what bolts on an eagle 5.7/6.4/6.2 are torque to yield/one time use?

[michiganpat]

I am really having trouble finding solid info on this. hopefully there's a chrysler service tech that can answer this on here. on my 2011 charger, I had a lifter failure on cyl #5 and the cam wiped with 118k miles. I've got all the parts on the way to fix it. one thing I did do was decide to go from a stock cam to this one by MMX: 5.7 VVT HEMI NO TUNE REQUIRED NSR MDS Performance NA Camshaft by MMX

anyway, they told me the damper bolt, camshaft bolt, head bolts, and rocker arm bolts are all torque to yield and need to be replaced. I know the head bolts aren't, but does anyone know about the others? seems weird that the rocker arm bolts would be (well, any of them, actually).... I asked Sky on one of his Reignited vids on youtube, but he hasn't replied to my question.

 

[DionR]

I can't believe MMX would spread that around. They aren't torque to yield bolts, they use a torque to angle tightening procedure which is completely different. Sky did a pretty good explanation on his last video, I would guess you have seen it?

That said, it does appear that the factory recommends replacing some fasteners after each use. Here is what I find in the 2015-1018 Charger FSM I have.

No idea why they want the oil pan bolt replaced, but I can see some logic in the rod and flexplate bolts. Not because they are torque to yield, but because a failure is more likely. Maybe the oil pan bolts could be easily crossthreaded and cause a bunch of work? And the oil pan and felxplate bolt's don't use an angle method either.

The damper bolt doesn't even have a torque to angle requirement, nor a requirement to replace it.

I checked the procedures for the cylinder heads and rockers and nothing about replacing the bolts, nor anything for the cam bolt.

I would agree that it might be safer to replace those bolts, but I don't believe it is necessary. But just my opinion. I know I don't plan to replace them when I freshen up the motor going in my '73.

Ask Away! with Jeff Smith: The Truth Behind Torque-to-Yield Fasteners and Torque Angle Fastening - OnAllCylinders

 

[michiganpat]

awesome, thanks for the info!

Yeah, I saw his explanation about the head bolts, as well as others.

The only thing I can think of if maybe the oil pan bolts are torque to yield like the rod bolts....which is a real bummer, because I am planning on swapping the oil pump for a new melling M452HV oil pump, and I can't quite get the bolt holding the pickup out with the pan in place.....tho in his hemi truck vid where he did the same thing, but had to pull the pan because of the rear sump, Sky made no mention about replacing the oil pan bolts with new.....

 

[DionR]

The only thing I can think of if maybe the oil pan bolts are torque to yield like the rod bolts....

Just to be clear, the rod bolts are not torque to yield bolts. They are a bolt that has a torque to angle process to tighten them, but that doesn't make them a torque to yield bolt.

I know I am kind of harping on this, but the idea that all bolts with a torque to angle tightening sequence are "torque to yield" bolts needs to die. They are completely different things and unless talking about a 2.2/2.5 FWD Mopar head bolts, the label "torque to yield" should no longer be used.

 

[DionR]

No idea why they would want to replace the oil pan bolts. They can't be a stretch bolt, they are too small and short. Makes no sense, unless maybe a new bolt reduces the chances of an oil pan gasket leak and they are cheap enough (in the mind of the factory) so why not just swap them out.

 

[408 swinger]

I'm guessing the people that sell these parts and cam kits are just covering their ***. I installed a TexasSpeed replacement cam kit on 2015 Ram 6.4. This came with new damper and cam sprocket bolts. I have reused those bolts on countless builds with no issues. With that being said, every fastener does have a service life/limit.


A word of advice on the cam sprocket bolt, be careful when torquing that one. If not careful, you can partially sheer the locating dowel. Ask me how I know.....

 

[michiganpat]

Just to be clear, the rod bolts are not torque to yield bolts. They are a bolt that has a torque to angle process to tighten them, but that doesn't make them a torque to yield bolt.

I know I am kind of harping on this, but the idea that all bolts with a torque to angle tightening sequence are "torque to yield" bolts needs to die. They are completely different things and unless talking about a 2.2/2.5 FWD Mopar head bolts, the label "torque to yield" should no longer be used.

my assumption is if the FSM says DO NOT RE-USE THESE FASTENERS, IF REMOVED A NEW FASTENER MUST BE USED.... they are actually torque to yield (1 time use, you _could_ reuse them, but they won't provide the proper clamp force for the given torque spec anymore)

I suppose alternately it could be because they have a pre-applied patch of locktite, but they could just say to apply locktite before re-installing if that's the case.

I'm a mechanical engineer with 30 years experience, so I'm not flying totally blind.....and perhaps am a little overly cautious

 

[DionR]

my assumption is if the FSM says DO NOT RE-USE THESE FASTENERS, IF REMOVED A NEW FASTENER MUST BE USED.... they are actually torque to yield (1 time use, you _could_ reuse them, but they won't provide the proper clamp force for the given torque spec anymore)

I suppose alternately it could be because they have a pre-applied patch of locktite, but they could just say to apply locktite before re-installing if that's the case.

I'm a mechanical engineer with 30 years experience, so I'm not flying totally blind.....and perhaps am a little overly cautious

I understand, but that type of bolt isn't the only reason to replace it, as you have pointed out.

Here is the last paragraph in the article I linked above:

I don't know, maybe the rod bolts are TTY, or maybe the factory just doesn't trust them. Maybe it is a good application of the term. But I would also bet that way too many bolts are labeled as TTY when they are in fact not. In the end I guess I can't say they aren't TTY, but I still think it is an assumption to say they are.

The label is probably pointless in regards to the rod bolts, but it is important that the factory says to replace them. Which it does not say about any of the other bolts originally questioned here.

 

[michiganpat]

I understand, but that type of bolt isn't the only reason to replace it, as you have pointed out.

Here is the last paragraph in the article I linked above:

View attachment 1716487911

I don't know, maybe the rod bolts are TTY, or maybe the factory just doesn't trust them. Maybe it is a good application of the term. But I would also bet that way too many bolts are labeled as TTY when they are in fact not. In the end I guess I can't say they aren't TTY, but I still think it is an assumption to say they are.

The label is probably pointless in regards to the rod bolts, but it is important that the factory says to replace them. Which it does not say about any of the other bolts originally questioned here.

it wouldn't shock me if the hemi rod bolts are TTY.....looking at the replacement chrylser oil pan bolt kit ($80!) yeah, looks like they have a red loctite patch on them...the also look to be common to a ton of different applications (PN 6508448AA), and stupid expensive.....out of curiosity, what's the install procedure for them referred to in the table you posted, if you don't mind?

 

[DionR]

looking at the replacement chrylser oil pan bolt kit ($80!) yeah, looks like they have a red loctite patch on them...the also look to be common to a ton of different applications (PN 6508448AA), and stupid expensive.....out of curiosity, what's the install procedure for them referred to in the table you posted, if you don't mind?

The loctite could explain the requirement to replace them. Maybe some of the cost to??

Here's what I found for a RWD oil pan:

Looks like there is a separate one for AWD, let me know if you need that instead. Looks like it has a different sequence due to the front diff?