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Author Topic: What are the bolts that attach the cylinder head to the engine?  (Read 12515 times)

Offline jjs1234

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What are the bolts that attach the cylinder head to the engine?
« on: February 19, 2016, 01:15:10 PM »
Max BMW states them as 11 12 1 464 069    SCREW - M10X135

I thought they were Hex Head but then I got confused that they might be Torx, or Allen? :dunno2:


Asking to see if I have the right tools for the job.

Thanks!


(Might do a k75 piston swap) :2thumbup:

Thanks!
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Offline Martin

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #1 on: February 19, 2016, 02:04:53 PM »
JJS they are Allen bolts, and what is causing you to change the pistons.
Regards Martin
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Offline jjs1234

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #2 on: February 19, 2016, 02:25:50 PM »
because the k75 pistons are an upgrade with higher compression.


Its a worthy upgrade i'm told.


Ill end up doing a timing chain rebuild too. Guides and all.
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Offline Martin

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #3 on: February 19, 2016, 02:41:45 PM »
 :2thumbup:
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Offline The Mighty Gryphon

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #4 on: February 19, 2016, 02:54:30 PM »
On my k100 the cylinder head bolts had Torx heads on them.  I suspect they are the same on the K75 in order to handle the high torque they are tightened to.
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  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline Martin

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #5 on: February 19, 2016, 03:02:29 PM »
Sorry I just looked at a parts fiche I should have checked further.
Regards Martin
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Offline jjs1234

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #6 on: February 19, 2016, 03:11:07 PM »
Torx then...


Okay thanks!
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Offline Bill

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #7 on: February 19, 2016, 03:19:19 PM »
Seems to me you are going to short 1 piston  :yow
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86 K100 R-?L?T parts collection in loose formation...

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72 CB750

Offline jjs1234

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #8 on: February 19, 2016, 03:45:58 PM »
buy 4 on motobins
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Offline Laitch

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #9 on: February 19, 2016, 04:50:41 PM »
Quote from: jjs1234 on February 19, 2016, 01:15:10 PM
Max BMW states them as 11 12 1 464 069    SCREW - M10X135
I thought they were Hex Head but then I got confused that they might be Torx, or Allen? :dunno2:
Asking to see if I have the right tools for the job.
Thanks!
Couldn't you remove your valve cover to take a look at them yourself, jj, or did you do that but were unsure about what you were seeing? Hadn't you better do that anyway to verify?
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Offline jjs1234

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #10 on: February 19, 2016, 05:30:10 PM »
I was going to, I was placing an order for tools though.

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Offline The Mighty Gryphon

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #11 on: February 20, 2016, 10:18:53 AM »
My bolts took a Torx T50.  I got mine at the NAPA store.  They have them in black for impact tools.  It was recommended to me to get the one with extended tip so you don't need to use an extension on your torque wrench.  Brace yourself, they ain't cheap. 

You might also want to get a good breaker bar with a cheater.  Those guys are a bitch to break loose.  Mine took a 20" cheater.  And here's hoping you don't break any of them like I did.
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  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline jjs1234

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #12 on: February 20, 2016, 02:19:21 PM »
How do you end up taking them to the correct spec?
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Offline Laitch

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #13 on: February 20, 2016, 04:42:50 PM »
Quote from: jjs1234 on February 20, 2016, 02:19:21 PM
How do you end up taking them to the correct spec?
It's hard to know what you're driving at with that question, jj, so I'm just going to supply this link and affirm that site as a handy place for information.

Maybe you could rephrase your question?
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Offline jjs1234

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #14 on: February 20, 2016, 05:12:30 PM »
Text to speech on this phone sucks.


My question was, how do you torque them to spec? I imagine to get the correct torque you would need a half inch drive?
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Offline Laitch

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #15 on: February 20, 2016, 05:49:15 PM »
Quote from: jjs1234 on February 20, 2016, 05:12:30 PM
My question was, how do you torque them to spec? I imagine to get the correct torque you would need a half inch drive?
It's best to leave your imagination out of this, jj—right now anyway.
First, take the cover off and see what you've got.
Next, if you've got Torx heads, get the socket that Gryph recommended; then you may need to get an adaptor to fit both the socket and the torque wrench you're using. Which torque wrench type do you have—click, beam, digital, fandango or what? What size is its drive? You'll need to adapt one to the other if they're not the same size.
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Offline jjs1234

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #16 on: February 22, 2016, 10:53:07 AM »
Its a 3/8 drive twist handle (analog?).


I dont know what I was thinking, I got a T50 its 3/8.

Harbor freight sells a digital attachment torque wrench for a 1/2 in drive if I need that leverage.
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Offline Laitch

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #17 on: February 22, 2016, 11:18:37 AM »
Once Martin reads your response I'm sure he'll step right up. Torque wrenches are among his many specialties.
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Offline Martin

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #18 on: February 22, 2016, 12:06:48 PM »
Laitch I'm pleading the Fifth, can a Aussie plead the Fifth? :dunno
Regards Martin
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Offline Laitch

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #19 on: February 22, 2016, 12:08:49 PM »
Quote from: Martin on February 22, 2016, 12:06:48 PM
Laitch I'm pleading the Fifth, can a Aussie plead the Fifth? :dunno
Regards Martin
He can drink a fifth but it's more like 750ml.
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Offline The Mighty Gryphon

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #20 on: February 22, 2016, 05:45:20 PM »
Those cylinder head bolts need to get torqued to 36 ft-lb with an intermediate torque of 25 ft-lb.  Whatever size wrench goes that high will do the job.

Breaking those puppies loose is quite another thing.  Time, corrosion, heat/cool cycles and original assembly without anti-seize means you need to break at least twice that 36 ft-lb.  Use a 24" cheater and wear gloves because they snap pretty hard when they let go.
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  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline Martin

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #21 on: February 22, 2016, 11:44:05 PM »
I was just over my mates place helping to resurrect a K75 RT. I thought I would check out the basis, for my saying that the cylinder head bolts were Allen bolts. He has a K75 engine without the valve cover, the head is held down by Allen bolts. I had scrounged some valve shims of it.  So could it possibly be an early one?? I've tried looking up part numbers and I can only find one number.
Regards Martin.
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Offline Martin

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #22 on: February 23, 2016, 12:49:30 AM »
 A picture of an Allen headed head bolt. Has anybody else seen these.
Regards Martin'
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Offline Inge K.

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #23 on: February 23, 2016, 11:02:16 AM »
2V models have allen bolts, 4V models have torx bolts.
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Offline Martin

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Re: What are the bolts that attach the cylinder head to the engine?
« Reply #24 on: February 23, 2016, 12:44:20 PM »
Thanks Inge :2thumbup:
Regards Martin.
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