BETEPok

Absolutely, this is very concerning. I have stopped driving the car to prevent any further damage. My suspicion now is that the lifters were not replaced by the shop who rebuilt them. Everything else you mentioned like the tensioner and filters and so on were replaced. This makes me think that when I open the engine up on a stand I'm going to find wear and scoring on the oil pump since it would be sucking contaminated oil. Hopefully the Porsche OE oil filters did a good enough job that the brand new (and very expensive crankshaft) suffered no damage, bearings aren't so important as I can replace them easily. What I really am NOT looking forward to is removing the heads, which I'd rather avoid doing.

The oil thermostat was replaced and seems to be working properly, I've had the urge to make sure of that when this all started.

Alternative theory is bad quality replacement bearings, or the oil pump was previously damaged in the donor engine and was never up to the job in the first place. All things considered, this would probably be the best case scenario, but I should not get my hopes up.

Cheers,
Aleks

GregBBRD

A note above, in your text, in red. Indeed, the Porsche engineers knew what they were talking about....
If more "experts" could read and follow the Workshop Manual, I'd have a little bit less work rebuilding engines the second time and could concentrate on just rebuilding the worn out ones....

FredR

Thanks for the clarification- makes perfect sense. Presumably they figured out that it is better to relieve any build up of pressure internally than do so by blowing the filter cartridge apart - must take a shed load of crap to achieve that and for sure there was a whole load of the horrible stuff in the original GTS motor from my current 928 that I pulled apart thus following the WSM instructions in this regard is imperative.

That being the case what should the OP do regarding the crank oil passageways [that in part are dead ended] if indeed he has been circulating contaminated oil to some extent?

GregBBRD

The first thing to do (always), when you suspect something might be wrong inside an engine, is to remove the oil filter, cut off the top, remove the filter element, cut it off the internal support structure, and spread it out.
The oil filter is essentially the "X-ray" picture of what is going on, internally in your engine....without the radiation.
They make oil filter cutters, for this, but a vice and a hacksaw or a die grinder with a small cut off wheel works OK....you just need to ignore the metal the gets inside the can, when you are cutting off the top.
(Type "oil filter cutter" into your computer's browser and be prepared for a bunch of choices.)

I cut open every filter on every rebuilt engine I build, immediately following the 45 minute "test session" on my engine test stand and inspect it for debris/abnormal metal pieces. Regardless of how clean things are, there will almost always be a few tiny little pieces of aluminum, and occasionally a small chunk of sealant or gasket material, in this filter.
I cut open every oil filter on every freshly rebuilt engine I build, immediately following the 100-300 miles "test session/tuning session" that occurs once the engine is in the car....again, looking for any issues. This filter should be very clean.
We are generally changing the oil from the break-in oil to "normal oil", at this point in time.

The cam belts always need to re-adjusted at 1500-2000 miles and we will almost always do a third filter "check", at this point in time. The filter should be perfectly clean, at this inspection and oil changes/filter changes then go back to the routine maintenance schedule (7500 miles, for us.)

You can get a copy of the Factory Workshop manual from Jim Morehouse's collection of copied 928 publications.
Roger at 928 R Us has and sells Jim's collection.
(How they do this, without violating Porsche's copyrights is a mystery, but they do.)

GregBBRD

I've written volumes about Porsche crankshaft bearing sizes, on this Forum, alone.
Might be worth searching for and reading, if you discover that you have an issue.

Wisconsin Joe

My understanding is that Porsche doesn't go after the sale of the copyrighted material, but they object to it being advertised, to include being listed as available on the website.

Lizard928

The hydraulic lifters and chain tensioners can be fully disassembled and cleaned to remove any and all contaminants/particulates from them.
The use of an ultrasonic cleaner does help with this. You also have to extract the check valve cover removing the ball and spring to properly get in there and clean everything.
I think it is even more important to extract the oil galley plugs on the heads and clean out all of the passages in them.
However, regarding the engine that Greg is referring to on BaT the lifters were replaced with a good used set that had no wear. The chain tensioners were fully disassembled and cleaned and I am certain that all contaminants were gotten out of them.
I changed the filter at 300km and there was nothing to note inside the filter. The oil was changed from a break-in oil to a normal running oil at that time. The engine runs strong with zero issues. It is coming up on the next oil change and I will be opening the filter again.

GregBBRD

The reason I inquired about what occurred, on this engine, was that I had a couple of clients asking about bidding on it.
No replacement lifters and no mention of disassembly and ultrasonic cleaning, on the invoice was....frightening.
The removal of my question as being non-constuctive, instead of simply addressing what was done was....doubly frightening.
No mention of a replacement oil pump on an engine with a thrust bearing failure was...terrifying.

I simply told my clients that I had zero faith in the process and not bidding would be the smart move.

Lizard928

The oil pump was replaced and came with the good used block.
Greg your question was worded in a way that came off as antagonistic which was why it was removed. If you had simply asked if anything had been done with the lifters/tensioners/oil pump that would have been answered right away. I am certain that you also replace a few items on cars or spend more time on them than you end up billing for which is what happened here. Before turning away interested parties why didn't you just call and ask? I would've been happy to answer any questions you might have had and then if you were not satisfied with the answers you could have told the interested parties that. I'm actually disappointed that you would not think to just pick up the phone and ask instead of potentially costing the owner a potential sale.
If I was not 100% confident that I was able to get everything out of the part it would not have been reused.

GregBBRD

Good points. It never even occurred to me to pick up the phone, in today's world of communicating by typing.

Regardless, in the end, as more details came to light, I'm quite comfortable with my decision to not give my approval to my own clients.

I also am not interested in possibly "staining" this car with my own methodology, so it's probably best to just move on.

I wish the owner a satisfactory sale. It is certainly a unique GTS.

Vilhuer

There was chance in '89 MY IIRR where factory left out one of the valves near oil pressure sensor at side of the block. It should not affect oil pressure but change was done during S4 years.

BETEPok

Noted, thank you.

Aleks