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Bling's AE70 Hardtop - Discussion


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It says something about high tensile bolts  being not good for cyclic loading, which doesnt really make sense in most situations, once the bolt is torqued correctly it is clamping components together,  you aren't relying on the bolt only in many situations so there isn't any cyclic loads I would think?

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2 hours ago, ajg193 said:

You'll be perfectly fine running 10.9/8.8, that's what Toyota did back in the day.

 

Do you have a screenshot of the relevant CCM chapter that states bolt strengths? From what I could see in the LVVTA Standards they just specify the minimum allowable bolt strength and don't say no to 12.9 - they also explicitly state that Nyloc is fine (minimum 2 threads protruding from nut) unless somewhere that gets hot like engine components of brakes.

Yeah i'm more than happy with 8.8 / 10.9. 

Pic of the CCM chapter I have in stock, I have the whole chapter somewhere as LVVTA had it available at some point for download.

http://iforce.co.nz/i/zn4shv1p.bc0.jpg

The nylocs were holding the brake rotor to the hub, so a bit toasty, so out they go. 

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1 hour ago, cletus said:

It says something about high tensile bolts  being not good for cyclic loading, which doesnt really make sense in most situations, once the bolt is torqued correctly it is clamping components together,  you aren't relying on the bolt only in many situations so there isn't any cyclic loads I would think?

Yeah it's all beyond my pay grade, but consensus seems to be that stronger isn't always betterer. I don't know much about the cyclic side of things. But from a brief look, it seems the braking / moving of suspension would fall into cyclic loading.


As to if 12.9 would ever cause me an issue, i'm not sure. Impression I get is no, in my use case it won't be a problem. I have new bolts so that it ticks that box and keeps everyone happy lol.

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There is quite a lot going on, but in basic terms it is about the ductility of a material. Mild steel is pretty weak and ductile but good for forming and welding.

There is a significant increase in strength from alloying, which along with heat treatments/grain sizing is how you get the increasing strength grades.

But after a certain point the strength increase is offset by the lack of ductility, so in a clean static environment a12.9 is sweet as, but as soon as there is some cyclic stress and a grubby environment you get tiny cracks that soon develop into big cracks. It actually takes very little movement to start propagating cracks, chunky stuff will still be flexing and loading up the bolts. This happens much slower in mild steel as the material will plastically deform at the edge of a crack and relieve the stresses.

12.9 bolts don't have as good an ability to deform so the crack will propagate much faster.

This is why welding forged suspension components in particular is a fucking terrible idea, that shit usually had some nice alloying done and the method of manufacturing ensures the crystal structure is of even size and nicely aligned. Then some donkey cuts and welds it, this; 1. Dilutes the alloying component where the weld is, 2. The heat completely fucks the crystal structure, sizes and alignment. 3. Introduces potential voids and inclusions in the join.

Thats pretty much it.

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  • 7 months later...
  • 1 year later...

Not a huge fan of adding weight to cars but do you have option to add rear strut braces/boot braces maybe some additional strut tower reinforcement plates (I know the ke/ae70 chassis can have strut tower cracking issues 

Assuming you already have a full sized spare in the boot?

Want to add any stereo equipment? Big subs tend to be heavy :p

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It's empty at the moment so that won't be helping things, probably less than half a tank of fuel. So half of the problem will probably be gone by the time I add a spare wheel, jack etc, fill the fuel tank (haven't dared yet as no fuel close to home). I do have a sub and was considering putting a floor in it to help secure that. With a lid to get to spare wheel. I'm not too worried about the adding of weight from a performance point of view, because it doesn't have performance. I need to actually source a spare wheel as I don't have one. Other than the Hoshino wheels on it now. I'll do my homework on the droop rules / regs in the meantime. But yeah adding sounds I have sitting here would help the situation, if it came to it. 

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  • 2 months later...

Thanks.

Yeah nervous for the first check would be an understatement. Not an easy task to fit a whole bunch of parts that weren't supposed to fit to your car. While at the same time meeting the requirements that comes with going down the cert path. LVVTA PDF's have been bedtime reading for quite some time. 

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Could you just have used drop shank wheel nuts - if they fitted your wheel no need to change studs and would pick up roughly 3 turns of thread...

Wheelnuts, Wheelbolts, Wheelspacers & Accessories

 

They come in a few styles, plain hex, spline drive, open ended and closed (black or chrome too)

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11 hours ago, oldrx7 said:

Good work, such an oddball shape of the 70 corolla series but looks so good.

Yeah not something you see every day / ever really. The shape really grew on me when I found my first one, hadn't seen one on the road before, not that I was looking, but yeah not many around. Those with them tend to have multiple if the internet is to be believed.

2 hours ago, CUL8R said:

Could you just have used drop shank wheel nuts - if they fitted your wheel no need to change studs and would pick up roughly 3 turns of thread...

Wheelnuts, Wheelbolts, Wheelspacers & Accessories

 

They come in a few styles, plain hex, spline drive, open ended and closed (black or chrome too)

Didn't actually know those were a thing! I do want to get some new nuts at some point as my current ones, even though were new, are flaking a bit. Might look into those, or at least measure my wheels for fitment. Cheers

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Measured mine while doing other jobs today, ~15mm inside diameter on the pressed in seats. If I had known about them I could put a bit of planning in to it. But as it stands i'm happy with the new studs as it will mean I can run common nuts and I already have them, so there is that haha. Cheers for the heads up though, they sound like they would solve the problem with minimal work. Pretty keen for some better quality nuts though at some point. Might hit you up if you don't mind, as so much garbage on the market these days it's hard to find quality. 

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  • 1 month later...

Looking good! My favourite E7 shape.

 

I just fixed a similar carb issue on my D21, the idle shut off/anti-dieseling solenoid wasn't working. It wasn't working because the ECU fuse had blown, but apparently it's not uncommon for them to fail. Assuming yours has one and it runs off the key like a Nissan, you can test it by having someone turn the key from ACC to ON and see if you can hear the carb clicking. You can remove the plunger that turns off the idle fuel circuit as a temp fix, but it'll run on even worse.

 

Mine was running on a bit, stalling at idle, backfired heaps on deceleration, but ran fine once it had some throttle.

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