My previous patrol was a 4500 running on LPG and I was advised to have the valves done every 20,000 which I did. I used to pay $100 for that but the 4800 is a twin cam so perhaps $150 would be a good guess. Perhaps someone with a 4800 on LPG may like to comment.
Thanks David, I will have to get into touch with some local garages to see how much they will charge. I do reallly hope it will just cost 150 to do that. I just spend quite a lot on purchasing it and getting it on the road recently. Thanks again,.
They 4800 guys, any idea how much it did cost to do the valves adjustment on GU series 3 4800?
Sit down when you get the quote..
The valves require shimming, and the shims come from Nissan.. Its a reasonable size job, get someone who knows what they are doing to do it if you are not comfortable doing it yourself.
Nissan quoted me around $1100 to do it about 6 months ago.. Ended up getting it done competently by a friendly mechanic for well under that..
Couple of tips - as others say its a pain and usually needs car to in in overnight cause engine needs to be cold \ run \ then cold again to check. When I wanted it done Nissan said they would sub it out to LPG 1 gas mob.
However you may consider the approach I took - Its not to hard to check yourself (1 hr with practise) all your looking for is not the absolute clearance value but rather to see that they have not tightened up - a bit loose doesn't really matter.
So I checked mine each 50,000 and now at 250,000km they are a bit loose but still don't really warrant adjustment.
Just had mine done by my mechanic for just under $400. I was lucky in that I didnt need shims, its a bastard of a job any my mechanic wasnt happy doing it....He advised me to do the checks every 20,000 km due to the fourby being on gas.
The 4.8 seems different to the 4.5, conventional, and just paid $220 to get it done. Twin cam and possible different system, could be more! But what a difference, quiet, more power and better fuel consumption....
I got mine done by nissan not so long ago. About $500 from memory. Just remember that the 4.8 must be stone cold, they cant be set otherwise. Ive got injection gas too, the nissan mechanics were ****ty with me because it was 'all too hard'. I only went to nissan because they had the right tools. You might be lucky with the shims, they can often switch them around and not have to replace them.
Well here is the living proof. Maybe I'm just uninformed & dumb, you can make you're own mind up. But no-one ever told me about the need to get this done with an LPG engine (wish they had). So - the story - I can tell you that if you don't (& this was probably all my mistake due to ignorance) then it can be catastrophic & VERY very expensive. My 2003 Ti 4.8 (with factory fitted from day 1 LPG) has done 165k to date & I've had it from new, cost $74,000 in 2003. Two engine re-builds so far at 85k & 145k. Both apparently due to the fact that (& I quote the excuse from Nissan dealer) "the Japs don't/didn't build the patrol 4.8 engine to the tolerances to cope with the high temperatures generated by LPG". Yes it does beg the question "why didn't you tell me this when I bought it?" Anyway, the upshot was; 1st time - engine re-build, recon the head & new valves - $6,500! 2nd time (13months later) - engine re-build, new head (+ an admission from the head re-build guys that they didn't re-seat the valve's correctly, so I got that bit for free) new valves again - Oh but hey hang on, wait! - the timing chain has stretched & all the teeth on the timing gears are stuffed! 6 weeks wait for them to come from Nissan in Japan! Re-build (& whilst test driving) the LPG converter packs it up! End result - bill $9,000! & yet still to this day (some 7 months later) the LPG abilities of it are still not correct (won't pull the boat + coughs & splutters). I'm now living in Qld & I used to live really close to Brighton in Victoria (so you can guess who the Nissan Dealer was). Obviously I wasn't/am still not pleased. I do love the big brute & I treat it right & it's had every service (yep by that Nissan dealer correctly & on time so far). I'm just really really pi&^%$#d someone didn't tell me about this a long time ago! I have no idea whether this is the "cure" or not but I can tell you it sounds a hell of a lot cheaper than my experience! So, take heed guys with 4.8's on LPG.
I just finished doing this on a customers car (TB48 on Gas). It had a slightly rough idle and you could hear it lightly popping every now and then out of the exhaust. Adjusting the clearance fixed this.
The 4.8 doesnt have the conventional threaded flat head adjuster with locking nut, It uses a bucket type lifter system with different size shims which fit into the bucket to adjust clearance. From memory the minimum intake clearance was .32mm, And the minimum exhaust clearance was .33mm. You use correct size feeler guages to slip in between the lifter bucket and the cam to check the clearance, if it fits you are fine. If it doesnt you have to measure the clearance using the different size feeler guages to find the tightest fitting one, This is your clearance. Write it down along with what cylinder and which of the two valves it is (valve 1 or 2).
Once you have done them all you have to remove the shims which are too thick making sure to keep them in order of what cylinder and valve they came off. Some say you have to take the cams out however in this case it was just a matter of loosening the cam bridges so that the cam would lift off the buckets, then i used a screwdriver and a magnet to loosen the shims from the buckets and pick them out. Once this is done you measure the thickness of the shim, and do a calculation to see how much it needs to be ground down or if you are replacing them, what size you need.
Calculation is as follows......
.33mm - .15mm = .17mm
2.23mm - .17mm = 2.06mm
Say cylinder number 1, valve number one clearance is .15mm, the minimum clearance should be .33mm......So you know that is tighter than specs. So you now remove that shim and measure its thickness. The shim measures 2.23mm, so you now have to replace that shim or grind it down. So you take the specified valve clearance of .33mm, and you subtract the clearance you currently have which is .15mm, you are now left with .17mm which is the amount you have to grind off your shim. So you now know in order for the clearance to be at minimum tolerance, the shim originally 2.23mm has to be 2.06mm thick. If you have the correct equipment to do so then you grind away checking with a micrometer until you reach the desired thickness and reinstall. However most ppl wont have the correct specialised equipment for this so you will need to buy replacement shims. With correct shim height of 2.06 still remaining, its just a matter of ringing an appropriate shop and ordering them.
Probably doesn't help with your need for an accurate quote, but explains things and makes the subject a little more clearer.