Bolt installation/locking

Prior to the running of the Repco Round Australia Trial I was involved in the preparation of the South Aus entry. Part of which was the installation of a Dana limited diff to the 240 Volvo entered.
In the early stage of the event the Volvo suffered broken crown wheel bolts The Volvo continued the Event with a normal diff.
After the Trial we received a Bulletin from Volvo Sweden advising of improved crown wheel bolts having a serrated face under the now flanged head ! If only...

Not related to the above. I often found while working over the years with Volvo that if the tailshafts had been re-fitted with the bolts [4] at either end with the bolt head toward the component ie gearbox/diff. This would make it easier for the fitter to install, the nut being easier to access. I would often find in these cases that the bolts would loosen. The nuts were the nyloc type.
I often wondered why this was so. The rotation contributing to the loosening?
Anyone?

I beleive these strange looking Ford flywheel bolts had a "magic" reputation ro never coming undone.

http://www.latemodel...ywheel-Bolt-Kit

I THINK its to do with the funny bumps acting as shock absorbers/inertia dampers against the vibrations .

Yes, it's known as a "place bolt" and indeed, it has magical properties.

Here's an apt description by Carroll Smith from his Nuts, Bolts, and Fasteners and Plumbing Handbook:


Carroll Smith on Place Bolts


and from The American Fastener Journal

How Place Bolts Work


EDIT: forgot to mention: Place bolts actually feel different when you torque them down... hard to describe but "dead," for lack of a better term. No spring or tactile noise in the action.

Edited by Magoo, 10 June 2013 - 07:27.

That book was exellent. I read a lot more. Unfortunately i did not get the place bolt. Is it the inward chamfer at the heads base that does it?

Yes, it's known as a "place bolt" and indeed, it has magical properties.

Here's an apt description by Carroll Smith from his Nuts, Bolts, and Fasteners and Plumbing Handbook:


Carroll Smith on Place Bolts


and from The American Fastener Journal

How Place Bolts Work


EDIT: forgot to mention: Place bolts actually feel different when you torque them down... hard to describe but "dead," for lack of a better term. No spring or tactile noise in the action.

But still replace them every couple of times they are undone. Most Fords use this style of bolt and flywheels never come loose,,, unless the bolt is 'old'. Falcon 6s are the worst.
GM products are even more susceptible. I replace them every time on race engines or the flywheel will come loose. 202 Holdens are shockers but new bolts, Loctite and ideally a dowell and they do not come loose. Chev bolts are good though on high RPM Holdens, over 7000rpm they need all the help they can get!

That book was exellent. I read a lot more. Unfortunately i did not get the place bolt. Is it the inward chamfer at the heads base that does it?

Yes, it and the convex shape in the top form a sort of diaphragm that allows the fastener to absorb huge tensile shock loads, including upon installation.

Yes, it and the convex shape in the top form a sort of diaphragm that allows the fastener to absorb huge tensile shock loads, including upon installation.

ah. The cutouts are to make it flex? More spring like action?

Edited by MatsNorway, 12 June 2013 - 07:12.

These 'Place Bolts' look interesting, where can I buy them in the UK? Are they an off the shelf part supplied by a car manufacturer and if so can I have a part number.
Thanks
Gary

These 'Place Bolts' look interesting, where can I buy them in the UK? Are they an off the shelf part supplied by a car manufacturer and if so can I have a part number.
Thanks
Gary

Place bolts are OE in a number of applications for Ford and General Motors, mainly flywheels and ring gears. I don't know this but I would think most any fastener house should be able to fix you up.

Edited by Magoo, 22 June 2013 - 19:23.

ah. The cutouts are to make it flex? More spring like action?

The marsden nut opperates in a simillar manner with verticle cutts down from the top of the nut about 1/3 and a hollow base.

marsden

Place bolts are OE in a number of applications for Ford and General Motors, mainly flywheels and ring gears. I don't know this but I would think most any fastener house should be able to fix you up.

Not here in Oz at least. Special bolts are genuine manufacturer only. They sell less and less choice. I buy most of my 'good' bolts from Caterpillar and even they have less and less choice.
Most of the specialist fastener sellers have amalgamated and seem to offer less choice for more money. Bearings are the same though the discounts there are ridiculous. Very large buyers buy less 80%. I buy most of mine through another bloke who buys less 50 or 60%. Though recently found buying the genuine bearing trade price was actually a bit cheaper.

For place bolt supply in the Uk try Real Steel in Uxbridge. They stock a huge range of US engine stuff so might well hold the Ford flywheel version at least.

http://www.realsteel.co.uk/

For high quality fasteners generally in Uk I have always used Orbital Fasteners in Watford. Not automotive specialists but they do 12.9 capsrews etc in any small quantity at very fair prices.

http://www.orbitalfasteners.co.uk

They probably won't have place bolts but may know where to source them.

BTW Lee's post mentions Caterpillar. I have heard that farm/ earthmoving machinery OEM's always use very high quality fasteners and are a potential racing source. Is this true, are any bolts " our" size versus jumbo sized?