Webers

[Leibinger]

I have a 62 MkII BN7 Tricarb. It was restored in the US a few years back. The engine had some trouble when I got the car (it was shipped to Germany, where I had moved in the meantime) so it had to be overhauled - the block had a crack.

The car now has a completely rebuilt engine: New block, new crank shaft, new forged pistons, Denis Welch DWR8 cam, alloy head with polished ports, larger valves (regular lift rockers), new manifold, sport exhaust, oil cooler. The ignition is standard. Then carbs are three SU HD6 with regular air filters.

Here are my questions:
1.) The shop where the car is at in Germany has no real recommendations on the needle and piston spring setup for this configuration of engine. The car runs so so at this point - plugs fouling up on low rpm and engine overheating on high rpm and power poor. I found a recommendation for a setup on the web at a British Healey club: SQ needles and 8OZ spring. Any thoughts on this?
2.) Everyone I talk to tells me to go to Webers on this type of setup. They say it will give me 30 to 40 bhp more instantly and will be much easier to tune. Make sense?

 

[Randy_Gay]

Since you have some Welch parts, do they have a recommendation?

 

[SHG]

email Joe Curto and ask him what to do. www.joecurto.com

 

[Leibinger]

No, not for the triple HD3 setup. They tell me to go to dual HD8s, which I don't want to do because it is originally a tricarb; the look is pretty much the same with HD6s as with the original HS4s.
If I had to change this, I think I would go straight to the Webers.

 

[Leibinger]

sorry - I meant "triple HD6 setup", of course

 

[Dave Russell]

It sounds like you have an interesting project. Just a few general comments.

Three H6 carbs actually have a little more venturi area than two H8's, by about 16%. But the two H8's might be a bit easier to tune.

You don't say what needles you presently have in the H6's. If the carbs came from a Healey they may be CV needles. If so, a change from CV to SQ needles would give leaner low end, richer mid range, & leaner top end. A change to four ounce springs may help.

I don't think the DWR8 cam is an extremely radical cam so the three H6 carbs may work pretty well. Maybe just the right increase over the H4's.

I'll leave suggestions on the Webers to some of the folks who have them on Healeys. A general comment on Webers, if you don't get the venturi size & jetting pretty close the first time, it is likely to cost you a bunch of time & money to try 6 each of the various many jet & venturi combinations.

I hope that the project comes out well for you,
D

 

[David_K]

I second calling Joe Curto.