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Manifold gasket sealing


Adrian

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On 12/11/2017 at 2:45 AM, ShaunW said:

I'm confident the v8 jaguar engine in my contemporary car will last at least as well. Better materials, better design, better consumables from day one.

It's too easy to get a rosy glow about these old cars but the truth is they were budget cars based on dated engineering even when new.  It's only weekly maintenance, multiple rebores, rebuilds and skims that's kept them going.

I'm not committing heresy here, just pointing out that they're not inherently special or better just because they're old, and new doesn't always mean worse. 

There is two big difference between modern engines and classics. The faults with modern engines are hidden by a computer compensating, secondly the engines are built with very little reserve factor so once clapped they are scrap.

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5 hours ago, Algy said:

There is two big difference between modern engines and classics. The faults with modern engines are hidden by a computer compensating, secondly the engines are built with very little reserve factor so once clapped they are scrap.

I understand the point you are making but if they're looked after they don't generally need much attention until they've done 300k miles plus, often many many more.  Even then it's perfectly possible to reline and rebuild them just like any other engine. The computer can't disguise what your ears are telling you and the diagnostics give you plenty of warning about what's on the way out before it turns into a drama. I think to generalise and say that modern engines are inferior does a great diservice to the engineers and materials scientists we have today and the superior design aids they have at their disposal.  Where I will agree that they're a pain, is the number of components that aren't easy to repair or have to be replaced because the internals aren't available from the parts bin.

I'd be interested to know what the highest verifiable mileage is for a Triumph engine that hasn't had major work done. Or the highest even if it's had work. I suppose there comes a time when the work has been so extensive it's only cosmetically the same engine.

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Oh ShaunW, I am not doing modern engines down by any means. I was just making the point that we had to fettle the old engines ore because they didn’t have the ablity to self tune, as the points and plugs burned or the carb went out of adjustment, we would hear it (or see fuel consumption go up). Now the engine has the ability to self regulate and compensate to a very high degree, until it can’t compensate any more. As a trained metallurgist I have seen the changes in the quality of materials used and the precision of the CNC machining has produced components to very consistent tolerances.

I do have to disagree with you though on one point and that is although the engines will in theory be able to be repaired, the chance of that happening in 50 years time I consider to be very slim for the following reasons: The replacement sleeves and pistons along with the sensors and fuel monitoring systems will probably not be available, as the manufactures are using built in obsolescence to try to force new car sales (so not producing as many interchangeable parts).

Yes most of our classics will have had at least a part engine rebuild if not a full rebore and regrind at 200K. In the day we had the head off just about every other year (due to the inability for the engine management system to control carbon build up, poorer quality lubricants, the poorer tolerances of manufacture as well as rate of wear). Modern engines operate in a much more optimum environment, due to the improvements in technology and the use of ECU compensating for the operating environment.

The biggest killer of cars, I see when visiting the garages that my apprentices work at, is ECU faults, making the cars uneconomical to repair (unlike the body work of the 80’s). Yes some modern classics may be kept alive but only by farsighted people collecting donor cars now.

I suppose it is the same with aircraft; second world war aircraft can be kept flying as the reserve factor on the airframe was so high, yet modern fighter aircraft have fewer failures and if they do can still fly but have a finite fatigue life. They are both great in different ways and I would be happy to fly both the same way as I am happy to drive old and new cars.

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There are a significant number of Landrover Engines going bang around the cam belt change time (Just after as a rule) which is due to weak oil pumps - the cam belt pulley is fixed to the pump and it cracks after a second belt is fitted - many now routinely replace the oil pump with the later designed one.

Not to mention the others that have busted cranks after the bearings spin and block the oilways.

The above are actually significant numbers, but a small % of those made - but when a new/reman engine is only available from LR for about £4k plus fitting - and that's using your old ancillaries - it does write off a lot of cars (To be fair a lot of Jags are being bought to donate the engine into a Discovery

I mention this purely from the perspective that moderns tend to be more highly tuned and engineered and result in thinner margins of error.

 

 

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