That rattle

"HammerheadFistpunch" (hammerheadfistpunch) 07/17/2014 at 16:10 • Filed to: None

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is it pre-detonation? or something else?

Sorry its kind of hard to hear, but its sounds like loose change. Happens when it gets hot only. 0:24-0:43 is best.

Party-vi > HammerheadFistpunch 07/17/2014 at 16:14

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Valvetrain? Didn't you just get a lot of work done recently?

dinobot666 > HammerheadFistpunch 07/17/2014 at 16:14

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By pre detonation, do you mean pinging? Don't you guys run really low octane fuels out in them parts?

Jedidiah > HammerheadFistpunch 07/17/2014 at 16:15

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Park it next to a wall so that the sound echos. It will be easier to tell if it pre-detonation or pinging that way.

It might be, but I cannot tell from this video.

HammerheadFistpunch > Party-vi 07/17/2014 at 16:15

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yeah, complete top end rebuild. Reseated the valves, decked the head, new shims, etc.

Jedidiah > HammerheadFistpunch 07/17/2014 at 16:16

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It might be valve clatter then.

HammerheadFistpunch > dinobot666 07/17/2014 at 16:16

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yes, but it shouldn't matter, its a 9:1 compression engine, should be no where near pinging on 85 especially considering this engine was specifically designed with poor quality fuel in mind and twin knock sensors.

HammerheadFistpunch > Jedidiah 07/17/2014 at 16:18

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I've never experience pinging outside the occasional pop so im not sure what to listen for. I just changed to a heavier oil and Im going to be listening for a while (piston slap is common on these motors) and if that doesn't do it I will put in 93 and see what that does.

Jedidiah > HammerheadFistpunch 07/17/2014 at 16:21

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Nibbles > Jedidiah 07/17/2014 at 16:22

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That's what I'm thinking. Might be time to recheck torque specs

HammerheadFistpunch > Jedidiah 07/17/2014 at 16:22

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yeah, that sounds like my noise.

Party-vi > HammerheadFistpunch 07/17/2014 at 16:23

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Is there any adjustment necessary?

Jedidiah > Jedidiah 07/17/2014 at 16:25

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Try running premium gas and see if it goes away. If it does, retard your timing.

Does the engine run on after you turn the ignition off? Cars that are improperly timed often run on if their timing is too advanced in addition to pinging.

HammerheadFistpunch > Party-vi 07/17/2014 at 16:26

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Its a shimmed tappet, once its set its set and they re-shimmed when they sent the head out to be worked on. Apparently the company they send the head to is top notch (but slow)

DetroitIron > HammerheadFistpunch 07/18/2014 at 02:45

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"Only when hot" means spark knock. If you put in 15-50 oil (Lexus recommendation for Saudi Arabian 1UZ-FE's) and it's still there... it's not valve train. You might need a new radiator as well- airflow is needed to cool the coolant; 20 year old fins in a radiator don't flow well.

Try replacing the knock sensors? The 1UZ-FE V8 has a temperature sensor that tells the ECU to adjust timing based on coolant temperature as well. My wife's '94 SC400 has 2 noises. The first is 20-year old alternator bearings ("rattle rattle rattle" when my foot comes off the accelerator at highway cruise- every other pulley is new) and the other is spark knock (under acceleration even though it's 91 octane). Just had the valve train done. The before/after is no different for these symptoms, but the shim job took care of the "clacking chorus" (best heard at idle when in gear with the brake on). So I'm after the knock sensors and the block's temp sensor (behind the thermostat). For engine problems, check the Lexus Owners forums in the web.

ProTip: The LS400 owners know what's up. Sc400 owners learned from them. So keep in mind common engine/different model in the forums.

HammerheadFistpunch > DetroitIron 07/18/2014 at 11:35

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ITs a new rad (10,000 miles or less) new water pump and tstat as well as a new fan clutch so I don't think its cooling thats the issue, besides it was only 90 yesterday and it was still going nuts. It happened after my top end rebuild. i have the 1fzfe not the 2uzfe but I know I have 2 knock sensors. If the sensors are bad though, shouldn't it throw a code?