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Possible valve stem seal problem
https://www.ausmini.com/forums/viewtopic.php?f=2&t=64235		 Page 1 of 2
Author:  jester99 [ Wed Jul 07, 2010 1:36 pm ]
Post subject:  Possible valve stem seal problem
last night while completing the assembly of my engine and adjusting the valve clearances, while turning the engine over a small spring fell out from behind a valve spring.

it is the little tiny spring that goes around the top of the valve stem seal. it has fallen off and is no longer on the valve stem seal.

is this a problem? do i need to remove the head to change the valve stem seal? i know it is easier this way yeh?

will this cause the engine to smoke do you think?

next question, can i reuse the head gasket if it has only been on the engine overnight? it was all tensioned down. or will i have to get another head gasket?

advice appreciated.

thanks, Jason 8)
Author:  Hanra [ Wed Jul 07, 2010 1:49 pm ]
Post subject: 
You could fill the cylinder with compressed air to prevent the valve from falling in!
Author:  jester99 [ Wed Jul 07, 2010 1:58 pm ]
Post subject: 
yeh thats what the techs at work do. but then you need a different kind of valve spring compressor to the one i have. the tools i have need to have the head off to use it.

was mainly concerned if it is absolutley nessesary to have to replace it now, or will it seal ok for the meantime?
Author:  Hanra [ Wed Jul 07, 2010 2:22 pm ]
Post subject: 
Can you borrow there valve spring compressor?
Author:  GT mowog [ Wed Jul 07, 2010 2:36 pm ]
Post subject: 
If it's on an Inlet Valve, yes replace it. Exhaust Valve, you'll get away with it no problem.

Depending on the Gasket you've fitted the head up with you might be able to remove the head and re-fit again no problem, but depends on the gasket.

Do as Hanra suggests, turn that cylinder over to BDC, fit air line fitting to spark plug hole and that'll keep the valves from falling in. Get an old rocker set, all you want from that is the rocker shaft and posts, fit it up, doesn't need to be tight, and use something like a fork ball joint splitter to depress the valve spring keeper, leavering from the underside of the shaft. Then you'll be able to remove the keepers and your away.
Author:  TheMiniMan [ Wed Jul 07, 2010 4:40 pm ]
Post subject: 
Well ,,, now that you`ve noted the spring falling off,,, that brings me to the next question,,, (which actually should be asked before answering your first question) & that is,,, """Have you over compressed a few (or all) of the valve springs when fitting the caps & collets"""???

If so---> that ---in turn--- would (or can... & usually does) , not only knock the springs off the valve stem seals ,,,---> But also can """CUT""" the tips of the valve stem seals causeing them to not work very well as seals,,, if you get my drift???

Now,,,, """IF""" you have actually done that,,, & maybe to a few of the stem seals,,,, then(if it were me,,, but then i wouldn`t have done that in the first place :-) ) But still,,, if i had,,, then i`d slip the head off & re-do """ALL""" the stem seals---> PRoperly... being very careful not to over-compress the valve springs,,, so as not to nick or cut or tear the tops of the valve stem seals

:-)

sorry,,, but i`d rip it off & check it all

& yes just bung the head gasket back on & give it an extra 2 or 3lbs of torque (provided you have good quality head studs & not just 2nd hand crappy std head-bolts)
Author:  jester99 [ Thu Jul 08, 2010 5:29 pm ]
Post subject: 
well i removed the cylinder head and discovered another 2 stem seals had the springs fallen off them.

bought a full set of new stem seals today and just spent the last 3 hours pulling it all down and very carefully putting it all back together.

BUT......

i re-assembled it all, loosend the rockers off before it fitted it all up, and after one turn of the crank, 3 of the springs around the valve stem seals have come off again!

so now i have to take the head off yet again!

after watching the operation of everything it does not look as though it is bottoming out and/or compressing the stem seal. the valve clearances have been backed off when i installed it all.

what other reasons could be causing this issue?

HELP :lol:
Author:  Morris 1100 [ Thu Jul 08, 2010 5:31 pm ]
Post subject: 
Could the valve guides be fitted too high?
Author:  jester99 [ Thu Jul 08, 2010 5:31 pm ]
Post subject: 
the head gasket came off undamaged, so i reused it and tensioned it 2 ft/lbs tighter.

how many times can i do this? or do i have to get another head gasket from the UK ?
Author:  jester99 [ Thu Jul 08, 2010 5:32 pm ]
Post subject: 
yeh ken at mini automotive mentioned this afternoon that there shuld be a ridge at the top of the valve guide. mine do not have ridges to clip the stem seal over. the tops of the guides are smooth.

could this be causing the issue?

or the guides could be to long.
Author:  jester99 [ Thu Jul 08, 2010 5:46 pm ]
Post subject: 
all the stem seal springs are fine and aligned correctly and no issues with over-compression during fitment of the springs/collets with the spring compressor, it seems the issue is when the engine is turned over.
Author:  jester99 [ Thu Jul 08, 2010 5:59 pm ]
Post subject: 
just spoke to the gentleman who sold me the brand new 12G295 head i have, he said this head had the origonal type guides still fitted when the head was made, which apprently didnt have valve stem seals, and the guides are slightly higher and do not have the groove for the seal to sit in.

he fitted seals to the intakes only when he assembled the head origonally for me.

he says oringonally this head would not have had seals and doesnt really need them, and there are some seals that are made without the spring, so it can use these without the springs on them if required.

so the end result i am hearing from him is that as the guides are not really designed for seals amd they are riding up on the guide and the top of the seal then hits the retainer and the spring falls off.

any suggestions what i should do?

should i run it as is and see what happens?

do i pull the head off and have different guides fitted? more cost.
Author:  GT mowog [ Thu Jul 08, 2010 6:10 pm ]
Post subject: 
These guides only had O rings for seals. They just fitted over the valve stems. They are crap.

If the head still has the original valve guides in it, then it is likely they have been 'swaged' and then reamed back to the correct size. Do yourself a favour - take the head off, have new guides fitted - the bronze ones aren't expensive (~$60 for a set) and have the valve seats re-cut. Then fit new guide seals.
Author:  jester99 [ Thu Jul 08, 2010 6:21 pm ]
Post subject: 
the head is brand spanken new. has been sitting in the shop i got it from for years and years still wrapped in wax paper. the guides are the origonal early type.

i bought the head as a brand new package, brand new springs, valves, seals, the whole head was supposed to be a brand new bolt on job. and the head was assembled by the mini specialist company i bought it from.

i didnt really want to now have to strip it down, and have a set of guides fitted then these ones are already new.
Author:  jester99 [ Thu Jul 08, 2010 6:23 pm ]
Post subject: 
what if i loctite the seals down? i read a post from a while ago where someone mentioned you can loctite the seals to the tops of the guides.
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