What can I do with this 3.2l engine?

[elgyqc]

I have disassembled the pre-broken engine out of the 2000 S that I bought recently. I have bought a used engine to go back into the car.

Because of the copper shavings in the oil pan I was expecting problems with the big end and main bearings.
What I found was the big end on the #2 rod had spun and scored that crank journal. The bearing shell of the main bearing next to it was also destroyed, but it did not spin and the crank and bearing carrier appeared OK except for that one big end journal.







Here is one of the fried bearings. The bearing carrier seems to be fine when the offending bearing is removed.



The rest of the engine looks good for 169259 KM (105172 mi). All pistons and the 5 other rods are OK.

Originally I had planned sell the engine as-is or part it out, but when I saw how limited the damage I started thinking about rebuilding it… as cheaply as possible. I don’t have the money for a “change everything while you are in there” rebuild.

The crank and bearing carrier where inspected by a local specialist and they pronounced the bearing carrier undamaged and they can repair the crank for about $400.

But I also found there is scuffing in the cylinders. I say scuffing because the marks do not appear to be scoring, from what I understand from multiple discussions and videos.

Representative photos of the cylinders.







I can't feel the marks with my finger and I feel nothing with my fingernail except maybe one scratch per cylinder I feel a little bump.

So the question is what to do about the cylinders. I definitely can't afford sleeving and new pistons. If there is a way to clean up the cylinders and put the old pistons back in with new rings, that would be doable.

So… the options as I see them.
1) part it out.
2) put it back together with new bearings and rings and hope the scuffed cylinders will last…
3) find a way to clean up the cylinders and put it back together with new bearings and rings and hope the cleaned up cylinders will last…

Any suggestions are welcome.

[blue62]

Originally Posted by elgyqc

I have disassembled the pre-broken engine out of the 2000 S that I bought recently. I have bought a used engine to go back into the car.

Because of the copper shavings in the oil pan I was expecting problems with the big end and main bearings.
What I found was the big end on the #2 rod had spun and scored that crank journal. The bearing shell of the main bearing next to it was also destroyed, but it did not spin and the crank and bearing carrier appeared OK except for that one big end journal.

The rest of the engine looks good for 169259 KM (105172 mi). All pistons and the 5 other rods are OK.

Originally I had planned sell the engine as-is or part it out, but when I saw how limited the damage I started thinking about rebuilding it… as cheaply as possible. I don’t have the money for a “change everything while you are in there” rebuild.

The crank and bearing carrier where inspected by a local specialist and they pronounced the bearing carrier undamaged and they can repair the crank for about $400.

But I also found there is scuffing in the cylinders. I say scuffing because the marks do not appear to be scoring, from what I understand from multiple discussions and videos.

Representative photos of the cylinders.







I can't feel the marks with my finger and I feel nothing with my fingernail except maybe one scratch per cylinder I feel a little bump.

So the question is what to do about the cylinders. I definitely can't afford sleeving and new pistons. If there is a way to clean up the cylinders and put the old pistons back in with new rings, that would be doable.

So… the options as I see them.
1) part it out.
2) put it back together with new bearings and rings and hope the scuffed cylinders will last…
3) find a way to clean up the cylinders and put it back together with new bearings and rings and hope the cleaned up cylinders will last…

Any suggestions are welcome.

First the cylinders need to be measured "properly" for taper and roundness.
If they measure "Within Spec." then do a standard honing procedure on the cylinders.
That scuffing could very well clean up with just a standard honing job.
Your out very little money to do the above.

If the cylinders measure "Out of Spec." Then they would need sleeved.

[Homeoboxter]

I wouldn`t do conventional honing on the Lokasil bore. I did it in my 99 engine but in retrospect it probably wasn`t a good idea. Your bores seem damaged because of the pistons seized in the bores due to the lack of lubrication. What do your pistons look like? The bores allegedly can be reconditioned to some extent with the Sunnen AN-30 compound, some people had good results with it. I`ve never tried it. The problem with this in your case is that the pistons have a ferrous/iron coating which may have been damaged because of the seizing. This may lead to aluminum-to-aluminum (since the bore itself is is Al-Sil) contact and subsequent seizing. If you have plenty of time you may try, I`d be very curious to see how it turns out. You may end up wasting your time though.

Check out these links: https://goodson.com/products/an-30-silicon-compound
https://www.youtube.com/watch?v=TpjB0e_eaBA
911uk.com - Porsche Forum : View topic - Identifying bore scoring - with photos

You may consider Nickel Silicon Carbide plating, $750/bank.
https://www.millennium-tech.net/indService.php?id=1

[elgyqc]

Originally Posted by Homeoboxter

... Your bores seem damaged because of the pistons seized in the bores due to the lack of lubrication...

The pistons did not seize... they all slid out normally when I separated the cases

Originally Posted by Homeoboxter

What do your pistons look like? The bores allegedly can be reconditioned to some extent with the Sunnen AN-30 compound, some people had good results with it. I`ve never tried it. The problem with this in your case is that the pistons have a ferrous/iron coating which may have been damaged because of the seizing. This may lead to aluminum-to-aluminum (since the bore itself is is Al-Sil) contact and subsequent seizing. If you have plenty of time you may try, I`d be very curious to see how it turns out. You may end up wasting your time though.

Check out these links: https://goodson.com/products/an-30-silicon-compound
https://www.youtube.com/watch?v=TpjB0e_eaBA
911uk.com - Porsche Forum : View topic - Identifying bore scoring - with photos

You may consider Nickel Silicon Carbide plating, $750/bank.
https://www.millennium-tech.net/indService.php?id=1

The pistons seem to be OK, I'll have to do a closer inspection. I'll have a look at your links.

[blue62]

I had not considered the "Lokasil" bores.
I believe a "lokasil" treated block can be honed but you would want it done by a competent shop that is familiar with "Lokasil" treated Aluminum engine blocks.
A google search will find you some info on the issue.

[seningen]

Originally Posted by elgyqc

The pistons did not seize... they all slid out normally when I separated the cases



The pistons seem to be OK, I'll have to do a closer inspection. I'll have a look at your links.

My guess is you have thrust wear. The motion of the pistons going up and down have a component of pushing against the wall. Partly due to geometry of the rods/wrist pins and probably gravity as well.

It's been awhile, but I did send off some blocks to have them nikisiled and then honed by Millenium Technologies

[elgyqc]

Originally Posted by seningen

My guess is you have thrust wear. The motion of the pistons going up and down have a component of pushing against the wall. Partly due to geometry of the rods/wrist pins and probably gravity as well...

That makes sense. All of the scuff marks are on the top (as in top of the engine, not top of the cylinder) and bottom, which is what I would expect for thrust wear.

I had a closer look at the pistons. There is only normal wear on the skirts as far as I can see (not that I am an expert), the rings look like new and turn easily in their grooves, the rod bushings are tight when I try wiggling the rods laterally.

[elgyqc]

I have decided to sell the engine, it is in the parts for sale section here:
Porsche Boxster S 3.2l engine for parts or rebuild.