197 pistons in f7r

[GTaylor]

Hi all,i have just had a 172 engine epicly fail,so im puting my old cammed f7r engine back in. trying to find out what cc size a 197 head is so i can compare it to my megane f7r head,if similar will fit 197 pistons to increae the compression ratio. any info would be much appretiated . regards greg

 

[Chip-mk1]

I dont have the figures to hand, but they are MUCH bigger volume heads on the 197 than on the 172 so you might be alright.
The williams and 197 both share the circular shaped ends to the chamber, where as for some reason the 172 are cut off and made much smaller (im guessing they were chasing head gasket reliability, then on the 197 they realised they had over done it on the 172 so went back to the superior williams shape)

 

[GTaylor]

Cheers for the reply,i fitted a 197 piston earlier,block fitment is fine . Your right the cylinder bowl is bigger,also the valve angle is less steep on the megane head. im going to measure the volume see what compression it will be,think head gaskets may differ in thickness also. on different subject did u finish that manifold with the pulsar plenum?looking to complement the cams and increased compression. regards Greg

 

[Chip-mk1]

Yes mate I did, gave a nice linear spread of torque that drove really well and revved hard, not quite as good peak torque as standard though.

 

[Jaff.]

Greg where in Swansea are you mate?

 

[GTaylor]

Interesting with the mani,will look into that shortly. Hey jaff,i live in swansea town centre,cars ar up unit in gorseinon,have to pop up sometime

 

[Jaff.]

Cool, not far to travel then lol. I live in Britton ferry and the car is in Ammanford fair way to travel lol