Andrew Harper

Hi,

Want to get other owners opinions on this.

I'm fed up with the downpipe installation, there is very little room for a socket in there and I remember reading about owners replacing the studs with hex head bolts.

I can get these in Marine grade St/St and I'm wondering if any of you have used this route without any problems.

My Dad was in engineering for 30 years and said there should be no problem except not to over tighten them of course the Stainless is stronger than the aluminium and will strip the thread out.

I've measured them and they are M10 x 25 x 1.5 thread (to the base of the nut)

Obviously I would need to use some washers as well.

Cheers,

Andrew.

sevensheaven

iTrader: (1)

I've used SS allen head bolts for over 4 yrs. No problems. I had to cut an allen socket down for clearence.
I also had to shorten an standard allen wrench.
Terry7

Andrew Harper

Cheers matey,

I've found a problem with the moulding of the metal being so close fitting I can't get the socket over two of the nuts properly, would rather use the same route as yourself. Don't feel like hammering away at metal. Especially brittle stainless.

In an ideal world I'd like Torx head, but they are only really for engine applications.

What length of bolt did you use?

dgeesaman

iTrader: (7)

The allen head bolts in grade 12.9 are good. M10x1.5mm x 25mm long worked for me. Get an allen wrench with a nice short bend to reach the tough spot. The reason I still use OEM is because it's made of Inconel material that handles high temps better.

Do not get stainless unless it's something exotic because they operate at over 1000F and have substantial preload. Marine grade stainless (presumably 18/8 or 316) is made for corrosion resistance more than strength and high temperature service. These go into cast iron, not aluminum BTW.

You definitely don't want to use hex head bolts. The heads are way too big.

Dave

Andrew Harper

Arrrgghhh! Sorry Dave.

Sorry my mistake I meant Allen Head......it's been a long day!!! lol

I suppose I could go for exotic Titanium! lol

scrubolio

iTrader: (8)

i used hex heads bolts when i reinstalled my DP, it wasn't that bad. don't use the regular sockets, use a wrench or those passthrough sockets and for extra torque, go buy a steel pipe 1-1.5 feet long that just fits over the butt end of the wrench/ratchet and you'll be golden. the right tools help out significantly

dgeesaman

iTrader: (7)

The M10 hex head bolts that I found were big enough that they wouldn't lay flat on the flange in the tight corner. It may work with a slightly different bolt and a different downpipe but it's going to be close.

Dave

GARCO MOTORWORKS

I have been using ss allens on the down pipe , pipes ,to turbo for 14 years no problems on any of the cars .I have an allen wrench cut just for the one tight bolt on the bottom .