Slash five head gasket leak

[melville]

gspd wrote "The solid ones easily took over 60ft/lbs without budging."

In all my years being around these bikes and reading what other people write about these bikes, I can honestly say I've never heard anyone mentioned a load anywhere near this. I really find that hard to believe. Why then did BMW limit the torque to 29-31 which I think was the highest for some years. If they can take double that, whey didn't they provide a range of say 30 to 40 and say that was good? Maybe we're talking apples-oranges. If 25 is good enough, why go any higher?? It just doesn't make sense.

I'm perfectly happy with my 0-150 ft-lbs wrench for use in appling 25 ft-lbs of torque for the head bolts. I calculated the amount of water in a bucket hanging on the end of my beam wrench to equal 25 ft-lbs. I read the wrench scale and know that if I hit that mark, I'm well within any kind of reasonable reading. Works for me.

Kurt in S.A.

gspd was testing COLD cases. Our motors (like my beloved VWs) are assembled a touch loosely and only develop full head/piston/case clamping force when warm. If you're running hot, on a VW that can be the equivalent of 60-80 ft-lbs from a cold torque of 22 to 25 ft-lbs. I've heard the cold assembly of air-cooled motors described as "a bunch of parts, flying in formation until warm."

[gspd]

In all my years being around these bikes and reading what other people write about these bikes, I can honestly say I've never heard anyone mentioned a load anywhere near this. I really find that hard to believe. Why then did BMW limit the torque to 29-31 which I think was the highest for some years. If they can take double that, whey didn't they provide a range of say 30 to 40 and say that was good? Maybe we're talking apples-oranges. If 25 is good enough, why go any higher?? It just doesn't make sense.

I am not suggesting to torque them to 60, I'm just saying that they should be easily capable of that without pulling out.

I'm perfectly happy with my 0-150 ft-lbs wrench for use in appling 25 ft-lbs of torque for the head bolts. I calculated the amount of water in a bucket hanging on the end of my beam wrench to equal 25 ft-lbs. I read the wrench scale and know that if I hit that mark, I'm well within any kind of reasonable reading. Works for me.

I'd imagine that puts you in the ±20% ballpark, close enough for rock 'n roll..
Keep in mind that the torque recommendation for any fastener is always only a fraction of it's breaking/stripping point.
They wouldn't recommend 25, 26, 27, etc if the thing will strip at 28, 29, 30. etc.
They recommend the torque that will compress the gasket adequately and hold everything in place.
Studs puling out of airhead blocks is an old problem, they should not pull out because you exceed the torque rating by 10 or 20 percent. If you really exceeded the fasteners capability, you would be just as likely to strip the threads at the nut end, and that never happens. Like I said, the fasteners themselves can handle over 60lbs easily, the aluminum threads in the block often cannot They should.

[gspd]

gspd was testing COLD cases. Our motors (like my beloved VWs) are assembled a touch loosely and only develop full head/piston/case clamping force when warm. If you're running hot, on a VW that can be the equivalent of 60-80 ft-lbs from a cold torque of 22 to 25 ft-lbs. I've heard the cold assembly of air-cooled motors described as "a bunch of parts, flying in formation until warm."

Souped up VW motors will rip stock studs right out of the stock cases in one run.
The remedy: Case Savers.

If you soup them up even more, instead of pulling out, the case-savered studs will actually break, during a run (not while torquing them down).
The remedy: Oversized studs + Case Savers..

[Deleted User 61]

WWFHS?

[Frog]

There is more to the story...sort of.

About five years ago, I pulled the juggs and installed new pushrod seals...and sealed the bases. I also installed new head gaskets.

I torqued it down and just went along as normal. I NEVER WENT BACK TO TORQUE IT AGAIN.

Now five years later, I had a weeping cylinder base and weeping push rod tubes. My good friend and former BMW mechanic asked me if I had ever retorqued...or ever torque the heads when I do my valves. My answer...nope.

We torqued the heads and reset the pushrod seals...Those leaks are gone. But the cylinder base is still weeping a bit and now this.

I am guessing that my 5 years of running with loose heads....contributed to what I have now. The synthetic oil let it be more obvious.

I will redo my work and this time...retorque it...until it becomes stable. If it pulls a stud...then I will have to fix it (hope not). They felt solid the last time I was there.

I will still not torque them every time that I check my valves...assuming that they are stable.

Another case of my learning as I go.

I very much appreciate the input and help. So much of what I know comes from people like you. Thank you.

This new forum has sooo many options. I was a bit put off at first.

[Duane Ausherman]

This isn't for Frog, but just about everyone.

These heads and cases should be very stable. The test of that stability is the valve lash. If it doesn't move, then the head torque is OK. Don't fuss with it. Just do the tiny adjustment needed to set it back to where you feel it is ON. One should be able to go 5 years without a retorque.............. if it was just once checked after assembly.

I didn't do the test that gspd reports, but I find it reasonable.

[Zombie Master]

gspd wrote "The solid ones easily took over 60ft/lbs without budging."

In all my years being around these bikes and reading what other people write about these bikes, I can honestly say I've never heard anyone mentioned a load anywhere near this. I really find that hard to believe. Why then did BMW limit the torque to 29-31 which I think was the highest for some years. If they can take double that, whey didn't they provide a range of say 30 to 40 and say that was good? Maybe we're talking apples-oranges. If 25 is good enough, why go any higher?? It just doesn't make sense.

I'm perfectly happy with my 0-150 ft-lbs wrench for use in appling 25 ft-lbs of torque for the head bolts. I calculated the amount of water in a bucket hanging on the end of my beam wrench to equal 25 ft-lbs. I read the wrench scale and know that if I hit that mark, I'm well within any kind of reasonable reading. Works for me.

Kurt in S.A.

I think GSPD was saying he tested some trashed engines, just to see what it took to wreck the stud threads. Curiosity makes us test things.

[gspd]

WWFHS?

what the f is WWFHS ?


The reason for testing studs on scrap engines was to confirm or dismiss the myth that 28lbs is OK but only a slight bit more will pull out the studs.
My observation is that stock studs may or may not pull out, they are barely adequately anchored in the case.
There always seems to be at least one weak one. With case savers this can't happen.

I 'case savered' all 8 of mine early in my bike's infancy. (VW habit)
I would highly recommend that everyone does it during a rebuild.
I always torque mine to 30, I also run my valves on the tight side and adjust my carbs by ear.
So far, no ill effects, no leaks, no clacking, but it's too early to tell if this is THE way to go,
I've only beat-tested it for 400,000kms so far.
So far, so good.

If your 4 rocker studs don't feel as solid as the 2 other (6 & 12 o'clock) nuts, the studs are probably starting to pull out.

I'll post definitive conclusions when I get more mileage on the sucker.

[Frog]

GSPD:

The link that you provided for the case savers is not working for me.

Does anyone have a source for these?

Blaise

[gspd]

GSPD:

The link that you provided for the case savers is not working for me.

Try this link, scroll down to the 5th pic
http://www.dansperformanceparts.com/bug ... 20case.htm