Connecting rod data and wrist pin drill hole size!

[turbovanman]

Specs are for Turbo II and CB turbo rods.

Rods are 5.944"
Side clearance is .013"
Big end width-1.011"
Big end bore size-2.086"
Wrist pin .901
Weight 699 grams

Drill hole on top of rod, 3/32 and chamfer hole.

You should replace the rod bolts with ARP bolts when rebuilding the engine, followed by getting them resized. Cheap tip, Mopar 318-360 rod bolts are the same.

[mo' parts]

part numbers for the t2/common block rods are
4323957
4323958

[TurboBuggy]

What does the machine shop actually do when they "resize" a rod? Also what do they do when they shotpeen a rod?

[turbovanman]

What does the machine shop actually do when they "resize" a rod? Also what do they do when they shotpeen a rod?


They mill the cap and rod parting lines down so the big hole is smaller, then they rebore the hole.

Shot peen is when they blast it with ball bearings to work harden the surface.

[zin]

Shot peen is when they blast it with ball bearings to work harden the surface.

Another important effect of shot peening is to reduce "stress risers", these are any sharp edges on the rod that give rise to cracks and the nasty results that follow them. :mad: If you have the time, and the patience, polishing the beam of the rod will help even more (to be done before shot peening). The goal being to eliminate those "stress risers", not to make them pretty, or make them lighter (the beam is the last place you want to remove material). I don't know that our engines rev high enough to really worry too much about pulling a rod apart, unless it's a road race or other endurance racing application that requires the use of stock rods.

Mike

[turbovanman]

Another important effect of shot peening is to reduce "stress risers", these are any sharp edges on the rod that give rise to cracks and the nasty results that follow them. :mad: If you have the time, and the patience, polishing the beam of the rod will help even more (to be done before shot peening). The goal being to eliminate those "stress risers", not to make them pretty, or make them lighter (the beam is the last place you want to remove material). I don't know that our engines rev high enough to really worry too much about pulling a rod apart, unless it's a road race or other endurance racing application that requires the use of stock rods.

Mike

If you look at my blown engine pics, I removed the parting line on my rods and had them balanced.

[MOPAR2YA]

I assume the T2 and T3 use the same rods. My AREA spec sheet has the pin as .901. WOnder of .002 would make a difference.?

[turbovanman]

I assume the T2 and T3 use the same rods. My AREA spec sheet has the pin as .901. WOnder of .002 would make a difference.?

The TIII rods are supposed to slightly different????? but I guess .899 and .901 is close enough. I have seen alot of errors on the engine specs of TIII's thru the tech sheets.

[Directconnection]

I assume the T2 and T3 use the same rods. My AREA spec sheet has the pin as .901. WOnder of .002 would make a difference.?

Yes, .002 is too much clearance.

Pro-sys here at work says .9013 to .9017 is the finished pin bore diameter. Pin size is .9012" that give the possibility of only .0001" oil clearance which is too little. In race engines here with .927 pins, we shoot for .0010 clearance and .0007 on a street performance engine.Piston clearance on a race engine is .0007"

Simon, the other stats sound a bit off... the width is 1.015" and side clearance is .005" to .013" and that accounts for two rods on one journal of course. Center to center is 5.972" and housing bore is 2.0863 to 2.0869. Small end's bore for the bushing is .9679 to .9699.

[Directconnection]

What does the machine shop actually do when they "resize" a rod? Also what do they do when they shotpeen a rod?


1st, you bang out the rod bolts and do other slight prep work to them. Then, you remove material squarley on a cap grinder. No milling or snading... this special griner cuts the rod and caps square to the thrust surface of the rod. Then, press in arps and torque the bolts 3 times per arp requests and measure stretch. Now, because you removed about .002" on the cap and .002 on the rod, the housing bore is tighter and out of round more so than the tired rod was due to fatigue;) The ID is smaller and you use a sunnen rod hone machine that has a mandrel with stones on it that move out via pressure due to pressure settings and such. These stones rotate with te mandrel while being flooded with honing oil and you push and pull quickly the rods back and forth on the rotating mandrel to get and even honing and good cross hatching without taper.

[turbovanman]

Simon, the other stats sound a bit off... the width is 1.015" and side clearance is .005" to .013" and that accounts for two rods on one journal of course. Center to center is 5.972" and housing bore is 2.0863 to 2.0869. Small end's bore for the bushing is .9679 to .9699.


Well I measured the width of my stock TII rod so thats bang on. I measured 1.011" and I measured 2.088 bore diameter. As for length, just going by the books on the length.

I can't find my stock piston and pins to measure the pin diameter.

[Directconnection]

Can't use dial calipers to find the housing bores or pin bores of the rod and pistons. They are not accurate enough. A dial bore guage must be used or the sunnen rod hone gauge. I am sure your rod you measured is in the spec I listed, or close to it... otherwise, the bearing would have spun:eyebrows: