valter

Hi, I am pretty much new to this site and Porsche's, but really willing to learn a lot Always being a fan of DIY in automotive world, I have several questions. And I am sorry if they sound annoying or plain stupid.
How hard is to replace a head on '00 boxster? Seems to be due to over-revving and possibly floating a valve camshafts suffered significant damage together with other valvetrain components. Is a piston-valve contact possible or common on these engines? Do engine needs to be dropped for a head work? If timing chain broke, how I can be sure that motor is worth rebuilding? Is it possible to avoid using special tools? Thank you, I appreciate any advice!

Macster

variocam selenoids/etc. can be replaced with the engine in the car, but head replacement is I'm pretty sure going to require the engine be removed beforehand.

You'll have to remove the head(s) and the valves and replace all that kissed the pistons. You will have to very carefully inspect the pistons to make sure they suffered no damage that would render them failure prone once the engine's back up and running.

Of course, while you're "there" you'll have to very carefully inspect all the valve/camshaft hardware and make sure you replace what is damaged, or simply worn past some point. Remove and inspect the scavenge pumps in the heads to make sure they don't have any metal debris in them is say a valve spring or retainer or anything broke.

I'd inspect the oil pump, high pressure and scavenge side for any signs of distress.

Pretty much you'll have to go through the engine top to bottom, front to back looking for any damage resulting to the suspected valve contact with pistons and of course addressing what caused that to happen in the first place.

At the same time you'll want to look for damage so severe that the engine's not worth rebuilding. If you see metal debris on the high pressure side of the oil pump, on the "clean" side of the oil filter housing, in the high pressure passages that lead to the main bearings, piston oil jets, etc., then the engine's scrap. If metal debris made its way into the head oil scavenge pumps and beyond -- thus into the camshaft bearings, etc., -- the engine's scrap.

If any head valve broke and the piston pounded it into the head the head's almost certainly scrap. If any cylinder damage occurred, the cylinder's block is scrap and thus the engine.

IOWs, if the collateral damage from valves making contact with the piston extends much beyond the fairly easily replaced parts: valve, spring, retainer, then the engine's scrap.

As for the difficulty of this... I would not want the Boxster engine to be my first exposure to engine work of this nature, but if you've done other engines and have the time and patience and are willing to expend time to learn, its doable.

Also, you have to know when to cut your losses and toss the engine. Nothing worse that putting an engine back together only to have it break after firing it up because it shouldn't have been rebuilt in the first place.

Along with this you'll have to learn what's required in the way of special tools that your average home mechanic with some engine work experience doesn't have in his toolbox.

The Bentley shop manual for the Boxster might be a good place to start.

Sincerely,

Macster.

AlpharettaRK

I think you'll find the Benley inadequate for such work. You will either need the factory manual or a friend that has access to one, IMO.
We haven't seen much in the way of valve train issues with these motors what makes you think it's so?
Cheers
Randy

99firehawk

I do it rather often and everytime I still get the jitters, i would not recomend it for the diy.

then engine must come out
you will need speical tools for sure 100%
after you price out a head and valves and a set of cams and lifters and a timing chain
and seals and gaskets
you will be in 4500 minumum

dennis a from pa

...over revved or missed a shift? The later seems more likely.

stumpjumper

damn, good time for a 3.4 or 3.6 conversion

valter

Wow, thanks a lot guys for all your replies Macster, special thanks for a VERY informative post!!!
Car has around 40k miles on it, and as dennis said, was definitely a victim of a deadly miss-shift of a previous owner. I worked only on American (LT1/LS1 ) engines before, so I hope it will help me. Call me crazy, but I am not sure what is more fun for me - putting the car together or driving it. I am thinking it can be a great opportunity to learn and have some fun, if teardown render the engine worthless, I am up to putting 3.4 in there.
One more question: If the car is in good cosmetic shape, but I have no way to verify conditions of many components like tranny, since it's not running, what should be a reasonable price for it ???

Macster

that car would be worth sans any engine damage, IOWs in at least good condition maybe even bordering on excellent. (See www.kbb.com for at least its definition of these conditions.)

Then call dealership and get quote on getting new engine installed. Deduct that from the price of the car and offer seller the difference for the car.

Of course, you want to be make sure the seller's initial asking price is reasonable to begin with. Use www.kbb.com or www.nada.com or other sites for some info on what the car's worth assuming the condition's good or borderline excellent.

If engine damaged due to missed shift, was it perhaps because owner had one too many track days? If so, then perhaps you would want to lower your estimate of the value of the car even more because chances are once you get engine running -- however you do it -- you'll find the clutch is in need of replacement (course, you'll do this when tranny/engine out of car) -- or tranny is near its end of life. Also, brakes/steering/suspension/wheel bearings/etc. could be trouble-some.

And check car for any signs of body/paint damage. A bent valve or two in the engine is not all the car might have...

Sincerely,

Macster.

99firehawk

2000 no s boxster with a bad motor in average condition i would offer about 6k