26 replies to this topic

[haz]

...get a room

cheers for the advice, I have some extra old school pistons from a triumph spitfire, so might indeed need skimming to match eachother

[pogie]

...get a room

cheers for the advice, I have some extra old school pistons from a triumph spitfire, so might indeed need skimming to match eachother

Cool, I've got a set of Triumph 2500 Pi pistons fitted to S rods in the garage. I asked Ian Hargraves, owner of Avonbar, about this set up and he said that they worked well, but being flat top piston meant getting the CR down to and acceptable level could be a problem. He also said that people made the mistake of machining the S rods to fit the Triumph gudgeon pins where they should have machined the Triumph pistons to suit the Mini pins.

I got them out of a rallycross engine from a Metro that had lost oil pressure whilst racing at Brands. It had a 84mm stroked crank and with the 74.689mm Triumph pistons would have given 1473cc. I bought the engine for £125 as a gamble that it could be salvaged, but unfortunately the crank was scrap and the block was warped along the mains and through the cam bearings??? I am going to go for a 73.5mm-1380 build for my next engine, my latest car is not the striped out pseudo-racer that my Clubbie was and I don't really feel the need to go super mad with the spec.

Interestingly, the guy who sold me the engine replaced it with a lump that was fitted with one of the first KAD 16v heads.

Edited by pogie, 19 March 2008 - 09:44 PM.

[haz]

shame about the 1500, worth the gamble though!

these spitfire's are far from flat topped... have a ganders  SP_A0064.jpg   144.61K   8 downloads

pins fit the rods a treat, skirts have been taken down so they dont foul on the rods and they fit the bore like a glove, apparently these were the pistons everyone used in their 1380s when everything was in black and white way back when

[pogie]

Interesting, I've never heard of Spitfire pistons being used in Mini lumps. I was also given a spare set of new pistons with the engine and you can see that they are flatter then a flat thing hidden up Kate Moss' jumper. The ones fitted to the rods have had valve pockets machined into them.

Oi, less of the black and white era jibes, I bought the engine in 1990 when I was already well into my 20s. We had colour stuff back then, I even had a VHS video that recorded in colour.

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•  IMG_0008sml.JPG   69.32K   9 downloads

[haz]

haha mossy would be proud of them babies!!

why the valve pockets? because of the long stroke i assume?

VHS?! i thought it was reel to reel in the 90s...

[pogie]

haha mossy would be proud of them babies!!

why the valve pockets? because of the long stroke i assume?

VHS?! i thought it was reel to reel in the 90s...

I'm not sure why the pockets are there but the engine was quite highly tuned with a high CR so it may have had a small deck height so it was probably just to clear the valves. I'm not sure what cam it was running, but it had to be hammered out of the block and it went straight into the scrap bin.

[mini93]

*OT* just to throw a spanner in the mix Kent x-flow engine, flat head combustion chamber is purly above piston crown

i didnt bother reading ether your nigglie argument in a circle or at least not much so you may well have picked up on that already

[JetBLICK]

You dont have to have flush pistons. If the chamber size allows it (for compression ration reasons) you can have the pistons higher than the deck height, basically taking up some of the gasket thickness. i think the theory is it means the combustion happens in the chambers in the head rather than the gasket area.

My pistons are 12thou above the deck at TDC, and its fine... to quote the engineers that said it'll be fine like that, 'it pulls like a train'

Edited by JetBLICK, 19 March 2008 - 11:34 PM.

[mini93]

also you can run them down the bore, for lowering compression ratio reasons tuuuuurboooo

[jessieparsons1]

chears to all u guys... as clear as it was between the squabaling! lol

thanks again, and usefull calculator!

x

[Sprocket]

shame about the 1500, worth the gamble though!

these spitfire's are far from flat topped... have a ganders  SP_A0064.jpg   144.61K   8 downloads

pins fit the rods a treat, skirts have been taken down so they dont foul on the rods and they fit the bore like a glove, apparently these were the pistons everyone used in their 1380s when everything was in black and white way back when

Oooooh look at the slits in those skirts

[haz]

is that a bad thing?