z3bra

I got mine out even though the head was stripped, had to shove an EZ out in the head, the EZ out square end in a socket that fit it and with a bit of good luck, it came out without further problems. As it is, I'm not about to put the stripped head one back in there and potentially shoot myself in the foot at a later date.

I've ordered some generic 12.9 grade ones from an industrial supply place for now, but what I was wondering is if there would be any additional interest for some of these bolts in an aerospace oriented high temp, high grade material.

With a lot of searching, I've managed to track down a source for them in metric but realistically unless I was to order in a decent quantity it would be prohibitively expensive. There are a couple of options I tracked down, one is a socket head just like the original except it's made of A286 which is good for use up to 650 degrees (celsius) continuously without losing it's strength. Alternately something like Waspaloy would be even better but fasteners in that stuff are stupid expensive and even more stupid expensive when they're metric and you live in the USA. It's also rated for about 1100 MPa which is about on par with a grade 12.9 bolt (slightly less) . The key benefit is that unlike the stock pieces which appear to be just grade 8.8 socket heads the A286 bolts wouldn't get annealed from the heat and become so prone to stripping out or becoming brittle. Also A286 is extremely corrosion resistant due to a very high nickel content. It's sort of a super-stainless for lack of a better term without being a nickel alloy such as Inconel. Other options would be something like a 12point external bolt head or a spline drive head although those would likely cost more. The price on these is probably in the neighborhood of 15-20 bucks per bolt unfortunately, but honestly compared to the nuisance of having to try to get one of the original ones out if it's really stuck I don't think it's a horribly bad price to pay.

If I can get some more specifics on these, would anyone else possibly be interested in this as a part? Other options I looked at would be replacing the bolts with studs, but locating a reduced nut that would fit where the socket head fits on the original is pretty tough to do. The last and least desirable option would be to drill out the threads on the turbo bearing section and switch to a 5/16 bolt instead but it might be easier to source parts and definitely a good bit cheaper.

Anyway If anyone's interested in this as an idea, let me know and I'll see about persuing it further.

Tom M'Guinn

At $20 per bolt, I guess I'd stick with the factory bolts.

z3bra

Just to put it into perspective the long factory bolt is $22 or so.

I paid about 10 bucks for a package of 5 of the 125mm ones in 12.9 grade from McMaster-Carr since none of the local bolt and nut supply places had anything over 100mm. The short one is no problem to find at least, got a box of 50 of those for 10 bucks since I was ordering from McMaster anyway and they have some sort of funky blue coating that's supposed to prevent hydrogen embrittlement. Hopefully a solid dose of Anti-seize will work as advertised when I have to pull the turbo again down the road to upgrade.

With A286 bolts this should be a one time replacement, not that most people hope to pull the turbo very often but the way that long bolt is in there, if you can't get it out normally it's going to make for a long miserable day. On the plus side, the factory use of a socket head while being more likely to strip is at least easy to get an EZ out into without having to drill the bolt. Alternately, ARP sells 5/16x5" 12 point stainless bolts that are rated at 170,000 psi that could work, but you'd have to helicoil the bearing section of the turbo which might bite you in the butt down the road if you needed it as a core or something. Or you could use NAS/MS type bolts too that way if you don't mind drilling and putting in inserts.

Oh well this was just an idea to toss around for consideration anyway.

CBRE

Im game for two bolts for $40, the price is nothing next to the inevitable agravation.. Let us know the status, I definetly want both the long and the short one.

z3bra

I'll try to see about setting it up as a group buy type thing. The hardest thing I'm running into is finding a distributor, I have specs from two manufacturers that already make the fastener in the right material which makes it an off the shelf part. Unfortunately, most of the distributors only want to deal in pretty big volume.

This whole thing would be so much easier if the aviation industry in the US would get off their hiney and switch to metric. Obviously it worked out ok for the automakers. Granted there's a whole lot less paperwork involved with regard to automotive parts compared to aerospace stuff. I think the big problem is that aside from a huge installed base of imperial measurement aviation fasteners they'd have to continue support for, the government probably doesn't want to spend the money to redo all the Mil Specs for metric. Also, it's unlikely aircraft manufacturers want to switch over either as it won't be cheap for them.

It's really pretty ironic since all the military maps and such are metric already and it was the government itself that initially was making the big push for metric yet they're the ones that are the biggest roadblock to widespread adoption in the aviation industry.

GaryK

I found some 12.9 metric allen bolts at a local bolt supply company that worked great, and appear to be much higher quality than the stock bolts. Don't remember the exact cost, but I belive they were around $4 each. I had to drill the old bolts out, fortunately with little damage to the mounting surface. I'd recommended copper anti-seize on the new ones.

z3bra

As long as the 12.9's work ok then I don't think the nice ones are worth the trouble it sounds like, and I use the copper stuff on anything that might even remotely benefit from it. I'm just glad mine actually came out without too much trouble, I was a bit ticked off when I saw the long one was already stripped out before I even touched it.