Timing belt question

Guys - My son has an '88 Corola and with about 60k on a replacement belt, it broke one the road. Not knowing much about the breed, is his engine toast? Thanks!

Reply to
TomNoller
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As a general rule, Toyotas with timing belts are non-interference - that is, the valves will not contact the pistons if the timing belt breaks. It is difficult to say whether the engine is toast without looking at it, but if all it has is a broken timing belt, then it should be OK.

Reply to
Ray O

Ray, this is very interesting. Ive heard this about the 3sGTE in my car too, especially with it being a boosted, low compression engine. Ive seen it written in belt manufacturer catalogues as a non-int engine, yet Ive many annecdotal accounts of people having to replace 3/4 of the valves and the guides due to belt failure on this engine. It has cut-outs in the piston crown for the valve.

Is RPM at breakage an issue? Assuming I was redlining it when it failed or is it more a luck thing - assuming the cam doesnt stop at max lift for one valve or whatever?

J
Reply to
Coyoteboy

This is a good question that I do not have a definitive answer for. In theory, engine RPM should not make a difference as to whether the valves will come in contact with the pistons. The clearance between the valves and pistons is so tight that just about any buildup on the pistons or valves can result in contact, and I think this is what causes some bent valves.

Reply to
Ray O

Strange, I was told by several different people that the 1.8 liter engine in my 95 Geo Prism LSI(corolla) didn't have a non-interference engine.

Reply to
Reasoned Insanity

According to this web site:

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the 1995 Geo Prism has a non-interference engine.

Reply to
Ray O

Thanks Ray, thats much appriciated.

Reply to
Reasoned Insanity

You're welcome! Keep in mind that it is not a good idea to find out firsthand whether your engine is interference or free-wheeling so get that belt changed at the mfr's suggested interval.

Reply to
Ray O

Totally agree, non-interference is not a codeword for non-maintenance lol. But its nice to know if you will have to shell out a months salary if it does let go. I'm suspecting the buildup is probably the main cause of clash. As you say, if its designed so the valves cant hit then you would suspect it would never contact. I was just wondering if the valves dont follow the cams exactly at high revs and maybe over-extend?

Reply to
Coyoteboy

Yeah, I'm definitely with you there. There's an old saying about an ounce of prevention but I'm a little too young to remember all of it. Changing the timing belt was one of the many things I did to my Geo when I got it though so I would know exactly where the maintenance was on it. The person I bought it from was supposedly a mechanic, but quite honestly I felt like calling him up and asking him what shop he worked at so I would know not to go there. He didn't have any kind of maintenance records whatsoever. I'm no mechanic by far, but at least I write down when things have been done to my baby.

Reply to
Reasoned Insanity

All of which reminds me ive not changed the belt on my baby yet.

Reply to
Coyoteboy

I've heard of a condition called "valve float" at high RPM, where the they do not close as fast as they do at lower RPM. That's one of the reasons for a redline, I guess.

Reply to
Ray O

Thanks so much, Guys! I've forwarded that website onto my son & hope his mechanic knows what's up.

Reply to
TomNoller

How hard was it to change it ? I have to do this on my 96 prizm as well.

Reply to
RT

I don't know about the 96' but on my 95' I had to take the starter off which is on the back of the engine. It was the biggest pain in the ass to get off. The rest was relatively easy.

Reply to
Reasoned Insanity

not close as fast as they do at lower RPM. That's

Just imagine a engine under a heavy load and then kaboom anything and everything happens at the wrong time. Just the kind of thing I bet send racing engine pieces flying.

I remember a customer back in the late 70's that raced those open ocean type race boats. The type with a three man crew. He was the mechanic (rode backwards in the boat) and was hurt bad just from a ignition coil wire coming off one of the engines under full power. I still remember him talking about the engine literally blowing up like its a given.

Reply to
Danny G.

Over the last week, my son's mechanic replaced the belt for about $250 (metro Atlanta) and it's running great. No internal damage. Thanks again, guys!

Reply to
TomNoller

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