By the way, if you are going to remove the cams you are also going to need a tool to compress the cam advance mechanisms. Here are some pics of that tool.

Dharn thanks for the diagrams but they are in inches, you need to think in metric and be one with the Germans :)

This afternoon I actual removed the bank 1-3 cover, camshafts and head. I had to file the diameter of the tool down to allow it to fit. The p253 actually did a good job of holding both cams down. It was very snug against the intake cam so it did not allow it to move much when removing the cover.

Nice work.

Doug,
I've been trying to create this tool as well, but can't seem to quite figure out the thread size. I assume it is metric, but M5 seems to big, and M4 is too small. then it comes down to TPI. I attempted to thread some taps to determine size and TPI but of course didnt try too hard, as taps will eventually "fit"!
Do you recall the exact size and thread?

It's 5mm REVERSE threads

Actually it depends on the date of the cam advance mechanism. On the early versions the thread in the base of the mechanism is 5mm reverse thread. In later versions it is 5 mm standard thread. I made the tool for my early versions with brass rod stock and metric dies. The trick is to find a 5mm reverse (left hand ) die. You can find the on line. Then you thread one end right hand and get a couple of right hand nuts, thread the other hend left hand and thread it into the vase of the mechanism. I don't have the part number for when they changed the tread direction.

P253 Cam Timing Tool
 

Hi, I just can't figure out how the P253 tool can work. I pulled the 2 cam plugs off my 99 boxster. The exhaust cam has 2 grooves( 12 and 6 o'clock) where the bottom of the tool is keyed where it will fit into the grooves. The intake cam has 4 grooves (at 12-3-6 and 9 o'clock) BUT the tool has just a diamond shaped fitting, there is no evidence that this top fitting is keyed in any way. I don't understand how this synces up the 2 cams. I'm doing work on bank 2 of a 99 boxster base. Am I missing something here? Can anyone shed light on this matter. Just want to be absolutely sure everything is synced before I turn the key!!!

Ok so what you do with the tool is fix it to the head into the threaded hole between the cams, insert the slotted side of the tool into the exhaust cam , then the diamond shape side should slot easily into the hollow end of the inlet cam, it should slide in and out , this is perfect timing , if it's out you need to loosen the four bolts on the cam sprocket behind the scavenge pump and move the diamond end of the tool until it slots in then tighten the sprocket .
Turn over the engine by hand and re check a few times,

OK ...Thanks for the reply...I guess the diamond fitting really doesn't have anything to do with slots on the intake it just slides.....Odd??

The two cans are already timed together inside the head as a pair , this tool basically times the cams with the crank, say for example the timing was our and the diamond plug won't slot in, to make it slot in you would loosen the bolts on the cam pulley to allow the cams to be turned without moving the pulley or chains . They you would push on the tool to align the diamond plug , this in turn moves the tool acting as a pivot on the slotted side of the tool into the cam slot , as you push the tool you are effectively moving both cams and when the diamond plug lines up you stop and tighten the pulley again, now the cams are in time with the crank, get it?
This tool is for 5 chain engines , the later 3 chain is a different tool I believe !

Thanks ....I understand the concept...I've read....that this tool is for timing the cams....if the Crank shaft is locked at TDC you're then aligning the slotted exhaust cam with the diamond intake cam with the tool bolted to the crank case.... they are then automatically aligned with the crank because its locked at TDC and the tool itself is bolted the crank case....correct? The bottom cam will have the slot going vertical aligning with the seams in the crank case......etc. BUT... what I don't get is there is nothing that remotely looks like a diamond in that top cam....(on my engine at least)....unless there is a diamond fitting that is somehow recessed that can't be seen.I can't figure out how the top cam is set when the only thing I see are 4 slots on the top cam. I have a 99 boxster and assuming is a 5 chain engine. I havn't tried to do anything yet maybe its all self explained when you bolt the thing on. Thanks for the reply.

The diamond on the tool does not lock anything. It merely engages into the cam recess so you can be sure the opposite cam is in the correct orientation. If it doesn't line up and fit in the recess, you are 360* rotation off. Bank 1 and bank 2 can not both be at tdc at the same time. Hope this helps.
.02

Exactly

Em.. Not really....doesn't make sense..why bother having the intake part of the tool in the 1st place and why have the tool bolt to the engine case. Also doesn't help if only the exhaust is timed... what about the intake cam? DIY 'camshaft upgrade' on Pelican site calls it a camshaft timing tool so does SIR tools. Yes both sides are done separately w TDC set for respective banks.....WAIT... Unless... your saying the only way to insure the cams are timed with each other is to eyeball the divots and colored chain link on the cam chain and then your just timing the exhaust cam with crank locked at TDC...which in turn times the 2 cams and the crankshaft. ...Think I answered my own question. So with this tool you would never know if a tooth skipped on the intake. If that actually happened the only way to correct it would be to remove the cams reset them relative to each other(divot and colored link)and re- install them. Correct? Sorry for the long reply ...just want make sure I get everything right before proceeding with my project.Thanks in advance.

Yes the intake and exhaust cams are timed with each other when they are installed in the head by looking at the dots on the cam sprockets , when done correctly the dots on both cams look like they are at 12 o'clock and there are a number of free links in between so there is a link on the tooth where the dot is then I think it is 7 (check this with your manual) free links then the dot for the other cam. Once the valve cover goes on that's it they are timed as a pair by the chain that's it
Now when you are timing that bank with the crank you need the dots to be at the top (12 o'clock on the cam sprockets and the crank at TDC
Now the tool, ok so again as both cams are linked by the small chain in the head if you turn one can I.e the slotted one , the other turns also so they both turn together.
The tool goes into the slot on the cam on the right side of the tool, exhaust cam I think and that gets locked in.
Now the other side of the tool has the diamond shape fitting , the outer edges or the diamond are the perfect size to fit in the end of the intake cam and you can see that this side of the tool can be plunged in and out.
So what happens is as you move the tool both cams are turning by the slotted side turning one cam and the chain inside turning the other so both are turning, and you keep trying the plunger diamond end till you hit the spot and it with plunge in and out of the end of the cam recess with out resistance.
Your cams are now perfectly aligned with the crank and you can tighten the cam sprocket up to lock the cams in time.
It just how the tool works , just the way it's made .
Now you rotate the crank a full 360 and time the other bank as they are timed this way, it's a common mistake to time both banks without rotating the crank so don't do this
Time left bank as above with dots at 12 o'clock then rotate 360 , lock tdc again then time the second bank with dots at 12 o'clock , the check each bank again two or three times by rotating the crank and re checking.
Hope this helps!!