Differences between BT7 and BJ8 engines.

[dcarlg]

So, I'm thinking about refreshing/rebuilding a BJ8 engine to install in my BT7.
I would like to retain the tri-carb setup and mechanical tach. My research has found that the cam, distributor and clutch are not interchangeable. What else do I need to know?
Thanks.
Douglas

 

[British_Recovery]

I put a BJ8 engine in a BN6, similar to what you plan. The generator bracket/side cover from the BT7 should be retained to mount your generator. The side shift gearbox, as well as the center shift 'box, will mount to the BJ8 backplate, and the BJ8 clutch can be used, making sure to use the correct BJ8 throw out bearing. Use the BT7 distributor with the BT7 tachometer drive. As far as the tri-carb set up, it should fit, but I used the 2" dual carbs from the BJ8. Also check which pulley width the BJ8 has on the crank, since later ones used the 1/2" width. Your BT7 would have 3/8" pulleys on the water pump and generator.
If I think of anything else, I'll post it.

 

[Bob_Spidell]

... making sure to use the correct BJ8 throw out bearing ...

I just bought a throwout bearing from Moss on sale--just looked at the sale items and didn't look at the catalog--and this had me double-checking the part I ordered. Holy cow; the bearings for BJ8s are listed at $99.99--I think it was $10 off on sale--and I see the bearings for earlier 6-cyl cars are only $19.99! Anyone know why the big disparity in prices? I presume they're all the graphite 'donut' variety.

 

[dcarlg]

Hi Bob,
I recently purchased a BJ8 throwout bearing from British Parts Northwest. $21.45. They have occasional sales.
I have no business interest, etc.
Douglas

 

[Bob_Spidell]

... I recently purchased a BJ8 throwout bearing from British Parts Northwest. $21.45. They have occasional sales.Douglas

Thanks! Was really glad to hear I overpaid by $60+

I've not known Moss to gouge (that much); gotta be more to the story (I think BPNW might even be a Moss distributor).

 

[Keoke]

I just bought a throwout bearing from Moss on sale--just looked at the sale items and didn't look at the catalog--and this had me double-checking the part I ordered. Holy cow; the bearings for BJ8s are listed at $99.99--I think it was $10 off on sale--and I see the bearings for earlier 6-cyl cars are only $19.99! Anyone know why the big disparity in prices? I presume they're all the graphite 'donut' variety.

Sounds liked a fat finger put the add in to me--:highly_amused:

 

[steveg]

I'd call Moss' tech support and ask them why it's so different. Maybe there is a mistake, in which case maybe a refund would be in order.

 

[Bob_Spidell]

I'd call Moss' tech support and ask them why it's so different. Maybe there is a mistake, in which case maybe a refund would be in order.

I plan to do that. I'm on a 'first name basis; with Michael Grant--their head of tech support--after the water pump fiasco.

 

[steveg]

I put a BJ8 engine in a BN6, similar to what you plan. The generator bracket/side cover from the BT7 should be retained to mount your generator. The side shift gearbox, as well as the center shift 'box, will mount to the BJ8 backplate, and the BJ8 clutch can be used, making sure to use the correct BJ8 throw out bearing. Use the BT7 distributor with the BT7 tachometer drive. As far as the tri-carb set up, it should fit, but I used the 2" dual carbs from the BJ8. Also check which pulley width the BJ8 has on the crank, since later ones used the 1/2" width. Your BT7 would have 3/8" pulleys on the water pump and generator.
If I think of anything else, I'll post it.

Add to the above: putting a BJ8 cam in an earlier 3000 is done all the time. Russ Thompson says he upgrades to BJ8 specs on all rebuilds.

 

[Randy Forbes]

Add to the above: putting a BJ8 cam in an earlier 3000 is done all the time. Russ Thompson says he upgrades to BJ8 specs on all rebuilds.

Addendum II:

The only snafu here, is when rebuilding the early 2.6 engines; they have a larger driving gear on the cam, and a smaller driven gear on the oil pump spindle. Though they can be swapped in pairs, the early blocks require a bit of spot-facing to clear the larger diameter of the driven gear.

Some trivial info that may be useful to one in a thousand (1:1000) engine builds (don't mind me, I'm still high from everyone agreeing with me in the silicone/Kevlar hose thread, lol!).

 

[Dandare]

Randy, how would you expect the BJ8 cam to perform in an otherwise standard gallery head 2.6 (or non Healey 3L gallery head)?

Danny

PS:

Some trivial info that may be useful to one in a thousand (1:1000) engine builds..

A fellow in another forum recently ran into this when rebuilding his early Austin Westminster engine with the said camshaft!

 

[Randy Forbes]

Randy, how would you expect the BJ8 cam to perform in an otherwise standard gallery head 2.6 (or non Healey 3L gallery head)?

Danny

PS:


A fellow in another forum recently ran into this when rebuilding his early Austin Westminster engine with the said camshaft!

Jim (aka healey blue) & LS apparently like it! It's been on the road for a few years now, and I'd think that one or both would've let me know if there're any problems. This engine was essentially an otherwise standard rebuild, save for some strategic choices on applying polymer coatings to certain components, primarily for temperature management & reduced friction/wear.

I don't think the BJ8 camshaft grind is so radical as to be starved for air/fuel supplied through the integral intake manifold, but there's little doubt that (combined) with the increased tract velocity of a 3000's displacement, the less restrictive manifold and larger carbs, it would see bigger gains.

 

[Dandare]

Thanks for the insight Randy.

Danny