This sounds like the piston pin [ wrist pin] wasn't hardened properly to create that amount of wear in such a short space of time.

Problem is, that the metal swarf created by the pin wear will have gone everywhere so it's now a major strip, wash, clean and blow dry with New piston pins.

I suppose that it is possible that the pistons were hitting the heads and thus overloading the piston pins - but the noise that usually makes is so loud you would turn the thing off in seconds from start up.

Beyond that I am lost for another idea.

David APi

I guess that when the crank was reground, that the thrust faces weren't properly measured or machined, thus the clearances were too tight.

It's the not regrind that has caused it, just the way it was done and who did it. I've not seen a clutch brutal enough to kill a thrust bearing on its own, there has to be an underlyting factor, and that to me points to the tolerances being over-tight.

Would check with teh guy who reground the crank.

Then invest in a new crank, unfortunatly that means forking out for new bearing shells again, but its the best route IMO.

And as Dave says, the gudgeon pins shouldn't be wearing like that.

The pins are perectly round with no flat spots and they all mic up the same as for the deck hight i can post this later after i measure it, I showed the macinshop and 4 mechanics and they cant work out why this has happened as they are so polished and not showing and sign of oil starvation ??

Just hit me, One of the bearing manufacturers that makes oversize shells for Subaru makes the thrust faces oversize too. Most times they won't fit because the thrust face have not been ground. We never have.

BUT it is possible under certain circumstances to get the standard crank to fit into the oversize shells which will then tear themselves to bits 'cos they're too tight.

If these shells for the reground crank are/were the oversize thrust ones, then that may be the answer.

David APi

Hi David
Does this mean he may have 2 problems, as the gudeon pins are very badly worn.

I was wondering that too. Maybe, is the best I can offer. The piston pins problem is unusual, as they do wear a bit after many thousands of miles but not to worn out in such a low mileage. So, something must have caused the wear.

However, the scuffed metal coming off the wearing thrust faces would get everywhere and is unlikely to damage the piston pins and nothing else. They are a bit tucked up out of the way, after all.

It's sort of something l'd like to see, to offer a safe opinion. But by the guys terminology; ' wrist pins ' being an American expression, I suspect that he is not in the UK.

David APi

Im from Windsor berks but couldn't remember how to spell gudeon lol thats why i just said wrist pins. im going to take a pic of em now and post it so you can all see how bloody worn they are.

The only link I can fathom with the thrust bearing and gudgeon pins is that the rods were not running perpendicular to the crank, due to the crank not seating centrally in the block, or moved around when the thrust bearing started to wear. But I'd expect to see signs of this on the big end bearings as well as the pins.

Bloody yanks get everywhere - Windsor now !!:lol: Wherever next !!

try; gudgeon or piston pin as I did.

Pics by all means, but if you want to chuck it all in a box and bring it up for a viewing here, we'll do whatever we can - no obligation to spend. Pics don't tell a whole story. The remains might.

David

I thought that too for a while, but I think the small end bush would wear long before a hardened steel shaft [ at least it ought to ...... ]

David

PS it is still a possibility, though slim - good thought!.

Here you are girls some pics for ya.

http://i67.photobucket.com/albums/h2...Picture074.jpg
http://i67.photobucket.com/albums/h2...Picture078.jpg

I know it dont show the wear that much but least you can see the sufaces.

Certainly does seem to show wear consistent with the rod not being central to the bore and tilting over to one side. As the wear appears to be on one side more than the other.

Maybe the wrongly positioned crank was the culprit due to the wrong position of the crank thrusts. Does that make sense?? I know what I am trying to say but it won't clarify.

Check the rods for straightness too l'd think. Easy enough to do, find a genuine flat surface and lay them down sideways You'll soon see daylight if it doesn't run straight up its length.

David APi

Ps going home now.

Thing is if i get 2 and sit them together they have the same amount of wear right along the lenght not more one end to the other also i used brand new eagle rods and all the pins have the same amount of wear on them?

oh unless you mean one unworn ring is narrower then the other showing the rod has slipped along the length about 1mm which is how much the crank moved.

Those gudgeon pins ( thanks for the spelling David) look nasty, I would agree that it looks like the connecting rods have been moving along the pin, there are score marks at each side, where the little end sits, do the little end bearings in the top of the rod, show any signs of excessive wear or overheating?

David, do pistons match all makes of rods at the little end, or are some machined to fit?

Just trying to help out, but without the block going to a machine shop to be measured, with all the relevant bits, I think the diagnosis via text is difficult.

I think all that you are looking at is a result of the original failure that occured not long after rebuilding the engine.

ACL lead/copper bearings do not have any lead coating on the thrust side, it's bare copper. So that suggests that your thrust bearings have not worn appreciably. I would guess that when your bearings went in the first instance the damage to the crank was done then and went unoticed.

What has caused it to fail this time around is anyones guess, but I'm guessing debris in the crank or oil cooler has entered the engine and caused the bearings to fail, causing further debris which has caused damage of it's own.

While I would certainly not recommend to regrind a subaru crank, a 0.25 regrind should not totally remove the hardened layer, and certainly not be the root cause of this second failure. Do we even know if all the journals were reground or just the big ends? Were the correct bearings mated to correctly sized journals and pins? For all we know the block was still full of abrasive material from the boring and honing.

New cranks, oil coolers and proper cleansing of parts prior to building, are often the elements overlooked by those offering "cheap" rebuilds or DIYers doing on a tight budget.

Scoobynet is littered with posts about how cheaply engine builds can be done and how expensive all us traders are, but there are more posts about failed engine builds done on the cheap!

To my knowledge all piston pin diameters in EJ20's are the same. But maybe sometimes people like Jun may make matching ' specials' of odd sizes. In this case I'd fully expect it to be the same. There is always a need to check clearances and fit but if they were new parts then it should all be OK and plain sailing.

I think the oversize thrust washers have caught you out.

David

Surely oversize thrust bearings would be wider and not fit in the crank if it hadn't had the thrust surfaces ground? The other alternative, is that normal main bearings had been fitted on a crank with ground journals, big oops.

Believe me Paul, they can be ' persuaded ' to fit I have seen it before.

David APi

I just love a good lump hammer !!!!!

There's been many a time I've moved a well worn engine by holding the crank pulley and felt/heard a large thunk from the huge amounts of end float...and on the odd ocassion it was a rebuilt engine :eek: I suppose loose is better than tight :lol1: