Thread: crankcase breather re-location on 3.9

Originally Posted by mandala1111

Hi there.
I have read that a few people that are running on LPG have recommended relocating the crankcase breather to help with back firing, from the rocker cover to near the air cleaner instead of it's present location going into the plenum.My question is does the small hose from the T that goes to the inlet maniflod need altering as well.
Cheers
Shane

Based on my experience with 40+ D1/RRC engines I have converted to gas it makes no difference at all. Leave it standard and concentrate on correct plugs/leads/timing instead. Shifting the breather can also oil up the MAF which is not desirable.

Thanks Bee utey.
I was a bit concerned about the MAF getting oiled up if it was relocated to the air cleaner side but what if it was fitted between the mixer and the MAF ?.I have always paid attention to the electrics being in top condition and have had useful information from you regarding timing.The car runs nicely for about 20,000kms and then just when I am thinking of doing the plugs again the car backfires and this has happened twice now at around 20,000 kms even when the engine seems to still be running well.I am putting a new engine in the Disco I bought and just trying to get it all running well before I drive it and risk any back firing.Last time it happened the air cleaner canister busted plus the risk of MAF damage.Is a backfire flap worth fitting.The gas system on the car I bought is an Impco mixer type.Is there any way that a Rover V8 can be bullet proofed from back firing.
Cheers
Shane

Originally Posted by mandala1111

Is a backfire flap worth fitting.The gas system on the car I bought is an Impco mixer type.

If you can fit a backfire valve between the impco mixer and the manifold inlet it would help. You need to take the outlet off the Impco mixer and machine it shorter/smaller to fit a 70mm backfire valve. I have done a similar mod on other EFI engines with success.