Page 1 of 1
lpg on GU 4.8 litre
Posted: Sat Feb 10, 2007 4:59 pm
by eastg8
Has anyone done this conversion and are the heads suitable for lpg?
Posted: Sat Feb 10, 2007 6:53 pm
by raptorthumper
I've heard bad reports on
http://www.patrol4x4.com/forum/ about the DOHC heads. Valves recess a fair bit every 20,000 klms and is a costly and labour intensive job to reshim. The std exhaust seats are relatively soft for LPG. Unless the head is rebuilt with hard stellite seats (also big money) not worth the price gain of cheaper LPG.
My 4.5 GU (with turbo) is the old 2 valve pushrod style with adjustable rockers, and i just readjusted the valves today (exh clearance had tigthened up a bit since last time) and it took 35mins to do. It's done 200,000 klms (mostly on gas) and when i rebuild the head its only $600-800 bucks, much less than the DOHC heads.
Posted: Sun Feb 11, 2007 4:29 am
by MyGQ
the TB48 engine (4.8L) is a new design engine from Nissan as it takes the pushrods out of the equation, but they didn't think too hard about LPG compatibility with this engine.
The TB45 engine is essentially a TB42 with a new head, its still pushrod driven, so it does not matter if it runs LPG or not.
Posted: Sun Feb 11, 2007 8:07 am
by Deleted User
PM viet667, He is the LPG expert here. -- knows Nissans and LPG
Posted: Sun Feb 11, 2007 9:22 am
by simcoe
as everyones said the 4.8's are no good on gas
dads mate who rebuilds heads(Rob who owns The Head Men in newy)hows that for a plug..lol told me to steer clear of them when i ws looking into buying one. last one he rebuilt cost about 1500 and that was just his bill, then the mechanic put it all back together.so all up prob a 3 grand job.
and as raptorthumper said its only a quick job to adjust the 4.5 tappets.
dad opened mine up to around 18thou,there abit noisy but i'd rather that then having a blown head.then every 12 months adjust them again.which is about 15-18 odd thou kays.