Joe944

Ok I think I have a bad valve in my n/a, it seems to be running on 3 cylinders and is down on power. My dad and his friend, (both mechanics, albeit not porsche mechanics) diagnosed it as a valve...

So should I pull the head and find out? How much work is actually involved in doing so? And how much would a good mechanic in or near the bay area charge to do such a job? I'd rather do it myself because I'm practically broke and need the car for college in less than a month.

If anyone can help please do so! I need to get rolling on this asap.

Perry 951

If the compression is down in that cylinder, it is probably dinged somehow.

Bigger question...why did it do it?

Joe944

That I'm not sure of, but the compression numbers were 150 in 3 holes and 120 in hole #2.

Basically I want to know how hard it is to tear the head off with a mechanics help (possibly 2) who doesn't work on porsche's normally.

I guess I'll find out what's up with it when I pull the head though eh?

JohnK944

It's not hard, the Haynes manual is good enough.

When you lift the head, be careful so that the lifters don't drop. I guess, try to get the head gasket to come off with the head.

Might as well get to the oil cooler seals while you are in there. It's a breeze with the head off.

AlexE

so..... what makes you think its just the valves?

scored cylinder walls... #2 cylinder...sounds very suspicious....

You might have a bigger problem than you think...

Joe944

The valve was what my dad suggested from listening to the car.

Joe944

So how many hours does removing the head usually take for someone who's never done the job before?

Florida951

Hmm Interesting.. I rebuilt my head before with a friend of mine who is a mecanic. We took it appart in a day(5 hours) and neither of us had ever worked on a Porsche before.

Read rebuild pictures

We took about two more days to put it back together because the exaust mainfold refused to get aligned to the head again, and also it took time cleaning all the parts and doing the job right.

I though it was a piece of cake...So much easier than I had imagined, specially the belts. Everyone makes a big deal about them, We trusted the automatic tentioner for the timing belt since the tentioner looked in perfect condition. since my mecanic friend told me to trust him he also tentioned the balance shaft belt by hand
(yes he used his hand to feel how tight the belt felt) after the rebuild the car has been running well. You should also get the head rebuilt at a shop, I got new valve seals, the head machined, valves seated, etc.

Wish you the best of luck on your rebuild.
Let us know how it goes.

Joe944

I'll keep you updated, thanks for the info =)

TomH

How does the spark plug look on that "bad" cylinder? Have you considered a clogged injector? Have you tried FI/valve cleaner (Techron)? I'd look at the cheaper possible fixes before pulling the head.

Even switching a couple of injectors and running your compression tests again, would at least rule out the FI system.

Joe944

I haven't checked the injectors yet, but now that you mention it, I was planning and doing it before. I'll check them out before I remove the head.