1.9L Escort interference engine?

[blkfordsedan]

Does anyone know for sure (definitively) if the 1.9L EFI Escort/Tracer engine is an interference design? I broke the timing belt on the '95 Tracer I just bought for my son. I'm having a local shop do the repair since I don't have the time to screw with it, and their "manual" tells them it is an interference engine. I did some web searching and have seen it stated both ways. I found one source that states the 1.6 and 1.9L were interference until 1991, when they were redesigned to be non-interference and that's why Ford extended the recommended timing belt replacement from 60K to 100K miles.

Can anyone confirm this?

FB71?

[Damkid]

I asked the same thing a while back was told they are non interference

[blkfordsedan]

I've read it both ways, and the shop doing the work said they have seen some that have bent valves and some that were O.K.. They suggested putting a belt on it and see what happens. I told them to pull the rocker arms off or spin the cam so both valves are closed and do a leakdown test by pushing pressurized air into the spark plug hole. I suppose the rocker arms would be loose if the valves were bent, but I've never even had the valve cover off or messed with a 1.9 before.

[Damkid]

From my understanding SOME non interference engines can bend valves IF the timing belt breaks at high RPM

[blkfordsedan]

I've heard that too. Also heard that if a belt breaks at idle on an interference engine the valves may not bend. I guess I don't understand either way. Seems to me it's a dimensional issue: The valves will either hit the pistons at full valve lift and TDC or they won't. I guess if it happens to break at the perfect time when none of the cam lobes are at full lift and the crank stops instantly. Never really thought about it much until now.

[JPT]

Everything I've ever read about 1.9 L Fords says that they are NOT interference engines. You should be able to slap a belt on and go.

I once read that even a non interference engine can still bend the valves if the timing belt breaks at high RPM. Supposedly, the sudden shock of the valvetrain coming to a stop can cause the cam(s) to reverse rotation momentarily and kick the valves open.

I do know that on some engines (Mitsubishis) a definite no-no is to spin the engine over backwards.

[takeone51]

im an avid escort owner, and the newer spi is a non interference engine. Like stated before slap on a belt and go!

[blkfordsedan]

I've found a lot more info confirming it is a non-interference than otherwise. It appears the Gates website calls it interference, which seems to be the source of most disputes. It's amazing how much off-the-wall tales and other stuff you can find on the subject.

[econoaddict]

Customer had a 94 escort with 1.9 towed from our shop last week with 3 badly bent valves, broke a t-belt rolling along at 60ish. He sold it to the scrap metal place

Also have a 1.9 escort head at the shop with battles scars it got when a t-belt broke, the head on the valve looked like it just exploded, little dents and divots all over the chamber of the head. This one was junked as well, the piston had a nice hole in it.

I will also say that I have repaired many with broken t-belts survive and still running great today.

[blkfordsedan]

Customer had a 94 escort with 1.9 towed from our shop last week with 3 badly bent valves, broke a t-belt rolling along at 60ish. He sold it to the scrap metal place

Also have a 1.9 escort head at the shop with battles scars it got when a t-belt broke, the head on the valve looked like it just exploded, little dents and divots all over the chamber of the head. This one was junked as well, the piston had a nice hole in it.

I will also say that I have repaired many with broken t-belts survive and still running great today.

So why is this? I don't understand. Is it a matter of valve reliefs in the pistons (i.e. some had them & some didn't), or are they actually an interference design and it just depends on where everything stops and how much momentum is carried through the crank and cam shafts (i.e. the RPM at which the belt breaks)? Should I pay them the extra hour labor to do a leak-down test?
Maybe it's safest to NOT turn the cam and just pull the rockers off to close the valves, just in case the cam stopped in the perfect spot? I would hate to bend a valve due to performing a leak down test. My belt broke while I was idling at a red light and it died. Of course, I cranked on it many times in an attemp to start it, thinking it was a fuel or spark issue.

[JPT]

To be absolutely safe (and certain that the valves are closed), I'd pull the rockers and then do the leak-down test.

[econoaddict]

To be absolutely safe (and certain that the valves are closed), I'd pull the rockers and then do the leak-down test.

This is what we usually do.

I think the damage is just a matter of where things come to rest vs. rpm vs. how long the crank spins after the break.

We see more that are OK than damaged ones.

[FB71]

'94-'95 1.9s had a piston issue; ie, the pistons would fracture, and chunks would come loose. It would look like a timing belt failure on an interference engine. Also, some 1.9s have been known to drop valve seats, also looking like the same type of failure. 1.9s are freewheel engines, have been since the 1.6 redesign in mid '83. Only the blue valve cover 1.6s are interference engines. All gray and black valve cover 1.6s and 1.9s are freewheelers. However, as stated, at a high enough RPM, the valves can float away from the tappets, and strike the piston face. This is a very unusual occurence in Escort/Tracer products.

[Biff]

for what it is worth, in the Napa parts book, they show the B6 DOHC for the Miata (90-91) as an interference engine.
It is not. Slapped a belt on and away it went after sitting open (someone took the VC off to expose the timing belt) to the breeze for several years under a hood of a Miata at a local bone yard I visit.

[blkfordsedan]

'94-'95 1.9s had a piston issue; ie, the pistons would fracture, and chunks would come loose. It would look like a timing belt failure on an interference engine. Also, some 1.9s have been known to drop valve seats, also looking like the same type of failure. 1.9s are freewheel engines, have been since the 1.6 redesign in mid '83. Only the blue valve cover 1.6s are interference engines. All gray and black valve cover 1.6s and 1.9s are freewheelers. However, as stated, at a high enough RPM, the valves can float away from the tappets, and strike the piston face. This is a very unusual occurence in Escort/Tracer products.

Thanks, that helps.

Thanks to everyone else for their input. I'll post the results when this is all over. This really sucks having someone else work on your car! I want to let them do their thing and not be a pain, but it's driving me crazy!