Harrop 2300 supercharger to Optimiser 6500

[PeeBee]

Picked up new studs today and a full set of wheel nuts. According to PAP the drv side rear wheel is a known culprit - would really like to understand this. I know since putting in the new motor the torque reaction is into that corner under hard acceleration, which by default means its vectored into that corner at all power applications.
Unsure whether this translates to greater load or single wheel reaction, puzzling. Anyway all rear studs getting replaced tomorrow, new disk installed, back to original, so am happy with the reliability over the last 350klm despite the wheel loss - glad it happened in Yarra Glen and not out the back of nowhere from a convenience perspective.

[Plasnart]

………I also confirmed the tapered nuts are the right ones for the GU4 alloys…….

Just be really really careful about this mate. That advice will be correct so long as there are tapered holes not flat-bottomed holes in the rims. You need to have the nut and rim nestle together for maximum friction grip.

[PeeBee]

Just be really really careful about this mate. That advice will be correct so long as there are tapered holes not flat-bottomed holes in the rims. You need to have the nut and rim nestle together for maximum friction grip.

Plassy I will have the wheels off tomorrow. The GU4 alloys have a tapered seat, the Y60 alloys have a flat end piece and require the flat nut. Funny enough when I was picking up 'my nuts' off the middle of the round about I spotted what I thought I spotted the 6th stud but it was actually a broken stud with a flat ended wheel nut , so obviously even the GQ alloy nuts and studs have a problem.

[Plasnart]

Plassy I will have the wheels off tomorrow. The GU4 alloys have a tapered seat, the Y60 alloys have a flat end piece and require the flat nut. Funny enough when I was picking up 'my nuts' off the middle of the round about I spotted what I thought I spotted the 6th stud but it was actually a broken stud with a flat ended wheel nut , so obviously even the GQ alloy nuts and studs have a problem.

Roger that. The only reason I stressed the point is my GU2 alloys had flat seats. Must have changed somewhere in between! All good.

[PeeBee]

Roger that. The only reason I stressed the point is my GU2 alloys had flat seats. Must have changed somewhere in between! All good.

Honestly will have a look. I stood in front of the guy at PAP that I have seen for at least 5 yrs and he told me this story.

[Brissieboy]

Definitely 60 degree taper on the Y61 17" factory alloys, and the handbook for my 2015 GU Y61 wagon states 97 ft/lbs tension. I do a recheck after a few hundred ks, and also re-do the tension anytime the wheels are played with by anyone else. Rattle guns are only for removal in my opinion.

[PeeBee]

Would you have a seating torque for the studs by any chance? I am just going to rattle a start on the new ones then use a torque wrench to seat them. I cant fand a a seating force or a torque listed anywhere. I guess slow and gentle or whatever the torque is to seat them firm against the diff housing end plates without over tensioning by screwing up the rattle gun?

[PeeBee]

OK, I found a source that gives a seating torque from a rattle gun at 210nm for an M12 x 1.25P wheel stud. I have trawled thru my text books and found the method to calculate the torque, finally, however I need to know the stud tensile strength, which isn't stamped on the stud like you find for a HT bolt. The equations spread across 3 pages, so I am happy to go with this published number. I seated the replacement studs with a 12V torque gun on the side of the road, rated at 300nm - its a cheapie that came with the 12V 10T jack I bought so I doubt this is accurate by any imagination. Anyway tomorrow I will set the torque wrench at 210 and see how close to the mark they are.

I also bought a tool off ebay that is a cupped spacer with a bearing and specific stud seating nuts, so these can be used later if the others break. Either way the complete set of rear studs are coming out, with luck thats the end of it. New nuts, torqued as advised within 97 - 120nm , using the ARP HT Stud lubricant to ensure the seating torque is friction free as much as possible.

So 210nm for stud seating and 100 - 120nm for nuts as a reference point

Did a bit more digging, rang the mechanic and he uses a Snap on 18V impact gun thats not adjustable, relatively new, and rated at 540nm, so maybe here is the final piece of the puzzle, not throwing stones at him, but its a likely cause I think especially since the studs failed a 400klm after installation

[Brissieboy]

Maybe also try freezing the studs before installing them - should shrink them a tad and make it a bit easier. Not sure if this might reduce the strength of the stud, but they should be good to 0 degrees at least.

[PeeBee]

OK, decided to swap all the studs out on the basis they were all installed by the same method that resulted in the first wheel failure. Started at 8am, finished at 4pm, nice and easy, just repetitive. All the wheel studs in use are the longer Rear Wheel studs due to the Willwood kit upgrade. No real issues except could simply not seat the studs at 210nm, no way, so backed it off after noticing the wheel nuts I was using to pull the studs into position were all suffering from thread deformation and making it difficult to remove, Settled on 130nm which is more than ample - I mean they are seated well and truly so no point stressing the stud. Used ARP thread seating lubricant on the spline and the nuts, so the torque is a real value with friction removed to a great degree. Had to modify and install a new brake disk as the other one was too mangled to rework into a working form. Lucky I had a couple of spares.Studs 8.jpgStuds 7.jpgStuds 6.jpgStuds 5.jpgStuds 4.jpgStuds 3.jpgStuds 2.jpgStuds 1.jpg