Knockedy Knock...somewhere??

[Dave]

I hear what sounds to be a bottom end knock. It was just brought to my attention about 2 weeks ago, on my way home from the track.

I did have my manual switch turned on for my cooling fan, and whenever I turn my switch on for the fan, the engine sounds like its going to die but then comes back to life. The oil pressure, water temp, and volts stay the same though...I dont know if this is relevant or not. This was the only time Ive seen the oil pressure light come on, and it happended only at 3 stops.

But anyways, the knock has been there ever since, it hasnt gotten louder, hasnt changed at all, it does kind of go away at higher RPMs though. Its not really a knock at all, its almost like a ticking.

Any clues what it is?? My guess is it's wrist pins.

Oh BTW. Its an 89 Auto. Spirit Intercooled, with 98,000 miles.

[turbovanman]

That would be my guess, Wrist pin noise! If your oil pressure is fine, then your bottom end should be good. What is your pressure?
Have you checked the torque converter bolts?

[Dave]

Uh...oil pressure at idle, on the stock gauge is a little under half, closer to the lower side of the marker. I will be putting a mechanical gauge in around 2 weeks, but for now thats all I know.

How the heck would I check my torque converter bolts?

Thanks for the quick response, by the way.

[Phreakish]

pull the lower inspection plate and check to see if the converter bolts are all right...

I might suspect the lifters, I had a bad set that would collapse at high revs in my rampage... Then it would sound like hell for an hour or so, and go away at higher revs...

[Dave]

Quote:

Originally Posted by Phreakish pull the lower inspection plate and check to see if the converter bolts are all right... I might suspect the lifters, I had a bad set that would collapse at high revs in my rampage... Then it would sound like hell for an hour or so, and go away at higher revs...

hmmm...I should of checked the lifters when I had the head off...But how do I pull the lower inspector plate?? I have never even heard of that.

Then when I get the plate off, how do I know the bolts are alright??

[als]

there are 2 ways. one way is to use a screw driver to hold tooth wheel or starter drive gear. then thight the converter bolts if they move they are loose/ some people use loc,tight / to get to the flex plate there are 3 bolts one 10 mm bolt then the other 2 are at the mounts they may have a 15mm head or 18 mm. they should be 15mm then work the cover off . thats the hard part/ as it goes up by the trans / block. if you need jack stand i have some you can use. cause we don,t want you dead. the other way is have someone hold a socket on the crank bolt by the timeing belt. i,ve tryed can,t do it by your self.ALS

[turbovanman]

Quote:

Originally Posted by als i,ve tryed can,t do it by your self.ALS

You can do it by yourself, do it all the time,

[als]

how tall are you? i can,t reach the crank pulley with a ratch on it and turn a wrench on the converter/ my arms are all the way out no power? ALS o the shift thing bolts in they have one in town so i need boot too so i will go pull it and get extras.

[dwh4784]

I've done it myself too, and I never used the crank pulley. I grabbed any of the TC bolts I could get with a closed end wrench and turned it like that. It was harder on my 85 with only 3 bolts than my 90 with 4.

[Dave]

Well we are pretty sure it's not the torque converter bolts, or anything around there. The noise is definately in the engine.

[Jckrieger]

It could also be your pistons themselves. Almost every 2.5L I've seen has a noisy bottom end due to the fact that the piston skirts are so damn short. Once the bore or skirt wears just a little, the piston starts rocking and making all kinds of noise. Does the noise get quieter as the engine temp increases?

[Dave]

No, the noise gets louder when it warms up.

[Jckrieger]

Uh oh, then it could be a rod bearing or a wrist pin. So much for my piston slap theory

[Dave]

Oh well, it's going to OhioRob's on Sunday.

[turbovanman]

Quote:

Originally Posted by Jckrieger It could also be your pistons themselves. Almost every 2.5L I've seen has a noisy bottom end due to the fact that the piston skirts are so damn short. Once the bore or skirt wears just a little, the piston starts rocking and making all kinds of noise. Does the noise get quieter as the engine temp increases?

Yep, the last engine I blew up was really worn, you could hear the pistons slapping, especially at 60 mph. When I took it apart, you could rock them back and forth in the bore, doh! hahahahaha!