Thread: RRC 3.5 with 13:1 CR?

That'd be a 'typo', should read 8.13:1, the 8 is not visible by the sounds of it.

JC

Originally Posted by justinc

That'd be a 'typo', should read 8.13:1, the 8 is not visible by the sounds of it.

JC

That's what I thought at first, but I've read several references to 13:1 now.

Maybe they're carrying the same typo over.

Originally Posted by d@rk51d3

That's what I thought at first, but I've read several references to 13:1 now.

Maybe they're carrying the same typo over.

As far as I am aware, 8.13, 8.25, 8.37, 9.25, 9.35,and 10.25 were the only ratios Rover ever produced ex factory on any of their V8's, there are probably a few more in between that I may not know of, but 10.25 was IIRC the highest ever factory ratio, released in the P6b 3500S manual rover sedans.

JC

Dark51d3,you seem to be anally retentive about some relationship of 13:1 ,some inferred CR ratio and a engine number Believe me,no ROVER v8 ever has or ever will in street form .Once your getting close to 12:1, youll need Methanol and a real ignition system. With Rover V8s its a battle with Cam advance , with constant retarding due due to woeful timing chainss,woeful gears,woeful lifter to lobe forces,woeful rocker geometry,etc etc.
Dont confuse the engine number with CR ratio ,Its not useful , Fit and do a proper Wet and dry comp test before jumping to any conclusions.

Originally Posted by justinc

As far as I am aware, 8.13, 8.25, 8.37, 9.25, 9.35,and 10.25 were the only ratios Rover ever produced ex factory on any of their V8's, there are probably a few more in between that I may not know of, but 10.25 was IIRC the highest ever factory ratio, released in the P6b 3500S manual rover sedans.

JC

Haynes also list a 7.1, but was limited to certain export models.

Re-reading the list, I can see that the typo was caused by most likely a cut&paste error.

All Rover V8 Engine Numbers

So 8.13:1 it is.

Originally Posted by d@rk51d3

Haynes also list a 7.1, but was limited to certain export models.

Re-reading the list, I can see that the typo was caused by most likely a cut&paste error.

All Rover V8 Engine Numbers

So 8.13:1 it is.

Sorry it was 10.5, 10.25 in the P6b, Mine was a torquey little engine ,manual rover sedan, with HIF SU carbs, not those CD175's, definately made a 3.5 feel bigger than it actually was.


JC

I remember my P5B coupe had a 10.5:1 3.5litre and was always pinging its guts out under anything more than half load, even with timing retarded to zero advance. Built for much higher octane rating fuel than sold in OZ. Only solution was low comp pistons.

My very first RR was a 1976 and with great hope , I changed the engine to 4.4l V8, after rebuilding it with some special hi-comp rover (3.5l) pistons, hi-lift cam, etc, etc.
Went very well, after having to retard spark to stop low load pinging; compression test showed 240+psi! (12:1?)
The only way to turn motor off was to stall it in gear!
After a month of this nonsense, out it came and replaced pistons with 8:1 Rover ones.
Still ended up very powerful, but would stop when key off!