550k3 oil seals

[bigmockuk]

Had to strip the head off the 550k3 a few times for one reason or another and found each time that the oil seals between the barrel and head are flattened and compressed,first of all is there somewhere that does these seals without the need to buy a whole engine gasket set? and secondly is it possible (or has anyone done it) that instead of using oil seals that it would be possible to drill n fit dowels instead?   
im thinking it should be possible to have tight fitting dowels which would allow the oil to pass up into the head without the chance of oil getting sucked past the seals into 1 or 4 cylinders?

[Oddjob]

Those seals are meant to compress or there would be oil everywhere. Have they ever leaked? 

[bigmockuk]

thanks for getting back so quick,no1 cylinder smokes more than the others,when engine heats up and the others stop smoking no1 still smokes on acceleration,stripped the head off today,all pistons are dry except no1,the crown has a misting of oil on it,dont think its the valve guide seal as done not that long ago,new rings fitted too so im thinking oil is getting sucked past the seal,i dont like how these seals flatten the way they do but understand why

[Trigger]

Smoking can be a few things.
Piston to bore clearance is out of spec.
Damaged or worn oil ring.
Valve guides are worn and beyond spec.

[bigmockuk]

i had to replace the inlet valve guide and valve on no1 cylinder when i first got the bike due to lots of sideaway movement! it just seemed to always be no1 smoking tho, i could try checking the barrel for any warpage? i had to skim the head a while back due to this,im toying with the idea of drilling the barrel and head oilways to fit small pipes to replace the need for seals i think it can be done if i can find the correct diameter pipe

[Trigger]

Strange as the Exhaust valve guides usually go before any inlet guides 

It doesn't matter if you put a small pipe, it will still need a o ring around it to seal.

I am sure i have reconditioned a head from a member that had the same problem and it was a crack in the valve guide   

[Bryanj]

Trigger is probably correct there or the bore is oval, damaged,too big.
Personaly only ever seen those seal leak outwards as fire ring in gasket seals well plus you need a new gasket every time if its been run

[Trigger]

Bryan is spot on, you always have to change the head gasket and all the o'rings if fitted and the engine run.

It was Roy Hall that had the same problem and it was a hairline crack in the valve guide from what i remember. But, that was his engine and your engine is yours 

[Moorey]

   Didn't Roy only find the cause by having his cylinder head eddy current crack detected. It was on his 350f.

[bigmockuk]

thanks guys,i do remember on just one occasion the bike was ticking over and there was one gush of air from the front left between the head and barrel,just that one time,might be worth taking valve springs off no1 and have a look and recheck head again altho it was the opposite side,no 4, that was slightly warped at the start,the smoking is not unbearable,just under acceleration and the plug was black sooty but no actual oil on the plug just like i say a mist on the piston crown,gonna have a good look at it today. will fit new gasket and inlet valve seal too,would it be better to use a small layer of gasket sealant before fitting the oil seals do you think?

[Trigger]

   Didn't Roy only find the cause by having his cylinder head eddy current crack detected. It was on his 350f.

It was something like Moorey. I think i did a pressure test on the valve guide and the fairy was blubbering. I can not remember the full details now as, have done a shed and a half load of heads since then. Roy will remember   

[Nurse Julie]

   Didn't Roy only find the cause by having his cylinder head eddy current crack detected. It was on his 350f.

It was something like Moorey. I think i did a pressure test on the valve guide and the fairy was blubbering. I can not remember the full details now as, have done a shed and a half load of heads since then. Roy will remember 

I think Graham means the fairy liquid was bubbling 😂😂😂😂😂😂

[Bryanj]

And here was me imagining you in the dress and tiara Julie

[Oddjob]

I’m wondering if when the valve guide was replaced the ring under the head was missed off, that would cause oil sat around the head of the guide to get sucked down the guide when the valve opens due to the vacuum created in the inlet tract. Would never be a huge amount but enough to cause the problems you’re describing.

Also check the valve stem seal, I’ve seen the spring on them become displaced accidentally when being pressed onto the valve guide, would also look like the symptoms you’re describing.

[mickwinf]

another thought, did you replace the guide yourself? Trigger did mine and it involved heating the head and liquid nitrogen to cool guide, any excess force could do damage, and as oddjob mentioned did you use the rubber seal under the guide flange?