High Tensile, mains bolts
Turbo Mini Forums

Alex, If they are genuine ARP I think their minimum strength is better than SAE 8 so I don't think the supplier matters, you've just picked one with the hassle of importing from the USA, but which ARP part number would be right for a Mini with a strap?

Carl, what is "finnings" ? is it a supplier's name, I've searched but can't find one.

Rod.

Schrödinger's cat - so which one am I ???

you've been given links to people who supply them in the uk, why bother going to the states?



i might walk to the place and get a box full then start flogging them on seems nobody wants to phone

Sorry Iain, I missed that one and it's right at the top too

Mind you, your last suggestion might not be a bad idea - I've been searching the Net today for UK suppliers (no-one open to phone on a Sunday) and the only people I've found so far have minimum order quantities of 25 or 50 !!!

Schrödinger's cat - so which one am I ???

TMS will send you 1 or 2 bolts if you wish AS LONG as they have some in a box on the shelf. otherwise its a box. But to be honest, you could quite easily part the box out to people an here and cover you costs/make a couple of quid for the hassle

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Hmmm,

Earth moving = high strength.
Catterpiller = USA = imperial threads, not metric like everything here is now.

PM sent.

Schrödinger's cat - so which one am I ???

well if Some one is going to start selling a few ill take a set!!

ditto, id take a few sets

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

Hey,

I got in first !!!

It does make the point Iain made earlier though, about group buys of bits that are only sold in large quantities.

Rod.

Schrödinger's cat - so which one am I ???

On 20th Jan, 2008 iain said:
you've been given links to people who supply them in the uk, why bother going to the states?



i might walk to the place and get a box full then start flogging them on seems nobody wants to phone

Metric is for people who can't do fractions.

If you want 12.9 hex heads use a NAS bolt. You buy these according to what grip length you want and they do a few ranges as the length of thread is different.

12 point NAS bolts are really good, these are super high qulity aircraft bolts.

If you want good 6 point headed bolt use a NAS bolt. 12.9 spec in a normal hex head.

Even better still are the 12 point NAS bolts. If you use these ensure you buy the correct beveled washer for these bolts as they have a larger radius under the head.

I just received my 12pt ARP bolts for the center main that I am going to install a strap on. All ARP hardware is Johnny BA. I realize you guys have to pay some import tax, but I will give you the info just in case….



They were $4.31ea from APT in the US, they are approx. 3.75� long, there PN was 4AP3.750-5CF (I am assuming that is APT’s PN, doubt it corresponds to any ARP #)

hey guys dont know if this helps but im going out to california next month,
i could just bring a load back?

I learned something in the last half hour

how many of you know that the standard mains bolt used at least on the A+ engines are no ordinary high tensile bolt?

These bolts are called 'Place Bolts' and the six slot veriety used are grade 8 but have the added benefit of a special head that resists loosening.

Im happy that the standard bolts are more than up to the job. However, I have instructed my machinist to use M12 cap head bolts for the extra two on the 4 bolt main cap. Not strictly convention but hey, its my engine Besides Rover used a crazy mix of imperial and metric on the MPi block anyway

Doesnt help those with the Mains strap, with longer bolts, but at least you know what you need to look for.

As Carl said, don not use the three dash grade 5s they are a lower yeild strength than the standard bolts.

How many engines out there with these bolts in, I shudder to think!!!

http://www.aetnascrew.com/placebolts.htm

shot twice

Edited by Sprocket on 8th Feb, 2008.

Shot thrice, whoopsie

Edited by Sprocket on 8th Feb, 2008.

Hi all. Must concure with prievius posts, 8.8 is a metric grade, hence is found only in metric bolts. 3 lines is grade 5 not near good enough. 6 lines is grade 8 as per factory.
Mark

Dragging up an old post but do you have a cat part number for these carl? Having a bit of trouble trying to sort these out!

PMSL!

Sprock - have you calculated the under head stress/unit area on the cap heads to make sure you aren't going to yield the strap/cap material - may be worth dropping some hard (bmw head washers etc) under the heads - just a thought!

JK

If Carling made Mini engines
it would probably be like this one!

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

I am just getting around to installing my strap on the center main, which I made opposed to purchasing....anyway it was perhaps a tad bit shorter than I thought it would have been. Anyway, my 3.75" long ARP bolt are about .25" too long. So I have to order 3.5" bolts instead. My recommendation is double check this measurement for your application.

if you machine the cap down just to remove the hump, and use 1" thick bar the 3.75 bolts will be fine , but i always use a hardened washer too,

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

The other thing to bear in mind with cap heads - is that to use them effectively (like any bolt) they should be torqued to approx 75% of yield - caps normally come in 10.9 or 12.9 grade - hence the torque to achieve 75% yeld in the bolt is a lot higher than an 8.8 grade fastener - which has a very big impact on the under head/washer stress/unit area calcs.

JK

If Carling made Mini engines
it would probably be like this one!