AJP8 engine mods
Discussion
I'm curious about an article in this months Sprint about Engine Tech and work which they are involved in on a heavily modded. AJP8. Apparently they are using gunmetal main bearing caps, seemingly as an upgrade to cope with the projected increased power output of 1000 bhp. I happened to mention this to my father, who, whilst completely uninterested in cars / engines, knows a huge amount about metals and their numerous alloys, having been employed by the MOD for most of his working life. He confirmed that gunmetal is essentially bronze (i.e. c. 90% copper) and was so named because canon were cast from it before steel was known. He couldn't think of any reason that such a relatively weak alloy would be used in such a highly stressed application. A forged steel alloy would be more usual. Any engineers care to explain?
7.
7.
(I think the wordings were used slightly wrong there, its not gunmetal, just similar, completely different alloy composition)
Nikel-ali-bronze, like gunmetal but with a high content of feckin-expensive nickel!
Nickel Aluminium Bronzes contain around 10% aluminium with additions of iron and manganese for increased strength and further toughness. Produced to NES (Naval Engineering Standard) designations. Normally use for gears and big torque handling bearings.
Highly corrosion resistence - also specifically design to handle massive shock-loading - steel caps would crack with fatigue - nikel-ali-bronze caps will just absorb the shock and smile! (its the same shite MOD uses) www.dstan.mod.uk/data/02/872/01000100.pdf )
Tensile values typically in excess of 700 N/mm (45 tonnes/sq inch)!
Oh and the main criteria was block expansion, we could not afford crankshaft walk due to thermal expansion of the ali block, and steel does not expand at the same rate, where as nickel-ali-bronze has very similar expansion properties.
I could go on forever, but that should be enough to keep your old man occupied.
Nikel-ali-bronze, like gunmetal but with a high content of feckin-expensive nickel!
Nickel Aluminium Bronzes contain around 10% aluminium with additions of iron and manganese for increased strength and further toughness. Produced to NES (Naval Engineering Standard) designations. Normally use for gears and big torque handling bearings.
Highly corrosion resistence - also specifically design to handle massive shock-loading - steel caps would crack with fatigue - nikel-ali-bronze caps will just absorb the shock and smile! (its the same shite MOD uses) www.dstan.mod.uk/data/02/872/01000100.pdf )
Tensile values typically in excess of 700 N/mm (45 tonnes/sq inch)!
Oh and the main criteria was block expansion, we could not afford crankshaft walk due to thermal expansion of the ali block, and steel does not expand at the same rate, where as nickel-ali-bronze has very similar expansion properties.
I could go on forever, but that should be enough to keep your old man occupied.
Number 7 said:
I'm curious about an article in this months Sprint about Engine Tech and work which they are involved in on a heavily modded. AJP8. Apparently they are using gunmetal main bearing caps, seemingly as an upgrade to cope with the projected increased power output of 1000 bhp.
Firstly you've mixed up two companies: ET and AutoC/TVRC; secondly there are so many mistakes that you can't believe much.
Good to see you utilising the NES/DefStans, we live and breath them.
Not so many years ago, you couldn't have got a copy of something like that for love nor money if you weren't involved in defence projects.
There is so much information and experience distilled in them, they are without doubt the best source of free information now some of them are available on the web.
A good example is on page 15/16 of one of the source DefStans here it explains why NAB was developed over gunmetal for submarine use, during the cold war this sort of handy information would have been restricted.
Harry
>> Edited by HarryW on Thursday 4th August 20:59
Not so many years ago, you couldn't have got a copy of something like that for love nor money if you weren't involved in defence projects
. There is so much information and experience distilled in them, they are without doubt the best source of free information now some of them are available on the web.
A good example is on page 15/16 of one of the source DefStans here it explains why NAB was developed over gunmetal for submarine use, during the cold war this sort of handy information would have been restricted.
Harry
>> Edited by HarryW on Thursday 4th August 20:59
HarryW said:
Good to see you utilising the NES/DefStans, we live and breath them.
Not so many years ago, you couldn't have got a copy of something like that for love nor money if you weren't involved in defence projects
There is so much information and experience distilled in them, they are without doubt the best source of free information now some of them are available on the web.
A good example is on page 15/16 of one of the source DefStans here it explains why NAB was developed over gunmetal for submarine use, during the cold war this sort of handy information would have been restricted.
Harry
Trust me, even though I wasnt alive back then, me mate dave can get anything...
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