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Theo Whitmont
New User
Username: old_mate

Post Number: 4
Registered: 04-2020
Posted on Saturday, 25 July, 2020 - 20:10:   Edit PostDelete PostView Post/Check IP

Emboldened by the success of my first post I now seek the advice of the collective again.

Does anyone have some advice or information about why I this hole graces the engine of my 1934 20/25?

I havenít seen similar holes in other cars.

Certainly someone felt there was a need ...... but what?

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Dorien Berteletti
New User
Username: dorien

Post Number: 4
Registered: 01-2013
Posted on Sunday, 26 July, 2020 - 00:10:   Edit PostDelete PostView Post/Check IP

Are there any threads in there?
Presumably you are getting some oil splashing out or do you have a suitable bottle stopper to fill the hole?
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Theo Whitmont
New User
Username: old_mate

Post Number: 5
Registered: 04-2020
Posted on Sunday, 26 July, 2020 - 10:52:   Edit PostDelete PostView Post/Check IP

Thanks for your interest Dorian.

No threading - just a clean hole.

No oil splashes out and there is no stopper in place. The car has been in my family for 50 years and it has never been thought of.

It also begs the question, what might have fallen in there over the years? Iíve never avoided driving the rain - maybe this should be a consideration??
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Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 653
Registered: 05-2016
Posted on Sunday, 26 July, 2020 - 11:35:   Edit PostDelete PostView Post/Check IP

This is purely a guess: I reckon it's a breather hole to evacuate crankcase pressure but it probably should have a grommet fitted and a breather pipe from the grommet heading towards the air intake or down towards the road to release crankcase pressure to the atmosphere. I could well be mistaken.
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David Gore
Moderator
Username: david_gore

Post Number: 3748
Registered: 04-2003
Posted on Sunday, 26 July, 2020 - 12:26:   Edit PostDelete PostView Post/Check IP

Larry,

I think you might be on the money here.

This type of crankcase breather was common on Australian cars with UK/USA parentage derived from post-WW2 models.

We had a 1954 FJ 6 cylinder Holden which had both an oil bath air filter and a crankcase breather pointing down to the road as you suggest. This model Holden was a locally enhanced clone from a US 1948 Chevrolet model.
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Theo Whitmont
New User
Username: old_mate

Post Number: 6
Registered: 04-2020
Posted on Sunday, 26 July, 2020 - 17:24:   Edit PostDelete PostView Post/Check IP

Thanks gents,

Considering itís been open to the skies for past 40 years, is there an argument to do nothing, or am I dicing with danger now that the old girl is seeing a bit more road time?

One suggestion I received some time before joining this forum was to have it soldered shut, painted over and pretend it never happened. This is also an option but what are the implications? It seems that this sort of hole is quite unusual so does that indicate an issue with this particular car rather than with the model?

Thanks in advance.
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Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 654
Registered: 05-2016
Posted on Sunday, 26 July, 2020 - 21:01:   Edit PostDelete PostView Post/Check IP

I suspect that the hole might have been drilled to relieve crankcase pressure so as to reduce oil leaks from the valve cover to head jointing face. I think that there is an interference fit between the valve cover and head and because of this oil leaks can be a problem. I've read that some folk have fitted a bespoke gasket but usually without success. Personally I would be inclined to fit a grommet and hose with a low pressure non return valve or at least with a gauze filter that could be occasionally cleaned. I would be concerned about insects or crud finding their way into an open orifice on the valve cover, I've noticed that flies appear to like engine oil or maybe it's the heat emanating from the engine that attracts them.
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Dorien Berteletti
New User
Username: dorien

Post Number: 6
Registered: 01-2013
Posted on Sunday, 26 July, 2020 - 22:51:   Edit PostDelete PostView Post/Check IP

Note that the 20-25 already has a breather hole that feeds in to the air filter/silencer.
If it were mine I would plug it with some sort of stopper to avoid dirt getting in. You could also make something up with a fine wire mesh screen.
I would most definitely NOT leave it open.
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Theo Whitmont
New User
Username: old_mate

Post Number: 10
Registered: 04-2020
Posted on Monday, 27 July, 2020 - 20:19:   Edit PostDelete PostView Post/Check IP

Noted. Iíll have a crack at plugging it. My mind goes to a champagne cork ...... now that would raise an eyebrow or two!
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Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 655
Registered: 05-2016
Posted on Monday, 27 July, 2020 - 22:06:   Edit PostDelete PostView Post/Check IP

It would need to be a wine cork of the correct vintage. Less risk of popping.
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Dorien Berteletti
New User
Username: dorien

Post Number: 7
Registered: 01-2013
Posted on Monday, 27 July, 2020 - 22:45:   Edit PostDelete PostView Post/Check IP

I was going to suggest that but most are a smaller diameter.
Might need something more mundane...check the local grocery store for a suitable lids/stoppers.
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Theo Whitmont
New User
Username: old_mate

Post Number: 11
Registered: 04-2020
Posted on Tuesday, 28 July, 2020 - 07:21:   Edit PostDelete PostView Post/Check IP



This would do nicely... it appeals to my inner mascot!

If only it could handle the vibration and heat I think I'll enjoy the thought and nothing more.
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Larry Kavanagh
Frequent User
Username: shadow_11

Post Number: 658
Registered: 05-2016
Posted on Sunday, 09 August, 2020 - 11:57:   Edit PostDelete PostView Post/Check IP

I wonder if this car was originally supplied to California? California had pollution additional control measures which required valve cover breathers.
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Theo Whitmont
New User
Username: old_mate

Post Number: 12
Registered: 04-2020
Posted on Tuesday, 11 August, 2020 - 20:31:   Edit PostDelete PostView Post/Check IP

No mate. A direct import from Derby to Sunshine Victoria. The engine is original so it remains a mystery why this was done (although the suggestions above make sense).

Iím gonna get it closed up with a custom screw-in plug. Will post photos when itís done.

Thanks for your thoughts.

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