Timing belt question, 99 Honda Accord DX

Hello, I have a 99 Honda Accord DX four door, manual transmission. I
don't drive very much. I bought the car new in Feb. 99, and there are
less than 25,000 miles on it. So that's about 2,500 miles per year on
average. I'm also a point A to B kind of driver - easy on the brakes,
easy on the clutch, smooth acceleration etc. The weather conditions
have been pretty benign: 7 years in the Bay Area, 3 years in Portland
OR.

So the manual says change the timing belt at 105k miles/84 months,
whichever comes first. Obviously, I'm past the 84 months by about 2
years, but a long way from 105,000 miles. I also know there are
several other things that should be replaced if the timing belt is
replaced.

I wonder if you experienced mechanics and/or DIYers have an opinion on
how necessary this replacement is at this time. I'm sorry if the
question is annoying. I know the manual says what it says, and it
follows that I'm questioning the recommendations given therein, and
I'm basically clueless on this stuff. But sometimes the cognoscenti
are in posession of knowledge the manufacturers for one reason or
another are reluctant to share. (For example, tire pressure.)

Thanks for any input you might have.

 

All one can deal with here are probabilities. Your belt is
more likely to fail than one changed at seven years; less
likely to fail than one driven in extreme weather over the
last nine+ years. Also reports are that if a timing belt
fails at lower speeds, chances are better that no engine
damage will occur.

I would at least try to find a good import shop and see how
much they want for the job.

 

The concern with low mileage but long time is with deterioration of the soft
parts in the belt. Chances are it could continue for a long time with your
usage, but then again it could be crumbling apart right now. The safe thing
to do would be to get it changed.

The other components everyone talks about (water pump, seals, etc.) are not
actually required by the manufacturer to be replaced, its just convenient to
do them preemptively when the timing cover is off because that's where they
are. I think with your mileage, I would not bother with those things.
There is little chance they are anywhere near needing change & would just
run up the price unnecessarily.

 

Someone mentioned changing the tensioner when changing the belt. Why? What
is usually bad with that?

 

1989 Accord here, single overhead cam. I had the belt break shortly after
buying it used, in around 1998 with 140,000 miles on it. No engine damage
.... just put on another one. It ended up getting oil on it and broke again a
few months ago (200,000 mi.) when my son was getting off of the freeway near
the house.(lucky). He cranked it over trying to restart it. I didn't even
know what an interference engine was and turned the cam and crankshaft over
several times, trying to get things lined up. No damage. I later replaced
the head gasket and saw that the valves and pistons were intact. Wonder if
Honda is just playing "CYA" in case there is carbon build-up and things make
contact.

 

Not true. If the cam(s) isn't/aren't spinning but the crank is, you
will, in all likelyhood, have a piston be introduced to a valve. It's
the mechanics of the engine and has nothing to do with speed.

And any belt that old has probably had enough age wear on it. There's
a reason they put a mileage and time limit on it. That belt lives in
an environment where the temps frequently hit in excess of 150F and
there are plenty of contamanents in the air.

--
- dillon I am not invalid

When you wish upon a falling star, your dreams come true.
Unless it's really a meteorite hurtling to the Earth which
will destroy all life. Then you're pretty much hosed no
matter what you wish for. Unless it's death by meteor.

 

Pardon? I mean, like I don't think that the valves and pistons CAN hit
each other. If anything were to make contact, it would be the carbon
build-up ... not "promoting" valves hitting pistons. Talk about putting
words into someone's mouth.

 

I think you are envisioning a literal breaking of the TB
apart, whereas I think many TB failures are not that
extreme. With the less extreme failures, the cam can may
still be moving somewhat in synch. The mechanics of the
engine are also such that it comes to a stop sooner when it
is under less load. Momentum and all.

Regardless, I am going by reports. I could be talked out of
the claims made that lower engine speed lowers the
probability of engine damage but without knowing more about
how TBs fail, I will stick with this.

 

Its bearings can fail. Based on advice here, I inspect it at
each TB change. Barring any sign of bearing failure, I
change it only every other TB change.

 

Dillon, four folks reporting personal experiences where
their broken timing belt did not damage the engine:
http://www.honda-tech.com/showthread.php?t=2201848 .

(For newbies, note the thread emphasizes that luck is a
factor in not damaging the engine. If your TB is due, change
it now.)

 

Always do the "pulleys" with the belt. Usually one idler pulley and
one tensioner pulley. The tensioner pulley gets its tension from a
spring or hydraulic tensioner. I personally like to use Gates Timing
Kits. The lube in the bearings dry up and they start to rattle and
loosen.

The hydraulic tensioners can be reused if they meet specs in the
repair manual on those engines. However, IIRC read about some VW kits
come with it.

http://www.gates.com/index.cfm?location_id=540

 

Pardon? What do you mean about the carbon build-up tending
to promote valves hitting piston?

Dillon raises a good point. I do not like my explanation for
why sometimes the engine is not damaged. When driving and
the TB breaks, it's true spark stops pretty instantaneously,
but ISTM the tranny will keep the wheels moving and so the
pistons moving for awhile, yet the cam is disconnected from
the crank, so I would expect pistons to hit valves. Unless
the valves can halt a slow((??) moving piston?

 

Post-o. Shoulda been "the wheels will keep the tranny (and
so crank) moving."

Okay.

The rest was my re-statement of what Dillon, not you, wrote.

 

the problem with the tensioner pulley is that the bearings are "loose fit"
from factory. so, people replacing the pulley are often wasting their
money because the new one will be almost exactly the same as the old one.
personally, i wouldn't consider changing the tensioner for the honda d-
series engine for at least the first two belts.

 

If it is truly an interference engine, it will almost always trash it out. I
don't believe that the A20A3 SOHC, that is in my 1989 Accord, is. It has
valve relief cut outs in the top of the pistons. The engine can be put at
TDC on number 1 cyl and then have the camshaft turned all day without
hitting the piston. I've done it and later removed the head ... not even a
scratch on valves or pistons.

 

Doesn't matter whether they're "loose fit" blah blah. It all
depends on a person's experience with ball bearings. I
propose that, at TB change 2, buy a new tensioner, but
compare the old one and new one by spinning them. If they
seem no different, then it is a better gamble to not change
it and just hold onto the new one until the next TB change.

 

The valves and pistons certainly CAN hit each other. That is the definition
of an "interference" engine. If the timing belt snaps, the cam stops turning
the valves instantly. If you have a manual transmission, the moving car
forces the crank and hence the pistons to keep moving and damage is almost
guaranteed. If you have an automatic, the crank MIGHT stop soon enough to
avoid serious damage.

 

The one belt that failed on me was a clean snap & as the car had a manual
transmission, you could hear the "ping, ping, ping, ping" as the pistons,
being driven by the wheels, bashed the valves.

Most modern automatic transmissions do not have a reverse pump in the
transmission that will allow it to turn the engine via movement by the
wheels. This is why you need an immobilizer to hold the crank when you
remove the pulley bolt and why you can't push start the car. Even a
catastrophic belt failure might not damage valves if the crank stops soon
enough.

 

Well this is the only other theory I have seen to explain
why at least some Hondas do not experience engine damage
when the TB breaks. Guess I will keep an eye peeled for
whether those reporting no damage had (or tend to have?)
auto trannies.

Not sure I follow your other part. Manual transmission
hondas also require an immobilizer (= pulley holding tool)
to get the pulley bolt off.

The only other explanation I can think of is that the
pistons either do always hit the valves when the TB breaks,
but it takes repeated hitting--the higher the RPM/torque,
the worse the pounding will be--to do serious damage. Maybe
the latter is baloney though. I am only going by the rough
schematics I have seen of interference engines.

 

Require is a strong word. If the clutch is in really good shape & the car
is locked in gear, theoretically you should be able to hold it using the
drive train as the immobilizer. That's how we did it on the 80's Fords &
Mazdas.