1MZ-FE with VVT an interference engine?
02-02-18, 09:55 AM
#1
Pit Crew
Thread Starter
1MZ-FE with VVT an interference engine?
Hello
I read somewhere that the 1MZ-FE engine is not an interference engine however the 1MZ-FE engines that have VVT are interference engines. And also heard that the 1MZ-FE with VVT is NOT a interference engine.
So looking to sort this out.
Has there been know valve damage to a RX300 with a broken timing belt?
I read somewhere that the 1MZ-FE engine is not an interference engine however the 1MZ-FE engines that have VVT are interference engines. And also heard that the 1MZ-FE with VVT is NOT a interference engine.
So looking to sort this out.
Has there been know valve damage to a RX300 with a broken timing belt?
02-02-18, 10:51 AM
#2
Moderator
The thought process is that VVTI can make the valve timing such that it can potentially hit the pistons once the synchronization is no longer being enforced with the timing belt.
On lexus V8 engines with VVTI, there are known cases of the interference.
On RX300 some data is available that there was no damage to the piston-valve when the timing belt broke. Some attribute it to the rpm being low.
Belt can break in many ways, and the worst is when the end snaps off and then the thing is whipped around and the timing belt cover gets destroyed.
My philosophy is change the belt on time. Most likely you will do this twice in your ownership. If you get to do it the third time .. great for you! by postponing you essentially do not get to skip one. Compare that to oil change .. where over long term ownership you can save about 5-10 services.
Other thing to consider is the drive train of the belt. Rollers are lubed for life and their life is not indefinite. Mine started turning blue when I did the first service at 90k. Although the tensioner needs examination and can be reused, but I change that too as the additional cost is relatively low and it is the leading cause of belt skipping teeth.
Good luck with your quest to find the answer, but my 2c says not worth pursuing.
Salim
On lexus V8 engines with VVTI, there are known cases of the interference.
On RX300 some data is available that there was no damage to the piston-valve when the timing belt broke. Some attribute it to the rpm being low.
Belt can break in many ways, and the worst is when the end snaps off and then the thing is whipped around and the timing belt cover gets destroyed.
My philosophy is change the belt on time. Most likely you will do this twice in your ownership. If you get to do it the third time .. great for you! by postponing you essentially do not get to skip one. Compare that to oil change .. where over long term ownership you can save about 5-10 services.
Other thing to consider is the drive train of the belt. Rollers are lubed for life and their life is not indefinite. Mine started turning blue when I did the first service at 90k. Although the tensioner needs examination and can be reused, but I change that too as the additional cost is relatively low and it is the leading cause of belt skipping teeth.
Good luck with your quest to find the answer, but my 2c says not worth pursuing.
Salim
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murphysf (02-02-18)
02-02-18, 10:58 AM
#3
Pit Crew
Thread Starter
The thought process is that VVTI can make the valve timing such that it can potentially hit the pistons once the synchronization is no longer being enforced with the timing belt.
On lexus V8 engines with VVTI, there are known cases of the interference.
On RX300 some data is available that there was no damage to the piston-valve when the timing belt broke. Some attribute it to the rpm being low.
Belt can break in many ways, and the worst is when the end snaps off and then the thing is whipped around and the timing belt cover gets destroyed.
My philosophy is change the belt on time. Most likely you will do this twice in your ownership. If you get to do it the third time .. great for you! by postponing you essentially do not get to skip one. Compare that to oil change .. where over long term ownership you can save about 5-10 services.
Other thing to consider is the drive train of the belt. Rollers are lubed for life and their life is not indefinite. Mine started turning blue when I did the first service at 90k. Although the tensioner needs examination and can be reused, but I change that too as the additional cost is relatively low and it is the leading cause of belt skipping teeth.
Good luck with your quest to find the answer, but my 2c says not worth pursuing.
Salim
On lexus V8 engines with VVTI, there are known cases of the interference.
On RX300 some data is available that there was no damage to the piston-valve when the timing belt broke. Some attribute it to the rpm being low.
Belt can break in many ways, and the worst is when the end snaps off and then the thing is whipped around and the timing belt cover gets destroyed.
My philosophy is change the belt on time. Most likely you will do this twice in your ownership. If you get to do it the third time .. great for you! by postponing you essentially do not get to skip one. Compare that to oil change .. where over long term ownership you can save about 5-10 services.
Other thing to consider is the drive train of the belt. Rollers are lubed for life and their life is not indefinite. Mine started turning blue when I did the first service at 90k. Although the tensioner needs examination and can be reused, but I change that too as the additional cost is relatively low and it is the leading cause of belt skipping teeth.
Good luck with your quest to find the answer, but my 2c says not worth pursuing.
Salim
I just wanted to explore the topic but will take your advise and not pursue the conversation (there are other things to worry about).
Thanks again!
02-03-18, 08:37 AM
#4
Lexus• 2.5L Non-Interference
• 3.0L V6 Non-Interference
• 3.3L V6 Non-Interference
• 3.0L Inline 6 (1992-97) Non-Interference
• 3.0L Inline 6 VVT-i (1998-2006) Interference
• 4.0L Interference
• 4.3L Interference
• 4.7L Interference
http://yourcarangel.com/2014/07/inte...complete-list/
• 3.0L V6 Non-Interference
• 3.3L V6 Non-Interference
• 3.0L Inline 6 (1992-97) Non-Interference
• 3.0L Inline 6 VVT-i (1998-2006) Interference
• 4.0L Interference
• 4.3L Interference
• 4.7L Interference
http://yourcarangel.com/2014/07/inte...complete-list/
02-04-18, 12:45 AM
#6
Agree with Salim....not worth pursuing. Have been reading responses to this question for at least a decade. Hotly debated by many with impressive credentials but no clear consensus.
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