Is the 2.0 Protege engine an interference engine??

yeah....have proof? I work at a dealer. all of the protege engines z5, bp, zm, and fs are non-interference. there are sources that have said that the fs IS interference, but it certainly IS NOT. i've seen hundreds of broken timing belts, mostly going between 155k miles and 185k miles... a select few have gone at about 100k-110k



The only major brand in america that produced interference engines is honda. every manufacturer has produced a interference engine at one time. mazda's last and final interference engine was the 3.0L and was in the mazda 929 and the MPV.
 
So why do do many people bend valves?

This. The topic has been debated to death. Bottom line, if the engine was designed to be non-interference, there would be no guys saying, "I broke the belt and bent valves." From reading tons of threads on this over the years, it appears that if you break a belt and higher RPM, you're more likely to bend valves. If you're just puttering around town, you're normally okay, which is why people claim the engine is non-interference. It seems to me that if there are examples of valves bent from belt breakage, you can't call this engine non-interference.
 
It's a non interference motor UNLESS you get the head decked, or have aftermarket pistons. Certain ones. I jumped timing and bent a few valves in my head years ago.Built bottom end, stock head, stock cams. It was bad.
So why do do many people bend valves?
 
yeah....have proof? I work at a dealer. all of the protege engines z5, bp, zm, and fs are non-interference. there are sources that have said that the fs IS interference, but it certainly IS NOT. i've seen hundreds of broken timing belts, mostly going between 155k miles and 185k miles... a select few have gone at about 100k-110k



The only major brand in america that produced interference engines is honda. every manufacturer has produced a interference engine at one time. mazda's last and final interference engine was the 3.0L and was in the mazda 929 and the MPV.

What dealer do you work at, my cousin works for Lou Fusz and my uncle was at Bommarito and maybe still there.
 
I'm one of those guys that had the tb break and bent valves back in 2011. I take blame as I pushed it too far thinking it was non-interference and the damage happened around 164K. No crazy sounds from the engine bay, just cruising along at 70mph on the highway, lost power and pulled off to the shoulder as another member experienced. Had my mechanic swap in a used engine along with other new parts and she runs great now.

Was suggested that the FS is in fact non-interference but at higher mileage, higher speeds and worn parts, s*** can happen?
 
I'm one of those guys that had the tb break and bent valves back in 2011. I take blame as I pushed it too far thinking it was non-interference and the damage happened around 164K. No crazy sounds from the engine bay, just cruising along at 70mph on the highway, lost power and pulled off to the shoulder as another member experienced. Had my mechanic swap in a used engine along with other new parts and she runs great now.

Was suggested that the FS is in fact non-interference but at higher mileage, higher speeds and worn parts, s*** can happen?

Did the mechanic tell you the valves were bent? did you see the bent valves personally? did he put a new belt on the old motor? if not, the valves were probably fine.
 
Yes he did (tore it down to confirm), no I did not and to my knowledge, no. For the record the mechanic is a family friend of my in-laws whom they went to school with and have been going to for 40+yrs and whom I've been using for 20yrs....so I trust him. Also why I paid over $300 to have the car towed from 3hrs away to his garage.
 
Yes he did (tore it down to confirm), no I did not and to my knowledge, no. For the record the mechanic is a family friend of my in-laws whom they went to school with and have been going to for 40+yrs and whom I've been using for 20yrs....so I trust him. Also why I paid over $300 to have the car towed from 3hrs away to his garage.

Well, at least you trust him. all that work i would have just gotten a new head and a new timing belt instead of a whole new motor.
 
Yep and he did suggest that but after talking it over with him and taking into consideration that the bottom end would still have 164K on it and the rear main seal was leaking I opted for a used engine. Picked one up at a local junk yard with 60K miles for $795.
 
Well guess what..the timing belt broke on my daughters 03 protege. The belt was broke in two and shredded. She was in 3rd gear slowing for a stoplight when it happened. Replaced the belt and the car wouldn't start. Did a compression test and sure enough, except for 1 cylinder, compression levels are between 80 and 100. It should be over 120. The valves are not seating all the way because they are bent. The engine is a clearance engine BUT...under the right condition, the valves can "tap" the pistons causing a slight bend in the valves....Doesnt always happen but, it can.
 
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Well guess what..the timing belt broke on my daughters 03 protege. The belt was broke in two and shredded. She was in 3rd gear slowing for a stoplight when it happened. Replaced the belt and the car wouldn't start. Did a compression test and sure enough, except for 1 cylinder, compression levels are between 80 and 100. It should be over 120. The valves are not seating all the way because they are bent. The engine is a clearance engine BUT...under the right condition, the valves can "tap" the pistons causing a slight bend in the valves....Doesnt always happen but, it can.

Yes it is a non interference engine, unless the head has been machined.

I'm sure there's some other condition too
 
Well guess what..the timing belt broke on my daughters 03 protege. The belt was broke in two and shredded. She was in 3rd gear slowing for a stoplight when it happened. Replaced the belt and the car wouldn't start. Did a compression test and sure enough, except for 1 cylinder, compression levels are between 80 and 100. It should be over 120. The valves are not seating all the way because they are bent. The engine is a clearance engine BUT...under the right condition, the valves can "tap" the pistons causing a slight bend in the valves....Doesnt always happen but, it can.

$20 says she downshifted into first. Valve float is about the only way to kiss a valve on an FSDE. I've had a belt break on one FSDE (coming off idle at a stop), no valve clearance issues. Two friends have also broken a belt (one under acceleration getting on the highway), I personally replaced the belt on it in a couple of hours and had him on his way. The other was replaced by the owner and is driving the car today.

I currently am in the middle of rebuilding another FS (I've personally built and repaired several) and can go home this evening and crank the engine over by hand with the timing belt removed, take a video and show you that there isn't an interference issue. If the block or head have been machined, it potentially could, but, again, highly unlikely. My experience over the past ten years with the FSDE is that valve-to-piston clearance issues don't exist.

Also, why did you bump a 3-year-old thread?
 
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