Post by bbh on Oct 2, 2017 19:49:09 GMT
Fitting (Thicker) BJ8 Brake Disk to an earlier car.
BN7 & BT7’s up to BJ8 26704, had a front brake disk which was circa 10mm thick. The overall disk measurements being 286mm in diameter and 36mm thick, including ‘bell’ housing.
BJ8’s from car number 26705 had a thicker disc of ½” or circa 13mm. The overall disk measurements being 281mm in diameter and 39mm thick, including ‘bell’ housing.
This change also corresponded to the change from Girling Type 14 to Type 16 calipers providing a pad with greater contact area.
There have been a few articles written on upgrading front brakes:
www.healey6.com/Technical/big
www.acmefluid.com.au/larry/brakes.pdf
Each of them recommends upgrading from the thinner “early” disks to the thicker BJ8 discs as this allows the use of bigger calipers and manages heat build-up better.
Now some reports suggest that this is a straight forward swap with the later “thicker” discs fitting all cars.
However other articles (correctly) suggest that on some cars the BJ8 disc interferes with the caliper mounting bracket.
www.fossewayperformance.co.uk/big-healey-brake-caliper-upgrade/
From some research for those who wish to upgrade (and keep with the earlier type of stub axle) I can see three options:
a. Change the original caliper brackets to one sold by the “performance outlets” which has been designed to take the later disc and Type 16 caliper. However at over £200 for the pair – not exactly a budget change.
b. Again, shopping at one of the “performance parts outlets” you can pick up a “Works Homologated” disk at 11.25” diameter (286mm), which are stated to fit all models (apart from those later BJ8’s). Beware though at first glance the price looks comparative with a pair of EBC slotted & drilled disks, but on closer look it is for only 1 disk!, So some-what north of £300 for a pair.
, ouch!
c. The original caliper brackets are quite meaty and will stand a bit of judicious thinning. Each may be a bit different but I found that thinning down the area around the caliper mounting hole and along the top and bottom of the bracket – where there is quite a thick protruding ridge (see picture), enough to clear the thicker disc worked fine, and certainly quite a bit cheaper than the other options. The only down-side is that there can be quite a bit of trial fitting to check if enough clearance has been achieved.
Before
After
BN7 & BT7’s up to BJ8 26704, had a front brake disk which was circa 10mm thick. The overall disk measurements being 286mm in diameter and 36mm thick, including ‘bell’ housing.
BJ8’s from car number 26705 had a thicker disc of ½” or circa 13mm. The overall disk measurements being 281mm in diameter and 39mm thick, including ‘bell’ housing.
This change also corresponded to the change from Girling Type 14 to Type 16 calipers providing a pad with greater contact area.
There have been a few articles written on upgrading front brakes:
www.healey6.com/Technical/big
www.acmefluid.com.au/larry/brakes.pdf
Each of them recommends upgrading from the thinner “early” disks to the thicker BJ8 discs as this allows the use of bigger calipers and manages heat build-up better.
Now some reports suggest that this is a straight forward swap with the later “thicker” discs fitting all cars.
However other articles (correctly) suggest that on some cars the BJ8 disc interferes with the caliper mounting bracket.
www.fossewayperformance.co.uk/big-healey-brake-caliper-upgrade/
From some research for those who wish to upgrade (and keep with the earlier type of stub axle) I can see three options:
a. Change the original caliper brackets to one sold by the “performance outlets” which has been designed to take the later disc and Type 16 caliper. However at over £200 for the pair – not exactly a budget change.
b. Again, shopping at one of the “performance parts outlets” you can pick up a “Works Homologated” disk at 11.25” diameter (286mm), which are stated to fit all models (apart from those later BJ8’s). Beware though at first glance the price looks comparative with a pair of EBC slotted & drilled disks, but on closer look it is for only 1 disk!, So some-what north of £300 for a pair.
, ouch!
c. The original caliper brackets are quite meaty and will stand a bit of judicious thinning. Each may be a bit different but I found that thinning down the area around the caliper mounting hole and along the top and bottom of the bracket – where there is quite a thick protruding ridge (see picture), enough to clear the thicker disc worked fine, and certainly quite a bit cheaper than the other options. The only down-side is that there can be quite a bit of trial fitting to check if enough clearance has been achieved.
Before
After