Dave is of course talking tosh. The load on the camshaft, all other things being equal, does not change just because there is a pushrod involved.
not until you use seriously high racing RPM where the pushrod mass has some effect, anyway.
How many cars are pushrod nowadays?
NT
ISTR: there was once a time where the different additives in engine oils could be incompatible, and cause it to gel or thicken. Along came the military, and mandated that all oils be mixable without (drastic) downsides.
(I tried to find my source, but google groups seem more broken than usual, returning 0 hits for "motor oil mix"...)
Thomas Prufer
Not many, but the new C8 Corvette uses pushrods.
Tim
Thomas Prufer wrote in news: snipped-for-privacy@4ax.com:
Seeing lots of stickers used to be something I looked for when buying a used car. It implied it had been serviced. Free advert for the oil company as well.
More likely I think improvements in combustion technology from a combination of injection, sensors, and ECUs, leading to much less soot.
The soot was as much as anything oil exposed to high temperature blowby gases.
The fact of the matter is that materials have come on hugely. A 1960s BMC A or B engine needed new big end shells at 30,000 and mains at
60,000 or a complete rebuild with rebore and new pistons at 90,000.Most modern engines are 120-180k before there is *any* noticeable wear.
Metals are harder, oils are better and machining is to far tighter tolerances.
My 2008 Peugeot has done 180,000 and it's still on its original clutch (*), exhaust system and shock absorbers. The timing belt was replaced at about
100,000 miles - not because it was worn but because this was the mileage stated by the manufacturer, and a broken belt would cause a valve/piston collision and hence major engine repair. The water pump was replaced at the same time simply because it is driven by the timing belt and the labour to replace the pump is the same as to replace the belt, so it makes sense to replace the pump just in case, rather than pay for a second lot of labour some time later on (the cost of a new pump is a lot less than the labour to replace it).OK, so it's needed a new catalytic converter and diesel particulate filter, two things that a 1960s BMC A or B engine would not have had, but those are there for environmental rather than performance reasons: the car would run (illegally) perfectly well without them.
I'm not aware of any rust on the body or on any of the structural members. My first car, a 1980 Renault 5, suffered from bad rust over the rear wheels, but even that wasn't structural.
(*) Although the bite point has gradually risen, there's no hint of slippage so it doesn't need replacing yet. I've never had a car before that has lasted beyond about 80,000 on the same clutch.
You might ask Turnip why he's talking crap. But only to be expected. And at various times he's claimed to be an engineer.
Wrong vowel ??
He is. You're not.
NT
Even a child who has played with a Meccano set would know there is more load on the cam of a pushrod engine than an OHC design. It is so blindingly obvious it takes a real fool to dispute it. No surprise you agree with Turnip.
Anywhere near the coast in the western or southern parts of the country and they rusted away long before they needed major engine repairs.
In the 60' and 70's people actually made a point of buying 2nd hand cars of the more up-market models that had only been driven in places like east anglia
And mixing synthetic oil with mineral oil seems to be a really silly thing to do. Modern cars run much hotter than they used to which is why synthetic oils are needed, especially if the car has a turbo where the oil gets very hot. Mineral oils cannot tolerate these high temperatures.
Makes you wonder what happens to the waste oil tank at the local amenity tip. People tip all sorts into this. can't see that being re-refined and resold.
Not so long ago he claimed to be out in darkest africa designing a radio system for the local dictator.
Yes. The question is whether it's significant.
I don't recall any sprung cam mechanism in Meccano.
I see you're making stuff up yet again.
NT
Why not, they're all ok for not-too-hot service.
NT
Then do some Googling on the subject of oils and pushrod engines. Even you should manage that.
I had a Rover 105R with a crankshaft seal leaking, so I always parked it over a drain.
Thanks Dave - fair point. We have no intention of throwing away our bottom of the range, 10yrs old, 4000m per year Panda, and so next time I change the oil I'll make sure I treat it to 3.8 litres of unmixed Right Stuff :-)
BTW, on the subject of engineers: we used to have someone here from "Puma Racing" (I think he was called Dave as well) -- his opinions would have been useful in this mix!
Cheers John
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