csmc711

iTrader: (4)

How much bearing crush would I need to measure the bearing? I am trying to stay away from the TTY point of no return "before" I fully install the rods but also want to get an ID measurement.

redbird555

iTrader: (14)

what do you mean by bearing crush? rod and main cap bolt are not TTY so you don't have to worry about removing them although I would not make it a habit. why not use plastigauge and measure bearing clearance if that's what you're referring to?

Exidous

iTrader: (11)

I'd imagine he means the pressure the top bearing puts on the bottom to hold them in place. Torque to spec and measure. As red mentioned they are not TTY but are TTA and are reusable within reason.

I'd prefer a dial bore gauge over plastigauge for sure and obviously this requires the mains be fully torqued down. Which you can do with the stock bolts.

KCS

iTrader: (20)

The rod bolts are not TTY. Like the main cap bolts, they torque to an angle value (TTA). You can torque them for preassembly and checking clearances.

To answer your question, how much bearing crush depends on your bore sizes. Since bearing crush is the press fit between the bearing OD and the bore ID, if you are thinking of making some sort of mock up fixture, you need the bore ID to be the same as the rod. How exact is dependent on how exact you want your measurement to be. But like I said, there really isn't a need since the rod bolts are re-useable.

csmc711

iTrader: (4)

Hello all and thanks for the replys. For rod cap bolts First Design, I found 15 lb ft first pass and 60 degrees Final Pass. I know what 15ft lbs, but I have no idea what 60degree ft lbs are. So, this leaves me with; is 15 ft lbs good enough to press the upper and lower together and get a true reading with my dial bore gauge?

I have not even got to the crank yet, lol. :/

KCS

iTrader: (20)

No, 15ft-lbs is not enough.

S10xGN

iTrader: (11)

There's no ft-lbs in the degrees. You know what a circle is, right? 60° is 1/6 of a circle. So imagine the bolt is the center of the circle and 0° is straight up. 60° is 2/3 of the way to perpendicular (90°), so you pull the wrench until the handle matches that angle...

csmc711

iTrader: (4)

Yes, I got that, but, if old stock small blocks use 35ftlbs/45ftlbs respectively, period, what is 15lbs + 60 degrees? Does that come out to 35ftlbs or??

ALL fasteners have a TTY point. Not that I have gotten that far, but, depending on the metal used and the diameter of the fastener, you should have a TTY spec. From what I have read above, it seems the rod bolts are TTA. At that particular TTA, how close, if at all are we to the TTY?

If someone was inquisitive enough to find out and know the answer to the question, that would help me determine if I wanted to torque the rod bolts down a second time just to check specs to torque them a THIRD time on final assembly, or, spend more money on this dumpster and buy a new set of bolts.

I would feel comfortable re-torqueing to 15ftlbs all day if thats a good enough crush factor for the bearings.

S10xGN

iTrader: (11)

The thing is, there's no set number that correlates to an angle. My LS7 rods bolts called for 20# and 70°, which I did using an angle gauge. After setting them all, I decided I "needed to know" what the actual torque was. I used a clicker wrench, started out low and increased the setting until the bolt moved as the wrench clicked. They were between 33# and 35#. As Kent stated, 15# is not gonna work...

MuhThugga

Does GM provide a bolt stretch spec on factory bolts?

csmc711

iTrader: (4)

Not that I am aware of. I am sure they have that buried in their testing facility, or, a min spec for who ever is producing/supplying the bolts. Doesn't really answer your question though.

Exidous

iTrader: (11)

You are way over thinking this. This is not a SBC. Torque the bolts to the specified Ftlbs then add however many degrees specified. Most keep to about 6-8 retorque cycles for safety but I have ever seen any documentation about stretch tolerances.

Google "torque to angle indicator" and it may make more sense.