Staking a pin with center punch

[JHZR2]

This is the “killer dowel pin” on a 5.9 Cummins. They can back out (mine isn’t), so people often put a little metal tab cut from a washer.

Ive read it may be better to stake it with a center punch, but I’ve never done it before.

Would the folks here cut a metal tab and bolt it via the adjacent bolt, secured with red loctite, or else just punch it?

If punch it, what’s the best approach/practice? What size? Use a pointy punch and hit it on the aluminum frame, on at the interface between the aluminum and the pin?

 

[SZR48207]

Thin metal tab to nearby bolt would be the least invasive right?

 

[mattd]

Can you get the bolt out past the gear? I would want a full circle hole instead of slotted in case that bolt ever loosened up

 

[JohnnyG]

What about safety wire? Can the bolt be removed and drilled? That would be my first choice. Looks like there are plenty of solid webs nearby that can be drilled for the stationary side of the wire.

 

[supton]

I'd be tempted to do a metal tab, under that bolt. But I'm not sure about a few things:

• What causes the dowel to back out? There is no force on it, right?
• What is the bolt for? If you put a tab under it, does that screw up a critical torque spec?
• The metal in this area, like the boss I see to the left, what is all this stuff?

I'm wondering if a simple sheetmetal tab could be inserted under the bolt. I'm guessing the dowel has no force to it, so almost anything will prevent it from walking out. Make the metal longer and then put a bend into it (not under the bolt head, but over the rest of its length) so as to add rigidity, if worried.

Alternatively, drill and tap near by, and do likewise. That might be tougher/less desirable.

 

[JHZR2]

I'd be tempted to do a metal tab, under that bolt. But I'm not sure about a few things:

• What causes the dowel to back out? There is no force on it, right?
• What is the bolt for? If you put a tab under it, does that screw up a critical torque spec?
• The metal in this area, like the boss I see to the left, what is all this stuff?

I'm wondering if a simple sheetmetal tab could be inserted under the bolt. I'm guessing the dowel has no force to it, so almost anything will prevent it from walking out. Make the metal longer and then put a bend into it (not under the bolt head, but over the rest of its length) so as to add rigidity, if worried.

Alternatively, drill and tap near by, and do likewise. That might be tougher/less desirable.

There’s no force on it. It just keeps some items lined up. But they can back out and ruin the timing and pump gears.

Sheet metal tabs are sold, but they can be cut from a washer (I have a washer to cut). The question I really had was is it best to use a tab, or just to deform the metal around with a punch, and if so, how?

 

[JimPghPA]

I never worked on one of those, but I would machine a boomerang shaped duel tab so there would be no way it could rotate, but keep the side towards the gear so it does not get into the area of the gear, even though the gear would probably clear it if it did. And then secure the bolt with a strong loctite, Red if there is any chance you would want to remove the bolt in the future, Green if you know it will NEVER have to be removed. And or if you want extend the length of the tab beyond the pin so it is into half round indentation so there is no way it can rotate.

 

[supton]

I'd hate to deform metal and then have to remove the dowel. Not knowing the usage of the dowel I'd go that route. Easier to undo.

 

[JHZR2]

I cut this from a washer. Only issue is I ground it slightly smaller than the bolt head. I’ll red loctite the bolt in. Any concerns?

 

[MasterSolenoid]

Can you get the bolt out past the gear? I would want a full circle hole instead of slotted in case that bolt ever loosened up

I like this idea, along with the 'proper' Loctite to insure the bolt won't loosen.

Oh, I see it's fixed / looks good.

 

[SZR48207]

Is it too thick?

 

[buck91]

Check the temp range but what about a thread locker like vibratite?

 

[ABN_CBT_ENGR]

If punch it, what’s the best approach/practice? What size? Use a pointy punch and hit it on the aluminum frame, on at the interface between the aluminum and the pin?

My recommendation on locator pins based on all types of equipment (FWIW)

Use a drift punch ( maybe 3/16) and sometimes a small chisel and come in from the side and move metal into the recession ( basically tamping it with a mound) with a drop of red or green Loctite.

On the washer you made in a different post as your solution, I do that too but want to point out one thing just so you can be made aware of it. ( its bitten me before)

That appears to be a alloy bolt in a cast housing (don't know if there is a thread insert there or not)

When introducing a washer type with a large cap nut you are introducing 2 more surfaces that can slip and back out plus the dissimilar metals ( with the parent thread being the inferior metal) can create problems holding tension under loads and can work loose.

 

[wpod]

While this is different it but will give you an idea link to proper AR 15 bolt stake

 

[ABN_CBT_ENGR]

While this is different it but will give you an idea link to proper AR 15 bolt stake

Personally I think it a perfect example- exactly what I was describing

 

[JHZR2]

My recommendation on locator pins based on all types of equipment (FWIW)

Use a drift punch ( maybe 3/16) and sometimes a small chisel and come in from the side and move metal into the recession ( basically tamping it with a mound) with a drop of red or green Loctite.

On the washer you made in a different post as your solution, I do that too but want to point out one thing just so you can be made aware of it. ( its bitten me before)

That appears to be a alloy bolt in a cast housing (don't know if there is a thread insert there or not)

When introducing a washer type with a large cap nut you are introducing 2 more surfaces that can slip and back out plus the dissimilar metals ( with the parent thread being the inferior metal) can create problems holding tension under loads and can work loose.

The BCG is kind of what I had in mind, however my concern was the dissimilar metals. That’s why I was fearful to do so.

I went with the red loctite and primer. I torqued to the required 18 ft-lb, plus a few degrees extra.

Though now I’m worried if I did the right thing. The bolt has fewer threads in the base metal now, though it has loctite fwiw.

I’ve put the cover on, and I’m afraid removal will cost me the crank seal. But I sure don’t want to go further than I am right now if I’m going to take it back apart... thoughts?

 

[SZR48207]

What does that bolt hold onto? That's why I asked if your tab is too thick.

 

[ABN_CBT_ENGR]

The BCG is kind of what I had in mind, however my concern was the dissimilar metals. That’s why I was fearful to do so.

I went with the red loctite and primer. I torqued to the required 18 ft-lb, plus a few degrees extra.

Though now I’m worried if I did the right thing. The bolt has fewer threads in the base metal now, though it has loctite fwiw.

I’ve put the cover on, and I’m afraid removal will cost me the crank seal. But I sure don’t want to go further than I am right now if I’m going to take it back apart... thoughts?

That dissimilar metal ( parent being softer) is honestly why you would use that method because it puts a mass there rather than a dimple that the harder pin can often brad flat. ( often times a chisel and notch works too)

If that picture is accurate and you have 5+ threads ( full threads) engaging- you will be fine tension wise from a mechanical perspective.

Removing it ( presumably without heat) with cast threads ( is there a thread insert there?- that would be a bit of a game changer) is going to put some significant stress there but with a good 6 pt socket and a cheater where you can apply even torque unscrewing it, you will most likely be fine). I would recommend if it concerns you to pull it before it fully cures and do the following.

I have learned ( and proven to myself) that in cases with soft metal ( and many other applications) that if I am using a thread locker simple as insurance ( since a properly engineered and tensioned joint is virtually impossible to work loose) I will use no more than 2 threads at the TOP and under the head ( and a light coat at that) to prevent core thread damage and potential wringing.

That has the same level of anaerobic locking and the bolt doesn't care which end you put the glue on

 

[spasm3]

Though now I’m worried if I did the right thing. The bolt has fewer threads in the base metal now, though it has loctite fwiw.

I’ve put the cover on, and I’m afraid removal will cost me the crank seal. But I sure don’t want to go further than I am right now if I’m going to take it back apart... thoughts?

I think you are fine. Looking at the lateral view of the bolt and tap you made, it looks like the tab may have shortened the bolt by one thread course. I don't think the bolt is so close to being too short that the loss of one thread length will cause failure, 1/4 of the bolt, yes i would worry, but one thread, and you have locktite. I think the repair is solid and the tab is ingenious. In hindsight, you might could have ground the tab thinner and or left a longer tab on the back side so it would hit the casting and stop any counterclockwise rotation. But i think its fine as it is.

 

[mattd]

A slightly longer bolt would have been ideal but the loctite should do its job. Wait 24 hours before running the engine