[flash]

with the cover on, because of the long spark plug tunnel, you really can't see much

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[vliegwielolaf1234]

 i just tried and removed a plug  ,no problem i can see the top of the piston , so if it is all screwed up in there , you wil be able to spot enough to now things are really broken , at least i would .

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[ds968]

Yes, Trevor looked inside the plug holes with a flashlight ( and a very good LED one, lots of lumens ..) and everything which was visible appeared normal. So guessing that means the problem is all at the bottom end... as in the rod flash mentioned ?

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[ds968]

And I have to say this again ; so lucky about the spare engine availability and right in my backyard, lucky to have friends who go out of their way and interrupt their daily lives to help ( not to mention their mechanical aptitude which to me is amazing ) lucky to have the collective wisdom and technical support of this forum , all without which the future of this car would be in serious question ; had the cost of a new engine and installation been prohibitive it's extremely likely I would have simply stored the car as nothing more than a spare parts "stockroom" for my other 968 . But this way, with a rather reasonable ( relatively speaking of course ) P&L cost anticipated , I'd be crazy not to have the new engine put in and drive it happily into the sunrise.....until the next time the sun sets on it :-( :-(

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[MCL968]

Flash is more familiar with these engines than I am, and thus more likely to be right about the rod. The symptoms add up, noise from under the car would be the rod banging around, loss of power, and the eventual locking of the engine. That would be the likely explanation if the rod failed somewhere in the middle.

 

I have only experienced mid-rod failure when a rod was compromised and was no longer pushing in a straight line. Usually from hydro-locking a cylinder from fuel or water in a boat motor (failed flapper valve on the exhaust). But with that said, I have experienced more than a few rods that failed at the crank end. The rod gets loose from the crank, the crank comes around and beats the rod against the block, producing a ruined crank, a bent rod, and a pound or so of block-burger in the pan. Rarely does this result in a locked engine, and typically the oil light comes on because the missing rod end allows the oil to flow freely from the rod journal, and system pressure drops.

 

And I have only seen this occur in engines that have been either recently assembled at the factory, or recently reassembled. Once an engine has a lot of miles on it, rod ends tend to stay put.

 

There is a possibility that you "backsided" a piston. That's when you basically pull the bottom off the piston, which allows the rod to move up and down in the cylinder independently from the top half of the piston, and eventually jam into something and stop the engine in a hurry. Backsiding pistons is a common experience for drag racers because of the lightness of the pistons, the huge acceleration curves and piston speeds, and the massive induction pressures used to generate the horsepower required.

 

Regardless, the solution is a new engine and a complete teardown to search for causes and salvageable parts. I still can't explain the totally seized nature of this engine, but weird things happen and every failure is a little different.

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[Ernie]

Can anyone explain how the potential "fragged rod" could lead to the filter disintegration? I'm trying to understand how that could happen? I am also curious, as I have a canton oil filter and am now concerned that there may be an issue with the filter. I don't recall there being any "bad news" about canton filters in previous threads though.

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[ds968]

On my other 968 the two previous Canton filter insert changes did not reveal any major mangling or disintegration, so I have to believe there was a link somehow to whatever happened here .. but if you look at the previous post from our member in the Netherlands , his experience reflects a fairly consistent pattern of damage ..

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[Ernie]

Thanks Dan, but I don't remember any other complaints on this forum about them. Flash says it's a better filter and enough of us run them in our cars, that I would think there would be a consistent pattern of problems with them? I'm not discounting vlieg's experience, but doesn't it make sense that we would see these filter problems more often? Maybe not as catastrophic as your experience, though? Keep us posted , as you may be the canary in the coal mine. Thanks

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[vliegwielolaf1234]

Since it is not a canton filter topic , still i like to share my findings .

 

I hooked up an oil pressure gauge to the variocam oil line , turned out i my case at cold start up, it took about 1.5 second longer before oilpressure was there , with the original porsche filter it was there instant .

 

Wat happend in my case , the oil runs back  from the filter and from the oil gallaries upwards to the cilinderhead where the check valve sits in the head , with the original oilfilter this does not happen and the oil stays up there , i was not happy  with that , the reason i checked was because i heard it every time i started the engine ,first noise and then the oil reaching the top and things went quiet again .

 

I took filter insert out and it turned out to be mangeld a bit , so i thougt that is the probelm , installed a new insert , same thing and still te slower oil pressure on start up and did it again new insert same thing, was not happy with it and went back to the Original filter .

 

 

 

Also i took an insert to a specialist in filtering oil of all kind's , mainly in big Industrial machines , he said it  looks cheap and crappy (the insert ) and there is not enough surface for the filter to be used with a interval of 20000km , wich is the normal intervall for the 968 engine ,

 

 

I think i am a pretty good  mechanic , rebuild plenty of engines including 968 944 911 and even good old usa v8's , a friend of mine has a engine shop and are into  tractorpulling (european champinon's) so i have an above average backup in knowlege there  , they know their stuff .

 

So i was not happy with the canton and what it does the 968 engine , also i believe that the slower build up would not  be fatal very quick , the mangeld up filter hower concerns me .

 

Overall i decided i am better of with the Original messy filter  .

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[Ernie]

Thanks for the explanation.

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[Bulti]

The Mann filters I use have 2 check valves in them. When you put a few rags around it when changing it, the mess is very managable and doesn't justify the cost of the Canton. At least not for me. They look cool though :-)

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[flash]

thinking that having oil sitting in the filter is a good thing is a common misconception.

 

actually, the original filter presents a pressure backup, and the system has to overcome that before it can send oil anywhere.  it is far better to send a small low pressure amount of oil to the bearings BEFORE starting the engine, i.e. during cranking, then to have instantaneous high pressure.  the canton filter allows no pressure head to have to overcome, and thereby allows the oil to hit the bearings sooner.

 

also, the gauge is misleading in that it does not send a reading until idle.

 

in a perfect world, there would be no filter at all, and no check valve at all.  but, we can't all have dry sumps.

 

the mangled filter is a result, not a cause, assuming it was properly installed.  this one is important.  you have to put the filter onto the lid first, and then insert it into the can.  also, you cannot tighten it beyond hand tight, or it will tear the end cap off.

 

as for the construction, it's really pretty beefy.  it can flow almost twice the volume of the OEM filter, and filters down to 8microns, as opposed to the 16 of the mahle.

 

i've been running this filter for 11 years now.  when i pulled apart my motor, every single bearing surface looked brand new, and specced out with zero wear.  the oil stays clean longer than with the OEM filter too.   it was getting dirty enough to change at about 4k miles with the OEM filter.  it goes about 7k with the canton, and that's supercharged to boot.

 

as for change interval, no matter what it says on the bottle, anybody who thinks they should wait 20000km on these cars is asking for a failure.  it's more like half that.  do an oil test.  the data will be very illuminating.  these cars run way too fat at startup for that.  supercharged ones are rich in heavier throttle areas as well.  that means dirty oil sooner.

 

this is one of those where somebody started some rumour and it got picked up.  it's like the K&N filter myth that some 928 guys started.  it was really that they over-oiled the filter, and not the filter itself that was the problem.

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[ds968]

Back to the bigger problem ( the filter is a peripheral issue and not really major enough for me to spend time dwelling on it ) - so we're replacing the engine with Trevor's , because as everyone said here, not matter what the problem may be , considering the engine is seized , fixing it would be harder and likely as coslty as replacing the engine, so a no-brainier option here. And if the guys want to subsequently take this one apart to get the exact answer of what exactly happened, that's up to them, we'll certainly post the findings. Just hope that this is an extremely rare occurrence on these cars and no one else here will ever experience it.

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[PorscheG96]

Dan, I'm inclined to re-use your cylinder head, not only based on its great condition but after reviewing the 968 oiling circuit, the oil filter should've saved it from any carnage. When we remove the head we will inspect it closely for any debris and possibly even strip it all down for a good cleaning. When the head is removed we can measure piston heights to see if a rod is bent or broken. Actually, we could do that with a dowel through the spark plug holes fairly quickly while were scoping...


So who wants to bet money on root cause of this engine failure? Losers put $ into the pot towards Dan's rebuild, haha.


In addition to the entire block we will need to replace the oil cooler and lines.

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[ds968]

Trevor, entirely your call on what components to use and which not to use ..whatever is in the better condition between the two would seem logical.

Yeah, I like the idea of a lottery where calling tne cause of tne failure gets the winner 50 % of the pot, and the other 50% goes to fixing it.

Whaaaat ? Lol.

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[flash]

before you pull the head, see if you can get the boroscope up to see if the valves are in place or not

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[Rap]

What just a doggone minute. It's Christmas and poor ole Dan has lost his engine. Shouldn't we just contribute to the cost of his new engine without needing to be enticed by the temptation of a raffle? It would be in the spirit of the season!

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[ds968]

Ha, funny RAP should say that...if we had only started this forum slush fund I proposed many years ago ( see thread link below )...

http://www.968forums.com/topic/7523-968-...entry72535

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[vliegwielolaf1234]

thinking that having oil sitting in the filter is a good thing is a common misconception.

 

actually, the original filter presents a pressure backup, and the system has to overcome that before it can send oil anywhere.  it is far better to send a small low pressure amount of oil to the bearings BEFORE starting the engine, i.e. during cranking, then to have instantaneous high pressure.  the canton filter allows no pressure head to have to overcome, and thereby allows the oil to hit the bearings sooner.

 

also, the gauge is misleading in that it does not send a reading until idle.

 

in a perfect world, there would be no filter at all, and no check valve at all.  but, we can't all have dry sumps.

 

the mangled filter is a result, not a cause, assuming it was properly installed.  this one is important.  you have to put the filter onto the lid first, and then insert it into the can.  also, you cannot tighten it beyond hand tight, or it will tear the end cap off.

 

as for the construction, it's really pretty beefy.  it can flow almost twice the volume of the OEM filter, and filters down to 8microns, as opposed to the 16 of the mahle.

 

i've been running this filter for 11 years now.  when i pulled apart my motor, every single bearing surface looked brand new, and specced out with zero wear.  the oil stays clean longer than with the OEM filter too.   it was getting dirty enough to change at about 4k miles with the OEM filter.  it goes about 7k with the canton, and that's supercharged to boot.

 

as for change interval, no matter what it says on the bottle, anybody who thinks they should wait 20000km on these cars is asking for a failure.  it's more like half that.  do an oil test.  the data will be very illuminating.  these cars run way too fat at startup for that.  supercharged ones are rich in heavier throttle areas as well.  that means dirty oil sooner.

 

this is one of those where somebody started some rumour and it got picked up.  it's like the K&N filter myth that some 928 guys started.  it was really that they over-oiled the filter, and not the filter itself that was the problem.

The external oil gauge i had hooked up to the head show a different story ,concerning the pressure ,, at start up .

 

For the rest , i wish everyone the best with their  canton filter and it looks real good , let me know as soon as you hit 300000km ,  the standard 968 engine with standard oilchanges and oil filter at 20000km has no problem reaching that kind of numbers .

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[Bulti]

+1 on Olaf's comments.


It's also difficult to believe that they make filters with check valves in them, if that would be worse for the engine than having none. If the filter drains it takes longer to build up pressure and you need enough pressure to force the oil through the bearings.

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