@Henry_b you started this, I hold you accountable for the last week of mental gymnastics.
BMW M62 4.4ltr V8 DOHC VANOS (variable valve timing to the rest of us) as fitted to many BMWs and it's only real relevance to LR was the fitting into the 3rd generation L322 Range Rover.
The rebuild thread started by Henry was very concise and as I was already looking at an L322 V8 with LPG I gave it a good looking over, then do as all prospective owners should do, went off and started reading up on potential problems with the vehicle with my desired engine, not too many purely engine derived faults all bar VANOS and timing chain guides. The perpetual mention of "timing chain guides" intrigued me, having been a Rover V8 owner many times over I was confused by the guides reference, the Rover being a central cam and push rod and rocker assembly to open the valves.
So what was all this guide thing about? Well, these are the guides and the main trouble spot of this engine.
A better look at the cam link chain tensioner and guide.
Schematic of the main timing chain guides.
For an engine who's timing chain has to run though 90 degrees I am very unimpressed by the fact that BMW chose to run some sort of plastic/nylon guide over a fit and forget idler sprocket and hydraulic tensioner. It just seems a very cheap and nasty way of achieving the timing of this engine.
So what went wrong? Well nothing much, apart from my head got to thinking about a better way of doing this, for sure I won't be upgrading one but it is a very interesting process to go though in thinking about the engine and what and where it could have been made better, obviously they want to assemble it fast and cheap as well as sell you a bunch of spares in the future.
Would an open timing belt inside a simple plastic cover have been better to time the two main cams and then left the VANOS inside the rocker cover? Or what about the use of actual idler sprockets inside the timing chain cover?
Well as I've no intention of spending a small fortune on getting engineering shops to tinker and as I don't actually have a machine shop of my own it seems as though the only thing to do would be to get an engine and get it fully rebuilt and ready to be installed in the vehicle of my choosing.
The question is, how long will the new timing chain guides last exactly? I've read that they will last for about 120,000 to 150,000 miles, obviously more than I would ever do in one but I can't find anyone to verify whether they last that long or whether I would be doing them every 50,000 or what?
BMW M62 4.4ltr V8 DOHC VANOS (variable valve timing to the rest of us) as fitted to many BMWs and it's only real relevance to LR was the fitting into the 3rd generation L322 Range Rover.
The rebuild thread started by Henry was very concise and as I was already looking at an L322 V8 with LPG I gave it a good looking over, then do as all prospective owners should do, went off and started reading up on potential problems with the vehicle with my desired engine, not too many purely engine derived faults all bar VANOS and timing chain guides. The perpetual mention of "timing chain guides" intrigued me, having been a Rover V8 owner many times over I was confused by the guides reference, the Rover being a central cam and push rod and rocker assembly to open the valves.
So what was all this guide thing about? Well, these are the guides and the main trouble spot of this engine.
A better look at the cam link chain tensioner and guide.
Schematic of the main timing chain guides.
For an engine who's timing chain has to run though 90 degrees I am very unimpressed by the fact that BMW chose to run some sort of plastic/nylon guide over a fit and forget idler sprocket and hydraulic tensioner. It just seems a very cheap and nasty way of achieving the timing of this engine.
So what went wrong? Well nothing much, apart from my head got to thinking about a better way of doing this, for sure I won't be upgrading one but it is a very interesting process to go though in thinking about the engine and what and where it could have been made better, obviously they want to assemble it fast and cheap as well as sell you a bunch of spares in the future.
Would an open timing belt inside a simple plastic cover have been better to time the two main cams and then left the VANOS inside the rocker cover? Or what about the use of actual idler sprockets inside the timing chain cover?
Well as I've no intention of spending a small fortune on getting engineering shops to tinker and as I don't actually have a machine shop of my own it seems as though the only thing to do would be to get an engine and get it fully rebuilt and ready to be installed in the vehicle of my choosing.
The question is, how long will the new timing chain guides last exactly? I've read that they will last for about 120,000 to 150,000 miles, obviously more than I would ever do in one but I can't find anyone to verify whether they last that long or whether I would be doing them every 50,000 or what?
