98 LS400 broken cam gears after timing belt change and JDM swap
07-25-17, 07:00 AM
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98 LS400 broken cam gears after timing belt change and JDM swap
Friend of mine bought a mint condition LS400 that had 100k and a blown engine due to timing belt failure shortly after a timing belt job. Threw out the engine because valves were bent. When it seized it locked up so hard it shredded the rubber flange between transmission and driveshaft. The owner claims his mechanic was very competent during the timing belt change and everything was done right. But somehow the M8x1.25 (don't remember exact) bolts that hold on the cam gear snapped and the cam gear broke off leading to belt and engine failure.
We bought a JDM engine because it was actually a little cheaper than all the high mileage used engines for this car. There were a few difficulties because it was from an SUV so fan location was slightly different and some of the vacuum lines were different, it also had a strange port for the hydraulic fan clutch of some sort that we've since eliminated. The thing is mint inside and runs like a new car, so I'm guessing we got a good one and what they say about imported JDM engines is true. However even if it has the claimed 50k or so miles on it, it did sit for a while so who knows if the timing belt can be relied upon? I'm guessing we should change it?
This brings me to the actual question for other LS400 owners. Are there any things to watch for during the timing belt job or any issues with these cam gear bolts snapping? What could possibly cause this? I thought maybe at first that mechanic was an idiot and screwed something up. However, I visited a junkyard a year ago and saw the same exact thing on one of the LS400s there, which really surprised me. I thought it was just a freak occurrence or crappy mechanic, but now I'm not sure.
I googled around and couldn't find much about the cam gears breaking off.
Also, what is everyone's favorite recommended belts? I know Gates always get a good rep, but personally I usually throw Dayco on everything and haven't had any issues yet after 20-30 timing belt jobs. Or is it better to go with OEM?
We bought a JDM engine because it was actually a little cheaper than all the high mileage used engines for this car. There were a few difficulties because it was from an SUV so fan location was slightly different and some of the vacuum lines were different, it also had a strange port for the hydraulic fan clutch of some sort that we've since eliminated. The thing is mint inside and runs like a new car, so I'm guessing we got a good one and what they say about imported JDM engines is true. However even if it has the claimed 50k or so miles on it, it did sit for a while so who knows if the timing belt can be relied upon? I'm guessing we should change it?
This brings me to the actual question for other LS400 owners. Are there any things to watch for during the timing belt job or any issues with these cam gear bolts snapping? What could possibly cause this? I thought maybe at first that mechanic was an idiot and screwed something up. However, I visited a junkyard a year ago and saw the same exact thing on one of the LS400s there, which really surprised me. I thought it was just a freak occurrence or crappy mechanic, but now I'm not sure.
I googled around and couldn't find much about the cam gears breaking off.
Also, what is everyone's favorite recommended belts? I know Gates always get a good rep, but personally I usually throw Dayco on everything and haven't had any issues yet after 20-30 timing belt jobs. Or is it better to go with OEM?
07-25-17, 08:34 AM
#2
Friend of mine bought a mint condition LS400 that had 100k and a blown engine due to timing belt failure shortly after a timing belt job. Threw out the engine because valves were bent. When it seized it locked up so hard it shredded the rubber flange between transmission and driveshaft. The owner claims his mechanic was very competent during the timing belt change and everything was done right. But somehow the M8x1.25 (don't remember exact) bolts that hold on the cam gear snapped and the cam gear broke off leading to belt and engine failure.
We bought a JDM engine because it was actually a little cheaper than all the high mileage used engines for this car. There were a few difficulties because it was from an SUV so fan location was slightly different and some of the vacuum lines were different, it also had a strange port for the hydraulic fan clutch of some sort that we've since eliminated. The thing is mint inside and runs like a new car, so I'm guessing we got a good one and what they say about imported JDM engines is true. However even if it has the claimed 50k or so miles on it, it did sit for a while so who knows if the timing belt can be relied upon? I'm guessing we should change it?
This brings me to the actual question for other LS400 owners. Are there any things to watch for during the timing belt job or any issues with these cam gear bolts snapping? What could possibly cause this? I thought maybe at first that mechanic was an idiot and screwed something up. However, I visited a junkyard a year ago and saw the same exact thing on one of the LS400s there, which really surprised me. I thought it was just a freak occurrence or crappy mechanic, but now I'm not sure.
I googled around and couldn't find much about the cam gears breaking off.
Also, what is everyone's favorite recommended belts? I know Gates always get a good rep, but personally I usually throw Dayco on everything and haven't had any issues yet after 20-30 timing belt jobs. Or is it better to go with OEM?
We bought a JDM engine because it was actually a little cheaper than all the high mileage used engines for this car. There were a few difficulties because it was from an SUV so fan location was slightly different and some of the vacuum lines were different, it also had a strange port for the hydraulic fan clutch of some sort that we've since eliminated. The thing is mint inside and runs like a new car, so I'm guessing we got a good one and what they say about imported JDM engines is true. However even if it has the claimed 50k or so miles on it, it did sit for a while so who knows if the timing belt can be relied upon? I'm guessing we should change it?
This brings me to the actual question for other LS400 owners. Are there any things to watch for during the timing belt job or any issues with these cam gear bolts snapping? What could possibly cause this? I thought maybe at first that mechanic was an idiot and screwed something up. However, I visited a junkyard a year ago and saw the same exact thing on one of the LS400s there, which really surprised me. I thought it was just a freak occurrence or crappy mechanic, but now I'm not sure.
I googled around and couldn't find much about the cam gears breaking off.
Also, what is everyone's favorite recommended belts? I know Gates always get a good rep, but personally I usually throw Dayco on everything and haven't had any issues yet after 20-30 timing belt jobs. Or is it better to go with OEM?
also, I'd like to see pics of the damaged cam gears! I wonder if your friends mechanic had a factory manual handy while he was doing the job..
Last edited by Scraape; 07-25-17 at 08:38 AM.
07-25-17, 08:49 AM
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I haven't had to do the timing belt yet, but how did yours go overall? Can you give me a time estimate or any tips? Did you have to remove the bolts that hold on the cam gears? I wonder if the mechanic that did the job on the failed engine had to touch those bolts or if they simply snapped on their own. Hmm, maybe he did cam seals too? Did you change yours or anything other than wp/belt?
07-25-17, 10:26 AM
#4
I haven't had to do the timing belt yet, but how did yours go overall? Can you give me a time estimate or any tips? Did you have to remove the bolts that hold on the cam gears? I wonder if the mechanic that did the job on the failed engine had to touch those bolts or if they simply snapped on their own. Hmm, maybe he did cam seals too? Did you change yours or anything other than wp/belt?
But I ended up finding out one of my cam seals were leaking.
Doing the cam seals was the hardest part because you have to remove the camshafts.
You can check out my build thread I'm pretty sure I have some info/pics/part#'s in there about it.
https://www.clublexus.com/forums/bui...s-ls400-5.html
Otherwise there is a tutorial in the stickys.
Pretty sure we kept the cam gears on the cams, we just used a service bolt to remove the cams (that is what the manual says to do).
this thread helped out a lot as well for me:
https://www.clublexus.com/forums/ls-...ith-vvt-i.html
07-25-17, 10:32 AM
#6
07-25-17, 11:45 AM
#7
It would be nice to see some pictures of the parts bolt etc. It could be a highly stressed bolt for some reason. Every one always wants to point a finger at the tech, sometimes its justified and sometimes not.
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07-25-17, 07:30 PM
#8
I haven't had to do the timing belt yet, but how did yours go overall? Can you give me a time estimate or any tips? Did you have to remove the bolts that hold on the cam gears? I wonder if the mechanic that did the job on the failed engine had to touch those bolts or if they simply snapped on their own. Hmm, maybe he did cam seals too? Did you change yours or anything other than wp/belt?
Removing the crank bolt is always an important step. Either get the tool for it or make your own. You can make one with a two by four, a hole saw set, drill, and a puller kit. Bag and label all your bolts.
Last edited by aptoslexus; 07-25-17 at 07:35 PM.
07-26-17, 02:32 AM
#9
Whoever did the timing belt is 100% at fault for the failure. It wasn't a component failure, it was technician error.
You bought a JDM celsior engine, not a truck engine. the JDM Celsiors had a hydraulic fan instead of the clutch-driven fan the US/Euro cars did.
To avoid a repeat of what happened, have a qualified tech who's familiar with toyota/lexus cars do the timing belt change. Or follow one of the tutorials in the FAQ and try it yourself.
You bought a JDM celsior engine, not a truck engine. the JDM Celsiors had a hydraulic fan instead of the clutch-driven fan the US/Euro cars did.
To avoid a repeat of what happened, have a qualified tech who's familiar with toyota/lexus cars do the timing belt change. Or follow one of the tutorials in the FAQ and try it yourself.
07-26-17, 01:51 PM
#10
Whoever did the timing belt is 100% at fault for the failure. It wasn't a component failure, it was technician error.
You bought a JDM celsior engine, not a truck engine. the JDM Celsiors had a hydraulic fan instead of the clutch-driven fan the US/Euro cars did.
To avoid a repeat of what happened, have a qualified tech who's familiar with toyota/lexus cars do the timing belt change. Or follow one of the tutorials in the FAQ and try it yourself.
You bought a JDM celsior engine, not a truck engine. the JDM Celsiors had a hydraulic fan instead of the clutch-driven fan the US/Euro cars did.
To avoid a repeat of what happened, have a qualified tech who's familiar with toyota/lexus cars do the timing belt change. Or follow one of the tutorials in the FAQ and try it yourself.
07-26-17, 04:44 PM
#11
Whoever did the timing belt is 100% at fault for the failure. It wasn't a component failure, it was technician error.
You bought a JDM celsior engine, not a truck engine. the JDM Celsiors had a hydraulic fan instead of the clutch-driven fan the US/Euro cars did.
To avoid a repeat of what happened, have a qualified tech who's familiar with toyota/lexus cars do the timing belt change. Or follow one of the tutorials in the FAQ and try it yourself.
You bought a JDM celsior engine, not a truck engine. the JDM Celsiors had a hydraulic fan instead of the clutch-driven fan the US/Euro cars did.
To avoid a repeat of what happened, have a qualified tech who's familiar with toyota/lexus cars do the timing belt change. Or follow one of the tutorials in the FAQ and try it yourself.
07-26-17, 07:30 PM
#12
Moderator
What are the practical implications of the difference in fan between the LS400 and the Celsior? And is that also true of the early first gen cars? I've noticed my car doesn't have the two electric fans in front of the radiator that the LS400s do. Mine is running perfectly right now but I'm trying to amass as much knowledge about these differences between the cars so that in the event something goes wrong I'm prepared.
Celsiors use those components and a fan to control the water temperature aiming to meet the Japanese traffic conditions. Our summer heat and the winter coldness are something special. We also have traffic jams often and we need to be patient with it. The hydraulic fan system used for Celsiors is to deal with those situations and is quite reliable. Local shops owners say,"As long as the correct hydraulic oil 08886-01005 is used and changed certain intervals, it never fails".
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creilly (07-27-17)
07-27-17, 08:06 AM
#13
Owing a Celsior in abroad needs some extra efforts to keep running when it aged and I know how you are worrying about. I don't know much about the Gen 1 but I know some about the Gen 2 and I have some experience to help local shop owners. But I only know about electronics related affairs and I have huge difficulties to deal with mechanical affairs. Attached is for an early Gen 2 but I believe most of those components are the same with Gen1.
Celsiors use those components and a fan to control the water temperature aiming to meet the Japanese traffic conditions. Our summer heat and the winter coldness are something special. We also have traffic jams often and we need to be patient with it. The hydraulic fan system used for Celsiors is to deal with those situations and is quite reliable. Local shops owners say,"As long as the correct hydraulic oil 08886-01005 is used and changed certain intervals, it never fails".
Celsiors use those components and a fan to control the water temperature aiming to meet the Japanese traffic conditions. Our summer heat and the winter coldness are something special. We also have traffic jams often and we need to be patient with it. The hydraulic fan system used for Celsiors is to deal with those situations and is quite reliable. Local shops owners say,"As long as the correct hydraulic oil 08886-01005 is used and changed certain intervals, it never fails".
Fluid level in mine was good, it seems that just like everything else on this car the previous owner took perfect care of it.
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