1G New Rods/bearings, stretch, and oil clearances help

[athlete3344]

Good afternoon,

I currently have a set of new Eagle rods (CRS5900MA3D) with King bearings (CR4481XP King XP Rod Bearings-6 Bolt-STD) and Im having a couple of issues:

1. Torqueing rod bolts to 43 ft/lbs (marked Eagle 1.5 38 ARP 2000) with supplied ARP Ultra Torque lube is not meeting 0.0048" - 0.0055" spec. Im getting closer to 0.003-0.0035 at 43 ft/lbs.
2. Rod oil clearances are still a little loose, ranging 0.0025 to 0.0034.

Should I continue torqueing rod bolts to meet stretch spec, then remeasure oil clearances? What would the limit be? I did torque a set of bolts up to 55-60 ft/lbs and measured stretch around 0.004, but decided to stop before going any further (found some evidence on the forums that new bolts were sometimes torqued higher to meet stretch spec).

mic set to 1.7780
	1	2	3	4
rod bore measurement	0.0033	0.0038	0.0037	0.0037
rod bore calc	1.7747	1.7742	1.7743	1.7743
rod journal	1.7713	1.7713	1.7711	1.7712
rod oil clearance	0.0034	0.0029	0.0032	0.0031
rod bolt torque	43	43	43	43
rod bolt #1 stretch	0.0025	0.003	0.0035	0.0035
rod bolt #2 stretch	0.0025	0.003	0.003	0.0035

 

[1990TSIAWDTALON]

What is the engines intended use? Your clearances aren't "bad". Tightening rod bolts more to get clearance specs is a no no. Do what the manufacturer says. If it's to loose for you, you need .001" UNDERSIZE bearings.

 

[athlete3344]

Mainly just a fun car. Not planning on tracking or dragging it. Ive seen most oil clearance recs in the 0.002 to 25ish range.

Im planning to call eagle/arp to get some guidance on rod bolt stretch vs recommended torque. I guess this is where my confusion mainly is - most references ive found have either sent it w/ manufacturer torque rec or use a stretch gauge to get the correct stretch and use the new torque value as a reference.

 

[1990TSIAWDTALON]

.003 is ok for rods. Since you plan on it being a daily sorta car, the undersize bearings would get you into the .002" range and the motor would live a longer life but .003" isn't a bad spec but would be more race oriented.

 

[BLACK'98DSM]

I also wouldn't suggest over torquing the rod bolts. I snapped the head off an ARP 2000 bolt because I followed the wrong torque specs.

 

[1990TSIAWDTALON]

I don't do bolt stretch unless it would be a full race build. You want the correct clearance on the crank journal for the engine to be happy. I corrected my statement to read UNDERSIZE bearings for a tighter fit. OVERSIZE for a looser fit. I am doing a 1st start on a very horsey V8 today, while its almost 80* and that motor has .003" rod bearing clearance. (Crossing fingers as I do every motor, ).
One way or the other, I won't forget this Christmas!
Marty

 

[diambo4life]

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Stretch>Torque reading. I would torque it to the stretch rating and measure the clearance. Just keep in mind that accuracy of torque wrenches can vary quite a bit then there's the issue of technique and lubricant used that can add variation in reading. Stretch is a more dependable method as you're simply measuring length of the bolt.