Micra 1.6L: timing belt or chain? Interference engine? HR16DE

[MetroMPG]

This is a question that comes up all the time for new cars. Fortunately we just have to look up the Versa sedan /Note specifications, since they both use the same HR16DE engine as the Micra does in Canada.

Answer: It's a chain.

[jeff88]

Is it an interference engine?

[UltArc]

What is an interference engine? The chain seems like it's better than a belt.

[AlphaMicra]

An interference engine is one where the pistons will crash into open valves if the timing belt breaks. Given the compression ratio of 9.8:1, it's likely this is an interference engine. Given that it uses a chain instead of a belt, it's unlikely this would ever be an issue.

[jeff88]

How is the compression ratio linked to the (non)interference design?

If it is an interference with a chain, somebody someday will have an issue, but it will be an anomaly at worst. More than likely user error.

[AlphaMicra]

How is the compression ratio linked to the (non)interference design?

Interference engines often have higher compression ratios, and the 1.6L in the Micra is relatively high.

If it is an interference with a chain, somebody someday will have an issue, but it will be an anomaly at worst. More than likely user error.

There are plenty of points of failure on any engine; I can't see the timing chain being any less susceptible than, say, the pumps or bearings.

[jeff88]

Interference engines often have higher compression ratios, and the 1.6L in the Micra is relatively high.

Are you saying that because of the higher strength/unlikeliness of failure from the chain, that the manufacturer can increase CR without worrying about an increase likelihood in breakage?

__________
Also, if one were to open up the engine, break it down all the way to the pistons and find the indents in the piston head for the valves, is that a 100% no doubt about it non-interference engine?

[AlphaMicra]

Are you saying that because of the higher strength/unlikeliness of failure from the chain, that the manufacturer can increase CR without worrying about an increase likelihood in breakage?

I would never make such an absolute assertion.

__________
Also, if one were to open up the engine, break it down all the way to the pistons and find the indents in the piston head for the valves, is that a 100% no doubt about it non-interference engine?

While indentations for the valves may be indicative of a non-interference design, I would again refrain from making an absolute assertion.

[Daox]

It could be interference or non-interference at the compression ratio its at. I had a 1997 Paseo, and it also had a 9.8:1 compression ratio engine and it was non-interference.

If I had to guess, I'd say it is an interference engine though. With a timing chain, you don't have to worry as much as you do with a timing belt. Not adding cutouts in the pistons for valve clearance allows for more optimized piston head design which should increase power and efficiency.

[AlphaMicra]

It could be interference or non-interference at the compression ratio its at. I had a 1997 Paseo, and it also had a 9.8:1 compression ratio engine and it was non-interference.

Huh, that's odd, MSN Autos pegs it at 9.4:1 http://autos.msn.com/research/vip/Sp...eo&trimid=1055

So did Motor Trend: http://www.motortrend.com/cars/1997/...pecifications/