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knocking noise, HELP!

 
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Old 06-15-2010, 03:56 AM
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knocking noise, HELP!

So im driving on freeway around 70mph this old toyota is trying to race me so i put it in third go to around 100 and slam it into second, engine reve'd to about 9k rpm. i got home checked compression it was all normal, but this knocking noise started coming from the head. i did valve clearance but it didnt go away but it deffenatly coming from the head, sounds like a bad valve.any help of what that knocking sound is would be greatly apriciated.
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Old 06-15-2010, 12:18 PM
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Re: knocking noise, HELP!

First of all, street racing threads are not allowed, even if that isn't the purpose of this thread.

Second, when you're at those kind of speeds, you do not downshift that far. You will bend your exhaust valves. Which is what you did. Bent exhaust valves. Probably all of them.
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Old 06-15-2010, 12:36 PM
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Re: knocking noise, HELP!

wait.. what you slammed it into second? I hope on accident and that you meant 4th. yeah.. I mean i do a lil bit of grip, but i dont post on here, unless its abt me vs a supercharged mustang ;D! or on the track. but.. damn. he did bend em. goodluck bud!
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Old 06-15-2010, 06:30 PM
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Re: knocking noise, HELP!

Def bent a valve, in the future when shifting don't use a pistol grip, hold it from the top of the shifter. With a pistol grip you will naturally pull it towards you and you don't want that. Oh and check my signature for engine knock advice!
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if it's knocking, don't answer it. it's prolly nothing but bad news bears.
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Old 06-15-2010, 09:21 PM
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Re: knocking noise, HELP!

Who shifts into 2nd when they are doing 100????
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Old 06-15-2010, 11:59 PM
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Re: knocking noise, HELP!

i forgot to menssion that 2nd gear was an accident,i was trying to put it in to 4th.but wouldnt my compression go down if i bent a valve? the compression is all fine, 220psi on all 4.how would i check if i bent a valve without leak down test or taking the head off?
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Old 06-16-2010, 12:44 AM
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Re: knocking noise, HELP!

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Originally Posted by Andrei View Post
i forgot to menssion that 2nd gear was an accident,i was trying to put it in to 4th.but wouldnt my compression go down if i bent a valve? the compression is all fine, 220psi on all 4.how would i check if i bent a valve without leak down test or taking the head off?
You dont really need to lol. bent valves due to downshifting at a way too high rpm for the gear your in is actually a very common problem. I will put money on the theory of a bent valve or even several.
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Old 06-16-2010, 01:24 AM
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Re: knocking noise, HELP!

A factory condition H22A4 only builds like 190 psi on compression checks unless you were running it until is stopped building (I've never done that on one), but yes you can bend a vavle and still show good compression. Do a leak down test. Set the in pressure to 100. You should see pressure of 98 to 88 psi in the cylinder on a still sound motor. You will be able to hear where the pressure loss is by sound. If it is out the intake you know it's and intake valve, same goes for exhaust. If you hear it from the oil fill cap then you know it's the rings.
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Old 06-16-2010, 01:42 AM
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Re: knocking noise, HELP!

my head is not factory, i swapped it with a jdm head, resurfaced it and used a thin head gasket thats why comp is so high.the car is running fine thats why i dont want to pay to do another leak down test cuz i already did one b4 i swapped the head. will anything happen if i keep driving it with a bent valve ( if its bent)?
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Old 06-16-2010, 01:56 AM
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Re: knocking noise, HELP!

good luck on finding a new engine :D!
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Old 06-16-2010, 02:07 AM
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Re: knocking noise, HELP!

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Originally Posted by Crf450r420 View Post
A factory condition H22A4 only builds like 190 psi on compression checks unless you were running it until is stopped building (I've never done that on one), .
You crank it til the needle stops. That's how a compression test is done.


EDIT (a year later O.o) Wow...I was stupid back then...
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Last edited by havikprelude; 02-22-2011 at 02:57 PM.
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Old 06-16-2010, 02:23 AM
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Re: knocking noise, HELP!

Actually, you would take a warm motor. Remove all the spark plugs and hold the throttle wide open. Then you crank the motor over for 3 pressure pulses and use that number. That would be why your numbers on an old motor are higher than the ones in the factory manual. A new motor will only get to 187 or 185 if you do the process correctly, but in the end if all of the pressures you get are within 10% you are ok either way you do it. You will find that using the factory manual gives you numbers you can't compare to with that method though.
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Old 06-16-2010, 02:34 AM
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Re: knocking noise, HELP!

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Originally Posted by Andrei View Post
my head is not factory, i swapped it with a jdm head, resurfaced it and used a thin head gasket thats why comp is so high.the car is running fine thats why i dont want to pay to do another leak down test cuz i already did one b4 i swapped the head. will anything happen if i keep driving it with a bent valve ( if its bent)?
You can probably get a leak down tester at Harbour Freight for under $30.
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Old 06-16-2010, 05:03 PM
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Re: knocking noise, HELP!

YEA CHECK HARBOR FREIGHT THEY GOT IT BUT YEA BRO SORRY TO SAY BUT U BENT SOME VALVES!
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Old 06-16-2010, 05:59 PM
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Re: knocking noise, HELP!

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Originally Posted by Andrei View Post
my head is not factory, i swapped it with a jdm head, resurfaced it and used a thin head gasket thats why comp is so high.the car is running fine thats why i dont want to pay to do another leak down test cuz i already did one b4 i swapped the head. will anything happen if i keep driving it with a bent valve ( if its bent)?
You will be in the market for a new engine..come on bro
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Old 06-19-2010, 07:14 PM
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Re: knocking noise, HELP!

but it only sounds like the knock is coming from second cylinder, and the compression is all fine.will i loose compression over time when those bent valves wear out?
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Old 06-19-2010, 07:38 PM
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Re: knocking noise, HELP!

newENGINE! :D! TIME FOR TURBO BUILD?!
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**** son, who knew floww could actually flow?
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Old 06-19-2010, 07:45 PM
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Re: knocking noise, HELP!

f*ck preludes all i been doing is fixing it for the past 2 years ill just sell that peace of ****.
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Old 06-20-2010, 02:35 AM
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Re: knocking noise, HELP!

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f*ck preludes all i been doing is fixing it for the past 2 years ill just sell that peace of ****.
slow down there buckaroo; theres 500+ PPL THAT LOVE PREUDES :D
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**** son, who knew floww could actually flow?
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Old 06-20-2010, 12:58 PM
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Re: knocking noise, HELP!

Sorry to say it, but the shifting part is driver. So, you are the cause of the issue on this one.
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Old 02-22-2011, 03:39 AM
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Re: knocking noise, HELP!

same problem for me shifted from 4th to 3rd when it was almost at the redline.ment to shift into 5th. now when i start it cold no problems but when it gets warm theres a knocking.im completely new to engines.so bent valves?
i was planning on rebuilding the engine at a mechanics class this summer just so i could learn about engines and to reset my odometer, but now i guess my valves are bent so no driving untill i rebuild it?
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Old 02-22-2011, 05:29 PM
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Re: knocking noise, HELP!

sounds like vavles 2 me
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