V10 oil pump torx screw replacement - what tensile strength should be used?
#1
V10 oil pump torx screw replacement - what tensile strength should be used?
While I had my V10 under the knife I had to replace all the torx screws holding the oil pump cover to the housing. The old ones basically snapped in half when I tried to re-tightened them to spec.
Here's my dilemma - I got on McMaster Carr and ordered replacements, basically going by the existing bolt dimensions. I settled on the ones pictured below because the head diameter was the same, but they had a T27 head instead of a T30 head. They are rated at 60,000 PSI (basically a grade 3) and now I'm wondering if I made a mistake in picking those. I know they probably won't fail immediately, but I am concerned about them failing in the future. I really don't want one of those heads to break off and fall into the timing gears. I loc-tited the hell out of them so hopefully the head wouldn't just fall off anyway, but you never know. On the other hand, the old screws were extremely brittle when I tightened them up, yet they didn't fail. Just makes me think maybe there's not a ton of force pushing outward on the oil pump cover anyway.
So, on to my question - should I remove these and reinstall torx screw with a higher tensile strength?
The only other offering from McMaster with those specs is a 130,000 PSI A286 stainless fastener... at $20 each!
Here's my dilemma - I got on McMaster Carr and ordered replacements, basically going by the existing bolt dimensions. I settled on the ones pictured below because the head diameter was the same, but they had a T27 head instead of a T30 head. They are rated at 60,000 PSI (basically a grade 3) and now I'm wondering if I made a mistake in picking those. I know they probably won't fail immediately, but I am concerned about them failing in the future. I really don't want one of those heads to break off and fall into the timing gears. I loc-tited the hell out of them so hopefully the head wouldn't just fall off anyway, but you never know. On the other hand, the old screws were extremely brittle when I tightened them up, yet they didn't fail. Just makes me think maybe there's not a ton of force pushing outward on the oil pump cover anyway.
So, on to my question - should I remove these and reinstall torx screw with a higher tensile strength?
The only other offering from McMaster with those specs is a 130,000 PSI A286 stainless fastener... at $20 each!
Last edited by Chowlie; 03-12-2021 at 09:16 AM.