My motor was assembled by my dads machine shop, hes not use to honda motors, but does great work. After 1500-2000 miles my block started to knock. Pulled the motor and here is what we found:

Eagle Rods / ACL Bearings






The clearances were within OEM spec, but on the tight side. Any ideas on what the cause is? Were thinking overheated bearings because of the clearances? Any other ideas?

 

Bearing fatigue,detonation,and/or preignition,excessive bearing load.

 

How does the crank look?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Scott_Tucker &raquo;</TD></TR><TR><TD CLASS="quote">How does the crank look?</TD></TR></TABLE>

yeah, are any of the crank journals scored or anything???

 

i have seen plenty of bearings like that and the crank looked like new.

 

Crank and mains look fine.

 

It looks like those bearings have been pounded out. Those are fatigue cracks. Are you sure it didn't have too much clearance? No heavy detonation?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Scott_Tucker &raquo;</TD></TR><TR><TD CLASS="quote">Are you sure it didn't have too much clearance?</TD></TR></TABLE>

no, the tightest ones were .0008".

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Scott_Tucker &raquo;</TD></TR><TR><TD CLASS="quote">No heavy detonation?</TD></TR></TABLE>

No, it were no signs on the pistons, I have not looked at the plugs. There was no reason for heavy knock. The only thing maybe bad gas.

 

forget assy lube? i prefer honda bearings man i hate acls, let me guess this sht happened before you tuned?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 951BRO &raquo;</TD></TR><TR><TD CLASS="quote">forget assy lube? i prefer honda bearings man i hate acls, let me guess this sht happened before you tuned? </TD></TR></TABLE>

It's not from dry startup.It's not from lack of oil.I've used ACL's with good luck and haven't had these problems.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 951BRO &raquo;</TD></TR><TR><TD CLASS="quote">forget assy lube? i prefer honda bearings man i hate acls, let me guess this sht happened before you tuned? </TD></TR></TABLE>
No. Tuning was done as soon as i turned the key. By Turbogixxer(Kenny).

 

post pics of the pistons, crank journals, and or spark plugs or cylinder head.....

 

.0008" is on the tight end of the spec. I'd go almost double that on a performance build. I targeted mine for .0015" when I built my motor a couple of years ago. Still runs perfect with rev limit at 8750.

Also use a stretch gauge when you torque the rod bolts.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Speed Industry &raquo;</TD></TR><TR><TD CLASS="quote">.0008" is on the tight end of the spec. I'd go almost double that on a performance build. I targeted mine for .0015" when I built my motor a couple of years ago. Still runs perfect with rev limit at 8750.

Also use a stretch gauge when you torque the rod bolts.
</TD></TR></TABLE>

None of the building was done by me or OMG B16. When we get it apart, it will be checked better.

 

any update on this?

 

looks like pitty. might have been caused by contaminated oil.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MeanGreenMachine &raquo;</TD></TR><TR><TD CLASS="quote">any update on this?</TD></TR></TABLE>
Yes. Here https://honda-tech.com/zerothread?id=2038326