If the pistons, rings and cyls are tight and at spec, with 4% leak down you could just fix the heads.

I'll share an observation on valve guides that I have observed over the years. NEVER EVER lug these motors in hot climates! I monitor head temps in my 3.2L, actually I monitor a lot of items and sensors. If you drive below 3000RPMs in hot climate >80F the cyl head temps sky-rocket! I believe this to be the root cause of valve guide wear. By the time the oil temps go up it's to late!

Reason the temps go up so fast are 2 reasons:
1 - The engine fan not spinning fast enough.
2 - Thermal load goes up a lot at lower RPM. At a lower RPM the injector pulse width goes up and the amount of work (heat) per stroke goes up proportionally to IPW.

You simply have 2 bad things happening at the same time, fan spins slow and thermal load going up! Very bad.

On a 90F day If I drop RPMs to 2500RPM vs 3000RPM by simply selecting 5th gear instead of 4th I see CHTs go up by more than 50C! The valve guides take a beating.

I'm curious how this motor has been used, has it seen significant lugging? Driving around in hot temps at 2500RPMs or less?

Service records show it spent most of its life in Florida and Houston, Texas. They also hint that the PO was not much of a car guy (he didn’t even change his own wiper blades), so low rpm use is possible.

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This is the first I’ve heard of this! Extremely useful if not counterintuitive. The technical knowledge on this forum never ceases to amaze. Drive it like you stole it, particularly on hot days😉

Its Time!

Great comments by all, I went into a project in 2005 and now after retirement I am working to get it running. Do not start more disassembly!!! Now I do not remember where I put parts after 2 moves, buying things and then finding the original ones.
1. Inventory all, mark it all and give it a number.
2. Place all in clean boxes/containers and tag/mark/label with the number.
3. In a sheet write the number and description of item on each box.
4. Do it your way, don't put a number until part is checked and cleaned ready to put in service.
5. Now buy what you need and upgrade parts as you feel.
No one can tell you the great feeling when you are seeing progress. Take a break and enjoy work/progress before you leave the working area.

I remember in Germany a lot of Porsche mechanics that used to work at Zuffenhausen Porsche and worked independently, if the motor had 5% or less they worked the motor and miles/Km was not a factor. They never took the pistons out. The pistons/cylinders was left untouched! I was shocked about that and they told me that they will not re-ring Porsche pistons; they will replace all if a full rebuild was needed.

Enjoy your Porsche, Its a very nice one...

Best to you,

Jose

I rebuilt my engine at 186K miles re-using the Alusil jugs. I even consulted with Bruce Anderson. The most wear I could find on any cylinder was .0015". Well within spec.

My recommendation is to clean them up REAL good. Like in a parts washer. There is carbon packed into the pores, between the bits of silicon. Removing this carbon improves your chances of the rings seating properly. And, as Mr. Anderson said, don't baby it. Use regular 30W oil for start up and drive it like you stole it.