Big M

I have a 1990 Protege LX, DOHC, 181k, everything ran fine.

I was on the highway. I was cruising at around 4k rpm when the car died and the tach went to 0. It looks like it was the timing belt.

Now I'm researching whether this is an interference or non-interference motor. I'm not getting many answers, so maybe someone here can help.

And if it's non-interference, how likely is it that I might still have managed to do some damage?

Thanks.

midnightblue97

No Mazda four cylinder engines are interference designs except for I think the F2.
PRobably didn't do any damage, just line everything up and put a new belt on.

Bill

I have been told by people @ the local Mazda dealership that the LX DOHC is an interference fit engine, but can't confirm it to be fact.
Go ahead and install a new belt and try to start it up. If the valves are damaged already, it's not gonna make a difference. If they're not trashed, let us know!!

greenlantern94

i forget what interference fit means, but i am 100% positive that the proteges have pistons with valve reliefs in them. which means that if the timing belt breaks, you don't damage the valves. you're fine.

Big M

thanks, everybody.

I'm feeling a bit reassured now. All that's left is to put the new belt on and see if it works. I'll let you all know what happens.

UCSBgeek

LOL, they are NON-interference engines, 100%. My belt broke at 91,000 miles (well, looking at the service records, got the car @149,000)... but you get the picture. It was alright.

Big M

IT'S ALIIIIIIVVE!!! IT'S ALIIIIIIVVE!!!

It was idling a bit high, then settled down. Sounds pretty much the same as before...I haven't driven it since it broke on Thanksgiving day (1,2...FIVE days).

It sucks taking a test drive after something goes wrong and you haven't driven it in so long. I always get worried about every little thing that I don't remember from before, probably normal stuff I just tuned out. But aside from my OCD/paranoia, the Protege's back in black, baby!!

So, if anyone's worried, or if you do a forum search and have come across this thread, here's your answer:

1990 Protege LX 1.8 dohc: NON-INTERFERENCE!

Bill

Alllright! That's nice to know about the interference fit.