Another valve stem thread.

[stuffedpike20]

My 1098 smokes on start up, and I am sure it is worn valve stem oil seals. It is a low mileage unleaded head.

Reading through threads on here, the cure is to fit valve guides with a groove, and new seals that fit into those grooves.

I have just seen the same problem being fixed on an XR3i on Wheeler Dealers. They fitted new valve stem oil seals that seemed to have a much wider 'skirt' than the originals. It looked like the outside of the skirt was metal, and that the valve spring seated on it, thus holding the seal down at all times.

In section the seals were like a top hat section.
If there was a seal similar to this for the A series; there would be no need to replace the valve guides when the oil seals wear.

Is there a seal like this from any other car that would fit an A series?

[philthehill]

Do you mean these seals as per links below.
https://www.ebay.co.uk/itm/140434335708 ... gJkFPD_BwE

https://www.ebay.co.uk/itm/364168007550 ... R-aJ6brPYg

[stuffedpike20]

Yes Phil.
Will any of them fit an A series? And am I right that the valve spring seats on the skirt?

Thanks.

[stuffedpike20]

Do you mean these seals as per links below.
https://www.ebay.co.uk/itm/140434335708 ... gJkFPD_BwE

https://www.ebay.co.uk/itm/364168007550 ... R-aJ6brPYg

I see the Caterham ones are 16.4 mm high, inner 12mm diam, outer 34mm diam, with a valve stem diam of 8mm.
My cylinder head is on my car, so I don't know if these would fit.

[philthehill]

Given the measurements above and having compared the measurements relative to the 'A' Series valve guide the seal in the link would not fit.
The base of the spring does sit on the bottom flat face of the seal.

[stuffedpike20]

Thanks Phil.

It would be great to find some that would fit because not everyone has the skill or tools to change valve guides, but some people could probably change valve stem oil seals without too much bother.

Perhaps ESM could start making them?

[MikeNash]

Mr Pike,
Your smoke on start up seems curious to me. My 1098 doesn't smoke on start up even though it has NO oil seals on any valves at all. Long ago I stopped fitting them to exhaust valves on the reasoning that they needed all the lubrication they could get and then stopped fitting them to the inlet valves more recently because they always broke up and disappeared anyway. (I'd had the little "O" ring type.)
Just to check, I started my Trav this afternoon after it had been standing for about 3 weeks and watched it closely; as usual no smoke. Perhaps I'm just lucky, but it seems to me that a decent fit of valves to guide is sufficient; my installation is nothing special.
Regards from MikeN.

[svenedin]

Mr Pike,
Your smoke on start up seems curious to me. My 1098 doesn't smoke on start up even though it has NO oil seals on any valves at all. Long ago I stopped fitting them to exhaust valves on the reasoning that they needed all the lubrication they could get and then stopped fitting them to the inlet valves more recently because they always broke up and disappeared anyway. (I'd had the little "O" ring type.)
Just to check, I started my Trav this afternoon after it had been standing for about 3 weeks and watched it closely; as usual no smoke. Perhaps I'm just lucky, but it seems to me that a decent fit of valves to guide is sufficient; my installation is nothing special.
Regards from MikeN.

Just to add to the above, my car does not smoke on start up or at all really. The head is original from 1969 and
the valve stem oil seals have never been replaced (at least during my 34 year tenure) so they will have disintegrated decades ago.

[oliver90owner]

Smoking on start-up could well be a sign of oil going down the guides - but another better(?), or alternative, symptom is a puff of blue (not black) smoke after sitting idling for a while (like at a level crossing or very slow traffic lights) and revving slightly before starting off. The higher vacuum (lower pressure) in the manifold/head inlets, caused by the throttle plate being closed, would tend to draw oil down the inlet valve stems/guides if worn.

No particular trouble with exhaust valves because they are more likely to be under a tiny positive pressure (due to any back-pressure within the exhaust system) - but if oil was to be going down the exhaust valve stem/guides it would likely be caused by excessive crankcase pressure (worn rings/bores) or a poor ventilation system. That would be fairly obvious by high oil consumption or oil leaks from the crankshaft seals and other indicators.

All simple observations - without needing any reliance on modern measuring tools.

[stuffedpike20]

Thanks all for the comments.

I do not have excessive oil consumption, or smoke at any other time other than start up, which is why I suspect the valve stem oil seals.

I would love to find some 'skirted' oil seals like the ones Phil linked to above to try.

John

[stuffedpike20]

There are classic mini oil seals for sale on fleabay.

They do not look to me like oil seals that would have been fitted to original minis. I am not sure if they are some sort of improved design.
I have asked questions about them but have not had satisfactory answers.

[svenedin]

There are classic mini oil seals for sale on fleabay.

They do not look to me like oil seals that would have been fitted to original minis. I am not sure if they are some sort of improved design.
I have asked questions about them but have not had satisfactory answers.

There are 2 types of valve stem oil seal. The early type is just an O-ring and it fits into a groove on the stem of the valve itself. They do not work terribly well. The later type is sometimes called a "top hat" oil seal. This type fits onto a groove on the valve guide (not the valve itself). To use the later top-hat type the later valve guide with a groove must be fitted. The early valve guides do not have the groove to retain the later seal.

Stephen

[philthehill]

Below is the type of original oil seal fitted to the early 'A' Series engine.
https://www.ebay.co.uk/itm/195343923534 ... R9bJtrfSYg
Below is the type of 'Top Hat' seral as fitted to later 'A' Series engines.
http://www.minispares.com/product/class ... 01160.aspx
The above 'Top Hat' seal to be fully efficient does need to be fitted to valve guides with the seal retention groove.
ESM sell the shorter grooved valve guides for use in small bore engines.
https://www.morrisminorspares.com/engin ... l-p1209547
Valve stem seals of whatever type only need to be fitted to the inlet valve guide(s)/valve stem(s).
Early 'A' Series engines were fitted with a shroud that fitted inside the valve spring and which contained a flat washer type rubber seal. It was found that it did not reduce the amount of engine oil going down the valve guide so was discontinued.
The small rubber ring fitted to the valve stem is next to useless and soon gets chewed/mangled so totally loosing any oil prevention powers. They might as well be left off for what use they do!

I have ordered a set of the Ford valve stem seals (as per link above) to see if they can be adapted but I have a feeling that they will not be suitable for the 'A' Series. I will report back on here one way or another.

[stuffedpike20]

Thanks folks.
Searching 'valve stem oil seal' in ebay throws up some possible seals. The Vauxhall ones look promising, but the listing does not give dimensions.
Buying all sorts of sets on the off chance that one would fit an A series would be a bit drastic.

I admire your pioneering attitude Phil!

[philthehill]

Update!!
The Ford valve stem seals have just arrived.
A first look has produced in my mind the possibility for fitting them to the 'A' Series
The valve seal holder which fits under the valve spring is steel so the base can be held in the chuck and turned/reduced to suit the 'A' Series valve spring seat.
When I get a minute - the next step is to put one of the Ford valve stem seals in the lathe and go from there.
I will post on here how I got on.

Ford valve stem seals 2.JPG (68.66 KiB) Viewed 19253 times

Superb fit on a 'A' Series inlet valve

Ford valve stem seal 3.JPG (59.21 KiB) Viewed 19246 times

First snag
The standard 'A' Series valve spring (22mm I.D.) will not fit over the bottom raised centre (23mm O.D.) of the Ford valve stem seal. Thinking it through - if I carefully relieve the inside of the bottom valve spring coil to give a 23mm I.D. it will fit.
A gentle pass with a well oiled 23mm dia stone to the bottom coil allows the BMC valve spring to fit the Ford valve stem seal.

Ford valve stem seal 5.JPG (68.94 KiB) Viewed 19217 times

The BMC valve spring fitted to the Ford valve stem seal.

Ford valve stem seal 4.JPG (82.11 KiB) Viewed 19216 times

All I have to do now is reduce the Ford valve stem seal bottom face to fit inside the recessed Minor inlet valve spring seat and we are nearly there.

[stuffedpike20]

https://www.ebay.co.uk/itm/304504388653

https://www.ebay.co.uk/itm/114637102126


Two Vauxhall ones here. Unfortunately the most likely looking ones are expensive.
Is anyone in the Vauxhall owners club?

I will ask the sellers if they will provide measurements, but do not hold out much hope.

[stuffedpike20]

I had some confusing measurements back for the expensive ones, and they seem to be much too small.

No measurements for the other one yet.

[philthehill]

I have this morning in the lathe reduced the dia of the Ford valve seal metal retainer to fit the 'A' Series valve spring seat.
I had to knock the valve guide into the head by a further 2mm to get the Ford valve seal and metal retainer to sit properly.
It all fits as it should when assembled and has adequate clearances therefore I see no reason why it should not work.
But to be honest modifying the Ford valve seal metal retainer to suit the 'A' Series head is not worth the effort and I have the tools and the skills to carry out the modification.
In my opinion for what it is worth it is better to fit the ESM grooved valve guides and BL top hat valve stem seals than play around trying to make something other than BMC/BL parts fit.
So I will not be trying any other valve stem seals on the 'A' Series head but continue to use grooved valve guides and BL top hat seals.
At least I had fun trying.
Phil

[stuffedpike20]

Thanks for trying Phil.

It is frustrating to think that there might be a skirted seal out there somewhere that would fit an A series without any modification.

[oliver90owner]

Thanks for trying Phil.

It is frustrating to think that there might be a skirted seal out there somewhere that would fit an A series without any modification.

There probably is but the store-man, of old, is no longer. One needs the registration number of the vehicle or they cannot locate a part on the computer system these days. Knowing anything about the dims/specification/appearance is often a mystery to the supplier. Such is progress!