N62 engine valve stem seals

[bosanci28]

Originally Posted by X5only

Yeah, you don't need much - I put in about 3 feet and it does its purpose perfectly. Most bungee cords are about 4.5 feet standard length. It takes 2-3 minutes to push it into the cylinder you're working on. Of course the cams are still in and no messing around with timing and such - that's the genius of these tools The procedure is well explained in this video https://www.youtube.com/watch?v=r_z0PmoRmT4 and the AGA tool video https://www.youtube.com/watch?v=YacOx2ydMbI

By the way, which insurance company are you using?

How thick are those bungee cords ?
The shop that did it for me used air applied to cylinders, and they have that AGA tool set. As for the warranty, i have Alpha Warranty Services alphawarranty.com , purchased it with the car 2 years ago, and it did paid off now with those valve stem seal replaced., good that i got it as if not i had to do it myself.
Thanks for those videos.

[X5only]

Originally Posted by bosanci28

How thick are those bungee cords ?
The shop that did it for me used air applied to cylinders, and they have that AGA tool set. As for the warranty, i have Alpha Warranty Services alphawarranty.com , purchased it with the car 2 years ago, and it did paid off now with those valve stem seal replaced., good that i got it as if not i had to do it myself.
Thanks for those videos.

Just a standard bungee cord, like this one I got from home depot.
https://www.homedepot.com/p/HDX-48-i...8OPB/206802336.

Standard ones fit into the spark plug hole with ample space around it. You just cut off one tip end of the bungee cord and burn it with a lighter so that there're no frills.
Here're the specifications of a standard bungee cord.
Cord length (in.) 48
Cord thickness (mm) 8
Cord width (in.) .315

If the shop used the AGA or BST tool, clearly they didn't remove the cams. The purpose of these tools is to change the valve stem seals without disassembling the engine further than the removal of the valve covers. No cams removal and such. Shops therefore make more money as they do more valve stem seals jobs in a much shorter time. For this reason it doesn't make sense not to do the valve stem seals if you're going to remove the valve covers - you've already done 80% of the valve stem seals process. They're right there staring at you and all you need to replace them is the $350 BST tool and a $2 bungee cord So if you're chasing vacuum leaks and going to change the valve covers and other seals, why stop there if you know about this process? I didn't know when I did my valve covers twice chasing vacuum leaks, and what a waste of time, money and energy as my X5 still smoked on extended idle of 10+ minutes! And it's not like the valve stem seals last the life of the engine.

[jpcallan]

Originally Posted by jpcallan

Neither rope nor air pressure is absolutely needed as long as you are certain the piston is at TDC on the compression stroke.

I just finished a valve guide/stem seal job for my friend in my driveway on a 2008 X5 E70 4.8L N62TU. While doing bank 2 (I started on the driver side), I worried constantly about dropping a valve into the cylinder. At the same time I kept asking myself "How can a valve drop into the cylinder on a high-compression engine at TDC? Since the combustion chamber volume must be small to create the high compression, the clearance to the top of the piston at TDC must be tiny."

Calling and talking with AGA about that very question - they said I was correct; with no air pressure at TDC, the valves would drop onto the piston top, moreover, are serviceable by replacing the valve keepers using a flat screwdriver with a pat of grease to hold and position the keepers. The down side to the rest-on-the-piston method is the valve stem drops too low for the AGA Keeper Tool to be used. One of their mechanics told me he never uses the compressed air method, preferring the speed of not having to deal with attaching the air supply via the spark plug hole.

No rope (or bungy cord) needed is needed. I learned this from one of the mechanics at AGA; I mentioned this earlier in this thread (quoted above). It isn't really necessary to use compressed air, insert rope or a bungy cord.


As long as the piston is brought to TDC, the valves will rest quite nicely on top of the piston, only dropping a little bit more. Without compressed air in the combustion chamber, there's no chance the engine will turn over, so no need for the Timing Chain Lock Tool either.

[X5only]

Originally Posted by jpcallan

No rope (or bungy cord) needed is needed. I learned this from one of the mechanics at AGA; I mentioned this earlier in this thread (quoted above). It isn't really necessary to use compressed air, insert rope or a bungy cord.


As long as the piston is brought to TDC, the valves will rest quite nicely on top of the piston, only dropping a little bit more. Without compressed air in the combustion chamber, there's no chance the engine will turn over, so no need for the Timing Chain Lock Tool either.

You're indeed correct and I too struggled with this question. It had an air of mystery around it. I'm suspecting intended to instill fear into the hearts of DIY'ers However, the key is that if the cylinder is at TDC, you're safe. But even at TDC there's a 6mm hole and the valves are at an angle as opposed to vertical relative to the cylinder. So you can't just fish it out with a magnet. If it slips for some reason, such as accidentally rotating the engine, it's enough where you don't have a way to pull it back up without a nice long fight. Further, the AGA tool requires cylinder #2 to be just past TDC or before TDC. One has to be very careful there not to drop the valve. You see in the pictures I have used towels to cover the sides of the timing gears. I'm pretty sure you took the same precautions. If something falls into the engine depths there (say a stem keeper or a nut etc), you know it will be a disaster. I think using the cord or air pressure is the same thing - to prevent a disaster and make the work easier.

[X5only]

Valve stem seals done! Engine timing perfect. Buttoning up the engine now after replacing all other seals and gaskets.

[mr_robot]

What seals did you use?


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[X5only]

Originally Posted by mr_robot

What seals did you use?


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Elring 199440 made in Germany, from Europarts. They're the improved version in design and material over the original factory ones that I replaced.

[mr_robot]

Darn, I used new OEM. Wondering if they ever revised itm


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[jpcallan]

Originally Posted by X5only

You're indeed correct and I too struggled with this question. It had an air of mystery around it. I'm suspecting intended to instill fear into the hearts of DIY'ers However, the key is that if the cylinder is at TDC, you're safe. But even at TDC there's a 6mm hole and the valves are at an angle as opposed to vertical relative to the cylinder. So you can't just fish it out with a magnet. If it slips for some reason, such as accidentally rotating the engine, it's enough where you don't have a way to pull it back up without a nice long fight. Further, the AGA tool requires cylinder #2 to be just past TDC or before TDC. One has to be very careful there not to drop the valve. You see in the pictures I have used towels to cover the sides of the timing gears. I'm pretty sure you took the same precautions. If something falls into the engine depths there (say a stem keeper or a nut etc), you know it will be a disaster. I think using the cord or air pressure is the same thing - to prevent a disaster and make the work easier.

Actually, there is no danger of a keeper, etc. falling into a cylinder as I faithfully used the black plastic spark plug hole guides provided with the AGA kit and the flag rod to plumb the piston TDC position, as well as faithfully using the AGA cam chain lock tool to prevent any crankshaft movement. With the rope/bungy method there still exists the risk of dropping a valve into a cylinder when backing off the the piston a bit so the valve can extend into the cylinder to put the rocker arm back in place.

You raised the issue of the camshaft balancing lobe on cyl #2. I did the valve stem seals on an 2008 X5 with N62TU engine; #2 had no balancing lobe as described in the AGA Kit (manual manual in error), but did have a balancing weight lobe on #6 (not described in the manual) that I had to work around. I've not seen anyone else describe this anomaly, but did confirm it with AGA tech support. AGA's kit instruction manual is in need of some updates and revisions.

[X5only]

Originally Posted by mr_robot

Darn, I used new OEM. Wondering if they ever revised itm


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I understand the OEM ones are also improved. Some folks use the ones from the N63 engine as they're deemed more robust. I chose Elring 199440 since that's what I see being used in the AGA video and almost in every DIY videos I've seen.