Mud-club

Vehicle & Technical => Range Rover => Topic started by: clbarclay on July 07, 2007, 09:38:27

Title: Changing pistons
Post by: clbarclay on July 07, 2007, 09:38:27
I'm looking at getting a another 3.5 engnie and either rebuilding it to go in mine or replacing mine and rebuilding the orgional latter.

As far as I can tell the only significant differance between an 9.35 and 8.13 compression ratio block is the pistons. Does this mean if I buy an 8.13 block I can just fit new pistons to get 9.35 compression again?


Secondly, if I do change the pistons could I fit and run 9.75 compression vitesse pistons withough too much difficulty or would I need items like a Vitesse ECU?
Title: Changing pistons
Post by: Range Rover Blues on July 13, 2007, 17:13:17
I don't think the EFi is clver enough to worry about the CR too much, it's the dizzy you will need to match whatever pistons you fit.

As for a higher CR, might be cheaper to find a high CR short engine in good nich and fit that, perhaps with a new cam (3.9) and followers/rockers and crank shells if you feel that way inclined.
Title: Changing pistons
Post by: clbarclay on July 13, 2007, 18:17:45
I don't feel very inclined at all (the wallets evan less inclided at the moment). I'm just mulling over ideas having seen a complete 3.5 v8 rebuild kit for sale that included new 9.75:1 pistons.
Title: Changing pistons
Post by: Range Rover Blues on July 14, 2007, 00:48:43
Depends what it costs.  Would you fit new pistons without any machining on the bores though :?
Title: Changing pistons
Post by: clbarclay on July 14, 2007, 08:47:32
Fear not, have already bear that in mind along with skimming heads.
Title: Changing pistons
Post by: Range Rover Blues on July 15, 2007, 00:40:04
Skimming heada a good idea, if you fit the composite pitons rather than the ali plate ones they compress to 1.2mm rather than 0.5mm respectively, so you can machine 0.7mm away without effecting the CR at all.  There is a witness mark on the front of the head if you know where to look so that you can judge how much has already been skimmed.
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