Thread: crank case pressure

Crankcase pressure is generally caused by compression ring blowby. Gas is a very "dry" fuel, compared to petrol. During run in usually a richer fuel air mixture helps to flush the "fines" from the tight bores. The reason the first few oil changes are so important on a new engine, and the reason most mechanics would assert a petrol only run in period. At least I sure would. Give her a compression test, she might be showing some very premature wear.
A pressurised crankcase is from piston ring blowby. Worn bores and rings. Sorry.
Or even worse a cracked piston? I'll shutup now, alright?

Shorty.

you could also get blowby if the ring gaps are lined up.....or if you have blocked breathers.......

could you tell me where the breathers are please thanks zacc

Originally Posted by DEFENDERZOOK

you could also get blowby if the ring gaps are lined up.....or if you have blocked breathers.......

........but it's not likely that LPG has caused a blocked PCV system/breathers or the rings to "line up" [Especially not so early! ]......but it is likely to produce results as Shorty has suggested! [Especially so early! ]

Originally Posted by cazzz12000

could you tell me where the breathers are please thanks zacc

Carburettored? .......or EFI?...........What year(-ish) model is the EFI if fitted?

Its a 93 EFI Disco

Hi Cazzz
If I was you I would make the motor WORK to bed it in.
Find a BIG hill,Greenmount or Bedfordale whichever is closest.
Run the hill in TOP gear,but start off with VERY low revs so it wants to stall,when you get to the top start again and then go again.
It should help.
Andrew

Originally Posted by cazzz12000

Its a 93 EFI Disco

On top of rocker cover drivers side is a thick hose leading to a cylinder screwed into rocker cover.......remove hose, unscrew cyliner, soak in kero to clean out - if really filthy, replace wire guaze with a wad of stainless steel pad [like for dishes +pots+pans, from supermarket, cost= $1.00.......

Next, go to passenger side rocker cover at rear is a 1 1/2" black plastic breather, carefully pull cover off clean and lift out sponge air filter, if its ok then clean in kero or replace .....they usually disintegrate! [from LR or your LR parts supplier = $5.00].

Then clean inside of that hose from the driver's side rocker.....follow it towards LHS of top of engine to TEE, carefully pull hoses off TEE and clean the metered orifice inside with aerosol carby cleaner, poke gently with wire.......clean 2 smaller hoses after TEE and their connections into Plenum with the spray carby cleaner.

If plastic TEE has embrittled from heat and fumes [it prbably has] and breaks, replace with new one from LR Genuine in plastic OR obtain the upgraded chromed brass from suppliers like Graham Cooper.

Don't use ordinary plastic TEE - original has a precise sized orifice........otherwise idle and low speed running will detiorate.