1Eighteen

Tii pistons ? Any good ?

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I have acquired a set of used pistons.  But they look like this, so are they toast ?  Or salvageable ?

 

They are early Tii oversize pistons.

 

 

GEDC1645.JPG

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If thats all the damage there is it could be removed as it's not on the thrust side of the piston. You'll need to measure and inspect the rest of it for wear especially the ring lands and groves, from what I can see from the picture there doesn't appear to be any scuffing on the skirt.  

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Thanks.  The rest of the piston (s) look ok.

 

I will get new rings if I use them.

 

 I managed to remove the raised metal using some emery cloth earlier.

 

It looks like the pistons have been hitting the crank.  Is that possible ?

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1 hour ago, 1Eighteen said:

It looks like the pistons have been hitting the crank.  Is that possible ?

That's a drop onto something damage.  With that much upset metal, that was not while in the engine.

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They could not have done that in the bore and then come out of the bore.

That little lip would have been cleaned off.  So it happened after the engine

was torn down.  Maybe how they were packed.

 

Shoot us a pic of the skirts- from what I can see, they look ok, but the

amount of varnish makes them look pretty used, and the ring lands in particular,

as Marty's son says above, are not all that long- lived...

 

t

 

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Rightly or wrong Toby, I had my OCD hat on and gave these a good clean to remove the carbon build up, which wasn't that significant to be honest.  Came off easily with a bit of degreaser and elbow grease and...ahem.....using the parts cleaner (which for some reason the wife keeps using for dishes, silly woman !!)

 

The skirts look really good, some minor vertical scratches, but nothing major.  I don't have a micrometer to hand, so I'll ask the engine shop to measure them before doing any rebore work, to ensure they are ok.  As for the ring lands, I have taken a chance and ordered new rings, so I'll have to measure the gaps once they're fitted, as you can see, I have removed the old ones to clean them.

 

One compression ring is stuck solid, hence only 3 pistons in the picture, it is being soaked.  Any tips to get it off would be appreciated ?

 

My plan is to mount these heads onto my original rods, using the original wrist pins ?  Is that going to be OK ?  Say YES, because I forgot to number and pair the rods that I pulled these off !!!  :(

 

 

GEDC1647.JPG

GEDC1648.JPG

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I see why you want to use those- they look really clean.

I hope the lands are good.

 

Do give them to your shop before they bore- they can bore to the specific piston, and compensate

a little for wear.  I wish we could get slightly overthickness rings...  it's not hard to clean up the land on a lathe.

 

Yes, your rods will be just fine.  I mark rods out of habit, but the only thing that is critical

is that the cap and rod stay together.

 

Nice- I hope they work!

 

As for a stuck ring, start working at the gap, being really careful not to damage the piston.

You'll get under it, and as you start spreading the gap, it'll break.  That's ok- then you can get

under it a bit more, break off another chunk, and so on.  I've soaked them in gasoline to try

to get the carbon to soften.  That 'sorta' worked...  then I've used the original, squared end of the

broken ring to clean the gap, again being really careful not to gouge the top and bottom lands.

 

hth!

 

t

 

Edited by TobyB
stuck ring

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Ya oughta use the piston pins that from the postons, not the original.  And it's best to not mix the pins.

Edited by jimk

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Cheers guys.  Very helpful.

 

I managed to release the stuck ring after a good soak in some degreaser.  All the pistons cleaned up really nicely. 

 

I have also mounted them onto the engines original rods, but used the pistons own pins, although, I have to admit they were mixed up by then !!  :wacko:.  The original rods have new bearings, as does the crank, as part of the rebuild, so I had to use them really.

 

It's a LONG story, but I am not actually doing the rebuild (apart from this work).  I will just be putting the short block together and it will be going back to the shop for the reassembly.  Originally I was going to just line cylinder #1 (as I couldn't afford new pistons), but I scored these pistons for a song, so it would be silly not to rebore now.

 

One last thing bugging me:

 

Obviously the 'new' pistons are now DRY.  Is it a good idea to give them an oil bath in new oil before storing them ?

 

 

 

 

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Yes.  Otherwise they will corrode like crazy...  yes, aluminum is really reactive.

 

I'd missed the pins- I have to admit, I've never worried too much about them, as long as the fit was tight.

 

t

 

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