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+--- Thread: To interfear or not - Interference engines (/showthread.php?tid=11288)
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To interfear or not - Interference engines - FirebirdPhil - 23-08-2020
So there are 2 types of engine "Interference and -Non Interference" - OK Mazda have a rotary design - that's another story.
It is only important to know once your cam belt/chain snaps - is it terminal to your engine or not?
So what does all this mean?:
In an interference design, the valves open enough into the cylinder milliseconds after the piston starts pulling back.
These engines depend upon the proper operation of the timing belt to ensure that the piston and valve don't try to be in the same place at the same time.
Hence the disadvantage this type of design has when a timing belt breaks suddenly. This is generally a bad, bad thing.
A non-interference design means the valves don't occupy the same place as the piston, a broken timing belt will mean your engine stops but probably not a lot else - simples!!
So what type is under your bonnet?
As for Supras...
4M- ???????
5M-GE is non interference
6M-GE Probably not interference.
7M-GE and 7M-GTE are non interference...
1jz-GTE ?????? STAV will know!!
2jz-GE and 2jz-GTE are non interference UNLESS VVTI then they are interference.
Please add to the list, we may have a fair database in a few months????
To interfear or not - Interference engines - P.Lindblom - 23-08-2020
FirebirdPhil 2jz-GE and 2jz-GTE are non interference UNLESS VVTI then they are interference.The GTE is non interference, but if you snap the timing belt on a GE you'll get a valve salad
Edit: Sorry, you're absolutely right. I was thinking about the IS300 which has the VVTi-version.
To interfear or not - Interference engines - purplewitch - 23-08-2020
Phew.... when I read the title I thought you were announcing you'd joined Gary Glitter's fan club lol
To interfear or not - Interference engines - Phil01 - 23-08-2020
purplewitch Phew.... when I read the title I thought you were announcing you'd joined Gary Glitter's fan club lolor as it appears The Jimmy Saville fan club, (dirty *******)
To interfear or not - Interference engines - purplewitch - 23-08-2020
He always was overly creepy, on tv and in person
To interfear or not - Interference engines - toxo - 23-08-2020
It's worth knowing that Toyota's non interference design is only *just* non interference (and they seem to have stopped doing it now anyway). If your timing belt lets go above 3.5krpm your valves will probably be toast anyway, interference design or not!
3S-GE and GTE are non-interference up until 1999 (BEAMS -GEs from the late JDM MK2 MR2, Rav4 and Altezza are interference, GTE from the Caldina is interference).
1UZ-FE is non-interference up until VVTi was introduced. Hence 2UZ and 3UZ are inteference as they are built around the same engine as the VVTi 1UZ.
To interfear or not - Interference engines - Phil01 - 23-08-2020
toxo It's worth knowing that Toyota's non interference design is only *just* non interference (and they seem to have stopped doing it now anyway). If your timing belt lets go above 3.5krpm your valves will probably be toast anyway, interference design or not!
3S-GE and GTE are non-interference up until 1999 (BEAMS -GEs from the late JDM MK2 MR2, Rav4 and Altezza are interference, GTE from the Caldina is interference).
1UZ-FE is non-interference up until VVTi was introduced. Hence 2UZ and 3UZ are inteference as they are built around the same engine as the VVTi 1UZ.
Nice one John. Very good information
To interfear or not - Interference engines - toxo - 23-08-2020
I guess having big chunks out of the top of the piston surface adversely affects combustion and fuel efficiency, so they stopped doing it around when everyone got bothered about being super efficient.
To interfear or not - Interference engines - FirebirdPhil - 23-08-2020
I started this thread because the IS300 I have bought should in theory need a belt, the change isn't in the service history and the previous owner - admittedly only a short time didn't do it. I did phone Lexus Leeds who the majority of service history is with, they didn't do it, and the next 2 stamps reported a blank......
The belt looks like new - I assume a well worn belt (100K) will look knackered??
To interfear or not - Interference engines - toxo - 23-08-2020
Silly question perhaps but are you actually looking at the state of the teeth, not just the top of the belt you can see if you remove the top cover?