Fast Marina Magazine

Hi there, I snapped a stud bolt whilst changing tyre. Can't seem to find replacement bolts that easily. The head is 15mm, shoulder 12mm and the threaded length 40mm. I've been all over the place (Rimmers, Mick Dolphin, Earlpart, MiniSpares etc) and can't seem to find anything. Does anyone know what I need? The wheel has a centre cap which may explain the length of the thread. I have got plenty of stud nuts 3/8 unf. Help appreciated. Thanks.

What torque are you using to do up the wheel nuts?
Only should be about 25 to 30 foot pounds from memory as they should not flatten the natural spring cone in the pressed wheel as this helps keep the wheel on the hub.
I thought Rimmers had them?
What Jubilee have you got or what is the number plate?
Jubilees have same wheel nuts as a Triumph spitfire or GT6 should have a plastic washer on the nut.

My reg is UGK 719 M. I'm ok for the nuts its the bolts I need.

Are so your the new owner of Dave Richardson's Jubilee which was fully restored! The one with the white stripe tyres.
That one should be a nice solid motor now.

The wheel studs are imperial not metric. The thread is 3/8” UNF

Here you go, it even has a Marina part number https://www.rimmerbros.co.uk/Item--i-21H5774

JubileeNut wrote: Wed Oct 04, 2017 7:16 pm What torque are you using to do up the wheel nuts?
Only should be about 25 to 30 foot pounds from memory as they should not flatten the natural spring cone

Interesting. That translates to just 33-40Nm which is what my torque wrench is calibrated in. My modern Fordy-Volvo specifies 110Nm for its alloys and I thought that was so they weren't over tightened. I don't understand the terms about flattening the natural spring cone or plastic washers. My Marina has long domed chrome wheel nuts (a bit rusty actually, they could do with renewing) and I'd got some bent studs from somebody swinging on them too much. I've managed to tweak them straight enough but could find no reference to wheel nut torques in my books, and when I dared try my torque wrench set to 110Nm I could tell I was going to shear them off! So I used my Draper telescopic wheel wrench on its short setting and just 'felt' them tight enough, which left loads more I could turn them.

The maximum tightening torque will be based on the diameter of the stud/bolt. Your modern bolts are often 14mm (9/16” app.), whereas Marina studs are 3/8” UNF (9.525mm). Even if they are all high tensile steel, the breaking strain of the two studs are different.

This is a table from a bolt supplier. Not sure of the differences between S/T/V but if you can compare the torque settings from 3/8” to the 9/16” you can see the difference.

On the subject of the bolt hole in the wheel. They deform and lock into the wheel nut. If you over tighten, the stud hole will permanently deform and the locking action is lost.

MarinaCoupe wrote: Wed Oct 04, 2017 9:42 pm
On the subject of the bolt hole in the wheel. They deform and lock into the wheel nut. If you over tighten, the stud hole will permanently deform and the locking action is lost.

...and that is something I never ever knew, or dreamed could happen. Learning all the time

S T & V are different tensile strengths of the bolt and should be stamped on the head of the bolt.
Dave

Thanks David.

Thanks for all your help and information. Bolts sourced and ordered.

JubileeNut wrote: Wed Oct 04, 2017 8:02 pm Are so your the new owner of Dave Richardson's Jubilee which was fully restored! The one with the white stripe tyres.
That one should be a nice solid motor now.

It's a beauty. Came from Aberystwyth but had been in the West Midlands before that from what I can tell. I had to have the driver's seat welded as it had collapsed. Also had to sort out the electronic ignition (optronic) and carbs refurbished and turned. Running sweet as a nut now.

MarinaCoupe wrote: Wed Oct 04, 2017 8:26 pm The wheel studs are imperial not metric. The thread is 3/8” UNF

Here you go, it even has a Marina part number https://www.rimmerbros.co.uk/Item--i-21H5774

Cheers Chris. Appreciate your help.

"It's a beauty. Came from Aberystwyth but had been in the West Midlands before that from what I can tell. I had to have the driver's seat welded as it had collapsed. Also had to sort out the electronic ignition (optronic) and carbs refurbished and turned. Running sweet as a nut now."
This was the car I was fussing Dave Richardson to sell to me when I was looking for a Jubilee. No luck until I had gone ahead with another car which was in a worse state. but got that up to scratch. Dave sold it to a chap in Dudley who restored it. He was looking to sell it when I met him at the NEC so I guess he did and it moved to Wales. Now on to you. Where-a-bout's are you based? If we can get Kevin to bring his Jubilee to Nene Park next year and you also go we could have 4 of the 5 on the road Jubilees in one place?