Head nut came loose!

[camshaft]

Hello all, I recently started hearing something from my right jug and it didnt sound good, when i took of the valve cover i found a head nut missing (i can see it and it can be retrieved).

 

Anyway, I need to know what the proper sequence is for the nut torquing, the BMW manual and clymer dont show exactly which fasteners to tighten (i would think it would be the 4 nuts and then the one torx nearest sparkplug according to picture in the clymer manual on pg 73), there are 4 nuts and 3 torx, but the clymer manual shows one of the torx (lower rear) to be conidered a nut . I need a better picture b/c the clymer and the bmw manuals both state to tighten the torx bolt (M10) - in singular-not plural.

 

Any pictures or descriptions would be most helpful.

 

Thanks much.

 

P.S. any ideas why this would happen besides the 600 mile service being improperly performed?

 

[lazywizard]

There are Nuts and Bolt. 4 each nuts torqued in crosswise manner to 20Nm (I think - check the values)then 180 degrees more in 90 deg increments. The 10mm bolt is tightened next and there is a 6mm bolt by the cam chain tunnel, obviously less torque... More folks will respond but I think you should re-torque the head, ie, loossen all nuts and bolts (6 total- stay away from the valve train) and go down the road. My 96RT developed an oil leak on the rh side on the bottom rh side, where the gasket is thinnest. At 600 miles I re-torqued.

[DEF]

WOW.....I would ask the dealer for my money back....contact BMW, contact the BBB.........that could have been a disaster causing major engine damage.

[crashtap]

Where was your service done? BMW of Milwaukee?

[camshaft]

Well, the service was done long before I owned the bike, I bought it w/ about 2500 it now has about 8500 (1994 RS). In fact, the dealer that did perform it; according to the records is now out of business. So I just need to put it back together correctly. But yeah, if that nut got into the cam chain....

[camshaft]

Where was your service done? BMW of Milwaukee?

 

No, it was not (we mustve been posting at the same time). It was perfomed in Indiana (i dont want to name names... of course they are out of business....)

[bmwmick]

Well, the service was done long before I owned the bike, I bought it w/ about 2500 it now has about 8500 (1994 RS). In fact, the dealer that did perform it; according to the records is now out of business. So I just need to put it back together correctly. But yeah, if that nut got into the cam chain....

 

If your head gasket is not leaking, re-torque the bolts ONE AT A TIME. Do not loosen them all or a new head gasket is in your future. If you plan to replace the head gasket anyway....nevermind.

 

Mick

[lazywizard]

Yes, the One at a Time detail is important. Sorry to mislead.

[camshaft]

Update: my head stud stripped out of the block!!!! Anyway now i guess im F*#@ed, what is the best-longest lasting solution here, helicoil, insert, etc.???

 

I was kinda thinking that it already happened, considering it went this long after the 600 mile service. If improperly torqued the nut wouldve fallen off long ago. --Arent the early production oilheads supposed to do this (read: bitter sarcasm)???

 

^^^open to suggestions.

[bmwmick]

Here is what Tom Cutter had to say about this.....

 

I Helicoil a LOT of Airhead blocks where the factory overtightened a certain stud for a period of four years and NEVER admitted their error. In fact they issued service bulletins blaming owners and dealership mechanics for the problem. I just did one today. I have one of two specially made fixtures for this highly specialized repair.

 

Attempting to drill and tap the block without an alignment fixture is certain to result in a crooked repair, that will rapidly fail again. At that point, the damage is unrepairable without totally stripping and welding the block.

 

Want to torque your head studs without risking damage to the studs? Follow BMW instructions. They work. Make sure to loosen the nut at least a half turn before the initial torque. Want to find a magical torque figure as Ben seems so determined to do? Use 42 foot-pounds. When you get tired of the head gasket leaking, install a new one and then follow BMW instructions for torque.

 

Tom Cutter

Yardley, PA

]http://www.RubberChickenRacingGarage.com

 

Mick

[camshaft]

Here is what Tom Cutter had to say about this.....

 

I Helicoil a LOT of Airhead blocks where the factory overtightened a certain stud for a period of four years and NEVER admitted their error. In fact they issued service bulletins blaming owners and dealership mechanics for the problem. I just did one today. I have one of two specially made fixtures for this highly specialized repair.

 

Attempting to drill and tap the block without an alignment fixture is certain to result in a crooked repair, that will rapidly fail again. At that point, the damage is unrepairable without totally stripping and welding the block.

 

Want to torque your head studs without risking damage to the studs? Follow BMW instructions. They work. Make sure to loosen the nut at least a half turn before the initial torque. Want to find a magical torque figure as Ben seems so determined to do? Use 42 foot-pounds. When you get tired of the head gasket leaking, install a new one and then follow BMW instructions for torque.

 

Tom Cutter

Yardley, PA

]http://www.RubberChickenRacingGarage.com

 

Mick

 

Does the above apply strictly to airheads?

[bmwmick]

It applies to Oilheads too.

 

Mick

[RFW]

More folks will respond but I think you should re-torque the head, ie, loossen all nuts and bolts (6 total- stay away from the valve train) and go down the road.

Yes. Loosen and retorque ALL head bolts properly. Then go to the dealer and properly ream out his mechanic! Properly torqued head bolts do NOT come off! They may need a subsequent retorquing as the gasket relaxes a bit, but they DON'T get so loose they come right off!

 

Bob.

[camshaft]

More folks will respond but I think you should re-torque the head, ie, loossen all nuts and bolts (6 total- stay away from the valve train) and go down the road.

Yes. Loosen and retorque ALL head bolts properly. Then go to the dealer and properly ream out his mechanic! Properly torqued head bolts do NOT come off! They may need a subsequent retorquing as the gasket relaxes a bit, but they DON'T get so loose they come right off!

 

Bob.

 

Update: The stud pulled out of the block, not likely the techs fault (unless it was grossly overtorqued). What would the shop cost on this type of repair be?

[SWB]

Update: my head stud stripped out of the block!!!! Anyway now i guess im F*#@ed, what is the best-longest lasting solution here, helicoil, insert, etc.???

 

I was kinda thinking that it already happened, considering it went this long after the 600 mile service. If improperly torqued the nut wouldve fallen off long ago. --Arent the early production oilheads supposed to do this (read: bitter sarcasm)???

 

^^^open to suggestions.

 

It was probably stripped, all or partially, before you noticed the problem, which is likely why the problem occurred.

 

I got my Beemer checked out by a pretty-good dealer in San Diego County when I first purchased it. About 75 miles after the bike left the dealer, it sucked the front fender around the wheel at 80 mph causing me some level of concern, i.e. steering traction for a tire riding on top of a plastic fender is minimal. I needed both a new front fender and a change of underware. It's possible that the fender bolts were already loose, or it's possible that when the service tech checked the front brake pads, he forgot to put a couple of the bolts back in, or forgot to snug them down (can't use much torque at all on those anyhow). I think the latter was probably the case, since I lost three of the four bolts.

 

In any case, although the dealer has an outstanding reputation, but I could have died from a tech having a "bad day". Stuff happens.

 

Now my bike gets serviced by me.

[ShovelStrokeEd]

To replace the cylinder/head stud threads in the block, you will, indeed, need a drill fixture. Since 3 studs remain and there are probably two dowels as well, it should be no big deal to make one. Some careful measurements and a couple hundred bucks to machine a 1" plate plus some additional dollars for drill bushings and you're on your way. You may be able to borrow one from a well equipped dealer and save the expense.

 

This is, of course, not a trivial exercise, as some expertise is certainly required. Maybe best left to a dealer as a mistake could result in replacement of the block.

[RFW]

Update: The stud pulled out of the block, not likely the techs fault (unless it was grossly overtorqued). What would the shop cost on this type of repair be?

It was grossly overtorqued, likely as not. A stud threaded into an aluminum block will not strip if normal tightening torque is used. The only other possibility is that the hole was never tapped properly in the first place, but that is pretty unlikely.

 

Bob.

[mikefigielski]

Sent you a private messeage, might have something in the Boneyard that will help. Left a phone # also, feel free to call.

Mike

[camshaft]

Update:

I finally got the cylinder head and cylinder and piston off and will now be taking it to an engine builder to correct the pulled stud.

 

Question, what type of gasket/sealer should I use when reinstalling the cylinder and head? The stuff used on the cylinder to block was tuff stuff to break free and am wondering what to use when reinstalling.

[DEF]

Update:

I finally got the cylinder head and cylinder and piston off and will now be taking it to an engine builder to correct the pulled stud.

 

Question, what type of gasket/sealer should I use when reinstalling the cylinder and head? The stuff used on the cylinder to block was tuff stuff to break free and am wondering what to use when reinstalling.

 

3 Bond 1209 is what is recommended for oilheads....can't say for airheads........but, it is likely the same (my opinion).

[camshaft]

Update:

I finally got the cylinder head and cylinder and piston off and will now be taking it to an engine builder to correct the pulled stud.

 

Question, what type of gasket/sealer should I use when reinstalling the cylinder and head? The stuff used on the cylinder to block was tuff stuff to break free and am wondering what to use when reinstalling.

 

3 Bond 1209 is what is recommended for oilheads....can't say for airheads........but, it is likely the same (my opinion).

 

Three Bond is not available anywhere I can find, what is a good substitute?

[Slartidbartfast]

Don't know about the base gasket but the new design head gaskets are made from multiple layers of metal, as opposed to the old fiber/cardboard construction. I doubt they will stick.

 

There is a thread about this problem on ADVRider. It has been suggested that the studs can pull out due to overheating (?). Also, a couple of people have indicated that more than one stud tends to go at once, particularly the exhaust side, and that you should consider helicoiling the others while you're in there.

[camshaft]

To be totally honest, I did hear a metallic expansion/contraction pop noise during about the 10th minute of a TB synch (yes I had 2 fans cooling the heads and cylinders) about 1k before i started hearing loose hardware.

 

Any other opinions on the studs as well as a good threebond 1209 substitute?

[bmwmick]

To be totally honest, I did hear a metallic expansion/contraction pop noise during about the 10th minute of a TB synch (yes I had 2 fans cooling the heads and cylinders) about 1k before i started hearing loose hardware.

 

Any other opinions on the studs as well as a good threebond 1209 substitute?

 

I've always used Permatex Ultra Black RTV sealant. Never had problem. Just remember to clean ALL the oil residue and put the RTV on so thin you can see through it.

 

Mick

[camshaft]

Thanks for all the replies, my bike is back from the engine shop where they installed 3 new inserts (1 was already done...).

 

I have one more question, how much torqe to apply to the studs when installing into the block?

 

Thanks again.

[camshaft]

Any ideas? The BMW and clymer manuals state nothing about cylinder stud torque. The engine shop suggested that 10ft lbs would be adaquate for some of their race engines. Just wondering if anyone has any idea about cylinder stud torque on these engines in particular before the assembly begins tommorow.

 

Any suggestions appriciated.