Oil channel stud

Hi,
I Finally got around to pulling the head and barrels from my XJ750P to replace the various gaskets and o-rings to try and fix an oil leak from the front of the head gasket area... again!

On putting it all back together... torquing the final bolt, being the rear oil channel bolt with the copper washer I nearly get to the torque spec and then before she torques it decides to stab me in the eye and pull out of the crankcase instead (Popped the top of the dome nut too... sometimes I really hate that damn torque wrench)

Here are my questions.
1. I know I have to helicoil this stud but... being that it is one of the oil channel studs does that make for less surface area to drill and retap?
2. Is there some new technology that I'm not aware off that will magically fix this? (thinking of a chemibolt alternative...)

PSFingers crossed for the latter)

 

I dont think there is a "chemibolt" solution. There are products that make claims (J B Weld as an example) however I think these are used in low stress areas. This should not have happened. Did you make the conversion from newton meters to pounds feet correctly? When was the torque wrench last calibrated? Was the stud screwed deep enough into the block? The latter question is due to popping the top of the domed nut. Studs usually have a min/max depth in the spec.

 

I feel a bit thwarted by my own over zealousness to fix a leak!

I figured there wouldn't be an easy fix but... you have to put the question out there.

I used the specs in the service manual for torque settings, so no conversion on my behalf.

As far as calibrated torque wrench goes... not since I've owned it and it used to be my father's so... in saying that though 7 of the other bolts torqued up... and in saying that I've always felt a bit scared of using this 1/2" drive torque wrench since I can break most motorcycle sized bolts with the amount of leverage on it. Either way I'm going to get it tested or use a tested one next time around, that is for sure.

Whether the stud had screwed itself out a few threads and I didn't notice it is a good question and I should have checked(will in the future of course) but I can't be sure before I strip everything down again.

Just so I can buy some helicoils in preparation, would anyone know the thread size/pitch of the stud at the case end?

Thanks

 

That is a bummer. Helicoil is a good strong fix I would not trust anything else As far as torque wrench size try to use a wrench size that will be reading in the middle two thirds of its scale thats where it is the most accurate. Say your 1/2" wrench goes from 0 to 300 ft. lbs and a 3/8" wrench goes from 0 to 150 ft. lbs which would you think would be more accurate for a reading of say 75 ft. lbs. As far as calibration you can test yours against someone else's to just compare the last time I had mine done it cost more to calibrate it than a new one cost nowadays but then again that was also to repair it as my youngest son decided to use it loosen the bolts on his truck leaf springs because he could not find the breaker bar, so he breakered my torque wrench instead (ask me how I found out Ill give you a hint wheels studs are supposed to stay on the rotor not sheered off in the end of the lug nut thats still in the socket or the time my brother borrowed my brand new torque wrench to work on a motor then tells me later that they were not building a motor they were tearing down a motor but I digress) What was the question? Oh ya no magic just good ol Helicoil to the rescue. Good luck to you

 

Hi Waldo,
You know after taking a better look at my torque wrench I think it might be due for the 'only the cast-iron jobs' type of application. It goes up in increments of 10 ft/lb(upto 150 ft/lb)so the 23 ft/lb was a bit of a guess on my behalf anyway.

I might go work on the other bike for awhile... while the disapointment wears off and the enthusiasm kicks back in!

 

Woot! what a relief!

Now I can see why it seemed strange to pull a stud out of the case. That case is hard as hard and there is so much thread into the case that I think the case would crack before letting the stud slide out.

In saying that...

Have a look at this!






Need a few other things but I'm glad I'm not heli-coiling and it goes to show the nature of these engines.

 

I probably have this stud from my parts engine pm me i'll check

-Lou

 

Dang now thats a site stretched that one just a touch

 

Thanks for the offer Lou!

But I have a stripped case sitting here with no transmission (XJ900), I knew there was a reason I'd been accumulating so many high quality, slightly broken, parts.

 

Classic bolt stretch from over-tightening. Waldo is correct re: 1/2 vs 3/8 torque wrench and the accuracy being in the middle range. I guess I'm spoiled as I have the torque wrenches calibrated at the shop.

Its possible the bolt was stretched by some PO and that is why the domed nut broke through and the torque was "off" and the oil persisted.

 

An update.
Decided to measure the length of all the bolts from the case face to the end and the front oil channel bolt was taller than the 2 studs on the other side of the motor too.

Pulled the 2 oil channel studs from the XJ900 case which both measured the same height as each other and the other side of the case (140mm ish).

Looks like I have at least 2 stretched studs, very wierd and a bit confusing.

Tip: heat the case up around the stud with a gas torch or heat gun 'before' trying to unscrew and put a nut on the top (one you don't mind squishing the dome on) and give it a nice hard smack or two squarely with a hammer. A good pair of vice-grips wouldn't go astray either (mine aren't so flash as you can see from the shaft of the stud)

 

You can also put 2 nuts on the threads, tightening them together to lock them. A wrench applied to the lower nut should then screw them out without the damage from vice grips.

Did you check part numbers to make sure that the 900 studs are the same as yours?

 

Hi JF,
Good idea on the nuts! Didn't think of that one.

Just checked the parts lists and both the XJ750 and XJ900RK use 90116-10330-00 there.

Funny thing is all the other studs match part numbers between the 2 models except on the XJ750 the front on far left bolt is an single odd part number(4H7-11364-00-00), although measuring it against the stud behind it reads 140mm also.

 

Put it all back together tonight.

The studs from the XJ900 torqued up spot on but while I was torquing a few of the other studs I could definitely feel a sort of give that made me uneasy.

They all made it up to 23ft/lb though but even so I'm wondering if some sort of overheating event has caused some of the studs to soften... sounds crazy but it's the best answer I can come up with to explain the ability to stretch a stud so much without snapping it.

Has anybody experienced this sort of phenomenon before?

Thanks again for your input!