problems

boostfreak2011

New Member
Jul 9, 2011
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jersey
my supra when i first started was fine i started the second time when the car reaches 2500 rpm i get a knocking noise in the head and when it passes 2500 rpm it goes away i know its not a rod knock because if it was u will hear it at soon as its on please some help with this
 

hvyman

Dang Dude! No Way Man.
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Apr 17, 2007
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Thats a pretty vague question.

You sure the noise is coming from the head and not something loose that just happens to vibrate at 2500?
 

hvyman

Dang Dude! No Way Man.
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Apr 17, 2007
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If the valve clearance was out of spec the noise would be noticeable all the time.

tho anything is possible.

Are the cam caps in good order and not worn?
 

Nick M

Black Rifles Matter
Sep 9, 2005
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"Rod knock" is a very generic term. Most mean a spun or damaged bearing. If it knocks when you start, and goes away with some engine speed, it is the bearings. It goes away because you have some oil on it. It could be the head itself, with the same condition.
 

hvyman

Dang Dude! No Way Man.
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Apr 17, 2007
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They have buckets and shims. You check the clearance between the bucket/shim and the cam.

Id also pull off a cap and make sure the journal is smooth and not chewed up. 7m cams dont have bearings. they have a special smoothed out surface and over the years lack of maintenance they sometimes get chewed up.
 

supraguy@aol

Well-Known Member
Dec 30, 2005
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Atlanta
Poodles;1733938 said:
Sounds exactly like an early rod knock...

Yup. R.K. isn't always noticeable at all rpms. In fact, it usually reveals itself at light throttle, between 2500-3500rpm, at least in my experience.
Loose shim clearances sound to me like someone typing really fast on a manual typewriter under the valve covers.
 

boostfreak2011

New Member
Jul 9, 2011
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jersey
so lets say it is a r.k. and i caught it early can i just change the bearings. Then car has not been driving since i bought it and when i heard the noise i never started it again.i mean when i bought the car i trailer it home it hasnt seen the road yet since in my hands.
 

supraguy@aol

Well-Known Member
Dec 30, 2005
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Atlanta
jetjock;1733994 said:
Check the crank pulley...

Yup- I had that happen to me too. Sounds exactly like rodknock.

As for changing the bearings, who knows? Kinda depends on what caused the rodknock. Oil starvation could have gouged the crank journals, an out-of-round rod end would have to be resized.