Interference? (1 Viewer)

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dnp

dnp

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I want you folks to help me clear something up.

I'm nearing 90K on the '99 LX, so it is about time to start deciding on who I want to use for the T-belt, H20 pump, etc. replacement. Based on several good recommendations I've gotten about a shop in my town, I decided to stop by and "interview" them today. While talking to one of the owners, I started to get a good feeling about him, until he made a statement that is contrary to what I thought was true. He said "yeah, you need to go ahead and get the belt changed, but even if you didn't, and the belt ended up breaking, it wouldn't hurt anything." When I told him that I was under the impression that the 2UZ-FE WAS an interference engine, he said "the dealer may TELL you that, but none of the Toyota belt-driven valve systems are interference....haven't been that way in over ten years." I asked again, and he said the Toyota V8 is a non-interference engine.

My question is: is the 2UZ-FE an interference engine or not? I hope I'm wrong in thinking it is; however, even though I'm going to have everything changed anyway, if this guy is wrong on something that fundamental, I want to know before I make a mistake on a mechanic.

Please advise.

Thanks,

dnp
 
Hmmm...Very good question !
The ONLY place I have heard that the 4.7 engine is NOT a clearance motor is in these forums...Even the Toyota service reps say it has (valve) clearance..but I personally do not know of a single instance in which a t-belt failed to find this out.....
 
I am of the understanding the 4.7 IS an interference motor...that is why the TBelt is such an issue getting it replaced at the 90K mark...
 
i have toyotas engines appart here at the dealer weekley ALL the ones on the lexus side are Definatley interference motors
 
I see this alot- it has been argued on many forums. Can someone simply explain what interferece means, in terms of the valve clearance and timing belt?
 
Just because he is confused about the motor being a interference motor doesn’t make him a bad mechanic. Why don’t you use the dealer? How much are you going to save?
My .02.
Dean
 
Back when I had my Tundra I was on Tundra Solutions a good bit and there was a guy that had to show his Mr. T service manager the Tundra FSM page where it said that the engine WAS an interference engine. He didn't post the page # so I can't verify that it actually says this in the Tundra FSM. Maybe some of you dealer guys could look into that for us.

Personally I think it's just too many valves with such tight tolerances not to get screwed up if the belt went.
 
DMX84 said:
Just because he is confused about the motor being a interference motor doesn’t make him a bad mechanic. Why don’t you use the dealer? How much are you going to save?
My .02.
Dean
Click to expand...

Well, the way I look at it, to make a definitive statement that he was SURE the engine was non-interference makes me wonder what other "assumptions" he might make during repairs. He also made the comment that I would "know" it if the timing belt was not reinstalled properly (meaning, if it were installed with a cam advanced or retarded a tooth in either direction, the engine wouldn't run right, it would throw a code, etc. While that certainly COULD be true, I've done enough of my own repairs for long enough to suspect that this may - or may not- be true. The vehicle may simply run with reduced performance or other side effects)

With regard to taking the truck to a dealer, I guess I've just had enough personal experience with dealerships to believe that the last place one will generally get good work is at a dealership. You would ordinarily think this line of reasoning would be backwards, because, arguably, they should be the most educated about the vehicles on which they work. However, for what ever reason, the service departments in the dealerships at which I have worked seemed to perform the sh**iest work I've seen (and these weren't Kia dealerships - lines carried and repaired were Chevrolet, Mercedes, Porsche, Audi, and SAAB. The only dealer with whom I was associated that did exemplary work was (no surprise) Ferrari)

Anyway, I just believe I'm more likely to get a quality job at a non-dealer that has the Lexus specialty tools and has adequate experience with them. Let's face it, for the most part, most multi-valve new cars operate fundamentally the same way. If a mechanic is adept at repairing cars, has the proper tools, and CARES about his work, he can repair just about anything out there.........I'm just trying to find "that" guy.
 
Augie said:
Gates definition of interference and link to application guide.

They list 2UZ-FE as interference engine.
Click to expand...

Thanks. Good link.

If replacing the oil seals is important, why don't they include them in the timing belt kit with the pulleys? I guess they could just go ahead and rebuild the whole motor while they're in there? Its kind of like going to Midas for a brake job. They'll sell you a whole new brake system if you let them, when all you need is pads.
 
Well...after searching various forums ...The general consensus (when this question is asked) is the 2-UZFE engine is one of the FEW (if not only) t-belt driven motors that DOES HAVE interference between the piston and valves in the event of timing belt failure.

I guess that is just ANOTHER reason to follow Toyota`s recommended interval for replacement !! I can assure you that anyone, who even waits until the LAST minute to replace the belt (@ 90,000 Mi ), will never have to find out the hard way ...Plus, the cost of a SINGLE tow bill from, say, more than 50 miles away from a repair shop, would surpass the price of the t-belt job in the first place...not to mention any damage inflicted by the failure !!!!

AFTER THIS THREAD, I now feel that I am on "borrowed" time , and I will get mine done ASAP !!
 
DMX84 said:
Just because he is confused about the motor being a interference motor doesn’t make him a bad mechanic. Why don’t you use the dealer? How much are you going to save?
My .02.
Dean
Click to expand...
Define "bad".

I would disagree here. That is a major concept within the design of the engine. It is not like asking a guy what is the tolerance range for a 100 series valve guide and him not knowing off the top of his head. Could he do the work? Probably. Would it be a quality job? Probably. But it speaks to the general riff between understanding the engine and following a manual to do the work. I can follow a manual and do about anything if I have the right tools. But that does not make me a mechanic. That essentially makes me a robot. Point being, if you want a mechanic, you need someone who understands the design of engines in general and particular engines. I learned the hard way with a 993 Porsche that there are mechanics and then there are techs. And that there are 100's, sometimes 1000's, of dollars in differece in terms of cost to you. Send the standard stuff to a tech but do not expect to be able to have a conversation about what they did and why.

Just my .02
 
Jukelemon said:
Define "bad".

I would disagree here. That is a major concept within the design of the engine. It is not like asking a guy what is the tolerance range for a 100 series valve guide and him not knowing off the top of his head. Could he do the work? Probably. Would it be a quality job? Probably. But it speaks to the general riff between understanding the engine and following a manual to do the work. I can follow a manual and do about anything if I have the right tools. But that does not make me a mechanic. That essentially makes me a robot. Point being, if you want a mechanic, you need someone who understands the design of engines in general and particular engines............
Click to expand...

That follows my line of reasoning on this issue exactly.
 
Julkelemon, very well put, and I tend to agree with what you said, but I think you guys read a bit more into what I was saying. Just because he said that it was not an interference motor doesn’t make him unknowledgeable at everything else. I will attest that allot of mechanics lack quality workmanship, including dealerships. But with the dealer you are a little more comfortable knowing that they used genuine parts with warranty. If the other mechanic talks the talk doesn’t mean that he will walk the walk (and he may even know the tolerance range for the valve guide).
It’s hard to find a good mechanic, and I tend to try to do the stuff myself if possible, so I know what I’m getting.
It’s good to go talk to the guy you are about to trust with your prized possession.
Dnp stated that this guy came highly recommended by other people. Sounds like he’s done this before, but if you don’t have a good feeling about him, don’t use him, because you will not be happy in the long run. Been there, done that myself.
Keep looking till you find the mechanic that makes you comfortable with all the right words, than look at his product/workmanship and see if it matches what he said.
I hope the best of luck in your quest for the right mechanic.
Dean
 
If they are interference engines they can't interfere much. I have spun the crankshaft as well as the cams independently with no timing belt on and couldn't sense any contact. I'm not saying that they don't touch at high revs but it sure can't be very much.

The engine in question is in our first gen Sequoia and is running perfectly well as of today with 300,000 miles on it.
 
lowenbrau said:
...and let me congratulate myself for the epic dead-thread revival. There is probably a more current discussion somewhere.
Click to expand...
I just read in another forum that the pre-VVTI 2uz motors are non interference. Yes, no, maybe??
 
Hi guys, just wanted to revive the thread again, just because I feel it is very important information and it has been a game changer. I am looking to get a 100 series and the timing belt maintenance made me paranoid.
I am currently a lube tech at a Toyota dealership. A 2000 Cruiser came in because of a horrible noise and it wouldnt start. I helped push it in, and later asked the master tech who worked on it what had gone wrong. Note that he is also the highest paid mechanic in the whole dealership chain due to his proficiency. He told me that the bolt for the timing belt tensioner had snapped, and the belt was skipping teeth, but luckily it was a non interference engine. I continued to question him, and he stated that the 4.7 became an interference engine in 2005 when they added variable valve timing. That Land Cruiser drove out of the dealership with it's original engine.
 
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