5 GT Turbo Compression height of standard gtt piston.

[ReidarUF]

Would anyone have info of the compression height and the height of that slightly raised area of the standard gtt piston?
Also the distance between the edge of the piston and the highest piston ring grove is interresting.

They doo seam a bit lower than that from the Alpine turbo and also have the grooves further down. I found this picture on another forum.

 

[Adey]

its very slight 2mm possibly or less. i can try an measure a piston for you at the weekend

 

[ReidarUF]

That would be great Adey!
I have a 83,5 Brazilian crankshaft that I'm thinking of using together with a R5 Alpine(Gordini in G head. Witch I need pistons 3,25mm lower than the R5A ones. According to Franzose.de the R5A ones is 37,5mm plus 5mm dome and the R5A turbo 36mm plus the 4,5mm raised area.
If the gtt ones is another 2mm lower and also have the highest piston ring a bit further down it might be possible to machine to similar design as the R5A ones but low enough for it all to go together.
If it gets tigt mecaparts have a 2,4mm (blody expensive) headgasket intended for the rear engined R5 turbo.

 

[ReidarUF]

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[ReidarUF]

Found some info on the gt turbo pistons in an ebay ad today. Aparently their crown hight is 37,5+1mm so in total 4mm lower than the Alpine ones. So plenty low enogh for a 83,5mm stroker aplication.


Might need some modification along the edge to fit the profile of the R5 Alpine head and to clear the valves.
I've calculated that if piston of the same design as the Alpine ones but 3,25mm lower together with the 83,5mm crank would result in about 11:1 in compression. I dont think there is enough material in the gt turbo pistons to replicate the Alpine design but it will probably still be higher than oe on the R5 Alpine.