The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: JJH on March 10, 2017, 09:25:04 AM

Title: cylinder head washer
Post by: JJH on March 10, 2017, 09:25:04 AM

1979 BMW R65
Hi guys, one of the washers that is required to attach the cylinder head to the cylinder has left.  I looked for it, I asked nicely for it to come home.  I did the sweep the garage with a magnet, no luck.  Unfortunately BMW wants $4.55 for the washer.  Normally this would not be a problem since Zn steel washers are easily available.  But the washer is 3.5 mm thick.  I can't find them at Grainger, McMaster-Carr or the local hardware store.  I can find the right size in about 2 mm thick (or less).  Can I double up?  Or is this a time when only BMW will do.  Also if you happen to find my washer, please tell it to come home.

Thanks,

John

Title: Re: cylinder head washer
Post by: Matt Chapter on March 10, 2017, 11:13:03 AM

Quote

attach the cylinder head to the cylinder

For clarification, this is the relevant fiche and part number:
http://www.maxbmwmotorcycles.com/fiche/DiagramsMid/B0000044.png?v=12082016 item number 5.  BMW part number  11 12 1 336 872.

My thinking is that the washer height affects how tightly the nut holds the head against the gasket.  Height in this case is probably critical for achieving a good seal with the correct torque values.  5 bucks, take it out of your beer budget, that'll larn ya!

Title: Re: cylinder head washer
Post by: Barry on March 10, 2017, 11:40:40 AM

$4.55 for a washer seems excessive. Other than the fact it's a strong washer I can't see how it would be special.  It's not as if the torque value is that high.  I checked the BMW workshop manual and they don't even get a mention.

The washer will come home but only after you have bought a new one.

Title: Re: cylinder head washer
Post by: Bob_Roller on March 11, 2017, 04:19:48 PM

You can use two thin washers, just make sure they are steel or stainless steel .

A general rule in aviation, is that you need to have one complete thread protruding beyond the nut .

Also there is a right way to install a washer, look at a thick washer from the edge, one edge will be rounded and one will be sharp, the rounded edge goes against what you are bolting together .

Title: Re: cylinder head washer
Post by: JJH on March 13, 2017, 02:56:19 PM

Thanks for all the advice.  Bob would it be the best idea to have the same washers on both sides or does that matter.  Or should I/ can I keep the BMW washer on one side and the double washers on the other.  Also do you know why they would use thick washers in the first place?
Thanks,

John

Title: Re: cylinder head washer
Post by: skippyc on March 13, 2017, 05:48:58 PM

I know they use thick washers on my BSA to stop the washer dishing and pulling into the head