1fz-fe Non-interference? (1 Viewer)

[silverhorse]

I though I read somewhere that the 1fz-fe is a non-interference motor?

 

[jlg32281]

I'm not sure. I know the 7MGE is a non-interference and it's a very similar setup. Hopefully someone that has torn these engines down will chime in with some real knowledge.

 

[silverhorse]

Thanks jlg32281 and love your sig line BTW!


I found it. According to my Haynes manual, cam installation section.
" This is a non-interference engine and the camshafts must be tightened in this position and later rotated back into the TDC position to allow the trust surface area to mate evenly without the hindrance of the spring pressure upon certain lobes"

 

[Girl und Panzer]

just out of idle curiosity, what IS a non interference engine?

 

[timer00]

Oversimplified: If the timing belt breaks on a non-interference design, there is enough clearance between the pistons and valves to prevent damaging contact. An interference design does not have sufficient clearance between those parts and engine damage would result from a broken timing belt.

Read more: What is the difference between a non-interference engine and an interference engine? How can one tell between the two? | Answerbag What is the difference between a non-interference engine and an interference engine? How can one tell between the two? | Answerbag
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[xoemor]

Nice explanation!

Oversimplified: If the timing belt breaks on a non-interference design, there is enough clearance between the pistons and valves to prevent damaging contact. An interference design does not have sufficient clearance between those parts and engine damage would result from a broken timing belt.

Read more: What is the difference between a non-interference engine and an interference engine? How can one tell between the two? | Answerbag What is the difference between a non-interference engine and an interference engine? How can one tell between the two? | Answerbag
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[jlg32281]

in agreement with the post above. a non-interference motor has enough clearance between valves and pistons that if the valve is at it's lowest point and the piston at it's highest, they never touch. engines that do have interference, the pistons will smash into the valves bending the valves, messing up pistons, etc. its generally not a good thing for pistons to "interfere" with valves to say the least.

 

[firetruck41]

Fortunately we have timing chains, so not much to worry about!

 

[ALCO]

Good to know, and wise that Mr.T designed it this way with chains.

My brother's F22B2 (Honda 4 cyl, interference type) threw it's timing belt at highway speed and after replacement has zero compression. No doubt there is major damage.

 

[TrickyT]

Fortunately we have timing chains, so not much to worry about!

Chains can break too - I've seen plenty, especially in SMC's. Even in 3FE's, which are gear driven, a known failure is where the fibre center section separates from the metal gear portion. For all these reasons, a non-interference design is superior in case of catastrophic failure. The downside is (typically) lower performance for the same cubic inch displacement.

 

[firetruck41]

Chains can break too - I've seen plenty, especially in SMC's. Even in 3FE's, which are gear driven, a known failure is where the fibre center section separates from the metal gear portion. For all these reasons, a non-interference design is superior in case of catastrophic failure. The downside is (typically) lower performance for the same cubic inch displacement.

Anything's possible, but fortunately, reports of broken timing chains on the 1FZ-FE have been few and far between here on 'mud (knocking on wood!).

 

[TrickyT]

Anything's possible, but fortunately, reports of broken timing chains on the 1FZ-FE have been few and far between here on 'mud (knocking on wood!).

Agreed!