Re-Torquing Heads on Oilhead

Anyone every have to re-torque the heads on an Oilhead? Is there a very specific procedure that needs to be performed by German Neurosurgeons with exotic stainless steel devices in a precise and timely manner?

I had to have the heads on my 00' 1150GS swapped with a used set of same (don't ask), and the shop wanted me to bring it back in for a re-torque and valve adjust. When I suggested I could do that myself (I've serviced my own bike since it went out of warranty and it hasn't blown up yet ), the service manager strongly suggested I not take that on myself . I didn't have time to get the whole story as I was in a hurry to motor, but my 600 miles are up and I suposedly should get it done now, or get on it myself soon. Can anyone divulge the secret formula, and or reflect on the soundness of advice I received from the service manager?

Nothing special going on here, the dealership wants your money. We all know how much better the dealership mechanics are at adjusting valves and balancing TBs. Follow the service manual, torque to spec. and you'll be fine.

as per the manual

Cylinder head
Tightening sequence:

After 1,000 km (600 miles), tighten cylinder head nuts
in diagonally opposite sequence:
1. Slacken one nut
2. Tighten nut to initial torque 20
3. Tighten nut to wrench angle 180°
4. Slacken and retighten M 10 screw 40


So if i understand this correctly I slacken one nut then tighten to 20NM then and additional 180°. I then follow the diagonally opposite sequence with the rest. then i follow the instructions for the M10 screw which is at 40NM. This is for after the first 600 miles

Very simple procedure really.

But y'all would be amazed how many folks screw it up.

Irazu summed it up perfectly. There is no magic the dealer uses to re-torque the heads. Just use a good torque wrench and you'll be fine. I did my own 600 mile service with no problems.

Yup same here. I was a little unsure about the 180 degree thing so bought a little device that fits between the socket and bar, this tells you exactly how far you've turned the bolt after you've got the initial tension setting.

dealer=stealer!! (most of the time & sometimes they create more problems)

Actually the good ones are worth their weight in gold. I patronize them when needed. I've visited a quite few accross the US -- there are a few good ones out there.

Sorta true; but, it is best not to use a torque wrench for the 180 degree rotation.

It could be that they used the initial torque setting with the 90° twist instead of the 180° procedure. It could also be why they were as insistant as they were about them doing it. They also check for oil leaks and other related stuff (warranty related).

The actual task of re-torqueing the heads is fairly easy, so feel free to go after it but be aware of the 'rest of the story'.

JJ

Would one of you Mechanical Gods 'splain to me the reasoning behind the 180 degree tightening of a nut after you've reached a set torque value? Most of the damage I've seen in the moderate amount of wrenching I've done has come from over torquing bolts and nuts and that sounds like a great way to do it. Why not just torque to a set value?
TIA.

Is that it is more predictable......

BTW, I have done this a few times...it is quite easy...

INstead of a guage....I just reposition the wrench to "vertical" and then rotate to "vertical" again...this makes a guage unnecessary...IMHO...and doing this with a long click type torque wrench is no problem....

I'm not an engineer, and I didn't stay at a Holiday Inn Express, last night, but I will take a shot.

There is static torque, and stretch torque (Not the right term, but the right idea). Apparently stretch torque is more accurate to stress the bolts and mating surfaces accurately. A simple torque value depends entirely on thread condition, any lube that has gotten on the threads, etc. If you use the stretch method, you are more accurately applying the nexessary torque for critical applications.

Or, I am full of shite! Either could be right!

Jim

Thanks Jims. I'm just used to having values associated with something like torque settings. If the 180 technique guarantees adequate torque I'll learn to live without the precious numbers. BTW, I believe I was told to retorque at each 6,000. You guys concur?
Chris

For what it's worth, BMW car engine heads have been bolted down with a torque-then-angle spec for decades - literally hundreds of billions of miles - with great success.

Torque to yeild is what the proceedure is called. The initial torque setting is quite low and is to set a starting point that avoids most of the problems with thread condition and the like. The second step, a certain number of degrees more rotation pulls a bit of stretch into the fastener. The engineers have figured it all out and say it is more accurate. After the re-torque at 600 mi. leave it alone until you need to remove the head. My experience has been that 600 mi. is not always enough, some times 1000-1200 mi. seems better. I think it is the number of heating and cooling cycles on the head gasket that is important.

Jim.

surely thats 360 degrees ??

:huh

How many degrees would vertical-to-horizontal twice be?

That would be 90. Up to down would be 180. Up and down are both vertical, so that's why BMW doesn't use that term and they're specific about 180 degrees. I learned this from a NSG BMW car mechanic wannabee motorcycle wrench. His reasoning for the 180 turn is " it's a BMW thing".

Thanks all for the great input! Sounds like a walk in the park. I'll have at it momentarily. Meanwhile, here is part B of the question; The service manager also suggested I adjust the valves as well as retorquing the heads. Now these are used heads with 10K miles on them already...is there really any reason I need to adjust them after 600 miles? I'm assuming that re-torquing the heads will not affect the valves...or am I mistaken there?

You want to see the procedure in a video? Take a look at this site: https://www.bmwmc.net

Recommended procedure: use Internet Explorer to open link, then
1) accept the java certificate
2) go to training/Video Service Procedures/R1100-R1150/
3) when the video starts playing in Windows Media Player, you can pause it and do a "Save As.."

Make sure pop-ups are enabled. Also, the page is encrypted and it seems that a signature error may prevent those running with "high" security measures on their browsers from running the script.

This is what you should see: