Terry's tale. (S3 resto ++)

Terry's tale. (S3 resto ++)

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Discussion

phillpot

14,406 posts

118 months

Friday 2nd December 2016
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Shorty said:
These were the bushes in my front AVO adjustable shocks
That, in my experience, is normal within a few weeks with Avo's !



Personally not mad on the yellow drums, but it's your car smile

Blue 30

Original Poster:

244 posts

52 months

Friday 2nd December 2016
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Good info on those AVO bushes, thanks.
Maybe something I'll have to address once its fully finished. Nylon ones are a maybe.... But too much to do yet!

Ah yes, those yellow bits. You know what its like when you have some paint left over... But on the plus side it saved me from getting bruised shins as I can clearly see them during the after work, night sessions.
You won't see much of them once the body & wheels are back on... I hope !
TerryB.

Blue 30

Original Poster:

244 posts

52 months

Friday 2nd December 2016
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The Diff !!
As I said above, the Jag g-box has a 1:1 ratio in 5th instead of the higher 5th that the T9 box has, so I needed a higher diff ratio. The Jags diff is 3.12, so the Sierra 3.14 is just about as good as you can get.... Well that's not true, as you could fit AN.other diff (jag,BMW etc). But then you get into needing a new diff carrier, plus new bespoke driveshafts.
Again, repeating myself, I want to do the whole project in a simple as possible format...
The rebuilt Sierra diff I obtained was already 3.14, plus it included conversion to Lsd & it has flanged outlets. This is built into a 7" casing, not the S original 7.5" casing.
On both diffs there are 2 pairs of bolt locations for fixing it to the carrier.
The 7" is on the left.
TerryB


phillpot

14,406 posts

118 months

Friday 2nd December 2016
quotequote all
Blue 30 said:
You won't see much of them once the body & wheels are back on... I hope !
I reckon they'll turn orange soon as they get hot wink

Blue 30

Original Poster:

244 posts

52 months

Friday 2nd December 2016
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The Diff continued...
Oh, the 7" or 7.5" refers to the crown wheel, not the casing.
If one fits the 7" unit to the Tvr carrier 'as is', it fits perfect on the front/lower bolt points, as does one of the rear/upper bolt points. The other has about a 20mm gap.
If you do that, once the diff carrier is fitted to the chassis, the diff is sitting offset !!!
Which means the propshaft input is offset. And it gets worse, if you measure from output flange to wheel flange one side is now longer than the other. No good for reusing the Tvr driveshafts...
That is my finding anyway...
The 'fix' is pretty simple (its what I did).
I cut off 10mm off the near side front/lower bolt point of the diff casting. This means that the offside front/lower point has a 10mm gap between diff casting & the carrier. I jest inserted a spacer.
The upp/rear bolting points are now centralised with a 10mm gap each side. Again, spacers are fitted.
Now when the output flange to flange gaps are measured they're the same. And my driveshafts fit.
In my case I fitted x4 new CV joints to the driveshafts.
What a pig those torx bolts are to remove !
Now replaced with high tensile cap head bolts (with locktite).
So that completes the rear end, for now...
TerryB

The completed rear.

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DJR 7

1,389 posts

192 months

Friday 2nd December 2016
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Would discs on the rear not be an advisable upgrade at this stage?

Edited by DJR 7 on Friday 2nd December 16:01

Blue 30

Original Poster:

244 posts

52 months

Friday 2nd December 2016
quotequote all
Mmmm...
You're not the first to ask or suggest I do just that.
In fact I have followed previous threads on that very subject. But I have decided to follow my own direction.
Although I cant/won't disagree that rear discs could be an advantage, especially based on a sporting driving style &/or if the car is used on a track etc.

So the following is just my thought on the matter (soapbox warning).

As we know the S has an inertia valve that acts as a 'master' shutdown of the rear brakes. So surely no matter what type of rear brakes are fitted, or how super-duper efficient they are. If the inertia switch is active under aggressive braking, then the rear brake effectiveness is being limited.
So why not just change the setting where the inertia valve comes into play, to gain a better rear brake from the type that's already fitted. That's without going too far and making the brakes too efficient and over biased to the rear. As we all know that would be very very bad...

Maybe I'll have to eat my words once the car is back on the road.
TerryB

phillpot

14,406 posts

118 months

Friday 2nd December 2016
quotequote all
Blue 30 said:
So why not just change the setting where the inertia valve comes into play, to gain a better rear brake from the type that's already fitted.
Because the more you use them the hotter they'll get. The big advantage of disc over drum is heat dissipation.

magpies

3,766 posts

117 months

Friday 2nd December 2016
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phillpot said:
Because the more you use them the hotter they'll get. The big advantage of disc over drum is heat dissipation.
also depends on how much you upgrade the front brakes and leave the rears standard.

Although I upgraded mine (front and rear) I believe the originals are more than up to spirited road use (maybe with pad /shoe material changes)

zombeh

593 posts

122 months

Friday 2nd December 2016
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At least if you leave the drums on you'll have a proper handbrake smile

GreenV8S

26,206 posts

219 months

Saturday 3rd December 2016
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Blue 30 said:
So why not just change the setting where the inertia valve comes into play, to gain a better rear brake from the type that's already fitted.
The static brake balance is purely determined by the mechanical and hydraulic leverages and should be set based on the static weight distribution. This is what determines the braking characteristics under light braking, such as when you are feathering the brakes through a corner.

The dynamic brake balance is established on top of that and just attenuates the rear line pressure to compensate for the weight coming off the rear wheels under braking. This is what determines the braking characteristics under very heavy braking. The bias valve doesn't change the static balance and shouldn't be used to try to correct the static balance.


Blue 30

Original Poster:

244 posts

52 months

Saturday 3rd December 2016
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I can't disagree with the science behind 'static' & 'dynamic'. But I have to point out that the S bias valve will (if its working properly) only activate under periods of (sufficient) inertia or a pretty steep front end inclination (downwards). So by that fact it cannot have any effect on the static braking effect setup. A screw or lever bias valve however would affect the static setup.
So going back to my original statement that under (dynamic) braking conditions where inertia is present & enough to activate (close) the supply to the rear brakes. There will be either reduced or no rear braking pressure. Which means no friction, so no heat, therefore no rear brake fade. Which for me is enough info to leave the rear 'as is'.
Purely from my personal encounters most brake fade is either due to old brake fluid &/or issues with the braking components.

I think its time (for me) to continue with the thread of the resto & conversion, but thanks for all the input, as its great to read such diverse opinions.
TerryB

Blue 30

Original Poster:

244 posts

52 months

Saturday 3rd December 2016
quotequote all
Guys...
So far my messages to this thread, are of already completed work (ie. In the past). Reasonably soon I Will be up to present date in work detail terms.
Of course I still have plenty to do. My best guess at my current work rate is about another 12months before completion. I will generally only post messages of work info that is completed, especially where it is of conversion type. As there's no point in seeing anything that didn't work out. But I will probably talk about it !!
So soon my posting rate will slow down somewhat. More so if I'm doing these messages instead of doing actual work.
(Including other work stripping down & preping my Panther for its spring respray, plus taking the heads off to get unleaded seats fitted), and an interior strip/refit.
TerryB

Alan Whitaker

1,928 posts

117 months

Saturday 3rd December 2016
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Hi All.
I work on the more BHP the better brakes you need, if you add 30% more power you need add 30% more brakes that's my 2 cents worth right or wrong thinking.

Alan

glenrobbo

11,990 posts

85 months

Saturday 3rd December 2016
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Braking requirements aren't really related to engine power output Alan, it's a combination of vehicle all-up weight and velocity that determine the size of braking surfaces and friction materials to do the job of stopping effectively without overheating, and within a reasonably short distance. Oh, and tyre footprint area and road surface type as well.

GreenV8S

26,206 posts

219 months

Saturday 3rd December 2016
quotequote all
Blue 30 said:
under (dynamic) braking conditions where inertia is present & enough to activate (close) the supply to the rear brakes. There will be either reduced or no rear braking pressure. Which means no friction, so no heat, therefore no rear brake fade. Which for me is enough info to leave the rear 'as is'.
If you do find you are overheating the rear brakes, your idea that the bias valve is going to compensate for that in any way seems like a non-starter to me. The bias valve doesn't work the way you describe it, and there are no circumstances where it reduces or removes rear braking or stops the rear brakes generating heat. (Anything that did produce that effect would have a very dangerous effect on the car's handling under braking.) What it does is reduce the rate of increase of the rear line pressure as you increase pedal pressure. In any case, nothing you do on the hydraulic side will give you more braking once the brakes have exceeded the temperature range that the linings can cope with. What'll happen in that case is that the car will tend to lock the front wheels under heavy braking and snatch a wheel if you're braking on an uneven surface or into a corner, together with smoke and burning smells from the rear brakes, and possibly a tendency to melt the grease out of your wheel bearings and set it on fire if you keep pushing hard.

My standard S2 was fine on the original drum brakes even when driven very hard on track for extended periods. However, the more power you have the more heat you can put into the brakes and it's certainly something to look out for during an upgrade. The front brakes on my S2 were similar to the original ones on my V8S. They were fine on the S2, and fine on the V8S for normal road use, but pretty marginal for track use and could be overheated pretty easily even with the standard engine. I've had a long succession of engine and suspension/brake upgrades over the years but in my case when I reached the limits of the brakes it was usually the fronts that ended up being the weak point - I only made one significant upgrade to the rears but upgraded the fronts several times.

Anyway, its your car and your project and I'm sure you'll soon figure out whether you have an overheating problem.

Edited by GreenV8S on Saturday 3rd December 16:48

Alan Whitaker

1,928 posts

117 months

Saturday 3rd December 2016
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Hi Glen.
Thanks for reminding me, I just work on big power big brakes, just like a lambo.

Alanxmas

glenrobbo

11,990 posts

85 months

Saturday 3rd December 2016
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Hi Alan,
I didn't mean to sound churlish.
I guess with your Lexus V8 twin turbo's mahoosive power output, your S may well achieve pretty high velocities, and all that extra plumbing will increase the all-up weight, therefore your bigger brakes are probably a good idea! wink
Keep up the good work, it's gonna be awesome! thumbupcloud9

Will we be witnessing the unveiling ceremony next year?

Alan Whitaker

1,928 posts

117 months

Saturday 3rd December 2016
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We will Glen but first I have a new kitchen to fit for Christmas

Blue 30

Original Poster:

244 posts

52 months

Saturday 3rd December 2016
quotequote all
Getting back on track.
No, not of the tarmac type.
I won't be going anywhere near one of those in my S.
I guess mine will be at the understated, subtle, comfortable, reliable end of the scale, rather than the raw racer or muscle car end.

Getting onto the resto of my front end.
No great revelations here either.
Just the usual, that's been done before.
IE. New steering swivel joints.
Poly bushes for the wishbones and shocks.
And a slight brake upgrade using 887/8 calipers & 278mm discs. I've bought Ford based servo & master cylinder just in case, as I haven't fully inspected those as fitted yet.
TerryB