valve seals

[Manute]

Hi!

I´m not sure to have them changed,but i´m checking my compression soon so maybe i´ll have a little surprise,so i´m gathering knowledge before i do nothing.

I have the worshop manual,and when it talks about changing valve seals it describes it with the cylinder head removed.My question is:is it possible to change valve seals withou removing the entire cylinder head?Removing only the camsaft, so i dont have to change cyl head gasket and not to do much more things.

My father is mechanic and says it´s possible in other cars,but 944 is unknow for us.

Thanks!

[SoCal Driver]

Possible with most cars. Have to make up a fitting for the spark plug hole so you can pressurize the cylinder. Keeps the valves from falling into them when you take off the valve springs.

Also raise the pistion to the top of the bore. Take off the yellow oil filler cap too as this lets the air that gets by the rings escape the crank galley.

Valve stem seals only keep out the oil from the cam galley. These have nothing to do with compression. If you are getting large clouds of white smoke behind you on high rev's during hard acceleration then it could be the seals. Might need valve guide replacement too.

Check the seals in the turbo too. These will bypass oil also.

[Manute]

Nice solution,yes!

But...sure they have nothing to do with compression? i tought the opposite...but i was not sure.
Regarding oil acceleration...do youknow the B52 bomber? I think it puffs less than me It´s not really white the smoke,it´s more or less black,so it might be oil.Also that would explain my oil consumption of about one quarter per 200 miles...
My first impression is that the cause is turbo seals,because i think they´ve never changed them,and also my turbo water pump does not function.I´m doing the compression check because it´s cheap and if it´s ok,i´ll get calm.

I posted a thread on turbo forum to know how to check if turbo leaks oil,I think i had read to remove intercooler pipes and look for oil there...if it´s so simple i will try it and see...am i wrong?

Thank you very much,it is very helpful the solution of valve seals,my father will be pleased,it´s the macGuyver of the mechanics!

[SoCal Driver]

Black smoke is running rich.

White smoke is burning oil.

Pressurizing the cylinder to hold the valves in is as old as are over head valves.

You really need to fix the rest of the things wrong with your car including the turbo water pump. Just price out a replacement turbo.

[Manute]

a replacement turbo??But tha´t would be very expensive!

And my turbo has only 77k miles!i think if i change the seals and the water pump it would be ok.

[SoCal Driver]

Yes a replacement turbo is a bit pricey!


Replace the turbo water pump!

[Manute]

yes, i prefer to replace that...(but is pricey too)

May be is only a relay after all....still not sure

[singpilot]

I was always taught that white smoke was coolant, blue was oil, black was fuel. Has been my experience. I know is nit-picking, and even blue smoke can look white.

Is a boring afternoon in NYC today, and I didn't want to get into it with Tabs about Nevada vs. California.

[ae1969]

MAnute.......

How does the car run??? DOes it idle/run fine?

[Manute]

Well....smoke is dark....is the only thing i can assure.My father says it´s oil...i think it´s oil,because fuel consumption is ok,i´m happy with that.I will observe next time a little more.

The car runs well,but i have not much experiencie with it...i have done about 4000 miles,It idles well,at about 840 rpm,very constant,only fluctuates sometimes a bit,but not often,and no more than about 50 rpm.It starts always at first attemp,normally after a week sttoped.

I cannot compare with a perfect car because i have´nt hear one,but i think it sounds well,like a engine in good condition.And also i think turbo spools well,dunno how might sound,but it seems it spools without problems...If there were no high oil consumption,i would think engine is perfect...Also all belts and front seals were changed 300 miles ago,i have´nt even retensioned the timing belt yet.

When i changed belts and all that,at the factory they show me all the complaints...little vibration on engine mounts,defective washer pump....little things.They said nothing about engine...i think they would have noticed something wrong.

And that´s all i know....thank you for your help,i have a lot of things to learn,and this car is very new to me.

It´s also a boring night here in Spain...better i go bed.What are you meaning with Nevada vs. California?Basket? i wish you enjoy it!

[ae1969]

Ok. You have 3 possibilities at this point........

1. Check compression.......... if its bad. You know your problem.

2. If the compression is good the turbo may have blown its seals ..... which can happen. Take a look at the intercooler pipes and see if their is a lot of oil in them. I haven't seen one set of pipes with out a little oil..........I am looking for a lot of oil, enough to justify the 1 quart of oil for every 200 miles.

3. But don't rule out the valve stem seals. Normally the seals breakdown over time and you get some oil smoke when you start the car, because the oil drips in while the car sits overnight. BUT. I have had valve seals pop off and it would cause high oil consumption almost to the point that you assume that it is a bad hole.......

But lets wait for the compression test.

Good luck.

[Manute]

I agree with your checklist...i have my compression checked the 30th,here we have to wait a month till they have room at the factory.

I have the hunch (i pray for it) that compression is o.k.,so i thinks it´s turbo seals or the valve ones.I dont know what is desirable...How much hours do you think are necessary? Materials i think are cheap,they are only seals...

So you had so much oil usage?I think i was at the Guiness book...You changed your seals,and then was solved?

I´ll tell you how things gone...thank you!

[SoCal Driver]

Can't be valve stem seals because the intake is under positive pressure and will blow any oil at the valves into the cam galley.

Think turbo seals.

[Manute]

i hope is that because might be less expensive isnt it?

Any idea of how many hours and materiasl price?

I actually work for the car....Thanks God my insurance price has decreased about 300 $!! Hurraaaa!!

[SoCal Driver]

You hope it's valve stem seals when these can not be the problem???

Must be something lost in the translation.

It's your time and money you can waste it as you feel like.

[Manute]

No,sorry,i did´nt express correctly,i mean that i prefer it is turbo seals,and i see very interesting what you say about positive pressure,i had´nt tought that before.Your statement is true,and now i discard valve seals.

Now i´m more or less sure that the problem is turbo seals,and i prefer this because removing cylinder head (I think in the factory they would remove it to change stem valves) will be more expensive,ans seals often are cheap,and removing the turbo i expect to be easier.

I have limited money,so i´m not doing anything I should´nt do...
Sorry if you misunderstood me,i´m still learning english and i don´t express myself as i would want.

You´d really helped me a lot clarifying my problem.

[SoCal Driver]

I'm still learning English too. At least most Englishmen think we Americans have the language about half right!

Try www.babblefish.com

Long story about the name. You will have to read The Hitchhiker's Guide To The Galaxy.

You have to remove the timing belt and the cam galley not the head itself. You can raise each cylinder to the top and use air pressure in the spark plug hole to keep the valves in place. The stem seals can be removed and replaced then. Old trick.

[Manute]

Yes, i understood how to change valve seals like you say...But i´m not doing myself (i don´t know if i could do),so, because i will bring it to the factory,i cannot tell them how to change it...I supose their procedure is removing the entire cyl head...if i tell them how to do it easyer, probably they´ll probably expel me from the worshop with a kick in my ass!

But well, we had demonstrate that this is not the problem...so not to worry about. Today i will take a look at intercooler pipes...i expect a little oil sea that confirms this.

Nice page,i will read it attentivly. I use a translator but it´s not very good...

And one thing...I prefer American than pure English....to me sounds better!

[SoCal Driver]

So you have socialized car repair too?

No such thing as an independent shop?

Do it your self. Screw the "factory" idiots!

[Manute]

Of course i would prefer to do it myself...But....this car is my dream,if I touch something internal to it it´s like i were doing surgery to my girlfriend...
And my father is a well experienced mechanic,it has more than 40 years of experience,so you may ask why we don´t do this...It´s because my father is diesel specialist,we dont have elevator and special tools,and the engines my father repaired where a lot simpler;you know diesel, firsts engines even dont need electrycal systems...

And also we dont have access to porsche parts...my father knows a lot of places to buy for Ford,Opel,Mercedes....and almost every car...but porsche.

And i have to admit it....i dont have guts to dare it...may be i´m a bit coward,but i waited a lot to earn this car and i just don´t want to broke something.

Also i don´t wanna go to an independent shop because,at least here, porsche is restricted to porsche....People of other workshops dont know how to treat this lady...and i know a few sites due to my father...

If my father was´nt pensioner and we had materials,we will do it ourselves.

Hey SoCal,do you want to came to Spain and lend me a hand? ;-) I trust your mechanical knowledge...And you would like mediterranean gastronomy and all that things for sure!