A friend of mine asked me about his non functioning difflock the other week, I had a look around under the bonnet and think the vacuum pipeing is missing under there but couldn't work out how its surposed to be. HAd a flick through my parts book and V8 sup but couldn't see the difflock plumbing - probubly missed it. I've also surched the forum but the only thread I think probubly answers my question is quite old and no longer has pictures. 10 seconds looking at a intact setup should answer my questions!
Firstly a bit about the vehicle and probubly an explenation why its broke in the first place (thanks PO)
I'm not sure if its the original engine but if it is its got SU carbs and whoever fitted them has done stuff like leave the carb breather pipes pointing down near the oil filter rather than connect them to the RH wing fitting (maybe down by the front of the engine is how its done on RR or car installations where the carbs came from? The truck hasn't had a hard life and I doubt its done that many miles so though I havn't checked the engine number I would expect it to be a stage 1 engine, probubly the original, thats just had a carb change (and derestrict?). The oil filler on the rocker cover is in the correct place so its not got car rocker covers. Its got the RR style air filter on top of the engine with the pipe up the middle, not the large fiter on the bulkhead (the export spec filter? I've only seen that setup in the flesh on a Saudi spec reimport). Gearbox wise I know it has a 1.174:1 high range and the speedo drive is well out so I suspect its a complete RR unit, maybe it was fitted with a RR engine, who knows.
The big vacuum pipe goes streight to the brake servo and does not have any takeoffs on it.
As for the difflock, there is a black plastic pipe running up the bulkhead on the right hand side to near where the accelerator cable starts, its got a streight end and it doesn't seem long enough to reach any part of the engine and having had a little look around the carbs (not that easy with the air filter in place) I can't see any obveous place for it to go on the manifold side - A photo would be great!
Should they plumb direct up or is there a vacuum tank and or non return valve to go inbetween? I'm guessing if the carbs were off a car or an LT230 equipped LR/RR there would not be a vac takeoff fitted as standard as it wouldn't have a use. There is a possablility this black pipe is the breather for the overdrive? The two gearbox breathers are on the left side out the way, they are white and have a 180° end like you'd expect of a breather.
Other stuff thats missing...
The warm air intake system isn't there, just the short pipe into the air filter between the carbs which is probubly an effective way of shoveling any water the fan happens to through streight into the air intake - making a V8 worse in water is a specal achivement! Should I actully worry about this, ie will it run badly when the weather is at carb icing conditions, or will it use more fuel (its quite good at the moment but thats no excuse to not try further improvments). It has the casting for the heat chamber on the RH manifold (the style with the horisontal joint) but the top bit is missing and it would probubly be quite hard to bolt anything to it as the studs aren't good. Everything else between that and the air intake is missing.
Rather surprisingly the RH manifold also has an EGR valve on it though again it is (thankfully) not plumbed in. Seems an odd thing to fit if it was never used so presumably there was a load of crap somewhere to make this go thats also been binned or the manifold is not original? Does no harm so I'll leave that be, just slightly surprised to see EGR on something thats not a 1992> diesel or US spec.
Underbonnet pipeing (esp diff lock)
Re: Underbonnet pipeing (esp diff lock)
Here is a picture of where the black plastic vacuum pipe from the diff lock connects to the inlet manifold on one of my Stage 1s, which has also had SU carbs fitted to its original engine, if this is any help:
Land Rover Stage 1 diff lock vacuum pipe to inlet manifold connection by Geoff172, on Flickr
Land Rover Stage 1 diff lock vacuum pipe to inlet manifold connection by Geoff172, on Flickr
2 1981 Stage One 109 V8 SWs
Re: Underbonnet pipeing (esp diff lock)
Yep, that might just be the money shot.