Oil Filter Stud Disaster

[MisterCinders]

This weekend, while dipping my carbs again for some fresh rubber, etc., I decided to revisit that dodgy oil filter stud.

Pulled the exhaust to make room, laid a catch pan underneath the engine and pulled the filter cover and filter.

The stud in question is at about 4 o'clock looking at the filter cover. The threads were pretty worn and denied a good grip for the nut.

Tried double nutting the stud to back it out. Nothing.

Soaked it in penetrating oil and PB Blaster.

Tried vice-grips. Nothing.

Rinse, repeat several times. Nothing.

Of course, now the stud is stripped to crap, so it HAS to come out.

The next morning, I picked up a torch and tried heating the bolt. Nothing.

Rinse, repeat several times. Nothing.

Then the stud snapped. Awesome.

I'd hoped to avoid drilling out the bolt, but it had to be done. Grabbed my set of lefty bits (no EZ outs, ever). Started small and worked my way up. So far, so good, except that the bolt was never moving, preferring to be bored out.

I taped off each bit for depth, worried that it might punch through. The stud was almost totally bored out when disaster -- the drill slipped, punching slightly through. Oil bled back through the hole (I hadn't drained the pan).

I let the oil flow out of that hole for a good while, hoping it would flush out any metal dust or shavings.

Then I carefully drilled and tapped out the hole for a helicoil. Before installing the coil, I ran a few more liters of oil through the stud hole, to flush out and stray bits.

Then I installed a new stud just hand tight, refilled with oil to see if it leaked past the stud. No seepage, but I haven't run the engine yet to really be sure.

Naturally (for me, at least) the helicoil is not quite straight. That made fitting the filter cover impossible. I used a Dremel grinder to open up the filter cover holes slightly. The extra play helped me navigate the slight change in stud position.

Now, I have every thing in place and fresh oil in the engine. Tonight I can re-install my fresh clean carbs and be ready to start her up.

I did a few searches and noticed lots of posts about "just drop the oil pan" to check things out. Best I can tell, my oil pan won't drop unless I remove the engine. I don't have the tools for that (e.g., no sprocket wrench or lift).

Is there some way to drop my oil pan without pulling the engine?

Should I be terrified of firing her up to the extent there could be some filings/shavings that did not flush out?

[Homie]

I don't think I would be overly concerned about any possible shavings. The way the oiling system works any possible debris would have to pass through the strainer, oil pump AND the oil filter before it got to the rotating parts of the engine. The odds of anything getting past the strainer and filter are slim. Just my two cents worth.

[Nessism]

I don't understand why you had to helicoil if you carefully drilled out the old stud. A simple chase-out with the proper tap should have cleaned up the threads. If you truly drilled though to the crankcase you may have troubles. Some sealer on the stud threads may help, but with that helicoil I'm not sure if that will work. You may have to go up one stud size, no helicoil - drill and tap the aluminum, and then epoxy the stud into the crankcase. Hope that isn't the case, but that's what I'd do if your current repair leaks.

[7981GS]

I agree with Ed on both the heli-coil needing some kind of sealant since the oil was leaking through your new hole and
the stock stud hole can easily be tapped 15-20mm's deeper as I have done it when installing new, longer, grade 12.9 studs to replace the short factory soft studs.

Eric

[TooManyToys]

If there is any oil seepage you can use Loctite 567 to seal both the Helicoil and the stud. It works very, very well.

[MisterCinders]

I don't understand why you had to helicoil if you carefully drilled out the old stud. A simple chase-out with the proper tap should have cleaned up the threads. If you truly drilled though to the crankcase you may have troubles. Some sealer on the stud threads may help, but with that helicoil I'm not sure if that will work. You may have to go up one stud size, no helicoil - drill and tap the aluminum, and then epoxy the stud into the crankcase. Hope that isn't the case, but that's what I'd do if your current repair leaks.

Despite my careful drilling, I managed to bore out the stud slightly off-center. So before going with the helicoil, the drilled out stud hole ended up offset by a hair, with one very thin side of the stud (<0.25mm probably) still in there. I tried tapping out the new hole for 6mm and/or picking out the old stud side first. Neither worked. Whatever was used to install the old stud would not give, and tapping across the two metals (steel stud and aluminum case) went nowhere.

Once I drilled out the larger 1/4" hole for the coil, the old stud piece finally gave way. With the new hole with just aluminum, tapping for the coil was much easier.

So far, I have the new coil and stud in place dry fit (i.e., without a sealant). I refilled the engine with fresh oil and let it sit over night with a white towel beneath to check for leaks. No drips appeared.

Last night I started the engine to move forward with the jetting. After idling roughly - because I will synch the carbs next - off and on for several minutes. There were still no leaks or drips.

Tonight I will have more time to proceed with tuning the pilots to get the idle straight and then vacuum synching the carbs. I'll keep an eye on the filter cover to monitor drips, etc.

If it all stays together through that process and after some riding, I plan to change out the oil and filter once more in a couple weeks. At that point I may back out the new stud to add some RTV or blue loctite to seal and secure it. When I tapped for the current coil, I ended up a bit shallow and should have gone in a little more. Right now the coil is flush with the aluminum, leaving the stud a couple threads out. If the coil sneaks out when I pull the stud, I'll probably tap the hole a few threads deeper, and use some sealant before installing a new coil.

[MisterCinders]

I agree with Ed on both the heli-coil needing some kind of sealant since the oil was leaking through your new hole and
the stock stud hole can easily be tapped 15-20mm's deeper as I have done it when installing new, longer, grade 12.9 studs to replace the short factory soft studs.

Eric

Going back over this, I suspect that the penetration may have been to the side. Since I was working hunched over the ground (don't have a lift), it was hard to keep things straight, level, etc. When the drill popped, it didn't go terrible deep, so I don't think it got 15-20mm behind the stud bottom.

The new stud ended up offset by a hair to outside and at a very slight angle down. Looking at the filter from the front, that places the breach up and to the right.