Cold start rattle 2-3 seconds then gone.

[Andratch]

Good catch, so was it the ARP bolts or incorrect install on the m10s? i hope this is no cost to you!
What about the oil pump? did they check that ?

No cost to me. This was with OEM bolts, not sure yet if they were torqued correctly or not.

[BL92]

Good catch, so was it the ARP bolts or incorrect install on the m10s? i hope this is no cost to you!
What about the oil pump? did they check that ?

[bavarian3]

IMO, this *was* catching it. This scenario is a little unique from the typical rod bearing failure. This was likely some combination of improper torque/stretch specs at install, and/or a bad batch of bearings from the manufacturer.

This set of bearings only lasted a few hundred miles, but in that time they started knocking/rattling on cold start when oil pressure was zero, and then after they wore more I started hearing a soft knock above 2k rpm. I’d be shocked if the oil analysis doesn’t come come back with crazy amounts of copper.

I don’t have the car back yet, but I did drive by the shop today and see that it’s parked off the lift so they must just be doing quality checks and test drive now.

Yes. and kudos to you for catching it. In the first video(although it's a video) I really can't hear any abnormal "rattle". In the latest video however, you can hear it.

[Andratch]

please do follow up with your blackstone analysis. curious to see if this could've been caught.

IMO, this *was* catching it. This scenario is a little unique from the typical rod bearing failure. This was likely some combination of improper torque/stretch specs at install, and/or a bad batch of bearings from the manufacturer.

This set of bearings only lasted a few hundred miles, but in that time they started knocking/rattling on cold start when oil pressure was zero, and then after they wore more I started hearing a soft knock above 2k rpm. I’d be shocked if the oil analysis doesn’t come come back with crazy amounts of copper.

I don’t have the car back yet, but I did drive by the shop today and see that it’s parked off the lift so they must just be doing quality checks and test drive now.

[bavarian3]

please do follow up with your blackstone analysis. curious to see if this could've been caught.

[bavarian3]

!! BIG UPDATE !!

I THINK WE HAVE OUR CULPRIT! The noise definitely appears to be rod bearing / bolt related. So, good news on finding the cause, bad news that it isn't a cheap fix for others that might be experiencing it.


The BE bearings were trashed. Note that these had ~300 miles on them, they were installed in January of this year (2024). The stock rod bearings from 2005 looked way better than these. Very, very lucky that the crank was undamaged.

They were all installed and torqued properly, however this was part of the "bad batch" - and it shows.


New WPS bearings going in, and sending the BE's back for investigation.

What the ... f

[Slideways]

my bushings are acl with original m10 screws...has anyone mounted the standard acl?

Redish uses that combo. Here is an example with plastigauge measurement:

[Giulianomitaly]

my bushings are acl with original m10 screws...has anyone mounted the standard acl?

[Andratch]

That's great news, congratulations! Did you do any used oil analaysis after the rod bearing change and after you started noticing the noise?

I captured some oil right before I sent it back to the shop for tear-down. That oil was the same oil that was added when the rod bearings were changed in January (granted, only 300 miles ago). I'm going to send that off to Brownstone just for the hell of it.

[Will]

That's great news, congratulations! Did you do any used oil analaysis after the rod bearing change and after you started noticing the noise?

[Andratch]

Stock rod bolts don't work like that. The final torque is an angle torque in degrees (not ft-lbs). They might not be telling the whole truth here.

Ah yeah, good point. Either way, it's pretty clear that the cause of the noise was "bottom end related," either bolts or bearings. I'll post pictures of the bolts as soon as they send them.

[Slideways]

I will ask for pictures of the bolts. They did test the torque before they were removed, and confirmed that they were all still "torqued to spec"

Stock rod bolts don't work like that. The final torque is an angle torque in degrees (not ft-lbs). They might not be telling the whole truth here.

[Andratch]

What did the shop say and are there any pictures of the previous bolts? If they incorrectly torqued the rod bolts, you won't know if it was the bearings or the bolts that led to the bearing failure.

I will ask for pictures of the bolts. They did test the torque before they were removed, and confirmed that they were all still "torqued to spec"

[ac427]

Andratch
Great news. I hope this is definitely the cause of the rattle and the mystery is finally solved.

[Slideways]

"I suspect that the shop was not accustomed to using OEM bolts, and followed the ARP torque spec with OEM bolts, and the two are different."

What did the shop say and are there any pictures of the previous bolts? If they incorrectly torqued the rod bolts, you won't know if it was the bearings or the bolts that led to the bearing failure.