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Old 04-08-2014, 12:47 PM   #251
MedicDG
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Hmm ... i'm kind of torn because the machine shop saw the crank and said it definitely could use a polishing. You could feel tiny bumps / unevenness in a few of the surfaces. Should I call polishing the crank off and buy a brand new crank?
buy a new one. Not worth it the risk.
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Old 04-08-2014, 04:00 PM   #252
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Ok - I called the machine shop. They use a 600 grit polishing method which should not remove any material from the crankshaft but simply clean the surface up. It is not "micropolishing".
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Old 04-08-2014, 05:27 PM   #253
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anybody have a sti motor for sale
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Old 04-08-2014, 05:33 PM   #254
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buy a new one. Not worth it the risk.
+2

not worth wasting money on polishing...buy a new one and sell yours to someone else that wants to mess with that
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Old 04-08-2014, 08:50 PM   #255
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After the polish recheck and see if it is with factory specs. If so it is good to go.
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Old 04-09-2014, 10:56 PM   #256
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Dang... So I've measured two rods with the King Bearings (STD) and the 7/16" ARP 2000's, and i'm coming up with clearances of .0036 and .0031... Is this normal for new rods? I've got the Brian Crower H-beam rods and the king standard size bearings. What bearings would I need to get around .0025 clearance??

Thanks!
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Old 04-10-2014, 08:12 AM   #257
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Bumppppp
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Old 04-10-2014, 11:25 AM   #258
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Proly from the polished crank?
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Old 04-10-2014, 11:37 AM   #259
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No, I compared the values to the oem spec. The crank was perfectly within spec as far as the crank pins are concerned.

I measured the inner diameter of the rod with bearing (2.0506) installed and subtracted 2.0470". That's how I got the clearances.
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Old 04-10-2014, 11:50 AM   #260
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One thing I thought was weird is I e-mailed Dustin at BC to ask for torque specs / special procedures from them for torquing the ARP2000 rod bolts into the H-Beam rods.

Here's what he said.

Quote:
The Arp2000 bolts use 45 ft lbs. Bring both sides of the rods to 10 lbs and then to 45 in one pull.
Yesterday I loosened all of the rod bolts and caps and put the new bearings in after cleaning both surfaces, and torqued the 7/16" bolt to 10 ft/lbs, and then to 45 ft/lbs with one pull. After taking a peak at the document sent to me, i've noticed that the spec sheet is saying that it should be higher. I'm not sure if by torquing them to only 45 ft/lbs I could have damaged them, if they were supposed to be torqued to 70 ft/lbs etc. The ARP 2000 rod bolts had their ultra torque lube on the studs, just the clarify.

I'm wondering if they need to be tighter, which is causing these larger than usual rod bearing clearances.
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Old 04-10-2014, 12:25 PM   #261
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A 2000 bolt 7/16" diameter thread would need around 80 lbs with moly to get the correct stretch, depending slightly on the length. Typically rods come with torque specs for you to use if you do not have a stretch gage. These torque specs are on average about 15% less than the perfect torque/stretch amount, perfect being 75% of the yield of the bolt. This is not a published fact, it is what myself and other machinists I know have noticed over the years. We think that they supply you with a lesser torque value so that there's no danger of a defective torque wrench or operator to over torque the bolt, surpassing the 75% yield. All rods need proper vetting before being used, checked for correct stretch/torque and then size after reaching the correct torque. That 45 makes no sense to me.
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Old 04-10-2014, 12:30 PM   #262
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A 2000 bolt 7/16" diameter thread would need around 80 lbs with moly to get the correct stretch, depending slightly on the length. Typically rods come with torque specs for you to use if you do not have a stretch gage. These torque specs are on average about 15% less than the perfect torque/stretch amount, perfect being 75% of the yield of the bolt. This is not a published fact, it is what myself and other machinists I know have noticed over the years. We think that they supply you with a lesser torque value so that there's no danger of a defective torque wrench or operator to over torque the bolt, surpassing the 75% yield. All rods need proper vetting before being used, checked for correct stretch/torque and then size after reaching the correct torque. That 45 makes no sense to me.
I should have added that you can't just give them more torque and then measure your brg clearances. You can only do this if those rods have been through the proper inspection by someone who knows what they're doing. It's something that gets overlooked on most privateer builds (and maybe some professional builds??) and IMO is another possible reason for rod brg failures.
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Old 04-10-2014, 12:32 PM   #263
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Originally Posted by Motion Machine View Post
A 2000 bolt 7/16" diameter thread would need around 80 lbs with moly to get the correct stretch, depending slightly on the length. Typically rods come with torque specs for you to use if you do not have a stretch gage. These torque specs are on average about 15% less than the perfect torque/stretch amount, perfect being 75% of the yield of the bolt. This is not a published fact, it is what myself and other machinists I know have noticed over the years. We think that they supply you with a lesser torque value so that there's no danger of a defective torque wrench or operator to over torque the bolt, surpassing the 75% yield. All rods need proper vetting before being used, checked for correct stretch/torque and then size after reaching the correct torque. That 45 makes no sense to me.
Hey Dale - thanks for the info!

Hmm - I just called Dustin, and he said that the actual bolt diameter is 3/8", which is why he gave me the torque specs he did. He said the 45ft/lb for the 3/8" should be right.

How should I approach adjusting the rod clearances are this point?

Last edited by BeastianSTI; 04-10-2014 at 12:52 PM.
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Old 04-10-2014, 01:56 PM   #264
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Hey Dale - thanks for the info!

Hmm - I just called Dustin, and he said that the actual bolt diameter is 3/8", which is why he gave me the torque specs he did. He said the 45ft/lb for the 3/8" should be right.

How should I approach adjusting the rod clearances are this point?
Quote:
Originally Posted by BeastianSTI View Post
Hey Dale - thanks for the info!

Hmm - I just called Dustin, and he said that the actual bolt diameter is 3/8", which is why he gave me the torque specs he did. He said the 45ft/lb for the 3/8" should be right.

How should I approach adjusting the rod clearances are this point?
So when you said 7/16" that was the socket size you used and not the bolt thread diameter? My ARP reference chart gives a torque spec of 50 lbs with moly for a 3/8" 2000 bolt so 45 is still too light. Not to knock anyone but it sounds like there is some guessing or generalizing going on here, not the proper way to build a motor. I can't say it enough, rods need to be vetted before you do anything with them, including setting bearing clearance. If you have too much clearance .001" (.025mm) under brgs will fix it BUT only if the rods are round at the proper torque value.
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Old 04-10-2014, 02:20 PM   #265
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So when you said 7/16" that was the socket size you used and not the bolt thread diameter? My ARP reference chart gives a torque spec of 50 lbs with moly for a 3/8" 2000 bolt so 45 is still too light. Not to knock anyone but it sounds like there is some guessing or generalizing going on here, not the proper way to build a motor. I can't say it enough, rods need to be vetted before you do anything with them, including setting bearing clearance. If you have too much clearance .001" (.025mm) under brgs will fix it BUT only if the rods are round at the proper torque value.
And by round at the proper torque value, you mean that the inner diameter is consistent around all 360* of the rod bearing/rod assembled?

I suppose i'll drop the rods off to my machine shop to have them check them out. What specifically should I ask them to check?
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Old 04-10-2014, 03:35 PM   #266
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Ask the shop if they have a stretch gage and can measure the stretch on your rods and note the torque req'd to get there. Bring them the sheet that you got with the rods, it should give the stretch amount. At this point they need to measure the rods for oor and size compared to the stock spec. Not all shops know that this is req'd, if they are among them, then find another shop.
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Old 04-10-2014, 03:46 PM   #267
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Dang - it really sounds like there isn't a whole lot I can do to put this engine together if everything requires a machine shop to measure stretch of bolts etc... I thought rods would have been OK to just torque to spec in the specified sequence. Becoming a lot more complex :/
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Old 04-11-2014, 10:03 AM   #268
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Hey guys, i'm sure we've all seen that video on youtube where "subaru-mike" assembles the motor:

https://www.youtube.com/watch?v=-gmtEQ1GpmA

I was going to follow this for torquing the case halves together to measure my main bearing clearances.

I noticed that he says go to 37 ft/lbs for the large bolts, and 20 ft/lbs for the smaller ones. This does differ from the manual, but i'm wondering if going to 37ft/lbs could be a substitute for going to 14.8 ft/lbs -> tightening another 90*.

Are there any good resources of tutorials on bolting the case halves together?
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Old 04-11-2014, 10:04 AM   #269
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Quote:
Originally Posted by BeastianSTI View Post
Dang - it really sounds like there isn't a whole lot I can do to put this engine together if everything requires a machine shop to measure stretch of bolts etc... I thought rods would have been OK to just torque to spec in the specified sequence. Becoming a lot more complex :/
Its amazing how the everyday japanese assembly line worker can build running motors isnt it lol.

Dude youre not building a uber precision race motor. These things were designed by engineers to be slapped together with varying degrees of precision.

You can get all crazy with stretch and quantify every little measurement if you want too but its wasted effort for a dd. Just torque that **** to spec and drive it.
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Old 04-11-2014, 10:10 AM   #270
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I plan on putting doing 400 WHP... I've always lived by "do it right the first time, or don't do it at all".

I don't want an aluminum paperweight because I didn't follow the proper documentation. All I know is that the key to a good motor is precision in measurements and torque.

I want to build it properly. Appreciate everyone's guidance on all of this.
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Old 04-11-2014, 11:35 AM   #271
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Originally Posted by BeastianSTI View Post
I plan on putting doing 400 WHP... I've always lived by "do it right the first time, or don't do it at all".

I don't want an aluminum paperweight because I didn't follow the proper documentation. All I know is that the key to a good motor is precision in measurements and torque.

I want to build it properly. Appreciate everyone's guidance on all of this.
You don't want to deviate from what Subaru torqued those case halves to when they machined the mainline so use their specs. The front main is very sensitive to torque because those 2 bolts are shorter.
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Old 04-11-2014, 11:43 AM   #272
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You don't want to deviate from what Subaru torqued those case halves to when they machined the mainline so use their specs. The front main is very sensitive to torque because those 2 bolts are shorter.
Could I throw the cases on the engine stand? I found that the block wanted to move around a lot when I was torquing the bolts before.
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Old 04-11-2014, 04:49 PM   #273
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OK - confirmed with the machine shop that just finished up the heads and what not that they take the bolts right to 37 ft/lbs as well instead of the 17 - > 90* approach.

Everything measured out appropriately - i'm ready for assembly now!!!
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Old 04-18-2014, 10:01 AM   #274
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Assembled the case with crank and rods last night. I couldn't find anything about bearing tang direction, so I put them all facing down.

Waiting for the piston ring filer to get here so I can adjust the top rings in each cylinder and get this puppy together
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Old 04-20-2014, 07:32 AM   #275
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Yup the wrx fsm calls for 37ft lbs i to do it this way.
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