968norway

I read an article years ago (968.net?) about chain stretch where they recommended changing the cam chain at 50k miles to avoid stretching problems, Hartech in England says 45k. Also the tooth profile is changed on the replacement cams, so it seems Porsche knew about the problem. I put in new cams at 160k km and changed the chain last year at 240k km, no apparent wear on the cam.

sydneyman

finally got around to take the cover off.. there is zero damage that i can see. even rotated the motor to see all of the sprocket teeth clearly... put the cover back on since someone mentioned it might just have been valve noise, started it up and it sounds horrible... took a video but can't seem to upload...

sydneyman

ok a quick update. there are metal particulates all through the head and block oil passages as evidenced by cutting my oil filter in half. the guy helping me says i need a new tensioner and valves at the very least most likely and is talking with an engine builder about how viable cleaning out the block without stripping it down is...

so at this point im at least taking the head off for a valve job and sourcing a new tensioner. probably should take the oil pan off and replace rod bearings as well.(even though they were done 2 years ago.)

so any ideas fellas? maybe get an 8v head and do a low psi supercharger? it would be cheaper than an 1800 tensioner for the variocam... a turbo setup with the 8 valve head would be cool as well but im not sure i want to mess with the added plumbing...

sydneyman

as to why the metal is there, the assumption is that it has built up over time from the last cam issue...

dougs968

Are the metal particles magnetic?

odurandina

V8 Chevy?

tamathumper

I'm the first to admit these motors are overly complex and underpowered in their stock form, but... Seriously?! V8 Chevy?! That's just wrong.

odurandina

I love the cars but i'm so over these engines and their endless $1,500~2,500 dollar repair bills, it's not even funny.

just a partial list;

tb/bsb/h20 pump1 etc, $1,500
oil cooler leaking $800
tb/bsb/h20 pump2
AC pump 1 replaced $1,600
ps pump $800
tb/bsb/h20 pump3 w/variocam/chain/pads etc, update $3,500 at a shop... RLer did it for about a grand less
starter motor $400
blown head gasket would have been $3,000 ++ but I used headgasket sealer to great success.
clutch $2,100
AC pump 2 dead. would have been $1,700.... I deleted it.
tb/bsb/h20 pump4 $1,500

this has been a car that has basically seen a best case scenario over it's 185 k miles of road use.

with the camshafts ready to go and time to do the rod bearings.....

and w/ my headgasket hanging by a thread, might as well add the overdue complete valve job....


sorry, but it's one thing to drive these cars 6 k miles each year....

it's another thing altogether to daily drive them.


I drive my 968 98% of the time...

for my specific application, it was time to cut loose of this endless money pit motor the day I bought the car. for all that money I could have enjoyed a serious horsepower kick in the tail. and had a car that would get to 70 mph in less than 6 seconds *(not 10 seconds).....

if you don't endlessly beat on it, all a v8 requies is oil changes, air filters, fuel filters, then do the valvesprings/pushrods/lifter and rebuilt ac pump swapouts every 50~60 k miles.

and then gives you tons of endless power and runs forever....


it's just a conversation about the endless money drain vs something that actually works.

and if that's wrong. I don't want to be right.


/

sydneyman

OD!!!!



And for those that don't know, the original cam issue happened at 91k and it now has a little over 93k... so if that puts things into perspective. the cams were replaced at 75k for a similar issue by the PO.

today i'll find out if the particulates are magnetic, thanks Doug! completely forgot to test that...

and im not completely against the chevy swap. i almost did it once when my 951 motor grenaded...

Of course, if i can find a reasonable solution with whats there, then i'll stay stock but at this point im not going to spend 5-6 grand on a basically stock motor with the original bottom end. im either getting rid of variocam and going with some type of blower or maybe go the S2 route with a much simpler tensioner and maybe get some headwork and some nice cams to make up for the lack of variocam. then again, those tensioners have their problems as well.

and to make the purists heads explode, im actually rebuilding a 4.6 rover V8 right now...

RajDatta

Please check your PM. If you think going to an S2 solution is the answer, you need to do some research. S2 tensioner is a very poor design. The tensioner is known to completely sheer off the head. It only has 2 mounting points. There is a reason why Porsche went with 3 mounting points for the 968 tensioner.

Your cheapest solution is to fix it with what you have. Going any other route will open a big can of worms and it would be yrs and serious $$ before it ever gets done.

Just saw this thread. Let me digest it and I will get back to you with some ideas.

RajDatta

Has anyone ever checked your oil pick up tube to comfirm that its not cracked? If the tube is cracked, you will suck in air and have erratic oil pressure, the same oil pressure that tensions the variocam tensioner. Your problem seems to be something else besides tensioner (if you did replace it last time).

What is your oil pressure like? It is very normal for the top end to make funny sounds when the oil pickup is cracked. I would strongly suggest checking this.

sydneyman

Hey Raj, responded to your pm! as far as the pick up tube goes, the pan is coming off soon to check for bearing damage and metal particles anyways so i'll check it out then. that being said, the pressure is fine with the stock gauge. not that i really trust the gauge for 100% accuracy...

and agreed with the s2 tensioner comments. ive seen what happens when they fail and its not pretty. thats really a nonstarter for me.

sydneyman

so heres the story now. to properly remove the metal particles from the motor, would require an engine out deal. with the cost of removal and putting everything back together, my mechanic recommends parting the thing out. I really don't want to do that and ive not driven the car for so long now that i thought i'd list it for sale for a reasonable price on here so someone else can fix her up and enjoy her. If theres any interest, ill post a for sale thread with pics and more info etc... its not perfect cosmetically but thats what i liked about it. a solid daily driver or so i thought.

we looked at a number of options ranging from 6-12,000 dollars. (simple "clean up" rebuild, rebuild with performance in mind, ls1, turbo, etc...) But dropping even that much after spending 5500 on this exact same issue earlier this year, not to mention 15 grand on suspension, interior, and exhaust work over the past 5 years of ownership is super depressing. on top of that it could use a respray.

I love the 968 but its just not worth having 35-40 grand invested in one. (unless its a replica turbo )

blue44

bummer, hope it works out for you...

Donn

flwbyu

So sorry to hear about all of your troubles! I am kinda going through the $ spent thing myself. Never boring...