From knowing nothing to having a Thunderbird supercharger on an m20b27i

[Ether-D]

No, I'm running ms2.

Regardless, I just removed the blower belt and the sound is still there. Internal engine something. I've had a sticking valve before, it was much louder than this noise. I've wasted a rod bearing before, much louder than this noise. It sounds to me like rod bearing light. Maybe just early bearing failure (or rod small end like LJ said). I'm gonna pull my other short block to drop in, and start collecting the stroker parts.

[MaxBell]

I was trying to look through the thread, I don't see if you have any updated engine management.

Are you just running the stock ECU?

[Ether-D]

Yeah, I like that. Fingers crossed...

[The Dark Side of Will]

It only makes the noise when still in vacuum. But I'll try that tomorrow anyway if only to check the s/c coupler. Thanks bro.

You said light throttle...
Could be that there's not much torque on the coupler at light throttle, as the engine's pulling air about the same rate the SC is delivering it (and the bypass is open, right?). When you put your foot down, the bypass closes, the throttle opens and the coupler takes a lot of torque, preventing play in it from making noise.

[Ether-D]

Noooooo nit what i wanted to read!!!bring it over this weekend and we can check it out.

I know, right? Yeah, maybe Sunday...

[Ether-D]

It only makes the noise when still in vacuum. But I'll try that tomorrow anyway if only to check the s/c coupler. Thanks bro.

[whodwho]

If the blower is on it's own belt try taking it off and see if it goes away. without boost is should stop any pinging and you can tell if the coupler is going bad by if there is any play when you move the pulley back and forth

[Sideways87]

Noooooo nit what i wanted to read!!!bring it over this weekend and we can check it out.

Sent from my SM-N900V using Tapatalk

[Ether-D]

I think it's getting worse. I put 50 more miles on it this evening and I think the knock/ping/whatthefuckevernoise is lasting til the mid to late 4000s now. I just remember thinking on the last motor that the rod knock was an unmistakeable sound. When it happened, I absolutely knew what the sound was. Now that motor had been run dry of oil and I was expecting that to happen, so that could be why it was so clear to me then. Idk bros. Time will tell.

[Ether-D]

BTDubs, thanks a lot for your suggestions Will and Lorin. It really helps to have people to bounce this shit off of.

[The Dark Side of Will]

I'm also going to disagree with Will and say that i have definitely heard early rod knocks that manifested themselves audibly only at a certain rpm band (usually lower rpm). The engine sounded "normal" at idle and high load/rpm. This did not last forever, and the rods eventually came out to say hi.

I may be thinking of my experience spinning rod bearings suddenly, then.

[The Dark Side of Will]

I thought that maybe the other engine noises were masking it at higher rpm.

There's no masking rod knock. Like I said, it gets way louder at higher RPM.

[Ether-D]

Adjusted valves. About 6 were mildly loose. Made zero difference in noise. I took a vid while driving but you can't hear the noise on the iPhone video. Maybe it's the supercharger coupler, I've heard they will rattle if wearing out. Or maybe I'll get to finally meet my rods. It's not really all that loud, but it's there. I think I'm done for today.

[Ether-D]

Yeah, when I had the rod knock on the previous motor, it started at 2500 I think. But my memory is a little foggy on this. The biggest problem with all of this is that there's nothing "new" about this whole engine. It's a mix mash of old and older parts. Makes isolating problems a little more difficult.

I read that .3mm is the "hot" valve clearance, so I'm just gonna check if one or two valves have had the eccentric slip or something.

I also changed the CPS with a spare I had and no change. Ohm-ed them both well within spec.

[LJ851]

Just pulled 7 degrees of timing across the board and it's the same. It mustn't be pinging right? I'm must be mistaking another sound for ping. Gonna go check the valve clearances now.

If it wasn't making the noise before and 7 degrees removed didn't change it, it probably is not pinging. Probably.

Pinging is a dirty sound without sharp edges, a tattered sound if you will. Unlike a valve tap or rod knock which are pretty tight, crisp sounds. A rod small end or a sloppy piston pin can make a noise that sounds to me like you are describing.

I'm also going to disagree with Will and say that i have definitely heard early rod knocks that manifested themselves audibly only at a certain rpm band (usually lower rpm). The engine sounded "normal" at idle and high load/rpm. This did not last forever, and the rods eventually came out to say hi.