2002 Sienna, does it have an interference engine or not?

[mrda...@gmail.com]

Subject says it all, thanks

Michael

[Engineer@pnb.retired_1987 Don Schmidt]

What is an interference engine?


<mrda...@gmail.com> wrote in message
news:d8080bf1-804f-41bf...@googlegroups.com...

[mrda...@gmail.com]

On Monday, June 3, 2013 2:26:04 PM UTC-7, Don Schmidt wrote:
> What is an interference engine?

If you change the timing belt, and it slips, and you continue to rotate the crankshaft with the camshafts out of alignment, the piston can slam into the valves, causing thousands of $$$ in damage.

Same issue if the timing belt comes off during driving. Not that that ever happened to me... (cough) bad water pump... (cough)

If it's non-interference, you don't have to worry - the engine is designed to allow extra space if the pistons go up with the valves opened.

I changed the timing belt on the '99 Camry, and my timing belt slipped a few times (first time, yeah it happens) but since it's a non-interference engine, no big deal, I just had to re-rotate everything to Top Dead Center.

I'm just not that familiar with V6 engines on the Sienna, is all.

[Jeff Strickland]

It's an engine where if the timing belt/chain breaks, the valves and the
pistons can run into one another.

The general rule of thumb is that a timing belt will be on a
non-interference engine so that if the rubber belt breaks on the freeway the
worst that happens is you are stuck on the side of the road, or center of it
if you can't get over. An interference engine will have a timing chain since
a timing chain should never break.




"Don Schmidt" <Don Engi...@PNB.Retired_1987> wrote in message
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[Jeff Strickland]

<mrda...@gmail.com> wrote in message
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If there is a belt, it should be an non-interference engine, if there is a
timing chain then you should expect the pistons and valves to occupy the
same space at the same time if the chain breaks.

If you were an engine maker and there was a chance that the pistons and
valves would collide at some point, would you drive the valves with a belt
or a chain?

[mrda...@gmail.com]

If I were an engine maker I'd do whatever my boss told me to do... ahahahaha. Plenty of times at work I thought something boss wanted was ludicrous, and said so, then boss took a deep breath and said, "One more time... I want you to..."

Economics dictate some of it too...

I found somewhere that the VVT-i 1MZ-FE engines are interference. Yay. I happen to have a VVT-i...

Cheers,

Michael

[Jeff Strickland]

<mrda...@gmail.com> wrote in message
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I don't want to argue with you, but economics says that if the engine parts
will have a fatal collision during the warranty period, then it would be
cheaper to use a chain than a belt. And, no matter the parts cost, it is
passed on to the car buyers, so the engine design would not be affected by
this constraint. Yes, they could ask, "How can we make this engine $50
cheaper?" and the answer would be, use a belt instead of a chain.

But the general rule of thumb is that if the pistons and valves can occupy
the same space at the same time, there is probably a chain.

[Geoff Welsh]

> .....

> But the general rule of thumb is that if the pistons and valves can
> occupy the same space at the same time, there is probably a chain.
>

Since we don't live in fantasy land, a rule of thumb is useless. Some
engines with belts are interference, some are not. If you work at a
shop, you look up every one individually if the belt already broke to
find out for sure.

this is an example list, although not the resource I used at the shop:

http://www.agcoauto.com/content/List_Of_Interference_Engines

GW

[uncle_vito]

You would think, but I had one break. Give it enough mileage, chains will
stretch and then break.


"Jeff Strickland" <crwl...@yahoo.com> wrote in message
news:koj4ck$np1$1...@dont-email.me...

[Hachiroku ハチロク]

Nope....Rules of Thumb suck. That said, the Rule of Thumb for Toyota
engines is, if it is a SOHC it is probably interference, if it is a DOHC
it is probably not.

And, I believe Toyota has gone back to chains on all of their engines.
But that still has had problems, like the chain tensioners on the 22R
series that would wear away after ~180,000 miles or so, usually more.

[uncle_vito]

Belt is on 2007 Highlander V6 DOHC. Chain between intake and exhaust cams
on each side. Water pump is driven by belt and needs smooth back side to
drive pump pully. Cogged top side drives cam pulleys. Have the service
manual. Too bad I cannot post drawing of belt.





"Hachiroku ????" <Tru...@e86.GTS> wrote in message
news:51ae9d1f$0$13585$c3e8da3$dd96...@news.astraweb.com...

[Hachiroku ハチロク]

Not so. The engine in the Tercel up until 1993(?) was an interference
engine, and it had a belt. My Mom's 1986 Camry 2.0 is an interference
engine and it has a belt.

Like I said in anohter post in this thread rules of thumb have to be
taken with a grain...:D

[nm...@wt.net]

On Tuesday, June 4, 2013 7:52:57 PM UTC-5, uncle_vito wrote:
> You would think, but I had one break. Give it enough mileage, chains will
>
> stretch and then break.

I've had two or three cars where the chain got a bit loose,
and then it ended up jumping a tooth or whatever, and the timing
was off. Still ran, but ran like crap.. I remember I had a 73 Cadillac
that did that.. Other cars too.
I remember I was with a friend of mine in his early 70's Pontiac
Le Mans, and we pulled into a burger joint for grub.
When we tried to leave, the car wouldn't start. Crank all day,
but dead in the water like no spark.. The timing chain broke,
evidently when the engine was shut off. It was running fine when
he killed the ignition.
My 05 Corolla has a chain, and I'm pretty sure it's an interference
engine. It has variable valve timing, etc..