Beach moth
<strong>Vag</strong>, I think I agreed back at #34, perhaps not well put.
An Australian built Gipsy can be identified by the manufacturers conversion to Imperial.
https://drive.google.com/file/d/13hs...1u0gkQhF1/view
hence the metric threads
https://drive.google.com/file/d/13hs...1u0gkQhF1/view
Last edited by megan; 18th Feb 2019 at 01:10. Reason: Link
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Gipsy juice
Just a quick note on the fuel thing, some engines use bronze heads, others aluminium alloy.
Depending on your version dictates fuel suitability. Bronze heads use Mogas, ( motor spirit 78 RON)
The reason is that high octane fuels 100 LL and above can cause pitting erosion adjacent the valve seat in the combustion dome ( if used for extended periods)
The culprit being the tetraethyl lead additive used as an anti knock additive. Aluminium alloy heads don’t suffer this problem due to its metallurgy. These alloy heads can use both fuels and benefit more from avgas generally
Depending on your version dictates fuel suitability. Bronze heads use Mogas, ( motor spirit 78 RON)
The reason is that high octane fuels 100 LL and above can cause pitting erosion adjacent the valve seat in the combustion dome ( if used for extended periods)
The culprit being the tetraethyl lead additive used as an anti knock additive. Aluminium alloy heads don’t suffer this problem due to its metallurgy. These alloy heads can use both fuels and benefit more from avgas generally
All the Gipsy Major's built by GM were "non-metric", as were the engines built by Curtis Wright, whether they were Imperial in AU I am not certain, but the US built engines were, I am reasonably certain, SAE.
Both my engines were metric ---- there were several studs that used to fail regularly, and from DH they were not cheap, about 5 pounds ($10)each --- in 1964, when I was earning about 20 pounds a week. I found an identical stud on a VW engine --- at about 2 shillings each. Once I fitted those VW studs, hey presto, no more breakages.
So much for "aviation quality".
Tootle pip!!
