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Grex > Cars > #120: Hydraulic Valve Lifters | |
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gull
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Hydraulic Valve Lifters
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May 27 01:25 UTC 2001 |
I used to own an old VW van. It required regular valve adjustments
(spec was every 6,000 miles) because it had solid lifters, and as the
valve stems gradually stretched with age the clearances would tighten
up. VW switched from solid to hydraulic lifters, at least on US-spec
vans, in mid-year 1977, eliminating the need for regular adjustments.
Because of this I've always assumed solid lifters were something only
used on older cars.
I recently bought a used 1994 Honda Civic. I was surprised to discover
that this car *also* has solid lifters, and requires valve adjustments
as well, though not as often. So now I'm curious. Are there any
advantages to solid lifters other than the fact that they're cheaper?
Are hydraulic lifters mostly something seen on American cars and cars
adapted for the American market, or are they common elsewhere as well?
The Honda is also the first overhead cam car I've owned -- is this
explained by there being a technical reason why OHC engines can't use
hydraulic lifters?
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| 12 responses total. |
mdw
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response 1 of 12:
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May 29 02:53 UTC 2001 |
My volvo doesn't require valve adjustments and is OHC, so I'm pretty
sure it has hydraulic lifters. Most motorcycles (and Honda started out
as a motorcycle maker) require valve adjustments.
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n8nxf
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response 2 of 12:
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May 29 12:24 UTC 2001 |
In one word: Simplicity! Solid lifters are simple and therefore more
reliable. I have adjusted the lifters on my '68 Opel (OHC), my '86 Nova
(OHC), just this weekend on my in-laws '72 R75/5 BMW motorcycle (Pushrod)
and will be doing it on my '69 R60US motorcycle (Also pushrod, as part of
a total engine rebuild.) Repairing the click, click of a hydraulic lifter
gone bad can be expensive. However, they are usually pretty darn reliable
these days.
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gull
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response 3 of 12:
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May 29 19:51 UTC 2001 |
Hmm. Is it really that bad? On the hydraulic lifter-equipped VW vans, I
think it was mostly a matter of removing the rocker arms and pushrod, then
reaching down in with a magnet-on-a-stick to fish out the lifter. Assembly
is the reverse of removal. ;> They did seem to go bad a lot, probably
because the oil temperatures on those vans were so high. (Mine had solid
lifters, though, so I can't speak from direct experience.)
I certainly don't mind doing the job. At least on the Honda I can do it
without lying on the ground. ;> I know a friend with an old Civic that has
a burned valve on one cylinder, and I can't help but wonder if maybe it was
just never adjusted, and eventually stopped seating. This was a really
common failure mode on the VWs -- once a valve stops seating, it can no
longer get rid of heat.
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n8nxf
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response 4 of 12:
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May 30 13:19 UTC 2001 |
Guy here at work was quoted $2,500 to have the lifters in his 6 cylinder
Montero replaced. The thing has under 60K on it and the dealership could not
isolate the noisey one so they were going to replace them all. I think it's
a 24 valve engine. He decided to keep driving it the way it was.
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gull
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response 5 of 12:
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May 30 19:23 UTC 2001 |
With a price like that, it sounds like they have to pull the heads to do it,
or something.
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scg
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response 6 of 12:
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May 31 00:28 UTC 2001 |
Interesting. My parents' Honda Civic died at around 45,000 miles (13 years
old, so it wasn't as bad as it sounds) due to cylinder head problems that
would have cost more than the car was worth to fix. Would that be related
to this?
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n8nxf
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response 7 of 12:
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May 31 12:45 UTC 2001 |
I doubt it. The head was probably warped, usually from the engine
overheating. Once that happens oil and antifreeze intermingle and even get
into the cylinders turning it into a steam engine of sorts. antifreeze does
not make good lubricant so crank shaft bearings wear really fast and my let
loose, if the engine is pushed, often putting a piston rod through the
engine's crankcase. These types of failures make for spectacular breakdowns
on the freeway ;-)
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gull
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response 8 of 12:
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May 31 15:26 UTC 2001 |
The other thing that kills Civics is if the timing belt breaks. If
that happens the camshaft stops but the crankshaft doesn't, and the
pistons smash into whatever valves happen to be open. 45,000 miles
would be *way* too early for that, though; the recommendation is to
change the belt every 90,000 miles.
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n8nxf
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response 9 of 12:
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Jun 2 20:39 UTC 2001 |
The Civic has an interference engine?
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gull
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response 10 of 12:
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Jun 5 13:12 UTC 2001 |
Sure does.
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n8nxf
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response 11 of 12:
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Jun 6 12:10 UTC 2001 |
That's another thing I like about my Toyota.
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gull
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response 12 of 12:
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Jun 6 14:14 UTC 2001 |
Interference engines have advantages, but obviously they won't forgive
neglect. (Though the belt change intervals on some of them are quite long.
The timing belt on my Honda is supposed to be changed at 90,000 miles, and
that's apparently a pretty conservative figure.) That's probably why
they're uncommon on American cars -- American cars are engineered with the
assumption that many drivers will do absolutely no maintenance, so they're
designed to hold up as long as possible under those conditions.
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