BJ8 Cam

[UnionJack]

Hey All,

I am currently restoring

a BN6 (photos in Healey Gallery) and am interested in making minor modifications to my car to increase safety and performance. I have already purchased all the goodies needed to convert to early 3000 style front disc brakes. I have been told by several of the "experts" that one of the best and easiest ways to make extra power is to install a BJ8 cam. Can anyone confirm this and possibly add specific advise about which phase, year, other modifications needed, effects on valve timing, etc.. might be involved in this conversion

. I have a spare 3000 engine that sat in the woods for 20 years

but I haven't been able to dissassemble it as of yet to inspect the cam. Any advise would be appreciated.

Regards,

Paul Casarona, BN6
Auburn, AL

 

[Pete Haburt]

Hi Paul;
I'm new to this particular forum, but have done a full restoration on my 61BT7 a few years ago, as well as a 76MGB I've had for 16 years.
The BJ8 cam is a little more agressive and will produce more power. You will need to use at least the 3000 head with seperate intake manifold to realize better breathing though. The early 1006's had the integral intake which restricted breathing, and you could not do anything about it.
I happened to be comparing cam specs a few years ago when I upgraded my MGB with a "BMC road" cam, and lo and behold the specs were the same as the BJ8 cam! It is not a radical cam at all, will still idle nice, but torque will be improved throughout the RPM range. If I was doing my BT7 head over, I would do some minor porting and polishing while it was apart. I did this to the MGB, and what a difference!
Peter Burgess in the UK is well known for his performance head work. He has a book published for MGB's called"Power tuning the MGB 4 cylinder"
I suggest reading it,as it explains all systems, head, ignition, carburation etc so you can fully understand what effects each modification has. While it is specific to the MGB engine, the concepts can be applied to the Healey engine as well.
Happy healeying(or wrenching for now)
Pete Haburt
61 3000 Mk1

 

[UnionJack]

Pete,
I have the later 100-6, a BN6 2-seater, all of which had the 12-port head with seperate alloy intake. Is there an advantage to the 3000 head over the one I already have? I didn't think they were interchangable. Didn't they have to siamese the cylinders when they pop that block our to 3- liters? Thanks for the tip on the book. I will be looking for it soon.

Regards,

Paul
1958 BN6
Auburn, AL

 

[John Turney]

Paul,

the 12-port heads are the same on the 3000 and late 100-6. The cylinder spacing change was not that great.

I've done several engine mods, but since I did them all at once, I can't say which ones gave the most bang for the buck.

John

 

[Jerry]

I bought the disk brake kit from Denis Welch. Anybody have any tips on installation?

 

[John Turney]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Jerry:
I bought the disk brake kit from Denis Welch. Anybody have any tips on installation?<hr></blockquote>

I have both front and rear. Which did you get?

John

 

[Jerry]

Just the front. I was wondering if the kit is as easy as it looks. Any tough parts? I also noticed that it does not have the dust shield.

 

[John Turney]

Jerry,

The front is pretty straightforward. You're correct, there is no dust shield. According to Geoff Healey, the dust shields makes the brake pads last longer. I can't say, since I have less than 1,000 miles on mine, but I assume he would know if anyone would.

Three points to mention:

- The stub axles have a tendency to crack in hard use. While you have everything apart, you may want to crack test the axles. Magnaflux makes a small die penetrant kit that you can use. Check especially the lip where the inner bearing rests. If you have the whole suspension apart, a machine shop can do it for you.

- I found it easier to get the shims right by assembling the axle with just a smidgen of grease, and then when the shim thickness is correct, go ahead and apply grease liberally to the bearings. If you need new shims, the BJ8 shims are a different size than the earlier ones. You will need the early, expensive ones.

- Make sure the disk has minimum runout (wobble) before attaching the caliper. I found that it varied a bit depending on how the disk was bolted to the hub. I recall runout should be less than 0.004". A small runout shortens the pedal travel, and also makes it firmer. I also recall that the holes in the disk were a really tight fit for the hub to disk studs. I recall I had to make the holes slightly larger (by 1/64").

Ok, maybe that's more than three points, but they were easier than the rears.

John

 

[Jerry]

thanks John, I have heard that you may have to shim the calipers to make them center on the rotor. If so, what size of shims are we talking? An extra washer or many differenct sizes depending on the axle? I have not started the project yet, I am waiting for a rainy weekend so I won't be driving anyway.

 

[John Turney]

Jerry,

I didn't have to use shims to center the calipers. They don't have to be perfectly centered, since the pistons will adjust themselves, so I would guess you're looking at washers instead of shim stock. Just make sure the washers are uniform thickness.

John