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1275 pistons
https://www.ausmini.com/forums/viewtopic.php?f=2&t=40312		 Page 1 of 2
Author:  72clubman [ Wed Mar 19, 2008 4:54 pm ]
Post subject:  1275 pistons
i just got some new pistons for my 1275 rebuild the have fedral mogul on the box and ae and the 20thou over stamped on the piston

does anyone know if these pistons are anygood, i have never heard of them but they cost a fair bit
Author:  simon k [ Wed Mar 19, 2008 5:10 pm ]
Post subject: 
hypatecs are known as the best for anything up to a full race motor - $100 for a set, and $50 for the hastings rings to go with them
Author:  72clubman [ Wed Mar 19, 2008 5:57 pm ]
Post subject: 
after searching the net i found this page
http://www.aptfast.com/APT_Parts/Aserie ... _Rings.htm

this is part number i have
P21253-20...
Piston, 1275 Cooper S Hepolite +20 Hi-Performance

so they are hepolite i have heard of these, what sort of quality are they does anyone use them
Author:  drmini in aust [ Wed Mar 19, 2008 6:07 pm ]
Post subject: 
Hepolite 21253s (9.75:1) are an OK piston, but Hypatecs are a bit stronger (smaller oil drain slot). And lots cheaper. 8)
Other than that they are comparable, even look very similar.

I have 21251s (8.8:1) in our 1293, they are a bit fragile so I don't take it past 6800. :lol:
Author:  simon k [ Wed Mar 19, 2008 6:09 pm ]
Post subject: 
hypatecs are copies of hepolites - but just as good
Author:  72clubman [ Wed Mar 19, 2008 6:28 pm ]
Post subject: 
any reason they are so expensive if they are not very good, my engine will be built to around 100 - 110 hp at the flywheel, the engine builder said he usualy makes the engines with 10:1 comp, and he ordered me the pistons, hope i havent been ripped off
Author:  drmini in aust [ Wed Mar 19, 2008 6:33 pm ]
Post subject: 
72clubman wrote:
any reason they are so expensive if they are not very good, my engine will be built to around 100 - 110 hp at the flywheel, the engine builder said he usualy makes the engines with 10:1 comp, and he ordered me the pistons, hope i havent been ripped off

They are expensive because they come in from UK, I'm not sure where they are made now. Might be Taiwan these days...
Hypatecs DO come from Taiwan, and they are bloody good- some people on here race with em, others boost with em. Hard to break... even when you are trying.

Nothing wrong with your 21253s, but I buy Hypatecs coz they are cheaper. 8)
Author:  Morris 1100 [ Wed Mar 19, 2008 6:35 pm ]
Post subject: 
Where are Hypatechs made?
Where are Hepolites made?

They are both good quality pistons. I think the Hepolites have been around a long time and Hypatech are fairly new.
Author:  drmini in aust [ Wed Mar 19, 2008 7:54 pm ]
Post subject: 
Hypatecs are made in Taiwan, imported by Precision in Melbourne.
Have been available for quite a few years now.
They are cheap to buy from either Minisport in Adelaide, or www.minis.com.au in Melbourne. :wink:

Lots of pistons etc come from Taiwan, back in the 90s Ford and Mazda got their Laser/323 engines built there, maybe Mazda still do. 8)

As for Hepolites, better ask `karcraft' on here where he gets `em... he's the importer.
Author:  Mike_Byron [ Wed Mar 19, 2008 9:01 pm ]
Post subject: 
Gee 72 Clubbie, you have to be realistic here.

Most modern metallurgy these days is pretty good. The pistons you buy are all capable of giving thousands of kilometres of good service.

With most modern cams the maximum torque is coming well below the maximum BHP so therefore the only gear that you need to be revving out in is fourth. But do that too many times and you will have red and blue flashing lights climbing all over you.

.
Author:  72clubman [ Wed Mar 19, 2008 9:12 pm ]
Post subject: 
Quote:
With most modern cams the maximum torque is coming well below the maximum BHP so therefore the only gear that you need to be revving out in is fourth. But do that too many times and you will have red and blue flashing lights climbing all over you.


This engine will be doing a few track days
the car will be a track day/weekender car so it will most likely be seeing 6500rpm you need to rev out most gears on the track to get the speed up

anyway it sounds as if these pistons should be fine, its not a all out race car that will be revving to 8000rpm
Author:  norton [ Thu Mar 20, 2008 11:00 am ]
Post subject: 
drmini in aust wrote:
Hepolite 21253s (9.75:1) are an OK piston, but Hypatecs are a bit stronger (smaller oil drain slot). And lots cheaper. 8)
Other than that they are comparable, even look very similar.

I have 21251s (8.8:1) in our 1293, they are a bit fragile so I don't take it past 6800. :lol:


Bugger I have a set of 25251s in a cooper S, I didn't know they were 8.8:1 and I never liked the look of the oil slot it looks very weak, each slot seems to go half the circumfrence of the piston. Has any one had the crowns break off one of these ? I dont suppose anyone can tell me the dish cc of the 21253 ?
Author:  drmini in aust [ Thu Mar 20, 2008 11:07 am ]
Post subject: 
norton wrote:
drmini in aust wrote:
Hepolite 21253s (9.75:1) are an OK piston, but Hypatecs are a bit stronger (smaller oil drain slot). And lots cheaper. 8)
Other than that they are comparable, even look very similar.

I have 21251s (8.8:1) in our 1293, they are a bit fragile so I don't take it past 6800. :lol:


Bugger I have a set of 25251s in a cooper S, I didn't know they were 8.8:1 and I never liked the look of the oil slot it looks very weak, each slot seems to go half the circumfrence of the piston. Has any one had the crowns break off one of these ? I dont suppose anyone can tell me the dish cc of the 21253 ?

Well I've heard a few stories from UK of them going bang, but never seen it happen here.
The dish of a 21251 is the same as a 21253, but the 21251 piston is shorter from the pin to crown, so it is further down the bore by over a mm.
I think 21253s are pretty well flush in a 1275 block. :wink:
Author:  norton [ Thu Mar 20, 2008 11:35 am ]
Post subject: 
drmini in aust wrote:
norton wrote:
drmini in aust wrote:
Hepolite 21253s (9.75:1) are an OK piston, but Hypatecs are a bit stronger (smaller oil drain slot). And lots cheaper. 8)
Other than that they are comparable, even look very similar.

I have 21251s (8.8:1) in our 1293, they are a bit fragile so I don't take it past 6800. :lol:


Bugger I have a set of 25251s in a cooper S, I didn't know they were 8.8:1 and I never liked the look of the oil slot it looks very weak, each slot seems to go half the circumfrence of the piston. Has any one had the crowns break off one of these ? I dont suppose anyone can tell me the dish cc of the 21253 ?

Well I've heard a few stories from UK of them going bang, but never seen it happen here.
The dish of a 21251 is the same as a 21253, but the 21251 piston is shorter from the pin to crown, so it is further down the bore by over a mm.

I think 21253s are pretty well flush in a 1275 block. :wink:


The engine I have was built in the early 90s by car a mob called Telltune they supplied the pistons maybe they got some compression back by decking the block and or the head . The pistons did very few miles and are in good nick, I was going to reuse them with new rings
Author:  simon k [ Thu Mar 20, 2008 11:47 am ]
Post subject: 
norton wrote:
The engine I have was built in the early 90s by car a mob called Telltune they supplied the pistons maybe they got some compression back by decking the block and or the head . The pistons did very few miles and are in good nick, I was going to reuse them with new rings


$100 for the new pistons is cheaper than having to pull it out and apart again because the pistons were 2nd hand.... I reused some Mahle forged pistons in my dad's engine with new rings - never again
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