try this on my personal engine after much more research!

Re: Manual transmission causes crankshaft wear!
 

As an aside I lost my phone that had every ones phone number on it.:rolleyes:
If you would like me to have your number it is the one listed on my website that ends with 2837. Thanks.:)

Re: Manual transmission causes crankshaft wear!
 

this is true, but almost all cars nowadays have a clutch safety switch so starter won't engage unless clutch is pushed in…..now, on my BRAT it never had that feature, but newer cars do. Would have to defeat the switch

Re: Manual transmission causes crankshaft wear!
 

I once used shim stock and a pair of scissors to add a bit of thickness to the thrust washers. Slipped them in behind the thrust washers. Worked a treat and a lot cheaper than a new crank.

Re: Manual transmission causes crankshaft wear!
 

The thrust bearing is in a fixed position and allows no movement in relation to the block. Shimming it would be a lot easier. sigh...

Re: Manual transmission causes crankshaft wear!
 

The question now is what can we do to prevent this other than the obvious of wiring the safety's to let the car start without the clutch depressed. Is there a different thrust bearing to use or some configuration of clutch?

Re: Manual transmission causes crankshaft wear!
 

I am going to look into a few things since I now know that there IS a problem. Until the other day I/we had no idea that there was a problem.
What I have been told is the softer/weaker the pressure plate/clutch cover is the less the wear.
I am going to see if other Subaru sized crankshaft bearings are able to be installed, or if there is a way to install more thrust bearings into our blocks without spending a ton on machine work.
What do the 1200HP 2.0 guys do?!
If anyone knows already feel free to guide us.:)

Re: Manual transmission causes crankshaft wear!
 

I dont think a lighter pressure plate is the answer, some of us have power goals in mind.

Re: Manual transmission causes crankshaft wear!
 

I am/was only reporting what a reputable Subaru mechanic has opined. I have always recommended higher stage clutches.
Only one time have I installed a stock Subaru clutch behind a 3.3 and it slipped instantly. Took it out, had the stock flywheel step machined for more pressure, it slipped again. Took it out, installed a custom flywheel with a stage? clutch, and it has been fine ever since.

Re: Manual transmission causes crankshaft wear!
 

Do you have a push clutch or a pull clutch? Obviously they each put a different direction of force on the crankshaft and thrust bearing.

This may be the reason Subaru switched to a pull clutch on the higher power cars with stronger clutches (WRX and STi). Maybe they were worried about possible thrust bearing wear... I've never really been able to figure out why Subaru went with the odd pull style clutch.

Re: Manual transmission causes crankshaft wear!
 

The engine was mated to a six speed with a hydraulic clutch that pushed on the clutch fork, and (presumably) as a result the noticeable wear was on the front side of the thrust bearing side of the crankshaft journal.
The engine is back on a stand, so I am going from memory.
As soon as I am done with my roof, fix the lawnmower and cut the grass, perhaps do head gaskets on the new Forrester, I will have a chance to get back onto it.
I will be investigating further, and will report as soon as I can.
lots to do, Tom. :rolleyes:

Re: Manual transmission causes crankshaft wear!
 

Just to collect more info on this issue.

1. What type of oil and weight did you run? What oil filter? (Not that I think oil had anything to do with it)

2. Was there any noticeable crank walk? How were the bearing clearances when you assembled the engine (tight, normal, or lose)?

3. Were there any oiling issues? Pickup tube clogged or cracked? O-ring on the pickup tube damaged? Oil pump leaking or damaged internally? Pan dented in against the pickup?

4. What journal is the thrust bearing in the EG33? I know the 4 cylinders were either 3rd or 5th depending on age.

Just want to get as much info as possible. I'll add more as I think of them. Yours seems to be the first EG33 with this issue. There have been minor reports of these issues from the 4 cylinder crowd, but mostly with the phase 1 3rd position thrust bearing cranks. The rear, 5th position thrust bearing motors didn't seem to have any issues.

Re: Manual transmission causes crankshaft wear!
 

1)The previous owner used 10/30 Mobil1 fully synthetic and a Purolator L30165.
2)Since I assembled the engine the tolerances were PERFECT!
3)Nothing was or is wrong with the oiling system!
4)I believe that the thrust washer is the fifth one back out of the seven main bearings, but until I get time to take it off of the engine stand I cannot say for sure.
This is not the first one with a worn crankshaft. A highly respected Subaru guru has seen this before on 3.3s with higher stage clutches.