cold start engine noise fixed by r/p timing belt tensioner

[Todd H.]

Just wanted to add a "me too" on this issue. I was dealing with a
really awful ticky engine sound that varied with engine speed. It'd
been happening for a few months that was much worse at low outside
temperature. The H-4 sounded like a diesel engine for the first 10
minutes of driving, but once if warmed up all was well.

My dealer replaced the timing belt tensioner. Evidently, they
commonly leak, and loose pressure. THe leaking is worse in the cold.
The noise you hear (at least as the service manager explained it) is
the sound of the tensioner pumping back up and ticking. Evidently the
tensioner works much like a valve lifter? The service manager
allayed my fears--my waiting for a month or two to get the tensioner
replaced did no harm to my engine as the noise I was hearing was from
the tensioner, not the valvetrain. The timing belt was in no danger
of slipping or damaging the engine.

I also got my 15k mi service...which seemed a bit steep at $250.
Supposedly they go through and tighten a ton of hte bolts on the car
and it takes 2 or 3 hours? Seems fishy, but I did it anyway. Any
comfort to lend?

Best Regards,
--
Todd H.
2001 Legacy Outback Wagon, 2.5L H-4
Chicago, Illinois USA

[Joel Shortlidge]

Really was it a 2.2 or a 2.5??? I am out of powertrain warrantee but
mentioned the problem before the end of the warrantee could I also get
it replaced for free, you think??

[DS]

I had my shortblock (2.5) replaced under warranty and ended up with a major
rattle in my shifter. The mechanic has ordered a new timing belt tensioner and
will replace it next week. The ticking was gone after the shortblock swap but
the rattle started at that point. He's convinced the tensioner is the problem.
I'm still in the powertrain warranty period.

DS

"Joel Shortlidge" <shor...@expert.cc.purdue.edu> wrote in message
news:3C503F0A...@expert.cc.purdue.edu...

[Gilles Gour]

"Todd H." a écrit :

>
> Just wanted to add a "me too" on this issue. I was dealing with a
> really awful ticky engine sound that varied with engine speed. It'd
> been happening for a few months that was much worse at low outside
> temperature. The H-4 sounded like a diesel engine for the first 10
> minutes of driving, but once if warmed up all was well.
>
> My dealer replaced the timing belt tensioner. Evidently, they
> commonly leak, and loose pressure. THe leaking is worse in the cold.
> The noise you hear (at least as the service manager explained it) is
> the sound of the tensioner pumping back up and ticking. Evidently the
> tensioner works much like a valve lifter?

To my knowledge, the tensioner is a closed unit, much like a shock
absorber. So this story of a leaking tensionner "pumping back up" sounds
fishy. Either Subaru modified this part completely or there is no
connection whatsoever between the belt tensionner and the pressurized
lubrication system of the engine.
Just my .01
Gilles

[George Hanna]

Chris, Thought you might be interested in this
Papa George....

[Joel Shortlidge]

I wondered also I have never heard of a tensioned being PART of the lube
system but the hydraulic ABSORBER could start leaking and lose
pressure??

[Gilles Gour]

Joel Shortlidge a écrit :

>
> I wondered also I have never heard of a tensioned being PART of the lube
> system but the hydraulic ABSORBER could start leaking and lose
> pressure??

Yes, but it would'nt "pump back up" like an hydraulic lifter would.
Gilles

[Todd H.]

2001 outback wagon -> 2.5

--

[Todd H.]

"DS" <david...@shaw.ca> writes:
> I had my shortblock (2.5) replaced under warranty and ended up with
> a major rattle in my shifter. The mechanic has ordered a new timing
> belt tensioner and will replace it next week. The ticking was gone
> after the shortblock swap but the rattle started at that point. He's
> convinced the tensioner is the problem. I'm still in the powertrain
> warranty period.

*sheepishly*

What is a shortblock?

[Bill Putney]

Joel - If I understand your statement, several makes of cars do in fact
have a tensioner that is pressurized by oil pressure (from the oil pump)
- my Chrysler Concorde is one of them; also, that type of tensioner may
be for timing chains only, not belts - but not 100% sure. To be honest,
I don't know if some of the later model Subarus have such a tensioner or
not - again, I'm not sure if your statement was intended to be in the
context of Subarus only, or cars/tensioners in general.

Bill Putney
(to reply by e-mail, if my e-mail address shows as "...@moonstzr.com",
replace the last letter of the alphabet with the first letter of the
alphabet)

Joel Shortlidge wrote:
>
> I wondered also I have never heard of a tensione[r] being PART of the lube

[Joel Shortlidge]

I was referring to cars in general? I think it would make the tensions
prohibitively expensive! Also it would be a probable leaking a failure
point? You would have to disconnect and reconnect the tensioned to the
system every time also??

[DS]

It is the block with pistons, camshafts but no heads or valves.

"Todd H." <sub...@toddh.net> wrote in message
news:m0adv3t...@k2.onsight.com...

[Todd H.]

"DS" <david...@shaw.ca> writes:
> "Todd H." <sub...@toddh.net> wrote in message
> news:m0adv3t...@k2.onsight.com...
> > "DS" <david...@shaw.ca> writes:
> > > I had my shortblock (2.5) replaced under warranty and ended up with
> > > a major rattle in my shifter. The mechanic has ordered a new timing
> > > belt tensioner and will replace it next week. The ticking was gone
> > > after the shortblock swap but the rattle started at that point. He's
> > > convinced the tensioner is the problem. I'm still in the powertrain
> > > warranty period.
> >
> > *sheepishly*
> >
> > What is a shortblock?
>
> It is the block with pistons, camshafts but no heads or valves.

Yikes. I thought it might have been something different than I knew.

Wow. What the heck happened to warrant the replacement of the entire

[DS]

Subaru will replace the shortblock to cure excessive piston slap noise. Once the
noise continues past warm-up, they will replace it. This appears to be a common
occurance for these engines. There are lots of people on this newsgroup that
have had this done.

Mine was so bad that they took a quick listen and ordered a new block. The car
sounded awful and I was even embarrassed to drive it.

DS

"Todd H." <sub...@toddh.net> wrote in message

news:m0lmeml...@k2.onsight.com...

[Bill Putney]

They're not a probable failure point - the design constraints are pretty
relaxed because they can make them with a significant amount of
clearance between the moving parts (piston and cylinder) because they
intenitionally leak oil to lubricate the timing chain (i.e., they don't
need anything close to a perfect seal). Also, cheap to make - simple
loose tolerance cylinder and piston. As far as disconnect/reconnnect -
they work just like a spring tensioner except the spring is a column of
pressurized oil. Of course the engine has to be properly ported to get
the oil to the tensioner, but that's an initial tooling problem - zero
cost once that's done.

It's done all the time these days. Chrylser, Toyota, Ford, many makes
have it on certain timing chain engines - those are just ones I know
about - probably many others. You can tell because for the first second
or so at startup you can hear the untensioned chain rattling around.
Also, you can really tell the difference in using an oil filter with and
without an anti-drainback valve - chain noise stops much quicker with
the valve.

[Joel Shortlidge]

CHAIN??? All Subaru's use timing BELTS??? That don't come near oil or
they will fail??

[Bill Putney]

I qualified my statements as applying to chains, and you agreed that
your statement was about cars in general. That was the context of my
statements. Re-read my very first post in this thread. I wasn't sure
if any Subarus came with timing chains or not because I'm not familiar
with the '90's and later.

However - not all Subarus come with timing belts either. The EA81 (used
up until '94 IIRC) used metal gears - IMO better than chains or belts as
far as reliability and maintenance costs (except when you make them out
of plastic or pot metal like G.M. tried doing for a coupla years). No
tensioners required either. I wish the mfgrs. could go back to them -
not sure why - noise, weight, cost?

[Reid D. Albee]

Hi Bill,

It would be cumbersone to devise a gear set for a gear only solution for an
overhead cam engine.

The E81 had the cam pushing push rods to valves on the cylender heads. The
crank gear drove the cam directly which was attached to a smaller camshaft
gear.

To use gears in the new overhead cam
engines would require more than two gears and would be heavy and prone to
problems with wear and tear.

The gearing would have to reach from the crank, all the way over to each
cam. Methinks that would be a nightmare to engineer.

"Bill Putney" <b...@moonstar.com> wrote in message
news:3C5740C2...@moonstar.com...

[Ross]

The new 3.0l H-6 uses a timing chain, not a belt.

Ross

[Bruce Hoult]

In article <8PH58.142$1v1....@eagle.america.net>, "Reid D. Albee"
<ral...@ptc-me.net> wrote:

> To use gears in the new overhead cam
> engines would require more than two gears

Why? I'm not aware of any law that says the camshaft has to spin the
same direction as the crankshaft.

> The gearing would have to reach from the crank, all the way over to
> each cam. Methinks that would be a nightmare to engineer.

2/3 of the way over, actually, to get a 2:1 tooth ratio.

Heavy, but you could use it as the flywheel.

-- Bruce

[Bill Putney]

I had thought about that. It would only take two gears if they were big
enough! 8^) (Kind of like the old joke of how many balls of string
would it take to reach the moon - only one if it's long enough).
Actually 3 gears I guess - one on the crank meshing with the two cam
gears.

Yeah, there would have to be trade-offs (weight, initial cost). I think
if the manufacturers put their minds to it, they could come up with a
workable solution. How much would it be worth to me not to have to
replace timing belts every 60,000 miles or whatever it is for a given
car? I think if consumers considered all the facts (extra downtime,
breakdown risks, and maintenance costs of T-belts over the life of the
car), they might be willing to make the compromise if gears were
available - but they don't think like that. They want to know lowest
purchase price and dont even know enough about what to consider as far
as maintenance issues down the road. And if I'm supposed to buy an
interference engine with T-belts, forget it.

I've seen aftermarket gear sets to replace timing chains for racers on
GM engines - three gears in the set IIRC (or is it 4 - don't recall if
that's for pushrod or OHC engine). Of course, to a racer the weight is
not significant, or at least is worth trade-off of getting rid if the
chain, and cost is not an issue to them like it is on a consumer
vehicle.

(BTW - in re-reading my previous post, I mistakenly said the EA81 was
used up until '94 - of course I meant up until '84 - or thereabouts.)

Thanks for the feedback.

Bill Putney
(to reply by e-mail, if my e-mail address shows as "...@moonstzr.com",
replace the last letter of the alphabet with the first letter of the
alphabet)

"Reid D. Albee" wrote:
>
> Hi Bill,
>
> It would be cumbersone to devise a gear set for a gear only solution for an
> overhead cam engine.
>
> The E81 had the cam pushing push rods to valves on the cylender heads. The
> crank gear drove the cam directly which was attached to a smaller camshaft
> gear.
>
> To use gears in the new overhead cam
> engines would require more than two gears and would be heavy and prone to
> problems with wear and tear.
>
> The gearing would have to reach from the crank, all the way over to each
> cam. Methinks that would be a nightmare to engineer.
>
> "Bill Putney" <b...@moonstar.com> wrote in message
> news:3C5740C2...@moonstar.com...
> > I qualified my statements as applying to chains, and you agreed that
> > your statement was about cars in general. That was the context of my
> > statements. Re-read my very first post in this thread. I wasn't sure
> > if any Subarus came with timing chains or not because I'm not familiar
> > with the '90's and later.
> >
> > However - not all Subarus come with timing belts either. The EA81 (used

> > up until '94 IIRC) used metal gears...

[Bill Putney]

AHA! 8^) I wonder if they have an oil-pressurized tensioner?

Bill Putney
(to reply by e-mail, if my e-mail address shows as "...@moonstzr.com",
replace the last letter of the alphabet with the first letter of the
alphabet)

[Bill Putney]

"Heavy, but you could use it as the flywheel." (referring to large gears
required to drive overhead cams)

Now there's a solution! Probably patentable. The new Hoult valve drive
train™. Watch out though - GM will probably want to make the gears out
of Nylon, and they'll have to be replaced every 40k miles at a cost of
$250. When you license it, Bruce, make sure you maintain application
design control so they can't do that. 8^)

Bill Putney
(to reply by e-mail, if my e-mail address shows as "...@moonstzr.com",
replace the last letter of the alphabet with the first letter of the
alphabet)

[DJ]

On thisWed, 30 Jan 2002 05:47:05 -0500,This Serf Bill Putney
<b...@moonstar.com> Did take chiesel to stone and scribi:

>I had thought about that. It would only take two gears if they were big
>enough! 8^) (Kind of like the old joke of how many balls of string
>would it take to reach the moon - only one if it's long enough).
>Actually 3 gears I guess - one on the crank meshing with the two cam
>gears.
>
>Yeah, there would have to be trade-offs (weight, initial cost). I think
>if the manufacturers put their minds to it, they could come up with a
>workable solution. How much would it be worth to me not to have to
>replace timing belts every 60,000 miles or whatever it is for a given
>car? I think if consumers considered all the facts (extra downtime,
>breakdown risks, and maintenance costs of T-belts over the life of the
>car), they might be willing to make the compromise if gears were
>available - but they don't think like that. They want to know lowest
>purchase price and dont even know enough about what to consider as far
>as maintenance issues down the road. And if I'm supposed to buy an
>interference engine with T-belts, forget it.
>
>I've seen aftermarket gear sets to replace timing chains for racers on
>GM engines - three gears in the set IIRC (or is it 4 - don't recall if
>that's for pushrod or OHC engine). Of course, to a racer the weight is
>not significant, or at least is worth trade-off of getting rid if the
>chain, and cost is not an issue to them like it is on a consumer
>vehicle.
>
>(BTW - in re-reading my previous post, I mistakenly said the EA81 was
>used up until '94 - of course I meant up until '84 - or thereabouts.)

Ok in my experience as a Diesel Mechanic almost all the larger OHC
diesel engines use an gear Chain to fed power to the cam...
Now about this DOHC gear chain,could we not use the existing flywheel
to drive the cams...
--
Cheers DJ
Member of clubSUB www.clubsub.org.nz
I don't suffer from insanity,I enjoy every minute of it...
1990 Subaru Legacy GT two litre turbo,5 Speed,"Big Bore"exhaust,
cold air box,adjustable boos,Cibie Super Oscars and personalised plates"ANARKY"
Stereo includes Panasonic head unit and DSP,8 disc changer,Pioneer 12" subwoofer
Altec amp,Front JBL splits and rear Warfdales...
1984 Leone RX Coupe,Big Bore,Twin Carbies,K&N.(RIP Bro'rolled it)
Latitude S39 25' 55.3"
Longitude E175 16'28.7"
ICQ 2985095
http://mysite.xtra.co.nz/~ANARKY
Remove nospam from email address to send email...

[Bill Putney]

DJ wrote:
> ...could we not use the existing flywheel

> to drive the cams...
> --
> Cheers DJ

Exactly! I think there may be crankshaft torque distortion and breakage
issues by hanging the flywheel on the front.

Absolutely no reason the cams have to be driven off the front of the
engine - just extend the shafts out the back instead. I thought about
that on my drive to work yesterday after my last post. Just some
modifications to the rear of the engine and flywheel (probably easier
said than done, but they tool up for new engines all the time).

I even am sure I remember reading of a production vehicle (can't
remember which - Jag, Volvo, Saab, Audi? Can't remember) that cams and
all the accesories and drive belts are on the *back* of the engine, so
it's not too far fetched for the manufacturers to implement this
relatively simple design alteration.

The only stumbling block I see is the tolerancing of the
crankshaft-to-camshaft center-to-center spacing (head gasket thickness
variation, head location, etc.) for proper gear meshing, but more
difficult problems than that have been overcome for worthwhile advances
in technology. Probably use thicker, more rigid gasket materials and
dowel pin locate the heads?).

[Joel Shortlidge]

Most Toyota DOHC use a belt to run one cam shaft then it goes to a gear
to gear set-up at the other end of the head to transfer power to second
cam!!

[Edward Hayes]

My vote is to use a chain drive like Porsche;Grand Vatrie;Mercedes;
etc on ALL interference type engines. Non interference engine could go
either way. Ed

Joel Shortlidge <shor...@expert.cc.purdue.edu> wrote in message

news:3C5EC648...@expert.cc.purdue.edu...

[Joel Shortlidge]

ya, that would be smart but the chain has more resistance and inertia
weight.

[Bill Putney]

Gears (no chains) is what I was talking about.

Bill Putney
(to reply by e-mail, if my e-mail address shows as "...@moonstzr.com",
replace the last letter of the alphabet with the first letter of the
alphabet)

[Edward Hayes]

Gears are more costly,are nosier and are more difficult to maintain
proper mess/adjustment. A chain with a hydraulic adjuster is by far
the easiest to maintain and service. In the case of Saabs and some
others the chain is running in an oil bath. That is one reason there
is NO change interval and I've seen cars with excess of 200,000 miles
and the chain is original. A well machined helical gear set is about
99.6 % efficient. If you need three gear-sets for each side of a flat
or V6 engine you end up with more power loss that a roller chain. The
belt system is the cheapest for the manufacture,has less power loss
and is quieter than gears or chain ; but the consumers pays dearly
for maintenance and the possibility of engine damage. I'll take a
chain over gears or belts. Ed

Bill Putney <b...@moonstar.com> wrote in message

news:3C632673...@moonstar.com...

[Edward Hayes]

It is interesting to note that the latest designed Subaru engine i.e.
H6 is chain driven like the more expensive cars.
Edward Hayes <Hay...@worldnet.att.net> wrote in message
news:v2we8.14136$Im1.9...@bgtnsc05-news.ops.worldnet.att.net...

[Bill Putney]

Gears cost more than a chain? Maybe - I'll take your word for it. As
far as the proper mesh (shaft-to-shaft distance), yes - I agree. One
of my earlier points was that solving that problem would be less
difficult than a lot of problems that had to be solved to get rubber
belts to work for a reasonable period of time, or to develop CV joints,
or for a miriad of other technology advances that have occurred over the
years but that we now take for granted.

If a manufacturer would do what I suggested and drive the cams off the
flywheel - that's three gears (two meshed to one flywheel). Maybe a
little more mass - but that mass is also giving additional flywheel
effect, so the flywheel could be a little lighter. Minimal friction.
And I bet they could solve the mesh problem without breaking a sweat -
special controlled crush gasket materials and pin locate the heads would
be a start (and maybe is all that would be needed) - how do the racers
that convert the factory chains to gears do it?

Not arguing with you, I just have different priorities (for instance,
the noise that gears would make would not be a problem - I doubt it
would be much if any noisier than a chain). Gears can be made pretty
quiet.

Let me put it this way - special measures and expense have to be taken
to make a chain that would be guaranteed to last even half the life of a
mediocre set of gears - I think of the EA81 Subie engines. Probably
would easily get 5 million miles out of the cam drive gears with no
special tricks - doubt that that has been tested though. And not that 5
million mile life is necessary. It just means you never even have to
consider that they would wear out.

So your choices would be timing chain #1, gears #2, timing belt(s) #3.
Mine would be gears #1, timing chain #2, timing belt(s) #3. No
problem. I like kicking ideas like this around.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with the first letter of the alphabet)

[Edward Hayes]

I am intrigued by your idea of using the flywheel for the cam drive
gear. Since the camshaft turns at 1/2 crankshaft speed the
circumference of the crankshaft would need to be 1/2? the
circumference of the cam gear. This assumption is for a only two
gears. One possible problem with a gear set is the engine power
pulses at low rpm. This may cause gear chatter which can cause
bernelling and eventual failure. Race engines do not have this problem
because of the high rpm and short engine life i.e. 500 mile or 24 hour
race. This is a good thinking exercise. Ed
Bill Putney <bpu...@moonstzr.com> wrote in message
news:3C7AD9AB...@moonstzr.com...

[Bill Putney]

Yeah - I thought some about possible low speed knocking. But then, what
about the EA81 Subaru engines with gear-driven cams? Were they
especially noisy? (Of course, cars in general are quiter now, so maybe
what wasn't noticeable in a late 70's/early 80's car would be noticeable
in a 21st century vehicle. Anyway, the cam drive gears *never* *ever*
failed on them, and they go for how many miles? Also they (the EA81's)
are a favorite for aircraft use *precisely* because gear drive is as
bullet-proof as you'll get for such a critical single-point failure
area.

*IF* the low speed cogging noise is a problem in reality and not just in
theory, there are solutions, of course at the cost of complexity and
maybe a little efficiency. For example - there is such a thing as
zero-backlash gears - basically the gear includes a thin section (just
imagine sawing right thru the plane of the gear) that is spring-loaded
against the main gear section (in a rotating direction) so that it takes
up any slack with the mating gear. Again, that would add some friction
and wear depending on how much pre-load needs to be designed in.

BTW - did you realize that the propeller on an airplane plane is mainly
to keep the pilot cool? Yeah - if you'll notice, if it ever stops, he
really starts to sweat! 8^)