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+--- Thread: extra plumbing in head and washers (/showthread.php?tid=1023)
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extra plumbing in head and washers - steve davidson - 30-03-2018
Hi all,
I've recently come in to possession of a new head that is different to any I've seen before. Along with the spark plug tapping there is an extra tapping in to each cylinder, I understand that these were done to facilitate the addition of a little extra fuel in to each pot during cold starting. In my case each of the 4 holes have been plugged with a nice brass washer complete with an odd “sandwich washer”. The washer has copper on both faces and something in between, see attached photograph.
A few questions;
1) Does anyone have a photo of one of these heads set up with the taps to allow the extra fuel addition?
2) Can anyone advise what this type of washer would be called and what material is sandwiched between the copper?
3) Unless I can find something better I though the existing washers could be replaced by copper crush washers, thoughts?
RE: extra plumbing in head and washers - jonmilne7@yahoo.com - 30-03-2018
These holes were for the taps for fuel. before chokes were put on carbs mainly before 1926
RE: extra plumbing in head and washers - Chris Garner - 30-03-2018
Steve,
These types of head are not that uncommon and you are right the blanked off holes originally held priming cups / taps fitted to very early cars. I'm afraid I do not have access to an illustration. My understanding is that the material between the two copper washers is asbestos.
If you not concerned with originality, and / or the presence of asbestos, then I'm sure a copper crush washer will suffice.
Having used several of these heads over the years I have straightened out the original copper washers best I can and refitted them without any leakage problems.
Trust this helps.
Chris
RE: extra plumbing in head and washers - bob46320 - 30-03-2018
Page 46 - The Austin 7 Source Book has a nice photo of the head and taps - as fitted to pre production cars (1923 ??)
BobH
RE: extra plumbing in head and washers - Zetomagneto - 30-03-2018
(30-03-2018, 10:42 AM)steve davidson Wrote: Hi all,They are copper/aspestos, you can get new ones from the VAR spares, Steve Newton is the Man
I've recently come in to possession of a new head that is different to any I've seen before. Along with the spark plug tapping there is an extra tapping in to each cylinder, I understand that these were done to facilitate the addition of a little extra fuel in to each pot during cold starting. In my case each of the 4 holes have been plugged with a nice brass washer complete with an odd “sandwich washer”. The washer has copper on both faces and something in between, see attached photograph.
A few questions;
1) Does anyone have a photo of one of these heads set up with the taps to allow the extra fuel addition?
2) Can anyone advise what this type of washer would be called and what material is sandwiched between the copper?
3) Unless I can find something better I though the existing washers could be replaced by copper crush washers, thoughts?
RE: extra plumbing in head and washers - Ian Williams - 30-03-2018
When you read a handbook for larger austin of the period, 12/4 for example, they all have what are referred to as decompression taps fitted to these holes, they were used to find compression stroke when setting timing etc. Quite why the factory continued with the expense of fitting them for so long is a mystery to me, one could remove a plug to effect the same thing.
RE: extra plumbing in head and washers - Adrian Payne - 30-03-2018
Hello Steve
I always make these gaskets by cutting out a section of old head gasket where the studs pass through.
Simples.
Adrian.
RE: extra plumbing in head and washers - Ruairidh Dunford - 31-03-2018
Steve,
Our ‘26 Heavy 12/4 is fitted with the priming cocks you ask to be pictured and also mentioned above. I have used them successfully to awaken the car from extended slumber on several occasions.
The car is not at my home just now but I can photograph them the next time I use it.
RE: extra plumbing in head and washers - steve davidson - 04-05-2018
(30-03-2018, 10:48 AM)jonmilne7@yahoo.com Wrote: These holes were for the taps for fuel. before chokes were put on carbs mainly before 1926
Thanks
(30-03-2018, 09:25 PM)Adrian Payne Wrote: Hello Steve
I always make these gaskets by cutting out a section of old head gasket where the studs pass through.
Simples.
Adrian.
Thanks Adrian, great idea. I didn't know why I was keeping a few old ones kicking around the workshop but now I do!
(30-03-2018, 09:05 PM)Ian Williams Wrote: When you read a handbook for larger austin of the period, 12/4 for example, they all have what are referred to as decompression taps fitted to these holes, they were used to find compression stroke when setting timing etc. Quite why the factory continued with the expense of fitting them for so long is a mystery to me, one could remove a plug to effect the same thing.
Hi Ian,
Thanks for the reply, I agree that it removing a plug is a pretty simple way to find the compression stroke. Combine a thumb over the port to find the correct stroke and then drop a dial gauge in and you can get TDC within a few thou and I reckon for static timing that's more than close enough.
We used to run a three-cylinder lister generator to make power for our homestead and that had the decompression leavers but that was more to be able to get some momentum up in the flywheel using the hand crank before trying to get compression in the pots.
(30-03-2018, 06:26 PM)bob46320 Wrote: Page 46 - The Austin 7 Source Book has a nice photo of the head and taps - as fitted to pre production cars (1923 ??)
BobH
Thanks Bob,
I've got one of the guys brining that book to our next meeting here in Brisbane. Thanks for the lead.
RE: extra plumbing in head and washers - Tony Press - 04-05-2018
[quote pid='9847' dateline='1525414548']
(30-03-2018, 06:26 PM)bob46320 Wrote: Page 46 - The Austin 7 Source Book has a nice photo of the head and taps - as fitted to pre production cars (1923 ??)
BobH
Thanks Bob,
I've got one of the guys brining that book to our next meeting here in Brisbane. Thanks for the lead.
[/quote]
As I have have mentioned, my 1929 Saloon light shaft engine still has these brass 'plugs' - I have never disturbed them.
Cheers, Tony.