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

Subject says it all, thanks

Michael

Reply to
mrdarrett
Loading thread data ...

What is an interference engine?

Reply to
Don Schmidt

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.

Reply to
mrdarrett

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.

Reply to
Jeff Strickland

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?

Reply to
Jeff Strickland

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

Reply to
mrdarrett

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.

Reply to
Jeff Strickland

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:

formatting link
GW

Reply to
Geoff Welsh

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

Reply to
uncle_vito

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

Reply to
Hachiroku ハチロク

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..

Reply to
nm5k

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.