fitting valve stem seals?

[Envoy CDX]

Hello!

None cav related, and is related to my Corsa..

So I have had my head skimmed and tidied up and now I'm looking to rebuild it. The one thing I'm worried about after reading threads from people saying they didnt fit these buggers correctly caused them to have to redo the who lot again.

Is there a secret to this? Can you over fit stem seals?
I can't afford to do this twice thanks - G.

[Robsey]

There are indeed all sorts of scare stories with stem seals..
I have done this job about 5 or 6 times.
Never had to repeat the operation once.

All I would say is push the seals over the guide ends with firm finger-tip pressure.
No need to use a socket or tube to press them into place.

I pushed my seals into place until the seal appears to pop into place.

Just take your time.
Most damage is caused either by tapping the seals too hard / far into place,
or forcing the valve stem roughly through the seal.

No need to use tape or lubricant to protect the seal whilst inserting the valves.

[Envoy CDX]

thanks Rob. Here's hoping it goes easily enough.

[Robsey]

There is no reason why it shouldn't go well for you.
Only brute force and clumsiness would cause things to go wrong.

The first ever job I did on a car was the stem seals on my 1980 Corolla KE70 way back in 1989.
I had owned the car for two months and was greener behind the ears than a green thing in a green place.


Firm hand pressure - that is all that is needed.
No tapping or hitting with mallets and persuaders.

[Envoy CDX]

There is no reason why it shouldn't go well for you.
Only brute force and clumsiness would cause things to go wrong.

The first ever job I did on a car was the stem seals on my 1980 Corolla KE70 way back in 1989.
I had owned the car for two months and was greener behind the ears than a green thing in a green place.


Firm hand pressure - that is all that is needed.
No tapping or hitting with mallets and persuaders.

sounds good to me.

[planetc]

I always used a socket that was the same size as the metal rim. I've seen them not pushed on far enough and riding the valve stem, and pushed too far stretching the seal away from the stem. A moderately firm push is enough, just make sure you can't pull it off again with any ease, it should be firmly stuck on the guide.

[Envoy CDX]

Thanks, Only 8 valves. Can't take all day can it?

[planetc]

I used to be able to pull the head off, strip, decoke, new seals and refit in under 2 hours. Couldn't do it now though.

[Envoy CDX]

I used to be able to pull the head off, strip, decoke, new seals and refit in under 2 hours. Couldn't do it now though.

Practice I guess?

[Robsey]

Practice and experience...

When you stripped a couple of heads off and refitted everything a couple of times, your speed and confidence increases massively.

I've done the Cav (C18NZ) about 3 times.
A Sierra Sapphire Azure, VW Polo mk2, Punto Mk2, Austin Maestro (A+), Corolla KE70 (4K).
All very similar in principle...
Only ever had one issue, and that was a wrong-sized head gasket on the Polo.

A full strip, thorough clean, and a cautious but careful rebuild would probably take a weekend if it's your first time.
Next time about 5 hours and so on.

It helps if you have a good simple layout to work on. (And the correct tools).
The Punto mk2 was the most frustrating for me due to how everything was put together in the engine bay.

Thankfully Vauxhall 8 valves are a piece of cake due to a good layout and simple mechanicals.
In my mind, if you can do a Timing Belt change, then you should be able to do a head-off job.
Setting up the timing and the tensions is the most critical part.
The rest is basic cleanliness and spanner / socket action.

[Envoy CDX]

Thankfully Vauxhall 8 valves are a piece of cake due to a good layout and simple mechanicals.
In my mind, if you can do a Timing Belt change, then you should be able to do a head-off job.
Setting up the timing and the tensions is the most critical part.
The rest is basic cleanliness and spanner / socket action.

Aye, working out how much paste to use on the valves, making sure I don't get any paste down the guides and so on :/

[colin1]

...working out how much paste to use on the valves, making sure I don't get any paste down the guides and so on :/

Does it actually need any at all?
I've generally found that as we moved away from the 70s cars didn't really need it, unless they're a complete dog that's been run on ratsh*t for most of its life.

If you're going ahead with that and you've got the head off/valves out, getting any (if at all) down the guides shouldn't be a problem if you can flush it; do you own a parts bath?

[Robsey]

I just smear a small bit all around the circumference of the rim of the valve with my finger tip.
Just enough to create a continuous dull grey ring around the valve head and seat.

I used a cordless drill to grind in my valves and seats - low revs. Forward, backward, forward etc.. and do not press too hard, let the paste do the work.

On completion, I usually back flush the guide bores with paraffin or old petrol and check for stray crud with a clean cotton bud / q-tip down the bore.

Same with the valves... after bedding in, wash the paste off with petrol or paraffin.

And when the bores and the valves are clean and dry,
that is when you can start to fit the seals etc.

[humbucker]

Count yourself lucky - I've just had to do this job on my Y32SE. Twenty-four valves to sort! Like Rob, I apply a smear of fine paste with my finger before lapping the valve in (manually). I then sprayed carb cleaner all over the head to flush out any residue before fitting the stem seals (pushed into place with small socket) and the valves themselves.

[Robsey]

I note that Gary's last post on this was on 7th June... I am sure that he did complete the fitting of valves and seals back in late June.
He just hasn't got round to fitting the head to the existing block on his Corsa.
(And associated mpi ecu / injection loom).

[Envoy CDX]

For quickness, and the fact I couldn't afford to be without a car if the MPi conversion didn't go as well as it was thought the original head was whipped off, all valves lapped (about 3-4mm of crap was pulled out of the head) seals replaced, and rebuilt due to the head gasket weaping.

Instantly noticed the increase in power after that was done. But don't know if it was down to a blown head gasket or the fact that none of the valves were able to close properly!

[Robsey]

Probably a combination of both..

Still - a nice project for next summer.
(Head swap)

[Envoy CDX]

We shall see. seems the sealant used between the head and cam housing has let go so may end up doing sooner than I thought :'(

[humbucker]

What about the blue Cavalier? What's happening with that?

[Envoy CDX]

What about the blue Cavalier? What's happening with that?

It is on hold currently (again) basically - long story short I bought a house it is sucking up every penny I have at the moment. Something somewhere has to give. As it stands at the minute I may up having to use the peasant wagon to and from work for the next 3-6 months - not something I particularly enjoy the thought of.