ranta18

Lets run down the possible causes for a knocking noise from a factory S2000 F20C engine. Keep in mind the story of ths engine:
The engine was beat on by the original owner, he traded it in and the dealership beat on it hard, then it was sold. Shortly after a rod bearing went. A completely new block was put in by Honda. It was driven hard and then boosted by a Vortech superchager. It was driven hard boosted and not fully tuned (AEM EMS). The supercharger was removed, engine turned back to stock, and the car was sold to a friend of mine. It has been running fine and all of a sudden there is a knocking noise.

Posibilities:
Valve clearance off
Bent valve
LMA's
Rod bearings
Main bearings
Loos flywheel or tranny bearing (knocking should stop when depressing the clutch)

Others?



Modified by ranta18 at 4:33 PM 8/5/2005

RacerXI

Both of those are possibilities that you have listed. Where is the sound coming from? I'd try to pinpoint the nature of the noise (rough location, head/block) and where it happens (rpm range helps a good bit). Does the sound increase w/ rpm also? Rocker speed & piston speed are quite different also. It could very well be rod bearings from detonation.

ranta18

From what I've been told (I haven't heard it yet, but will tonight) its coming from the block area. They took the pan off and looked at the rods (didn't take the caps off or look at the bearings) and there was little movement and everything looked ok. Rockers looked ok. What else?

Oh... it was also a quart low on oil when the knocking was first heard.

DaveF

common sense would be to check the oil for any "metalics"

ranta18

They said the oil looked fine.

DaveF

was the engine ever apart?

possible hydrolock? is it hard to start? compression test?

maybe they bent some valves ??

ranta18

Honda had it apart when they changed out the block, but you'd think they did everything ok. I believe the previous owner just put the Votech on, ran it, then took it off. No internal mods done. Stock intake. Here is a picture: http://www.rndauto.com/cars/kendall/s2k2.jpg

I'm going to give it a good look over tonight. Just trying to get everyones thoughts on possibilities.

LMA's?

RacerXI

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 &raquo;</TD></TR><TR><TD CLASS="quote">

LMA's?</TD></TR></TABLE>
My car did that exact thing about 2 years ago (or at least I think). The engine had a fairly loud knock at idle. After some driving you could run the car up to 7K or so and listen to the motor as the car geared down. The motor would go from a light tick around 5500 to a loud knock at idle. It's definitely something to consider. That is what I think it was anyway.

ranta18

Yeah, but I wouldn't be alive after doing that. She would KILL me if I drove it or took it to 7K or 8K with it knocking at idle.

ranta18

Motor is FUCKED! I'll post some pictures of the piston. The top/side of it is all messed up, combustion chamber messed up, etc. I guess thats what happens when you boost and don't tune.

RacerXI

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 &raquo;</TD></TR><TR><TD CLASS="quote">Motor is FUCKED! I'll post some pictures of the piston. The top/side of it is all messed up, combustion chamber messed up, etc. I guess thats what happens when you boost and don't tune.</TD></TR></TABLE>pics Did you just decide to take the head off?

ranta18

I came and saw it when they had it all apart. I just took the pictures. Here you go: