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RogerH

Alfin Drums

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HI Folks,

last year I had the drums skimmed due to some uneven wear. When I measured them after the skim I noted that they were on their max diameter.

Today I removed them to do my diff repair and have noticed that the steel brake surface is getting cracks in it. (on both drums).

 

Proper Alfins are now expensive and I probably do not need that extra quality.

I see TRshop do what appears to be an all steel 'alfin' - do they work better than the standard drum

 

Can the original Alfins be relined - I would have thought not.

 

Roger

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Original Alfins (Aluminium outer with steel lining) should be able to be re-lined but you would need a good engineering company to do it and I dont expect they would be cheap.There are Datsun 240Z ones around though they do need a little work to make them fit right and there are some poor ones of them around that dont last the course if you working them hard. I have 10" rears (Genuine period Alfins) and I dont know that I have seen another set like them.

Stuart.

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Hi Roger,

 

the fins are not to brake better but to cool the drims better.

Do you use your brake that much that your brakes suffer from getting too hot?

<_<

Ciao Marco

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Hi Marco,

I do not think I brake too much. There are no signs off excessive braking.

 

Roger

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Roger, then you do not need alfins. As Marco said they do not improve braking unless your are racing and the drums get hot. Buy your wife a nice

present with the money instead.

 

Simon

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Hi Simon,

when I bought them a fair few years ago, they were reasonably priced and of better quality that the standard drum.

 

They have now run their course and need changing. As a temporary measure I have bought standard drums (the machining quality actually looks half decent).

 

I like to tour hilly places (Scotland, Porlock hill etc) and feel they work OK. I probably do not need the Alfin refinement but they work.

 

I shall investigate if they can be relined but am not holding out much hope.

 

Roger

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Hi Roger,

Do not forget you loose HP to the wheels because the fins produce rotational aerodynamic drag. This will reduce your MPG, produce more pollution,

blah, blah, blah. Get the new dress for your wife instead.

 

Simon

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Hi Roger,

Do not forget you loose HP to the wheels because the fins produce rotational aerodynamic drag. This will reduce your MPG, produce more pollution,

blah, blah, blah. Get the new dress for your wife instead.

 

Simon

 

 

Not too sure about the loss of energy, quite hard to measure I can say, having spent many hours at Lucas Girling as a graduate trainee on the dyno experimenting with various disc brake cooling designs. We only focused on cooling efficiency and noise, as there was no significant kW absorbed power difference measured on the drive motor.

 

However it's surprisingly easy to overheat drum brakes, and once they get hot braking capability is severely impacted and it's hard to lose that heat without stopping and letting them cool down (if you can of course). Apart from work on the dyno, I'd previously proved this to myself while still a student in a 1970's Mini 998 with drums all round coming down the bank from Buxton towards Leek and trying to stop for a stationary car turning right...

 

Anyone using a sporty car with drum brakes in a hilly area, or who relies on the brakes working at full capacity all the time, should definitely consider Alfins.

 

 

Andrew

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.....Datsun 240 Z rear drums are finned and fit TR with 9" x 1.75" shoes if you drill out the stud holes to fit the TR studs.

 

https://www.triumphowners.com/resource/datsun-brake-drums/

 

https://zcarsource.com/brake-parts/brake-drums-shoes

 

http://www.gomog.com/allmorgan/datsunbrakedrums.html

 

https://zcardepot.com/brake-drum-rear-240z-260z-280z-70-78

 

 

Peter W

Edited by BlueTR3A-5EKT

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.....Datsun 240 Z rear drums are finned and fit TR with 9" x 1.75" shoes if you drill out the stud holes to fit the TR studs.

 

https://www.triumphowners.com/resource/datsun-brake-drums/

 

https://zcarsource.com/brake-parts/brake-drums-shoes

 

http://www.gomog.com/allmorgan/datsunbrakedrums.html

 

https://zcardepot.com/brake-drum-rear-240z-260z-280z-70-78

 

 

Peter W

Sometimes you do need to slightly machine the centre hole out too. FWIW there are a lot of rubbish repro 240z ones around as well that dont stand hard use.

Stuart.

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Sometimes you do need to slightly machine the centre hole out too. FWIW there are a lot of rubbish repro 240z ones around as well that dont stand hard use.

Stuart.

That is what the Morgan article says also.

Oh dear... cheap crap repro....

Peter W

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That is what the Morgan article says also.

Oh dear... cheap crap repro....

Peter W

 

 

I had a look for 240Z finned drums before going for the Bastuck TR variety, as I couldn't find (what I considered) good 240Z ones in Europe. Maybe it's worth another look as the design appears to be superior.

 

 

Andrew

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