Oh !
I'm pretty sure that they are totally different !
The thickness on the back end of the rods is different and so they wont go into the heads unless you modify them.
I cant remember if the 1.5 are thicker or thinner than the 1.7, I just know there is a difference.
I suspect the angle's would be different as well
There might be a difference in the overall length, because of the different
stroke of the 1.5/1.7 engines (67.2mm vs 72 mm).
(when assuming the piston pin vertical position of 1.5 and the 1.7 pistons are identical)
Well I have conrods out of both motors and though they have different part numbers they certainly appear the same. Will take engine rebuilder to confirm. Will post some photos of the old 1.5 pistons too quite a sight!
If the 1.5 and 1.7 conrods are the same, i guess the 1.5 piston would hit
the cylinder head because of the longer stroke of the crankshaft.
I think the pistons should be replaced to the 1.6 boxer ones (same diameter,
but the piston pin vertical position is different).
If you think i can give you the 1.6 boxer piston sizes, and you can compare
them with your 1.5 piston(s).
I suppose you could always do a check and see if its ok before closing up the engine ? If you already have the parts mentioned above, just fit the 1.5 crankshaft on the 1.7 block and take a 1.5 conrod, fit a 1.7 piston on it without piston rings or anything, and measure the top end to calculate the valve clearance !
You can do the same with a 1.7 conrod and a 1.7 piston and compare ! Then you can educate us as well
I'm probably a bit stubborn as I'm still not convinced to abandon this project. I'm not giving up supercharging yet ! I've got a few spare pistons to kill so I'll give it a shot and see how it goes :lol:
Tasos had his 1.7 8v engine supercharged for over 4 years and nothing like that happened to it ! He was running lean as well ! I will have a Dastek piggy back ECU parallel to the one of the chipped 16V ECU as well to manage fuel and ignition. Hopefully this will do the trick If not, a fifth injector is also in the plans. A mixture gauge will be a must in this situation. Much more meaningful than any other gauge.
I really think it was my intake manifold design. The pistons on the side are fine.
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