Bent Valve After Timing Belt Replacement / VVTi Engine

[Snow Wagon]

Hello Forum,
Looking for a little advice...
A guy reached out to me about working on his 2007 100 Series Land Cruiser w/ a bent valve.
Another shop just did the timing belt / water pump job and when they started it post job a valve (or valves...) was bent.
The other shop indicted that the issue was unrelated to the tb / wp job (very unlikely...).
The other shop is owned by a friend of his, so he's not pushing the issue.

I've done a lot of work on the 100 Series, including multiple timing belts.
From what I've read, the non-VVTi typically doesn't damage valves when a timing belt brakes.
Therefore, I would assume that a non-VVTi would not damage valves if a timing belt was installed incorrectly.

But, this is a VVTi motor.
If the timing belt was installed incorrectly, would it damage valves?
If so, how bad should I expect it to be?
Engine replacement time?
Pull heads and just replace some bent valves (and anything else damaged...)?
The motor has 230k on it and ran well prior to the tb / wp job (per the owner...).

Thank you in advance for your responses.
Tom

 

[vipergrhd]

Let's just forget the part that this was installed wrong, damaged is done. From my own personal experience, get the timing belt installed correctly I would do a leak down test on all cylinders I'm sure you will find right away how many cylinders are not building any pressure. If you are lucky enough you might have damaged on one cylinder head (bent valves) I have sent out a head and just replace the damaged valves no machine work no valve job just repair that is if you are on a budget. The proper way would be doing both heads with complete valve job and minimal surfacing, pistons could live with small indentations from the valves.

 

[Scotty UZJ100]

The VVTI 2UZ is an interference motor so if it isn't timed properly you will have valve to piston contact. So both valve and piston would have been damaged. You could probably bore scope it to find the marked up piston and go from there.

 

[excessive]

about 13 mins into this video, might explain what happened

 

[nissanh]

non-vvti is non interference.

 

[Snow Wagon]

Thank you for the responses so far.
Yes, it is my understanding that the VVTi engine (2006 & 2007) is truly an interference engine, where as the non-VVTi engine (1998 to 2005) is not really an interference engine (even though Toyota says it is...).

Anyone have real world experience as to how much damage is likely done?
I'm trying to give the owner an idea of what to expect.

Thank you.
Tom

 

[Trunk Monkey]

There's a couple threads out there on people that have had a VVTi engine timing belt break, think they've mostly ended up in engine replacement. Some of it depends on how quickly it was caught and how long it ran with the valves hitting the pistons. As was mentioned, bore scop and leak down will tell you a lot for next steps.

 

[nissanh]

Sorry, it happened to you. LIke Trunk Monkey stated, inspect the damaged valves, pull the head on that side and get new valves, new OEM gasket and call it done. Install an OEM toyota belt (not a belt that just say mitsuboshi) OEM toyota belt will have TOYOTA on it.

 

[97 AZ LC]

Sorry, it happened to you. LIke Trunk Monkey stated, inspect the damaged valves, pull the head on that side and get new valves, new OEM gasket and call it done. Install an OEM toyota belt (not a belt that just say mitsuboshi) OEM toyota belt will have TOYOTA on it.

Have you ever heard of a problem with a Mitsuboshi timing belt? I haven't. It is certainly OEM and seems to be a true OE equivalent, that is off the same production line as the OE/Genuine.

 

[Snow Wagon]

Thank you all for your responses.
The cruiser is 2 hours from me and I was trying to give the potential client a general idea of how much damage is likely.
Sounds like it could be 1 or 2 bent valves, a bunch of valve / piston damage, or anywhere in between.
I'd gladly scope / leak down test it if it was here.
I'm hopeful that since this happened during startup, after a timing belt change, that the damage is minimal.
If I do the work, I'll update the thread with what I find.
Enjoy.
Tom

 

[vipergrhd]

Hello Forum,
Looking for a little advice...
A guy reached out to me about working on his 2007 100 Series Land Cruiser w/ a bent valve.
Another shop just did the timing belt / water pump job and when they started it post job a valve (or valves...) was bent.
The other shop indicted that the issue was unrelated to the tb / wp job (very unlikely...).
The other shop is owned by a friend of his, so he's not pushing the issue.

I've done a lot of work on the 100 Series, including multiple timing belts.
From what I've read, the non-VVTi typically doesn't damage valves when a timing belt brakes.
Therefore, I would assume that a non-VVTi would not damage valves if a timing belt was installed incorrectly.

But, this is a VVTi motor.
If the timing belt was installed incorrectly, would it damage valves?
If so, how bad should I expect it to be?
Engine replacement time?
Pull heads and just replace some bent valves (and anything else damaged...)?
The motor has 230k on it and ran well prior to the tb / wp job (per the owner...).

Thank you in advance for your responses.
Tom

Thank you all for your responses.
The cruiser is 2 hours from me and I was trying to give the potential client a general idea of how much damage is likely.
Sounds like it could be 1 or 2 bent valves, a bunch of valve / piston damage, or anywhere in between.
I'd gladly scope / leak down test it if it was here.
I'm hopeful that since this happened during startup, after a timing belt change, that the damage is minimal.
If I do the work, I'll update the thread with what I find.
Enjoy.
Tom

The damage here is most likely just the valves even if it left a mark on the pistons it will be fine as long you clean it up, cost is unknown until you take it to the machine shop it's up to them what they are willing to do and at what price, some shops will not repair due to little profit and time consuming since they still have to adjust the shims on the bucket. What I don't understand is this so called friend is not standing behind his work knowing this happened after the job and not when it left the shop, why would the owner fork up the money to fix someone else's mess? A friend? I say stand his ground and make them fix it and no doubt that the mechanic was at fault. Just my 2 pennies.
Just to add, I know you just want to help the guy and I'm all for that but you once you get your hands dirty it will be hard to get out of it.

 

[Snow Wagon]

Hello vipergrhd,
I hear you.
I've already had a discussion with the owner about the damage and that I'm 99.99% sure the shop is to blame.
Evidently the shop is owned by a very good friend of his and their families are also good friends.
He doesn't want any drama and is willing to pay to get it fixed.
With friends like that, who needs enemies .
If it was my fault, I'd fix it on my dime.
He knows I'll be charging him time and materials and it is what it is.
There's a good machine shop near me that been in business forever, is reasonable, and I've had work done there before.
I'm hopeful they'll be willing to do whatever head work needs done.
Thank you.
Tom

 

[nissanh]

Have you ever heard of a problem with a Mitsuboshi timing belt? I haven't. It is certainly OEM and seems to be a true OE equivalent, that is off the same production line as the OE/Genuine.

No, but Toyota labelled parts are made very specifically to toyota standards, and no OE manufacturer can use those level of quality to make their own belt. I'd do a Toyota labelled T-belt 15 years or 100K miles without even inspecting. My 100 got a Mitsuboshi belt and coming closer to 10 years 50K miles.

OEM Toyota Aisin water pump can last 200K miles while an Aisin water pump about 120K miles. Toyota standards are (not after 2020) are pretty amazing.

 

[97 AZ LC]

No, but Toyota labelled parts are made very specifically to toyota standards, and no OE manufacturer can use those level of quality to make their own belt.

I think you made that up. OEM and OE parts often, not always, come off of the same production line and then go into different boxes and different distribution channels to sell at different prices. There's just no evidence that Mitsuboshi is cheapening their timing belts to put their own name on them. They are a well respected and long lived part. I would tend to agree with you on Aisin water pumps - reviews suggest lots of failures in the Aisin kits. I would never install a water pump that I had not personally walked out of the dealership. I think there's a lot more money in cheapening a water pump than in cheapening a timing belt.

 

[2001LC]

Clues, that will help you diagnose the damage remotely. First when and how did he find out and what were and are the DTC.
Doctor Doctor my ass is burning, what can I do? OR Doctor doctor my ass if burn, after I eat chile peppers! What can I do?

Then looking when and at how it happened:

Did only one cylinder get a P030*?
Is the engine correctly timed, when second shop looked. Which I'd assume that is why, second shop said; "The other shop indicted that the issue was unrelated to the tb / wp job ". They saw timed marks lined up, by sneaking a peak behind both cam covers. Pictures?

So either first timed wrong. Than tron down and correct by first shop. Not saying anything. Which "could" mean more than one cylinder has bent valve, if engine started (not just hand spun 720 degree, check of timing). Which then multiple P030*, would "likely" pop up. In this case, "may" (not will) have piston top damage and or bent connecting rod. I'd Replace engine. (note: during 720 degree spinning crank, to check timing. A VVT would bind. Added force would then need be applied, to spin crank. In this event, we could see more than one cylinder with a P030*. but connect rods likely okay)

Alternatively cause of bent valve.
In TCCN video above, at ~13 min. He shows setting cams to the T's and harmonic balance (crank pulley) to the plastic nub on lower cover. It doesn't matter so much, on the non VVT. So we typically use the hard marks (straight lines, rather than T's). But if, a cam disturb at all when set to "I". It will move, due to valve spring tension on cam lob. If this happens, (cam moves, due to spring tension) on a VVT. It may bend two valve in one cylinder. But, even then, valves rarely get bent. But if while belt off, crank or cam spun, on the VVT. Valves will be bent. But since this is a slow speed turning of cam or crank. It is not enough force, to likely damage piston other than a witness mark. It certainly, is not enough force to bent a connecting rod. Rebuild the head. Replace head bolts also, even if they spec okay.

Third alternative cause of bent valve.
Cam seal replaced on a VVT engine, is a big deal. Certain procedure must be followed. In this even engine may be on the marks, and damaged happen, after RPM taken up. This may have been owners first drive on HWY. So what DTC and when matters, as a clue. Likely muliple DTC.

 

[nissanh]

I think you made that up. OEM and OE parts often, not always, come off of the same production line and then go into different boxes and different distribution channels to sell at different prices. There's just no evidence that Mitsuboshi is cheapening their timing belts to put their own name on them. They are a well respected and long lived part. I would tend to agree with you on Aisin water pumps - reviews suggest lots of failures in the Aisin kits. I would never install a water pump that I had not personally walked out of the dealership. I think there's a lot more money in cheapening a water pump than in cheapening a timing belt.

I respectfully disagree.

 

[Rhetoric]

I respectfully disagree.

X2

I see Toyota parts as the best of the best of whatever the brand is. Aisin. Denso. Etc.

The stuff that has the Toyota logo ground off didn’t quite make the Toyota QC cut.

Owning one of these trucks has taught me to stick to Toyota parts and worry about it in 18 more years.

 

[Scotty UZJ100]

X2

I see Toyota parts as the best of the best of whatever the brand is. Aisin. Denso. Etc.

The stuff that has the Toyota logo ground off didn’t quite make the Toyota QC cut.

Owning one of these trucks has taught me to stick to Toyota parts and worry about it in 18 more years.

This. Eat the extra cost now so you don't have to do the job again prematurely. I just bought some diff seals labeled OEM toyota but they came in a small box with some Chinese writing printed on it. I tossed them out and ordered some new ones from toyota.

 

[abuck99]

Thread veered off topic already so I’ll add my .02

OE doesn’t always match OES- but if it’s a Toyota family supplier ( one that Toyota has an ownership stake in ex. Aisin is an OES for example) these parts often times match OE spec. And can be trusted to deliver lifespan equivalent to Toyota marked components. Key in purchasing OES parts to ensure matched quality spec is buying from a reputable authorized distributor or retailer: (not Amazon not eBay)-

Fwiw Mitsuboshi is OES- I have no concern that their belts are any different level of quality than the Toyota branded part- but have no empirical proof.

OP- good luck

 

[97 AZ LC]

I'm not saying they are always the same. I'm saying you've got to pay attention. Mitsuboshi branded belts have proven themselves over the years.