speyburn

The timing belt broke on my rx330 the other day. The engine shut off and I pulled over immediately. I know this engine is an interference type engine and there is likely valve damage and possibly more. I was traveling at a low speed when it happened, not sure if that matters at all. Had a mechanic look at it and he gave me two options. Replace the belt, water pump, plugs, etc and hope for the best or find a used engine to swap in. Option 1 his estimated cost was $700-900 with no assurance it would work. Option 2 would cost around $2k ($1k for engine plus 1k for labor and parts to install). Is there a relatively easy way to determine if there is significant enough engine damage to make option one a moot point? I should mention the car had $265k miles on it. I appreciate any feedback you can give me.

Felix

Wow, $700.-$900. is pretty spendy, really should be more like $500. w/ parts.......I'd pull the heads as that'd really be the only way to actually see the valves & pistons then you'd know....Then that'd give you a direction to go vs flying blind. Of course w/ another motor, you'll want to get a t/b kit w/ w/p & tensioner/idler....

Margate330

Wow that's a tough call.

If there is any way you can do the work yourself you wont be out anything but your time and the cost of the Tbelt to start it up and find out if you need to tear the engine down. Need to line up your cam timing marks and get engine at TDC Cylinder 1 intake stroke first tho.
With your mileage at 265k I can see a donor engine looking attractive if you have to pull your heads $$$.

matts6887

usually if the timing belt breaks thats usually bad news because it often results in head damage etc; and at that point u might just be better off looking into a "used" engine to replace it. Felix is right; pulling the heads is really going to be the only way to tell if there is any major head and or valve damage. If there is, again at that point u are probably either better off possibly considering getting a replacement rx(replacement vehicle) which while not cheap might be a better way to go; or just look into a replacement engine.

Lexuswiz

iTrader: (1)

It might not give you the full view but you could try to put a scope down all 6 spark plug holes and see if there is any damage on the cylinder head. Pulling the head would be best but if you're going to go there, might as well get another engine.

DennisMik

You could pull the valve covers off and check the height of the valve ends. This will show more severely damaged/bent valves, but any valves that are very slightly bent could be overlooked.

Felix

Wouldn't do any good if it took the head of one or more valves off thou.....I wouldn't run a motor w/ damaged parts my self.....

matts6887

I agree; i wouldnt run any engine with damaged parts either as that would most likely just make the issue(s) worse.

Audiqv8

Replace the timing belt. Do a leak down test to determine which cylinder(s) is/are bad. It will also help to isolate if it is the intake or exhaust valves. You can manually turn the engine until the cylinder is at top dead center to perform the leak down test.

Felix

Yea, Like mentioned above, you could just replace the t/b & see......But then how many ppl here has see a h/p engine w/ a t/b that has broke & have seen the results? Which is to remove the head & see the destruction & replace some valves & in a lot of cases to replace pistons as well. On this motor which is kind hard to get to bank 1, I'd at least remove the easier to get at bank2 head & have a look. Possibly this 3mz motor is more forgiving then other ones. With the miles on the OP's engine, I'd just replace it w/ another one.

Margate330

Ok time to be honest. lol
Please tell us true condition of this engine before this happened.
Does it have 265K well maintained miles and ran great?
Or is it dogged out and abused, smoked, ran like crap, etc?

PS- I never use anything but OEM TBelts. I've had aftermarket ones last and also had them Snap for no reason 10k miles later- only happened once for me to be believer in OEM Belts.

matts6887

indeed; i too wonder how the vehicle was actually treated; if it was well maintained and ran great etc like margate above said; then that would seem kinda off for it to suddenly snap like that even though yes it can happen. But; if it was ran hard and not maintained well enough, etc then yea that could mean another thing.

matts6887

I kinda agree here; in the end even though its not a cheap "event" to have happen; u might just be better off looking around at some areas salvage yards etc for wrecked rxs that still have a "good" used engine that u could buy and have transplanted.

Audiqv8

I would just replace the timing belt and replace enough parts to just get to the point where I could start the engine up for a few minutes to see if runs without any problem. I remember the RX300 is a non-inteference engine where a broken timing belt would cause no problems other than the inconvenience of being stranded on the road.

RX300 engine bore and stroke 87.5mm 83.0mm
RX330 engine bore and stroke 91.9mm 83.1mm
The stroke is almost identical except that the rx330 is 0.1mm
See the link below for more info.
​​​​​​https://www.clublexus.com/forums/rx-...le-moment.html

Margate330

Only asked about engine condition since that could help with ideas on which way to go and also how long OP plans to keep car.

Waiting to hear OP's update and hopefully good news.