Bottom left - exhaust valves - of cylinder #3. Can't wait to get this apart and see what's going on in there...

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So wait a minute. Have you found the issue before tearing the valve cover off?

TDC found and held in place with an M8 bolt from an old jet ski project.

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Just for fun... my garage and my project.

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I believe I have. In a previous post I said that I found the two exhaust valves are not in sync with each other. One closes and the other stays open a bit when I spin the motor. Jake said that it is common for the lifters or the valve springs to fail. I've decided to pull the valve cover off and see what I can see. If it is a spring or lifter and I can replace in the car then that is my plan. If it ends up being more than that then I'll drop the engine and start reading...

Ah! http://board.moparts.org/ubbthreads/...ins/thumbs.gif

This is looking a whole lot like a broken valve spring. To remove a broken valve spring without removing the head (and man do you want to avoid removing the head!) The idea is to use compressed air in the cylinder to hold the valve with the broken valve spring closed so you can put the new spring and keepers on the other end. As you have the engine locked at TDC (make sure it is TDC and not one of the other holes in the crank pulley) the valve train is unloaded and all of the valves should be closed. You'll need a special hose with one end a standard air compressor QD and the other a spark plug thread - I borrowed one once that looked home made - the best kind of tool. Pressurize the cylinder as high as you can and the valve will stick closed. Now you can replace the broken parts without further dis-assembly.

Do check with your bore scope to be absolutely sure there was not valve piston contact. If you can not determine 100% that they never touched, my advice would be to drop the head and replace the valve. If they touched, even a little, the valve is bent, and it will break and drop into the cylinder at the most inconvenient time.

Best of luck! looks like you'll be on the road in no time!

With the M96 engine a valve can bend from bounce, not just piston contact.

You must also ensure that the seat wasn't damaged from the valve bouncing off it. In engine repair and assembly one must never assume anything and quantify everything.

If not, the issue will find you.

Thanks James... I was just talking to a buddy of mine yesterday who was explaining the same procedure. He even has a homemade spark plug to air compressor hose! I have looked very closely at the top of the piston over and over and I see no indication of the valve touching it so I'm excited about that as well.

Before using the air to hold the valve closed to change the spring, use the same air to carry out a leak down test. Might save you lots of heart ache.

And this was the assumption I thought was already done. If it does not seal with just air pressure under a leak down... putting in a new spring is not going to help.

Ok, I just did a leak down test and I can hear/feel air out the exhaust. Should the air pressure alone be enough to force it closed? If this is the case how can a leak down test be used accurately if it forces the valves shut? This is my first experience with a leak down test. Just trying to understand. Is there a chance something else is holding the valve open slightly? I'm holding out hope that the spring is broke and something is physically holding it open slightly.

With an air leak test you are basically pressurizing the combustion chamber to perform a pressure test to see what is NOT sealing .
A bit like ressurizing your water pipe system at home to find/check for a leak .

We knew you had a leak , the compression test told us that .

What the air leak (leak-down) test tells you where it is leaking from .

The inlet and exhaust valves and the piston give you a "closed space "

Air will either leak by the piston (bottom end problem) or the head (top end problem) or the gasket (head gasket problem)

You've now found where its coming from ....

Right, that makes sense, but I already knew the exhaust valve wasn't closing because I saw it with the bore scope. I totally get the fact that the leak down lets you know if you don't already know. Once I saw the valve not seating as flush as the other exhaust valve I decided to take the cover off and see what I can see. It just seems like the leak down test confirmed what I already knew. Not sure what else it is telling me? Thanks again for everyone's input.

Now ask yourself this question. If air from the leak down test will not hold the valve closed. it tells you something...

The valve is bent. :(

If the valve was not bent the valves would seal and not leak when the cam has released the pressure off of the valves.

Time to pull the head off.

Spring is broke and appears to be keeping the valve from closing. I'm not saying the valve is not bent, but I don't see how it could happen. I'm going to replace the spring - because I'm this far into it and it seems silly to not try. I'll then do another leak down test before I put it all back together. If it fails that test then the head comes off. Is that a fair line of thinking?

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If the valve is good you can do a leak down now with the cams out and the spring off of the valve. if it does not seal valve is bent.

Pull the valve back while pressurizing (be the spring). If the valve does not seal under pressure it's very likely damaged. If you put the motor back together and run it you stand a good chance of dropping the valve. As you have a very understanding customer, that may be an ok gamble for you, because there is a chance it could be fine. It really depends on your level of risk acceptance. Me? If the valve did not seal perfectly I'd drop the head. listening to the motor crump after all that work would be just too painful. Keep us posted :cheers:

What James said, sorry I assume a lot things when diagnosing and giving advice at times.

Sent from my SAMSUNG-SGH-I317 using Tapatalk

I assume nothing and quantify everything. Its instinct at our level.

Sounds good guys! This has been a great learning experience for me. I'm extremely appreciative of all the advise! I'll definitely keep you guys posted! I'll try another leak down without the spring/pulling up.

Does anyone have a good exploded view of the valve/spring/clip? Or even a good pic of how the spring/valve goes together? Can't find a good pic of it anywhere, just wanting to see what I'm getting into and how to take the spring out.

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However I think some things must be assumed, otherwise we would pages just in each post.

One of the few things I did not take apart on my Box engine, but I'll assume it is typical. To get it apart you'll need to pressurize the cylinder and pull the valve back until the pressure seats the valve. That is what will hold the valve in place so you can work on it. Then you have to depress the disk at the top of the spring. Chances are it is jammed over the valve keepers (two little half shells between the disk and the valve stem). To break it free I put a large socket on the disk and tap the socket with the hammer. Take care the socket can not contact the valve stem. As the spring is broken chances are the valve keepers will fall out when you do this, so expect it and have something in place to catch them. Now that the disk is no longer jammed you have to push it to compress the spring while not moving the valve and while maintaining access to the area where the keepers are so you can pop them out with a dental pick or small screwdriver (assuming hey did not fall out already). As you have the new spring there for this procedure you put in the new spring, put the disk back on the valve stem, depress the disk to reveal the keeper grooves in tsh valve stem, re-install the keepers and release the disk allowing the valve spring to expand. You're done!

You'll find having the proper tool to do all of the valve spring compressing will be critical. I'll bet someone reading this has insight into what works best.

Needless to say, if the valve does not seat the head needs to come off.

Perfect! That makes sense.... placing the order at pelican parts today.

So before removing the spring I did a leak down test while trying to physically pull up on the valve. Success. It stopped leaking and appeared to seat well and passed the leak down test. Now to figure out how to get the spring compressor on the broken spring. ???

The "spring compressor" pushes on the disk at the top of the valve to compress the spring As your spring is broken it may be partially "compressed" already. Here is a you tube with one possible solution. Note in this you tube the head is off and a table top is used to stop the valve from moving. In your case you'll be using air pressure to stop the valve from moving. Congratulations on figuring out it was a broken valve spring. If it were me - I'd swap the spring and get it back on the road, but then again I'm given to drilling holes in my IMS and running the engine up to 7K RPM daily. :eek:

how to remove/install valves with household tools - YouTube

All the best!

Game on!

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So did you pay for express postage from Pelican? ;)

Ok, I'm going through everything tonight waiting patiently for my delivery tomorrow. After reading about the timing, I know you are supposed to line up the silver links with the dots on the camshafts. I pulled these out like this. I realize that technically they are still synced, but is this typical for porsche to assemble them like this? Is it wrong that I'm so anal I want to change it?http://986forum.com/forums/uploads01...1400725296.jpg

^^^^ duh!!!!


My $19 valve spring cost me almost $600 by the time they were done with me!

I have a later engine. Give this a gander, this guy is great.

Porsche Boxster S engine rebuild 08 - YouTube

Ohh but the enjoyment and story you will have when you are done -- nice find!

Mike

Seriously. I'm not complaining. This has been awesome. I have very little I to the entire project and couldn't be more thrilled with the condition of the car. So pristine.

Ok, motor guru's... I know that I already know the answer, but I think I just wasted all that next day air shipping $$$.

Playing with the camshafts I was checking out the solenoid and noticed that this looks like wear and not design. Motor has 80k. I'm thinking I should replace these chain guides instead of putting this back together like this. I think it was Wayne that pointed this out in one of the instruction guides. Thoughts?

Bottom
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Top
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Yes, those cam brakes are toasted.. Guaranteed that you have at least 6* of camshaft deviation from that.

Yes, broken sting, now to ensure there's no collateral damage and move forward.

Great thread. Good luck with the project.

Exciting Thread
 

I feel like I'm there and your are asking us to hand you tools

So this device is the same thing as the Vanos in my BMW...just works a little different and looks a lot different

Looking at the picture of your cam sprockets and chains the silver links should be over the dots on the sprockets, and you may want to replace those chains anyway along with the pads to tighten up the valve timing on this side, which leads to the other side...

One thing Jake brought up on an earlier post, when you put on the cam cover use the sealant sparingly. I found the recommended 1 mm bead is more than enough. There is a small drain back hole for the cam oil pressure that you have to be careful not to plug with sealant. If you do plug that hole, the plug in the end of the cam shaft blows off. search "Exxon Valdez" in this forum for more information.

Before assembly I cleaned the sealing surfaces first with acetone, then with brake cleaner - so far no leaks. Keep going!