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Is Our Engine an Interference Engine?

Capri to ST

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#1
I assume that it is, but haven't seen anything definitive. I thought of this while participating in another thread about timing belts. If our engine is an interference engine then obviously changing a timing belt on time becomes that much more important.

For those that don't know, my understanding is that in an interference engine if a timing belt breaks the pistons can keep moving while some of the valves may not be moving since the belt that drove the camshaft that moved them has broken. This means the piston and the valve can slam into each other and do a lot of damage to the engine.

Here's a good explanation I found.

https://jalopnik.com/heres-what-interference-engines-are-and-why-they-exist-1823935549
 


travs_st

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#3
With this car having a 10.0:1 Compression Ratio and some language from the service manual, I am pretty sure it is an interference engine. Service schedule says to change the timing belt at 10 years/150,000 miles.


""NOTE: Do not loosen or remove the crankshaft pulley bolt without first installing the special tools. The crankshaft pulley and the crankshaft timing sprocket are not keyed to the crankshaft. Before any repair requiring loosening or removal of the crankshaft pulley bolt, the crankshaft and camshafts must be locked in place by the special service tools, otherwise severe engine damage can occur.""
 


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Zormecteon

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Intuit

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#7
• 1.6L DOHC Non-Interference
• 1.6L SOHC Interference

from http://yourcarangel.com/2014/07/interference-engines-complete-list/

So NO it's not.
If that is what the source says, it is incorrect.

I saw this type of confusion all the time with regard to a line of vehicle, where none of the engine options were ever of interference design.

The cam sprockets may move when the belt is released. (valve springs may be pressuring them to) So it is critical that all instructions are followed to the letter. Do whatever is required to make sure that none of the pulleys are ever able to move once the tension on the belt is released.
 


Zormecteon

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#8
Every source shows that the DOHC 1.6 litre Ford engine is NOT. I cannot find one source that says it is. Perhaps ALL the listings are old and they're for a different 1.6 litre DOHC Ford engine.

Best idea is to follow the manual's scheduled maintainance schedule, which shows to change at 150,000 miles. ..the schedule for interference engines that I've seen generally calls for a change at 60,000 to 80,000.
 


koozy

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#9
Best source is people who actually build these motors, not print from non-ford sources. Contact Mountune, they base their business and build these motors for enthusiasts.

There have been a number of members who confirmed it is interference that had skipped timing issues. It’s also all over the service manual with warnings.

IIRC timing belts have evolved. 100k+ mile timing belts came about in the early 2000’s.


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Perfblue15

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#10
Best source is people who actually build these motors, not print from non-ford sources. Contact Mountune, they base their business and build these motors for enthusiasts.

There have been a number of members who confirmed it is interference that had skipped timing issues. It’s also all over the service manual with warnings.

IIRC timing belts have evolved. 100k+ mile timing belts came about in the early 2000’s.


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As someone who writes service on these engines and that has built a couple of these. They are interference. I lost a head when I timed my first try at one of these motors a tooth off. They are very tight clearance motors and are very much an interference engine. I wish I still had the picture of the destroyed valves to share.

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Zormecteon

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#11
the listings I'm finding then must for for the ZeTec and DuraTec engines and not for the EcoBoost type block.
 


koozy

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#12
As someone who writes service on these engines and that has built a couple of these. They are interference. I lost a head when I timed my first try at once of these motors a tooth off. They are very tight clearance motors and are very much an interference engine. I wish I still had the picture of the destroyed valves to share.

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I believe you!

You're not Greg on Youtube [nutkick] or a couch potato quarterback behind a keyboard [pcpunch] and actually work on your car [wrenchin]
 


Intuit

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#13
the listings I'm finding then must for for the ZeTec and DuraTec engines and not for the EcoBoost type block.
It's the head and its cams that are the difference between interference and non-interference; though small cut-outs in the pistons aren't uncommon.

<< ....... Engine performance is all about breathing and a higher-than-typical compression ratio. Superior breathing requires large valves that open deep into the combustion chamber, and high compression means a smaller-than-typical combustion chamber. This means the valves may need to extend into the area swept by the piston, and that’s where interference may occur. .......>>
 


OP
Capri to ST

Capri to ST

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Thread Starter #14
I asked Ford Performance, and they also confirmed that it is an interference engine. As I said in the original post, I was pretty sure that it was, but it's an important thing to know so I wanted to double-check. Thanks to everyone that gave their input here.
 




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