How to tell a non-interference engine@

[wijcc]

How can you tell if the engine in your car is an non-interference engine so if the cambelt snaps it will not damage the engine?
Thanks guys

 

[paradigm]

Can the pistons hit the valves if the valves are down and the piston up?

Yes - interference.
No - non interference.

Externally it would be impossible to tell. You'd either have to know or not.

 

[wijcc]

ok thanks, is there any online sources that can tell if the engine is a non-interference engine?

 

[Clarkey]

which engine and i'll tell you.

 

[wijcc]

1998 mitsubishi 1.6L (from carisma glxi)
1999 mazda 1.5L (from 323 lxi)

thanks

 

[Clarkey]

both of those are interference design.

 

[Nebzor]

Am I correct in thinking that non-interference engines therefore have less compression than equivalent engines that have interference?

 

[Clarkey]

that, or low lift cams.

 

[Dogbreath]

Am I correct in thinking that non-interference engines therefore have less compression than equivalent engines that have interference?

This is not always the case, but designing around this does tend to require compromises such as deeper piston cut-outs.

 

[ShakenNstirred]

How can you tell if the engine in your car is an non-interference engine so if the cambelt snaps it will not damage the engine?
Thanks guys

mine`s camchain

 

[Clarkey]

mine`s camchain

which can still fail...

 

[ShakenNstirred]

which can still fail...

true but a lot less likely, than a belt
your more likely to have a chain tensioner fail than the chain it self
you would have to be very unlucky to have a chain fail(thats why its service life can be over 200k)
or the life of the engine

 

[Deleted member 66701]

you would have to be very unlucky to have a chain fail(thats why its service life can be over 200k)

Tell that to 24v Cosworth owners

To tell if your engine is interference, remove the cylinder head, put no.1. piston to tdc, place 2mm of plastacine on the top of the piston, place cylinder head back on and replace bolts but leave them 5mm from tight, get a spanner that fist camshaft pulley(s) and cut it in half (this is important) - now turn camshaft through 360 deg - stop immediately if the head seems to lift slightly or it suddenly gets harder to turn, lift cylinder head and see if there are any marks on the plastacine - yes - interference, no - not interference.

 

[dalin80]

or have a look in autodata which will take 1/1000th of the time.

 

[wijcc]

thanks guys

 

[paradigm]

true but a lot less likely, than a belt
your more likely to have a chain tensioner fail than the chain it self
you would have to be very unlucky to have a chain fail(thats why its service life can be over 200k)
or the life of the engine

Tell that to DRZ, who had his fail on his BMW 525i.

 

[Sone]

the nissan 1.5 engine in the Almera seems to have huge chain problems aswell

 

[Lopéz]

or have a look in autodata which will take 1/1000th of the time.

This ^^

 

[Lashout_UK]

Cut the cambelt then try and start it.

(nb. Don't do this)

 

[BigglesPiP]

true but a lot less likely, than a belt
your more likely to have a chain tensioner fail than the chain it self
you would have to be very unlucky to have a chain fail(thats why its service life can be over 200k)
or the life of the engine

Not true, Escorts like to fail, the fools didn't use a siamesed chain.



You can try turning the camshaft by hand, with a piston at TDC when you have the belt off. Non interference engines tend to have 2 valves per cylinder too.