Timing belt question

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

TomNoller - 18 Jul 2006 22:20 GMT

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 this Message

Ray O - 18 Jul 2006 22:33 GMT

> 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!

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.

Signature

Ray O
(correct punctuation to reply)

Reply to this Message

Coyoteboy - 18 Jul 2006 22:38 GMT

> > 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
[quoted text clipped - 8 lines]
> Ray O
> (correct punctuation to reply)

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 this Message

Ray O - 18 Jul 2006 23:44 GMT

>> > Guys - My son has an '88 Corola and with about 60k on a replacement
>> > belt,
[quoted text clipped - 25 lines]
>
> J

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.

Signature

Ray O
(correct punctuation to reply)

Reply to this Message

Reasoned Insanity - 19 Jul 2006 01:39 GMT

>>> > Guys - My son has an '88 Corola and with about 60k on a replacement
>>> > belt,
[quoted text clipped - 33 lines]
> valves can result in contact, and I think this is what causes some bent
> valves.

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 this Message

Ray O - 19 Jul 2006 06:37 GMT

>>>> > Guys - My son has an '88 Corola and with about 60k on a replacement
>>>> > belt,
[quoted text clipped - 36 lines]
> 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.

According to this web site: http://econofix.com/tbelt.html the 1995 Geo
Prism has a non-interference engine.

Signature

Ray O
(correct punctuation to reply)

Reply to this Message

Reasoned Insanity - 19 Jul 2006 07:11 GMT

>>>>> > Guys - My son has an '88 Corola and with about 60k on a replacement
>>>>> > belt,
[quoted text clipped - 39 lines]
> According to this web site: http://econofix.com/tbelt.html the 1995 Geo
> Prism has a non-interference engine.

Thanks Ray, thats much appriciated.

Reply to this Message

Ray O - 19 Jul 2006 07:54 GMT

><snipped>
>>>
[quoted text clipped - 6 lines]
>
> Thanks Ray, thats much appriciated.

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.

Signature

Ray O
(correct punctuation to reply)

Reply to this Message

Coyoteboy - 19 Jul 2006 12:01 GMT

> 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
[quoted text clipped - 3 lines]
> Ray O
> (correct punctuation to reply)

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 this Message

Ray O - 19 Jul 2006 16:43 GMT

>> 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
[quoted text clipped - 11 lines]
> 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?

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.

Signature

Ray O
(correct punctuation to reply)

Reply to this Message

Danny G. - 25 Jul 2006 10:56 GMT

>>> 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
[quoted text clipped - 13 lines]
> 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.

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 this Message

Reasoned Insanity - 19 Jul 2006 14:53 GMT

>><snipped>
>>>>
[quoted text clipped - 10 lines]
> firsthand whether your engine is interference or free-wheeling so get that
> belt changed at the mfr's suggested interval.

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 this Message

Coyoteboy - 19 Jul 2006 15:57 GMT

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

Reply to this Message

TomNoller - 19 Jul 2006 23:12 GMT

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

Reply to this Message

TomNoller - 31 Jul 2006 01:21 GMT

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 this Message

RT - 21 Jul 2006 20:00 GMT

>>><snipped>
>>>>>
[quoted text clipped - 20 lines]
>mechanic by far, but at least I write down when things have been done to my
>baby.

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

Reply to this Message

Reasoned Insanity - 22 Jul 2006 01:56 GMT

>>>><snipped>
>>>>>>
[quoted text clipped - 29 lines]
> How hard was it to change it ? I have to do this on my 96 prizm as
> well.

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 a.s to get off.
The rest was relatively easy.

Reply to this Message