None Interference or what???

**MX6 addict** · 2-2-06, 8:20

This is a copy of a letter in Feb Car Mechanics;
PROBE ENGINE PROBLEM

I thought that I would send a quick e-mail about your December 2005 article on the Ford Probe, with particular reference to the non-interference engine.

I own a 1994 2.5 M-reg Probe that has covered about 80,000. Anyway, I was travelling in a 3Omph limit and probably doing about 25mph at the time. The car stopped; admittedly I turned key no luck. The mechanic did the same. Whether this had any bearing on the outcome I don't know but it was, I felt, the natural thing to do.

Anyway, it took out not the timing belt but the timing belt tensioner, and with it twelve out of 24 valves. Luckily there was no piston damage.

So I had to go out and buy another Probe - a 1998 2.5 model that had done 40,000 miles. They are, though, excellent cars (apart from needing timing belts) and needless to say that one had a service and cambelt change straight away. Phil Gurd Via e-mail

Interesting - do either of the Ford Probe clubs have anything to say about this one? Ed.

Any Comments???

**AdderMk2** · 2-2-06, 8:25

both of the 2g motors are interference, and if the car went more then 60k without having the timing belt changed, its at te fault of the owner....

thats why you are supposed to FOLLOW THE SCHEDUALED MAINTAINAENCE POINTS

**MX6 addict** · 2-2-06, 8:48

I think a lot of owners will be schocked by that, I thought 2G's were none interference!!!

**Hot Cheese** · 2-2-06, 8:55

I definately thought our engines were non-interferance.

Maybe he was just very unlucky, I don't think non-interferance engines will save you every time, but at that low speed you'd have thought so.

**MX6 addict** · 2-2-06, 9:08

I dont think speed is anything to do with it, the pistons and valves hit the same possition each time and if a valve is in the way of the piston when it reaches top, bendy time!!

**Wackyracer** · 2-2-06, 16:27

hell.... i have always read that we have non interference engines as well. In fact my local mazda place said it was!

**Einstein** · 2-2-06, 16:48

I am led to believe the 2.5V6 is non-interference.... that's why there was no damage to the pistons.. why the valves were damaged though is a mystery...

John

**Postal Dude** · 2-2-06, 17:35

According to the Autodata cd it's an interference engine!

Gerry

**chino9656** · 2-2-06, 17:53

I had my mechanic friend look up these engines for me once...he said all the 4-cyl probe engines were interference (F2 and FS engines). he didn't mention the KL's, though...that's a bummer. when the the timing belt broke on my 1st gen GT, it bent all 4 exhaust valves, and damaged one piston...had a little knick on it.

**AdderMk2** · 2-2-06, 18:15

yea. the F2 is technically a interferance motor, but most of us get away with breaking a timing belt b/c the clearances are high. there is very little overlap of the valves into the piston's stroke

dj2501 · 2-2-06, 18:38

advance auto parts said the kl's are interferance when i was buying my timing belt

**Ian F Chequer** · 2-4-06, 15:44

if it was an interference engine you would normally get either a single piston / valve hit (breaking a / the camshaft) or multiple piston valve hits (breaking all / some / maybe 12 of the piston crowns or valve stems).

Telstar claims to have had a cambelt break at 6000 revs and the engine survive, so I am wondering.

ifc

**AdderMk2** · 2-4-06, 15:52

an "interferance" motor is deemed so by placing the piston at TDC and measuring the overlap of the valves into the piston. On a F2T the overlap is very small. More often than not, when the timing belt breaks, it is usually at lower RPM's HOWEVER even at a high RPM.. the cam does not have enough kenetic force to continue to spin once the belt breaks. so it settles down into a "valley" and the valves are not fully extended. this is why it is RARE that an F2T will need the head removed after a timing belt breaks.

My car did it 3 times!

**cruisemad** · 2-5-06, 8:35

Ive bent valves in the past but I had skimmed silly amounts off the heads in an aim to increase the compression ration even higher. In fairness I was passed the 8k rpm point and still pulling though.

Kyle

**Einstein** · 2-5-06, 8:49

Quote:

Originally Posted by cruisemad

I was passed the 8k rpm point and still pulling though.

Be honest... you said you were in double figures

It's a wonder that's all the damage you did...

I would have expected pistons coming out the bonnet

John