FS: NOS Girling 16-4 calipers

[Chris Pomares]

Could these be used on the front of a long hood with m rears?

[Neunelfer]

Sure but, it would throw off your bias ratio something severe. I'd work on adapters for a rear set as well. These are, for all intents and purposes, 930 calipers. Very cool, early versions made by Girling but... basically 930 calipers.

[chris_seven]

I have seen an early Ex-Vic Elford SWB car (Polo Red) fitted with this type of Girling Caliper on the front but I couldn't see if they were 16/4 or 18/4 nor what was fitted to the rear.

You would, as already stated, change the front to rear brake bias ratio by a significant amount.

A standard 911 with a 19mm Tandem Cylinder produces a theoretical brake balance of around 61/39 front to rear.

If you fit a 16/4 Girling this will change to around 67/33 which will significantly impact on braking behaviour and could even increase stopping distances on Race Tracks. This assumes you have retained the rear M Type caliper with 38mm dia pistons.

The car may appear to stop more effectively as they will tend to lock the front more easily and the reaction time with regard to pedal input will be faster and this could generate an improvement under some circumstances but .....

the problem occurs when the balance between front and rear is upset and the front brakes generate enough force to lock before the rear braking force has been fully applied, hence an increase in stopping distance.

If you fit a 16/4 to the front and a 16/4 to the rear then the brake balance will become 50/50 and IMHO this would be quite dangerous and as soon as the car turned-in and weight transferred forward there would be a tendency to lock a rear wheel.

If you want to use a 16/4 on the rear I would advise using an 18/4 on the front although this will still tend tend to produce too much rear braking and produce a balance of around 56/44

The 18/4 has a 4 x 42.8mm diameter pistons compared to 4 x 38.1mm used on the 16/4.

They are available new as they have been re-manufactured for GT40's and Lola T70's.

By using a 16/4 on the front and fitting a Front M Type with a 48mm diam piston and 3" lug mounting centres to the rear you would also end up with a balance of around 56/44 Front to Rear.

You could deal with these issues by juggling pads/wheels/tyres but results may be vary depending on wet/dry conditions. The best way would be to add a Bias Bar Pedal Box and adjust accordingly.

In all of the above cases the pedal effort needed to achieve a given deceleration will change depending on the caliper combination you choose.

I thought the 930 Turbo used 4 x 38mm diameter front pistons and 4 x 30mm diameter on the rear.

This is a balance of around 61.5/38.5 Front to rear and is virtually identical to the standard car with M calipers with 2 x 48mm front and 2 x 38mm rear pistons.

[Neunelfer]

Precisely... and, you are correct on the 930 piston sizes.

[geneulm]

These are still sitting on the climate controlled conditions inside my office coffee table if anyone quants to make a go of it

[Chris Pomares]

Are the 84-89 Carrera rear calipers different then the SC ones? I thought I read they have 42 mm pistons? These Girlings up front?

[geneulm]

How about an I can’t believe these are still out there bump.

Honest to gosh NOS 917 rear brakes

[914-6gt]

I can't believe it either Gene. If I didn't have this pair of 908 Mag front calipers for my GT, I would buy your Girlings in a 'nano-second'.

Where else would you find a set of 917K vintage calipers at that price?

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Eric at PMB restored these for me...

[geneulm]

Ok. Bargain time is over: the 917 calipers are now $3,000 shipped CONUS.

Hey. It worked for Frank.

[geneulm]

These are STILL living in my infamous office coffee table!