After a week of wrestling with the tuning, she runs . . . superbly.

Seriously, you can feel the added power, and the revs are silky smooth.  The booming exhaust note (through my 1.75" LCB + 2-box pipe) is . . . sexy.

 

 

Here's an update.  After plenty of effort, which including needing to replace the speedo cable (the absolute worst task on the Mini) and then replacing the radiator I ham-handedly cracked when trying to wrestle it back in (the second worst task on the Mini), we have this . . . 

 

 

Grinding and "adjusting" the edge of the bulkhead gave me still only nominal clearance around that float bowl, but I have 2 of the 3 engine steadies mentioned in this thread (top left and bottom right).  Just in case, I will rig a simple fire-suppression system - basically run a hose from an extinguisher in the cabin into the bay through the console opening.  That way, should that bowl ever crack (God forbid), I can at least put the fire out in time to have something left to put on the flatbed.

Got a pair of No. 5 needles in there, and have it tuned for a nice steady idle and smooth revs.  Once I rig up the extinguisher, I can start testing her under load around the neighborhood.

Thanks much for all the help in this thread.  

Here's one version of the right-front engine steady.

//www.minimania.com/Search_Results/engine%20steady/All

There is a left hand and right hand. If you look at the brackets and hold them up to the transmission from underneath you can figure out where they go. Then you drill a hole into the front frame and bolt it in.

Jerry

Where do those bottom steadies attach though?  I was looking through my engine bay trying to figure out where another steady might go down there, and I am stumped.

two on the bottom, rear. One on top. Engine does not move!

Jerry

Where do you have that third engine steady?  Dog-bone on the flywheel side, top arm on the radiator bracket and . . . . ?

I do have heat shields in place, just no spacers.  I have about an 1/8" between the bowl and the bulkhead/MC.  Now to fab up some filter plates.

The clearance to the Brake master is minimal, ie: thousands. I do have the heat shields, you need them. Clearance to eveything else is enough. But, I have the engine set in place with three engine steadies. One on top and two down below. It does not move, and probably won't till the cheap rubber breaks down.

Jerry

If you haven't them yet, don't forget the heat shields -

//www.minimania.com/part/MSSK1004/Hs4-Twin-Carb-Heatshield-Kit---Black

//www.minimania.com/part/MSSK1006/Heat-Shield-Kit-S-s-Hs4

I am in Chicago.  How much clearance did you end up having in that build?  So far I can get the carb to fit, but clearances are super tight.  Given the issue is at the fuel bowl and sits above the exhaust header, the potential for disaster is pretty high.  What's a good threshold amount of clearance?

I have twin 1.5 SU on my 1380 LHD. Fitting is a pain. It required the following steps. 1. Adjust the engine stay as suggested above. 2. Machine the outboard face of the intake manifold. Took off 1.4 inch, there was plenty of meat there. 3. Made up an offset mounting for the Drivers side air filter. It is just a box about 4"x1.75"x 3 inch. I marked it out, bent it , welded it up, and then cut a hole on each side for the mounting and air flow. The holes are offset, of course.

Fitting is still tight but there is clearance. Works great but then I have a 1380 vs a 1275, might make a difference. I also suggest mounting an air/fuel flow meter for tuning. I could not have made it work without it.

Your profile does not say were you live but if around NOrthern California, there is a British car show on May 17th in Dixon CA. There will be lots of minis and about 290 other British cars. //www.ubscc.org/CarShow.htm

You can see the conversion in person there!

Jerry

Can anyone post a pic of the offset baseplate?  Although, I can make one based on the actual positioning, I'd like to know what the standard offset looks like.  For instance, if it won't accomodate my situation, I'll have to plan on using some custom filter plates long-term.

The float bowl in question does have a pretty heavy casting flange, compared to the other one.  So this actually may yield a few more mm of clearance.

I tried adjusting the radiator steady last night, but that didn't really get me anywhere.  I think I can grind a bit more around the base of the MC to pick up a bit more clearance.  THen I could fab up some offset filter baseplates to clear the MC up top.  That may get me in the ballpark.  If so, I'll order some actual offset filters.  If not, I can look into changing out that MC for something leaner.

I was going to suggest looking at the yellow band brake m/c. Not sure you won't have to do some other tweeks to the brakes if you use that. but it's tall and likely out of the way.

 

I have twin HS4 fitted to a LHD MkIV......no space issues....although my master is the tandem type.  Looks like the same manifold

Not too much carb at all.....I'm running great with #5 needles.....nice idle also

A wild guess: would swapping fuel bowls make any difference?

Here's what the other end of a 1275 transplant looks like. You can see the bottom of the split-system brake master cylinder has no pale under it. (Factory original, judging from the patina of age.) and the clearance between the engine and the firewall cross-member. My car was originally built with a 998cc lump, so I don't know if the engine mounts were moved forward in the transplant. Judging from some other aspects of that work, I strongly doubt it. The car, BTW is a mid 1980's body, so the crossmember may be a bit different than yours, but not where the master cylinders sit. The carb is a single HIF44, with spacer and the Minispares inlet manifold. There's about 1/4" or so between the carb and the crossmember and brake lines.

For comparison I have added a picture of a single HS4 on the same manifold

The 'dogbone' stock engine steady is on the clutch end of the engine - outlined in yellow in the attached photo.The plate under your master cylinders should be on the right side of the car in the location outlined in green. My car was built as a leftie, and it had that plate here (but it was broken so I had to fabricate my own out of aluminum checker-plate). In my car, the heater hoses pass through the plate, as it was built originally.

You should NOT have that plate under the master cylinders. Maybe some thin shims or similar to match the thickness - there's another thread somewhere about brakes locking up because it wasn't shimmed here roperly.

Becaus you do have that plate there, it is causing some confusion - other responders think you have an engine steady at the rad end, but that plate won't work on the rad engine - the water pump etc. is in the way of putting a dog-bone there. Rad-end steadies typically are positioned above the head, connecting to the head at the thermostat housing location.

EDIT: I now see you do have an engine steady on the front of your engine.

"Block one" = dog-bone on the right then?  Sorry to be dense.