M62 random musings.

@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?

The M62 has many shortcomings the lack of cylinder wall being No1 in my book,

Timing chain guide rails are peculiar regarding material design, very cheap, but that's modern BMW for you

Timing/Vanos is a nightmare to set up aswell.

Personally the only l322 that would get my money would be the later models with the Jag engines, proper engines they're very well built.
Plus you have the benefit of the later ZF6hp26 which is a proper load lugger of a box unlike the 5hp24.

However the Jag engines don't like LPG so its a double edged sword..

Henry_b said:

The M62 has many shortcomings the lack of cylinder wall being No1 in my book,

Timing chain guide rails are peculiar regarding material design, very cheap, but that's modern BMW for you

Timing/Vanos is a nightmare to set up aswell.

Personally the only l322 that would get my money would be the later models with the Jag engines, proper engines they're very well built.
Plus you have the benefit of the later ZF6hp26 which is a proper load lugger of a box unlike the 5hp24.

However the Jag engines don't like LPG so its a double edged sword..

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From your build I gathered that the block would benefit from top hat liners for the bores post 100,000 miles and I'm not convinced that the whole timing chain set up in combination with the liners would be worth it as the cost is proper mounting up.

I had read about the Jag engine and the 6 speed box being the better petrol option but I hadn't seen anything about it not liking the LPG, can you elaborate on why that would be exactly? Smashes out the valves or poor running?

dieseldog69 said:

From your build I gathered that the block would benefit from top hat liners for the bores post 100,000 miles and I'm not convinced that the whole timing chain set up in combination with the liners would be worth it as the cost is proper mounting up.

I had read about the Jag engine and the 6 speed box being the better petrol option but I hadn't seen anything about it not liking the LPG, can you elaborate on why that would be exactly? Smashes out the valves or poor running?

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The Jaguar v8's valve seats are soft, they'll last indefinitely on petrol.

But once on the hotter and longer burning LPG they suffer..

Henry_b said:

The Jaguar v8's valve seats are soft, they'll last indefinitely on petrol.

But once on the hotter and longer burning LPG they suffer..

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For the sake of a few quid on head work to get harder seats and valves fitted I'll take the Jag then, much cheaper and easier to do the heads than the strip out the whole front end of an engine.

Off the topof your head do you know the engine code for the Jag lump?

dieseldog69 said:

For the sake of a few quid on head work to get harder seats and valves fitted I'll take the Jag then, much cheaper and easier to do the heads than the strip out the whole front end of an engine.

Off the topof your head do you know the engine code for the Jag lump?

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Taking the heads off would be much easier than on the m62, everything is so much better in regards to design and durability

Its an aj41 lump.

4.4L the same displacement as the m62 but much superior..

305hp 441nm

The only thing of note to worry about on the Jag lump is the valley pipe, but if you're removing heads its a 5min job..

And if you get a N/A engine its about a 1 hour job, just a case of removing the intake manifold

Too many chain guides on that BMW engine

Yeah but we just rebuilt one and the chain guides were pretty easy to do.

biketeacherdave said:

Yeah but we just rebuilt one and the chain guides were pretty easy to do.

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Was that for a bimmer or an L322 Dave?

How was the oil pump chain?

The L322 its a daily driver now oil pump was all good we sourced a second hand bottom end I will do a complete write up at some point but have dozens of photos

The earlier Jag v8s had tensioner issues because they were plastic and cracked, mine has got a receipt for over a grand to have metal ones put in.

owas said:

The earlier Jag v8s had tensioner issues because they were plastic and cracked, mine has got a receipt for over a grand to have metal ones put in.

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That was the early iterations

3.2 and 4.0s were afflicted..

the 4.2 and 4.4s were cured of this issue..

@Henry_b just watched this an thought of you lad



Could be something for you too @lynall

dieseldog69 said:

@Henry_b just watched this an thought of you lad



Could be something for you too @lynall

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I often find myself sitting behind my desk studying then at the garage then at college often wondering if its worth it? should i up my game and aim higher? etc etc.

He has reiterated basically what the old techs in the garage say, the mechanic is a peasant at the bottom of the chain..

TBH i'm not one to give up but i'm seriously considering steeping back and reevaluating my situation.