Date: Fri, 22 Jun 2007 17:01:52 -0400
Reply-To: benoit <huotb@VIDEOTRON.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: benoit <huotb@VIDEOTRON.CA>
Subject: Re: Timing Chains, Belts, Gears, etc
In-Reply-To: <00d801c7b4ff$1c947520$55bd5f60$@com>
Content-Type: text/plain; charset=us-ascii; format=flowed
I'm backing up my knowledge because i have been playing in engine since
i was 9, yea, even if " Gas powered model airplane & car" have been my
first eperience (and believe me, it was a good scool), it followed by
moped, motorcycle, cars, airplane, VW Baja and now Vanagon & Bus's, my
hands have been dirty since i can remember. I have tried all kind of
stuff, some went good and some went bad, i'm a certified aiplane
mechanic and have a degree in airplane construction, i'm also qualified
in avionic. I have worked 3 years as a Honda mechanic, and i was not
changing brake's.
As opposed to most engineers, i get the work done and a'm not afraid to
get dirty, if it does't work, i try until i succeed (and i sometime also
think :-)
So let's say that i have been around.
In life, there is the one who talk and think and there is the one that
act, i'm the second kind. (not talking about you at all), i swap westy
wasser engine in 4 hours, and it's bleed!
I consider myself as a long trip Westy driver, and i had my share of
problem over the years, now, i want to enjoy the snenery instead of
thinking of what may happen in the back, but hey! that's me!
Regards, Ben
Jim Akiba wrote:
> Ben you can't be backing up your generalization with one example from
> a motorcycle engine? As to why it had a large effect on the bike, the
> cam gears for a bike are much smaller than for a car engine. Belt
> stretch will then translate into much higher cam gear angle changes
> and much greater slop in valvetrain timed events. This is what you're
> seeing with the bike. It does not translate as readily to car engines.
>
>
>
> Power transmission via belt vs. chain translates even less.
>
>
>
> Camping sounds good, and is a refresher... but my true passion lies in
> the means and technologies that allow us to do such things, which is
> why I'm here, typing my reply, happy as a clam.
>
>
>
> Jim Akiba
>
>
>
>
>
>
>
> From: Ben [mailto:huotb@videotron.ca]
> Sent: 2007-06-22 2:42 PM
> To: Jim Akiba
> Cc: vanagon@GERRY.VANAGON.COM
> Subject: Re: Timing Chains, Belts, Gears, etc
>
>
>
> Well, thell that to Honda engineers! In 93, when i ask what was the
> problem with my bike (low power band) this was the answer from Honda
> Canada. They have done excessive testing way before we, or other
> company did so about engine configuration (we all agree that Honda
> tried almost all possile engine configuration).
>
> The same CB 1000R when back the next year with a T-Chain, more torque
> in low RPM, problem with the chain. So you draw your own opinion about
> that my dear Jim. I'm far from being an Engineer, but i know and i
> read a lot about the subject..
>
> But on another hand, i was liking the fack that i had no chain or
> belt, another exemple is my 1983 CX650 Turbo, drive shaft instead of a
> chain (engine to wheel), what a pleasure to drive, but again, poor
> handling because each time you punch the bike, the rear was raising
> (torque/drive shaft). Some like Harley wnet with belt with good success.
>
> I often state motorcycle company as example, why, because they have to
> to the long way against competition, they try hard and they try
> everything. Of course, it would be nice to have a gear driven cam to
> crank engine, but company are staying away from those for different
> reason, i'm sure that one is a power related one.
>
> I said SOHC for low coast, good power and fuel economy, again, i fully
> agree that power wise, DOHC is the way to go, again, the Honda S2000
> with 2000CC as 250hp, no turbo, no nothing!
>
> As for GM..... oufffffff, sorry here but you guys loose me big time.
> Wile every company were working on smaller efficient 4cyl, those
> company were still "fiddling" with old V8 :-)
>
> Jim, your conversion is quite something and i have great respect for
> what you do, BUT, i now ( for now) drive a Subi, and i have the right
> to say that i'm more than happy and T-belt change should NOT be a
> concern at all wile thinking about a conversion. Subi have been in
> Westy way before anything was tried there, why, it's a boxer engine!
>
> Anyway, you guys do what you have to do, me, i'll go camping with that
> nice engine in the back of my van....
>
> Ben
>
> Jim Akiba wrote:
>
>There is nothing about the inherent design differences in driving the
>
>camshafts that will produce more power/torque in and of itself. I don't
>
>believe that the flexibility of a timing chain produces more power/torque.
>
>It will help dampen power pulses from the crank however, which contributes
>
>to longer wearing on valvetrain parts. The valve timing event placement is
>
>what will determine the output characteristics of the engine. The primary
>
>reason for not using timing gears on OHC engines is because of the distance
>
>between the crank and cams. The number of parts and rotating mass are
>
>somewhat prohibitive, and belts do have benefits mostly in cost of
>
>production and maintenance. The trend toward light chains however is
>
>continuing, and as Toyota demonstrated this year, if you can lower the
>
>spring rate on the valve springs and not sacrifice sealing or return
>
>speeds(they did so iva much lighter valves), you can run a much smaller,
>
>lower mass timing chain, which we will start to see more of in the next 5
>
>years. With older pushrods engines, timing gears are much more common. I
>
>have a set of timing gears on my 302, but they don't make sense for the
>
>majority of OHCs.
>
>
>
>As far as "almost all went back to SOHC 4 valves per cylinder" this is true
>
>of Honda, but not generally speaking. Also most DOHC 4 valves are simpler
>
>than SOHC 4 valve which usually require rockers or oddly shaped lobes to
>
>achieve, and the SOHC lacks any ability to alter the power making
>
>characteristics without a cam change. Through phasing changes and tuning
>
>alone, power adders can be made much more effective on DOHC engines.
>
>
>
>" So, now you may have to spend 600$-1000$ for a
>
>heas gasket job, a new T-belt, guide and maybe a tensionor after 100k miles
>
>of driving your Westy!" Ok, but you also already spent the money to convert
>
>it... and you still have an engine with 100k more miles on it. If you had
>
>gone with a conversion based off a world engine, you would spend the $600 on
>
>another engine with 10k miles on it, swap it in(just install work) and never
>
>get into the engine at all, and then everything is low miles all over again,
>
>for the same cost as maintaining your older Subaru.. and with far less risk,
>
>skill, knowledge, tools, time required. This is one of the additional
>
>benefits to owners that vanaru is going to achieve with their new
>
>conversion. Maybe you should have waited Benny ha. As far as who drives
>
>that much? Our Colorado customer Jason has put just under 30K miles on his
>
>westy inside of his first year of owning our conversion. So it can happen
>
>very quickly if people are really out there driving.
>
>
>
>Jim Akiba
>
>
>
>
>
>
>
>
>
>-----Original Message-----
>
>From: Benny boy [mailto:huotb@VIDEOTRON.CA]
>
>Sent: 2007-06-22 12:13 PM
>
>To: vanagon@GERRY.VANAGON.COM <mailto:vanagon@GERRY.VANAGON.COM>
>
>Subject: Re: Timing Chains, Belts, Gears, etc
>
>
>
>Hi (longish and boring stuff for those who don't like engine stuff)
>
>
>
>Gear Driven (cam to crank) gas engine have NO good torque/HP and poor torque
>
>curve, i know, i have owned a Honda CB 1000 with that system. That bike had
>
>NOTHING before 6000-7000 rpm, i said nothing. It felt like something was
>
>wrong, to tight. The funny thing is a broke one gear teath on the crank...
>
>
>
>The relation between the cam and crank have big variation in engine power
>
>curve and torque. With a belt, that very slight flexibility produce torque.
>
>We all know the story about DOHC VS single VS 4 valves per cylinder, many
>
>went DOHC with as much as 5 valves per cylinder (Yamaha Genesis), in cars,
>
>almost all went back to single (SOHC) 4 valves per cylinder. It was the
>
>best simplicity VW power VS fuel consumption. Chain, he he he, anyone here
>
>who have owned a Honda CX bike will stay away from timing chain, binder
>
>problem.
>
>My ZR 600 broke a chain because of a faulty bender, now, get that chain out
>
>of there... no easy way, that engine need to go on the surgery table.
>
>
>
>Now, let me do my corruptor thing about T-Belt change, that kind of pis****
>
>me off (he he he), i had a few p-mail about that subject, and i find that a
>
>bit... sorry to say, stupid. Most modern engine have T-Belt, they all need
>
>preventive change at 60k miles. In the case of a Subi, it's a joke, no more
>
>dificult than on Honda or Toyota, what the big deal on those???? On your
>
>wasser, you may go on 4 head gasket change in that 60k miles, you may even
>
>need new heads or a total rebuilt, so tell me, WHAT is the big deal on
>
>timming belt? Sorry guys but a timming belt does't break, that's urban
>
>legend.
>
>
>
>Now, another thing, about Subi head gasket problems... i have did my
>
>research way before i choose that path. The early 2.5L DOHC big scary flat
>
>four had """some""" problem (even, now we nead to undersand what "some"
>
>mean), even "Some" late 2.5L had heads gasket problem, Honda 1.6L and 1.7
>
>also have their share of ealy head gasket problem, now let see how bad this
>
>is! Fist of all, most problem found were in general between 60k mile and
>
>100k miles, on top, it is easy to see the problem as occasional overheating
>
>occur, so that said, ok, let say you need head gasket job, first there is NO
>
>need for new heads, it can be easily done with the engine in the "Van", no
>
>rusty bolt, no damage water jacket, no bent push-rod, bottom end O-ring
>
>replacement, pushrod seal.
>
>
>
>Now, how many of you will reach 60k-110K miles with your westy in the next
>
>few years? Also, in general, people have done more than 150k miles before a
>
>head gasket job was needed on most Japanese engine, and that is TOTALY
>
>normal on most 4cyl engine. So, now you may have to spend 600$-1000$ for a
>
>heas gasket job, a new T-belt, guide and maybe a tensionor after 100k miles
>
>of driving your Westy! Very far from a total Wasser engine rebuilt or
>
>re-seal each 30k-50k miles.
>
>
>
>I "would" take a Honda/Subaru belt or head gasket job anytime over a Wasser
>
>head job. 1/5 of the price on the Japanese engine and my hands stay way
>
>cleaner.
>
>
>
>NO one here will ever convince me otherwise. But don't get me wrong, a well
>
>maintain Wasser still as in place in the back of our Vanagon, i will give a
>
>honorable mention to that engine who worked so hard over the years to get us
>
>there, where we wanted to go.
>
>
>
>Ben
>
>http://www.benplace.com/vw2.htm
>
>
>
>On Fri, 22 Jun 2007 06:52:56 -0500, John Rodgers <inua@CHARTER.NET> <mailto:inua@CHARTER.NET> wrote:
>
>
>
>
>
>Just reading the post about "New Engine Conversion" - and I wonder -
>
>besides cost, is there any reason why engines have not had meshed gears
>
>to drive the cams. Piston type aircraft engines all have gear driven
>
>cams. No body wants to try to pull over and park on a cloud when a
>
>timing chain fails.
>
>
>
>Just curious.
>
>
>
>John Rodgers
>
>88 GL Driver
>
>
>
>
>
>
>
>
>
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