On an old Top gear that was on the other night, Jeremy Clarkson was saying that Honda's variable timing kit is so reliable that they have *never* had a failure ascribed to it.
Any truth in that rumour?
Obviously TG is always to be believed 100% and only ever factual, so I'm tempted to think they're right. But it seems unlikely...
From what I know of the mechanism if it fails all it does is not engage warp factor 9 at full throttle, the pins that lock into the second cam profile followers do not move far enough to fall out they are either engaged or sitting facing the inside edges of the second cam follower.
OTOH all the normal modes of failure can occur: over-revving (somethings gotta give :-) ), broken conrods (due to over-revving), pistons holed (usually only due to fuelling or turbo induced faults), broken cambelt etc.
Chris
I was behind an Integra VTEC type R just yesterday and it was blue- smoking quite badly when he floored it. I could smell it too. So maybe that will be the first one. I think I heard of a VFR800 vtec (bike..does that count?) that let go. And they need a big =A3500 service every 15000miles.
Al
PC Paul ( snipped-for-privacy@bitrot.co.uk) gurgled happily, sounding much like they were saying :
Back when the first (L-reg?) Civic VTis were in the UK, there were a couple as CoCars where I was working at the time.
One had had a stone-holed rad and been a little bit overheated. Thereafter, it spent roughly 50% of it's time in dock.
Whether that counts as a failure "ascribed" to the VVT, gawd knows - but it was one of the things that gave all sorts of shit. Quite why Honda didn't just lob a new lump in it, gawd knows.
IIRC this is a reference to the actual mechanism that engages the hot cam, and that mechanism has never failed. IIRC it's a pin operated by oil pressure, so it's hardly likely to fail...
Yes, as I understand. As others have said it's essentially a pin and oil pressure. Low oil pressure, the pin doesn't engage and the VTEC doesn't use the higher lift profile.
It does, doesn't it? Plenty of other bits may go wrong on a Honda... but not the VTEC gubbins.
Honda claim all sorts of things about the reliability of their engines. Even some in the trade believe them. They may well be more reliable than the average, but 'no failures' would be stretching a point. Unless they're rather more honest than others.
I'd reckon a problem caused by overheating due to a hole in the radiator is rather unlikely to be ascribed to VVT, don't you?
In message , PC Paul writes
As I remember the claim, it's specifically failure of the VTEC hardware, and it's more along the lines of never having had one fail under warranty.
Worryingly, I understood you perfectly!
Chris
I thought the claim was they had never a warranty claim due to failed VTEC.
-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!
I'd have had a job telling them where I was other than 'about 6 miles along the Bxxxx going generally South from yyyy.
That was the point - I *did* carry on regardless, until the engine stopped. Several times....
That's true enough.
In message , Adrian writes
To be fair to Honda, I think it's reasonable to expect something making
70bhp/litre with the aid of a turbocharger to be a tad more robust than a 100bhp/litre naturally aspirated job.Steve Walker ( snipped-for-privacy@otolith.demon.co.uk) gurgled happily, sounding much like they were saying :
75bhp/l - but the boost is managed for torque not power, with a higher compression than normal for a turbo - however the main answer is....Sure.
The original point was that the VTEC is not as infallible as claimed - it's fairly fragile, in fact.
I've had to rebuild a Land Rover 2.5 NA Diesel because it had a stone through the radiator, is that a fairly fragile engine?
Duncan Wood ( snipped-for-privacy@dmx512.co.uk) gurgled happily, sounding much like they were saying :
How badly was it cooked?
In message , Adrian writes
That was one of the early, performance orientated, models, though, and it wasn't actually the mechanism for swapping cams that failed. Although when you mention VTEC people always think of the high power, high revving performance lumps, the technology is used in all but the most poverty spec of Honda's four cylinder engines these days. Everyone else is doing something similar now, too.
Now Rover's VVC, that had a reputation for the variable valve timing mechanism itself being unreliable.
Started & ran fine, it just guzzled oil due to the scores on the bores. I wasn't driving it, so I cannot say how hot it got.
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