Cylinder Head Washers

[andut]

Just started to strip the engine.

Do I need to renew the copper / steel washers that go under the cylinder head nuts ?  I will definitely need a couple of the rubberised washers under the pillar nuts, so does anyone know a good source ? Just checked cmsl and  fell over when I noticed the cost !

Andy

[Trigger]

Just started to strip the engine.

Do I need to renew the copper / steel washers that go under the cylinder head nuts ?  I will definitely need a couple of the rubberised washers under the pillar nuts, so does anyone know a good source ? Just checked cmsl and  fell over when I noticed the cost !

Andy

Copper Yes, steel No if not damaged. The copper M8 can be bought anywhere for about £2 for a bag of 20. 

[andut]

The old washers look like copper coated steel washers - does that sound right ? Should they be copper and therefore replaced ?

[ka-ja]

Hi,
   I put the old ones back with a smear of hyomar on them, But make sure the two odd-balls (dowty seals) are in very good nick.---Ken

[andut]

Thanks Ken !  I'll definitely replace the 2 oddball washers - just need to find some !

[sprocket dog]

Hi,
I don't wish to hijack this topic, but I recently found that ALL my cylinder head washers were copper and there were no steel "Dowty" washers under the pillared nuts. This was definitely as from new, as I'm the second owner and I've only removed and refitted the head once before about 20 odd years ago before laying up the bike. 
Maybe this was the cause of the subsequent oil leak from the head gasket area after that last bit of work? This was so frustrating at the time that the bike was put aside until very recently...
If anyone has any thoughts on that, it'd much appreciated.
Thanks

Laurence

[ka-ja]

Hi,
    No offense Sp-D, Although the washers available now are in copper,the earlier ones were coated steel, but the two "dowty" type seals were a steel/rubber composite on the early motors, which suggests yours had been stripped at some point in its life, DS do the correct ones--Ken

   composite http://www.davidsilverspares.co.uk/parts/by-part-number/partnumber_90442377000/
   Also copper washers   http://www.davidsilverspares.co.uk/parts/by-part-number/hpart_90441377000/

[Bodd]

They were all steel washers on mine when I stripped it down   

[Lynx]

All copper on mine plus the 2 rubberised ones. I just re-annealed them by heating to cherry red before re-fitting.

[sprocket dog]

No offence taken Ken and I appreciate all the advice being offered here. Whilst I have no knowledge of this engine ever being touched,  it may well be that the head gasket did leak oil on this early engine and there was a  warranty "fix" in the first 20k miles/10 years of its life. This may have included fitting this full set of copper washers (which are 2mm thick!). On balance though, I think I'll now anneal them as per Lynx's suggestion and buy a pair of the Dowty type for the pillared nuts and hope that nothing ever leaks again!
Thanks again for the advice.

[Drew400]

Just a thought for the experts to reflect on...

What is the purpose of those cylinder head washers vis-a-vis oil? If a little oil seeps through from there, presumably it enters the rocker area. Assuming the rocker cover gasket is good, any excess oil can then only escape via the breather tubing.

I guess the copper expands at a different rate from the surrounding metal to either stop or allow leaks, whichever is preferable.

Is that correct? I will enjoy learning how wrong I am from the replies to come (and maybe they'll also help your thinking, Andy).

Cheers, D.

[andut]

I try not to think to often Drew, it usually costs me time & money !

I'll reuse the steel washers with a smear of Hylomar as per Ken's guidance and renew the two Dowty seals and keep an eye out for leaks when I get it back together !

[mike the bike]

The purpose of the copper washers is that they seal better than steel ones.   Because they're a softer metal they deform to the same shape as the head.   When reusing copper washers, you're supposed to anneal them by heating them to cherry red and quenching them.  This makes them soft again.