Resolved 1G - L19 Rod Bolt stretch

[Anfurnyy]

I've got some aluminum rod questions.

R&R Rods
Im getting around to torquing my rod bolts (L19) to check bearing clearances. I have a bolt stretch gauge that i'm using, torquing in sequences and checking the stretch and retorquing if need be.

I measured an untorqued L19 rod bolt, zerod out the gauge, Oiled the bolts with 30 weight (as per instructions that came with the rods) torqued the rod bolts to incrementally to 50ft/lbs. I checked the stretch and there is about .004" variance between the 2 rod bolts. one at about .0055, and the other at .001.

I double checked my Zero point with referenced Rod bold and it was good.

I broke them both loose and retorqued them again, both to 50ft/lbs and they stretched a little more again one to .007 and the other to .003. I stopped right here with this rod.

I moved to another rod and did all the same steps but torqued them to 40ft/lbs this time and almost the same variance. One to .0055, and the other to .002..

Double checked my torque on the bolts again at 40ft/lbs and it was right, and checked the Zero with the referenced bolt and it was zero again.

I noticed that the side that seemed to be stretching more was the side with the "R&R" Branding on it. Could the orientation of the bearing make a difference or is there REALLY that much of a difference between the stretch of 4 sets of bolts?

Pictures are in order of: 1st rod measurements, checking the zero with reference bolt, and 2nd measurements.

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[DSMPT]

Did you torque each side alternately in 3 steps? Assuming the bolt/rod threads are totally clean and lubricated enough, try to put a little more torque and see how it stretches. I think you are not torquing enough. The torque number would probably be somewhere approx 55-65 ft-lbs, depends on the bolt and the torque wrench.
R&R recommends .0065-.0070” stretch for the 3/8 L19, so to torque until the stretch number reaches that recommended number but don't exceed 75 ft-lbs. For instance, some bolt may have 55 ft-lbs, some 65 ft-lbs but that's not a problem if the both bolts have the same stretch. IMO if you exceed 70 ft-lbs and the bolt stretch is still far from the recommended number, you should inspect the bolt/rod, may need to replace or recondition.

 

[Anfurnyy]

First off Thanks for the reply, Its been bothering me all day

Did you torque each side alternately in 3 steps?

Yes. I snugged them both with a small ratchet (no torqued), once to 20 ft/lbs, then 35, then 50 alternating sides for the first one. The 2nd one i followed the same thing, just smaller increments.

Assuming the bolt/rod threads are totally clean and lubricated enough,

I cleaned them well and inspected the threads on both the rods and the bolts. Cleaned the rod threads out with just brake cleaner but i did NOT run a chase through it, although i can finger thread them in all the way with zero issues. I literally dipped the bolt up to the Head of the bolt into 30w oil and then threaded them in so i hope it has enough oil.

try to put a little more torque and see how it stretches. I think you are not torquing enough. The torque number would probably be somewhere approx 55-65 ft-lbs, depends on the bolt and the torque wrench.
R&R recommends .0065-.0070” stretch for the 3/8 L19, so to torque until the stretch number reaches that recommended number but don't exceed 75 ft-lbs.

Ill give it a go, after i RE-torqued the first set using the same 50 ft/lbs, one side stretched to .007 already. I just don't want to overstretch them just trying to check my bearing clearances.

For instance, some bolt may have 55 ft-lbs, some 65 ft-lbs but that's not a problem if the both bolts have the same stretch. IMO if you exceed 70 ft-lbs and the bolt stretch is still far from the recommended number, you should inspect the bolt/rod, may need to replace or recondition.

This is really was i was looking for. If it was even possible to get THAT much variance in stretch between 2 different bolts with the same torque.

So really just torque them till they stretch within specs, AS LONG as it doesn't exceed 75ft/lbs?

 

[DSMPT]

This is really was i was looking for. If it was even possible to get THAT much variance in stretch between 2 different bolts with the same torque.

I am not sure how much difference is too much but from my experience, max 10 ft-lbs difference could be possible. I had one rod like one bolt had 59 ft-lbs and 68 ft-lbs to reach the same stretch number.

So really just torque them till they stretch within specs, AS LONG as it doesn't exceed 75ft/lbs?

Not to exceed 75 ft-lbs is what R&R say, so shouldn't exceed that.

 

[jed344]

Long as you stay under max TQ and get the stretch to recommended all should be well. I have had rods before that where almost 10 ft-lbs apart per bolt.

 

[Anfurnyy]

Long as you stay under max TQ and get the stretch to recommended all should be well. I have had rods before that where almost 10 ft-lbs apart per bolt.

Thanks! That's super helpful. I guess I'll just keep torquing.

 

[Anfurnyy]

So I took everyone's advice and here was the result. Keep in mind I still never went passed 75ft/lbs

Rod 1:
1st bolt- .007 @ 55 ft/lbs
2nd bolt- .0035 @ 73 ft/lbs

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Rod 2:
1st bolt- .0065 @ 55 ft/lbs
2nd bolt- .0035@ 73 ft/lbs

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Im really not sure what I'm doing wrong honestly..

Pictures are in order of the listed above. I double checked my zero again before hand and it was right. I'm not putting any pressure on the stretch gauge, just holding it's weight. I might reach out to R&R and see what they say.

 

[DSMPT]

Yeah it looks something is not right. Maybe bolt itself or rod side. Better contact to R&R.
Another thing I can think for now is maybe bearing is the cause. Did you check the stretch number without bearings? Maybe the hole on bearings are too tight against the pin? then bearings are not crushed as it should. That's why you get the right number only on the first bolt, so I would try without bearings.

 

[Anfurnyy]

Yeah it looks something is not right. Maybe bolt itself or rod side. Better contact to R&R.
Another thing I can think for now is maybe bearing is the cause. Did you check the stretch number without bearings? Maybe the hole on bearings are too tight against the pin? then bearings are not crushed as it should. That's why you get the right number only on the first bolt, so I would try without bearings.

I didn't think to try without bearings. I'll give it a go. Thanks for the idea

 

[DSMPT]

I didn't think to try without bearings. I'll give it a go. Thanks for the idea

Also maybe you should start to tighten bolts from the 2nd one (the one didn't get the right number), then if the 2nd bolt would get the right number, the issue is probably not the bolt or rod itself.

 

[Anfurnyy]

Also maybe you should start to tighten bolts from the 2nd one (the one didn't get the right number), then if the 2nd bolt would get the right number, the issue is probably not the bolt or rod itself.

I'll try it from the 2nd side first on the 3rd rod. I was also just thinking about the bearing thing. Would it would really matter if the bottom bearing in the cap wouldn't spin, because it would just force the upper bearing to spin right?

From what I understand, these ACL bearing ends don't perfectly match where the cap meets the rod. Due to the dowel they are spun a little bit inside the rod journal? Like so:

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[DSMPT]

Maybe you didn't enlarge the hole properly (the bottom bearing is not in its position). In the pics I see no crush height in one side and too much height in other side. Should try to check without the bearings. I think that's the cause.

 

[DSMPT]

This is just my guess.
As the hole should be the green but when you enlarged the hole maybe it got like the red. On top, it looks the same location but the angle may be different and the hole location at back side slightly got different from the pin location.

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[Anfurnyy]

Maybe you didn't enlarge the hole properly (the bottom bearing is not in its position). In the pics I see no crush height in one side and too much height in other side. Should try to check without the bearings. I think that's the cause.

Are the ends of the bearings supposed to be even with where the cap and rod meet? Judging by where the hole is in the bearing I'm not sure that's possible unless you oblong the hole.

This is just my guess.
As the hole should be the green but when you enlarged the hole maybe it got like the red. On top, it looks the same location but the angle may be different and the hole location at back side slightly got different from the pin location.

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This very well could be part of the issue or maybe the entire issue. I didn't use a drill press or anything. I actually just drilled them by hand.

 

[DSMPT]

Are the ends of the bearings supposed to be even with where the cap and rod meet?

Not exactly even, that's the crush height. But both sides are supposed to have the same height. So the pics tell that the hole location on bearing is off. One side has zero crush height and other side has too much crush height and the bearing on the cap is locked by a pin, so it doesn't slide. This means bearings won't be radial pressured evenly after putting torque. That's not good.

This very well could be part of the issue or maybe the entire issue. I didn't use a drill press or anything. I actually just drilled them by hand.

Anyways should try to torque without bearings. If both bolts would have the recommended stretch number, then the bearing is the cause. If the result would be the same without bearings, then the issue may be the bolts or bolt threads on rods.

 

[Anfurnyy]

Anyways should try to torque without bearings. If both bolts would have the recommended stretch number, then the bearing is the cause. If the result would be the same without bearings, then the issue may be the bolts or bolt threads on rods.

Torqued without bearings today and got similar results as before.. looks like Ill be reaching out to R&R on Monday.

Bolt 1- .0065 @ 55ft lbs
Bolt 2- .0045 @ 73 ft lbs

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[DSMPT]

It looks it got more stretch but not enough. Yes you should ask R&R. They may need to inspect it. Please report back to us.

 

[Anfurnyy]

So here's the update after reaching out to R&R via email first, I called later.
Basically he said he doesn't even measure stretch, he cleans and lubes the bolts with Lucas 50w and torques then to 75ft/lbs.

I asked him on the phone about re-torquing after some time and he said nope, he never has and hasn't ever had issues.

I did end up buying 2 new sets just to be safe but I don't think I really needed to since I didn't torque over 75ft/lbs.. or maybe it's more about pulling threads out of the aluminum rods?

Here was our email chain:

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[bastarddsm]

From what I saw using a strech gauge, is you need to zero the gauge on each bolt. On ARP2000 bolts new out of package there was up to 0.005" variation. Also you have to be very deliberate and consistent when using the gauge to make sure it reads correct. It's almost better to have 2 people one holds gauge, other torques with a wrench.

 

[bastarddsm]

Reading his email he makes an important point. You have to tighten the bolts to the preload that he had when he honed the big ends. You can do it with torque, BUT, every time you torque and un torque the torque to preload relation ship changes. Also the lube changes it. If he does it to 75Ft*lbs with 50wt, and you decide to use ARP lube, you might only need 50ft*lbs to get the same preload. And you better hope your torque wrench is good. If he gave stretch numbers, that's more absolute, and you can use whatever lube you want, and don't really care about torque wrench calibration.

I do mine by strech, and also record the torque so I can verify stuff as a sanity check.

 

[Anfurnyy]

From what I saw using a strech gauge, is you need to zero the gauge on each bolt. On ARP2000 bolts new out of package there was up to 0.005" variation. Also you have to be very deliberate and consistent when using the gauge to make sure it reads correct. It's almost better to have 2 people one holds gauge, other torques with a wrench.

So my question with this is how could you possibly zero AND check stretch with 2 different bolts with the same gauge AND torque in increments? You'd lose your zero point for the first bolt, would you?

Or would you just put one of the markers that spin around the gauge where one or the other zeros at?

Reading his email he makes an important point. You have to tighten the bolts to the preload that he had when he honed the big ends. You can do it with torque, BUT, every time you torque and un torque the torque to preload relation ship changes. Also the lube changes it. If he does it to 75Ft*lbs with 50wt, and you decide to use ARP lube, you might only need 50ft*lbs to get the same preload. And you better hope your torque wrench is good. If he gave stretch numbers, that's more absolute, and you can use whatever lube you want, and don't really care about torque wrench calibration.

I do mine by strech, and also record the torque so I can verify stuff as a sanity check.

I think I understand this. Which is weird why they said use 30w or 50w oil if all you're going for is stretch.

If I had to guess, he probably hones them at 75ft/lbs. But that's just a guess.

I would prefer to do it by stretch but without 2 separate stretch gauges, and the funky ass issues this is all about I don't know what to do anymore

 

[DSMPT]

So here's the update after reaching out to R&R via email first, I called later.
Basically he said he doesn't even measure stretch, he cleans and lubes the bolts with Lucas 50w and torques then to 75ft/lbs.

I asked him on the phone about re-torquing after some time and he said nope, he never has and hasn't ever had issues.

I did end up buying 2 new sets just to be safe but I don't think I really needed to since I didn't torque over 75ft/lbs.. or maybe it's more about pulling threads out of the aluminum rods?

Here was our email chain:

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Probably it wouldn't be an issue if you torque 75 as he said, but the point was how come your bolts didn't get the recommended stretch.
I think he believes it wasn't measured properly. Could be he is right, since many factors could affect the number easily.
Also you should double check the hole position on rod cap side bearings. I think this is really important.

 

[Anfurnyy]

Probably it wouldn't be an issue if you torque 75 as he said, but the point was how come your bolts didn't get the recommended stretch.
I think he believes it wasn't measured properly. Could be he is right, since many factors could affect the number easily.
Also you should double check the hole position on rod cap side bearings. I think this is really important.

He very well could be right. This is the first time I've ever built a motor but I'm not afraid to learn and try my best to do it right.

You're talking about the dowel that keeps the bearing in place? How would one go about checking that? I know it's off centered from the center of the rod cap, because I checked that out too.

 

[DSMPT]

You're talking about the dowel that keeps the bearing in place? How would one go about checking that? I know it's off centered from the center of the rod cap, because I checked that out too.

The dowel pin position is off centered is normal, because you use the oil jet hole on bearing by enlarging.
What I am talking about is the hole on bearing side. According to the pic you uploaded earlier, the hole on bearing looks the position is off (or wrong angle) or maybe the hole is too small?
And assuming the hole has exactly the same diameter as the dowel pin, which means it doesn't slide at all, if you would torque the rod bolts being like this, the bearings wouldn't probably evenly get the radial pressured, or wouldn't be in the ideal position. That may cause some bad things. If the rods are steel, it wouldn't be a big problem, the rod cap doesn't have the dowel pin, so the bearing can slide into its position.

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[Anfurnyy]

The dowel pin position is off centered is normal, because you use the oil jet hole on bearing by enlarging.
What I am talking about is the hole on bearing side. According to the pic you uploaded earlier, the hole on bearing looks the position is off (or wrong angle) or maybe the hole is too small?
And assuming the hole has exactly the same diameter as the dowel pin, which means it doesn't slide at all, if you would torque the rod bolts being like this, the bearings wouldn't probably evenly get the radial pressured, or wouldn't be in the ideal position. That may cause some bad things. If the rods are steel, it wouldn't be a big problem, the rod cap doesn't have the dowel pin, so the bearing can slide into its position.

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I see. I did drill them out with a 3/16s drill bit. It's possible that it could be slightly off. I also know I did some test drills on my OEM bearings and it was MUCH much worse offset than the ACL bearings that are in there now.

So what might be your suggestion then? I don't necessarily trust any local shops around here to drill them for the dowel. Is there a good way to check if the bearings are drilled straight?