Fitting 3 HD6 to 6 cy Healey

[red57]

Hello, I am new to this forum and am hoping for a little help.
I am wondering if anyone has tried to install tripple HD6s on a left hand drive 3ooo?
I have been collecting bits for a while now to install on my car (57 100-6 w/3000 motor). I mocked-up the whole thing on a spare head on the bench. I was going to use stock tri-carb manifolds enlarged for 1 3/4 carbs but I ended up buying a set from Denis Welch. When I tried to install them I found the rear carb will not clear the steering column.
I realise the HDs (& all other semi-downdraft carbs I have) are built for 30 degree semi-downdraft. But the stock manifolds and the Denis Welch ones actually mount the carb at 25 deg. (which means the float chamber is 5 deg from vertical).
My solution was to mill the carb mounting surface at 32 deg, redrill & helicoil the carb studs at the new angle, and shave the head mounting surface of the manifold 1 degree. This mounts the carb at 33 deg semi-downdraft. With this rework I was able to get the rear carb in but I have only got about .200 clearance between the bottom of the car abd the steering column.
Now, after all the above, my burning question is: How much clearance is really needed? Has anyone attempted this on a left hand drive car?
I welcome all comments - my first race of the season is only a week away and I am finshing up the installation and hope to have it drivein this weekend so I can start making needles & fine tuning.

Thanks in advance
Red 57

 

[Stretch]

Hard to tell from your description. You need to assess how the carbs will move relative to the centerline of the crankshaft in response to engine torque as well as up and down from bumps. I would think 0.20 in. is on the short side for a race car.

 

[red57]

I agree, however my headers only have 1/8" clearance where they pass under the braces from the frame to the bulkhead and they have never touched (and that point is further from crankshaft centerline than the carb/steering interference). I am planning on putting some tape on the column and driving it as hard as I can on the street, then looking for any indication of contact. Part of the worry is that on the HDs the spot that would touch the column is the fuel 'well' under the jet - would hate to crack that and have fuel pouring out.
Thanks

 

[Dave Russell]

Sounds like a fun project.

.200" may be enough as is. You might gain a bit more by lowering (tilting) the steering column/wheel a bit. The steering box to frame mount has a slight bit of adjustment. The trim plates where the column goes through the firewall have a bit of adjustment, & the steady bracket under the dash has a bit.

I think I would try it as is first. If the carb is contacting the column, I think you will feel it as a vibration before any serious damage is done.

The carbs will move up/away from the column under acceleration & down toward the column under deceleration. With good engine mounts I doubt things will move much.
D

 

[red57]

You are absolutely correct, however, I have already moved the steering as much as I can without enlarging the hole in the dash or otherwise cutting metal so I am hoping to not have to go there.

But I have considered either flattening the outer column tube in a small spot where the conflict is (could theouretically gain another 1/8" and still not rub on the steering shaft), or cutting a small piece out and welding a 'flat' spot in the outer column tube.....

Thanks

 

[GregW]

One other though I'll throw out is shimming the engine mount to raise the engine a tad. Lots more work though.

 

[Patrick67BJ8]

Hello, I am new to this forum and am hoping for a little help.
I am wondering if anyone has tried to install tripple HD6s on a left hand drive 3ooo?
I have been collecting bits for a while now to install on my car (57 100-6 w/3000 motor). I mocked-up the whole thing on a spare head on the bench. I was going to use stock tri-carb manifolds enlarged for 1 3/4 carbs but I ended up buying a set from Denis Welch. When I tried to install them I found the rear carb will not clear the steering column.
I realise the HDs (& all other semi-downdraft carbs I have) are built for 30 degree semi-downdraft. But the stock manifolds and the Denis Welch ones actually mount the carb at 25 deg. (which means the float chamber is 5 deg from vertical).
My solution was to mill the carb mounting surface at 32 deg, redrill & helicoil the carb studs at the new angle, and shave the head mounting surface of the manifold 1 degree. This mounts the carb at 33 deg semi-downdraft. With this rework I was able to get the rear carb in but I have only got about .200 clearance between the bottom of the car abd the steering column.
Now, after all the above, my burning question is: How much clearance is really needed? Has anyone attempted this on a left hand drive car?
I welcome all comments - my first race of the season is only a week away and I am finshing up the installation and hope to have it drivein this weekend so I can start making needles & fine tuning.

Thanks in advance
Red 57

I wish I could help, but my engine went bad before I was to install my "brandnew" Ruddspeed triple manifold with HD6's. I accumulated articles on the Ruddspeed conversions and there's nothing mentioned about clearance problems. There's a significant differnce between the Ruddspeed manifolds for L'H & R/H drive cars.
Patrick

 

[red57]

Patrick,

You have made me jealous - I would love to find a Ruddspeed set I could afford. In fact, it was a comment I read about the Ruddspeed conversion for L/H being 30 deg and shorter to clear the steering that triggered my reworking mine to try and clear - I started at 30 deg but I only had .060-.070 clearance, so I kept working it until I got the the 33 total I have now. I don't want to go any further than I have to because aside from float bowl issues, the straigter the induction tract the better the flow.

With the research you have on the Ruddspeed do you have any info on their recommended needles and springs? I have been planning to start with Yellow, 8oz springs and CV needles but I have wondered what they used.

Dave

 

[Patrick67BJ8]

Patrick,

You have made me jealous - I would love to find a Ruddspeed set I could afford. In fact, it was a comment I read about the Ruddspeed conversion for L/H being 30 deg and shorter to clear the steering that triggered my reworking mine to try and clear - I started at 30 deg but I only had .060-.070 clearance, so I kept working it until I got the the 33 total I have now. I don't want to go any further than I have to because aside from float bowl issues, the straigter the induction tract the better the flow.

With the research you have on the Ruddspeed do you have any info on their recommended needles and springs? I have been planning to start with Yellow, 8oz springs and CV needles but I have wondered what they used.

Dave

The new Ruddspeed mainfold looks so darn good that instead of storing it in the garage cabinet, I have it on the book shelf next to my 50 volume Harvard Classics.
My wife doesn't seem to mind either and she's an interior designer!!

There's information on setting them up on a website and I downloaded it a long time ago. I'll research the info and let you know where the link is.

I may not ever use the Ruddspeed as I'm in the process of dismantling my car for complete restoration and not sure yet how I'm going to do the engine when it's time to put everything back together, but I never the less been compiling the info on it.

I'll let you know the set-up info. There's lot's of good stuff about the cams used and their performance, etc., complete with springs and needles info. Don't buy anything until you read the article(I think I got it from a UK web-site).
Patrick

 

[Patrick67BJ8]

Patrick,

You have made me jealous - I would love to find a Ruddspeed set I could afford. In fact, it was a comment I read about the Ruddspeed conversion for L/H being 30 deg and shorter to clear the steering that triggered my reworking mine to try and clear - I started at 30 deg but I only had .060-.070 clearance, so I kept working it until I got the the 33 total I have now. I don't want to go any further than I have to because aside from float bowl issues, the straigter the induction tract the better the flow.

With the research you have on the Ruddspeed do you have any info on their recommended needles and springs? I have been planning to start with Yellow, 8oz springs and CV needles but I have wondered what they used.

Dave

Dave,
Go to this website:
www.austinhealeyclub.co.uk
...and then go to the "technical" section and them you'll see "triple carbs".
Patrick

 

[red57]

Patrick, Thanks for the link - I had stumbled onto that a while ago, but couldn't remeber where I had seen it or how to find it again. Good info & very helpful.

And thanks to all who responded with helpful thoughts.

As a follow-up for anyone who is interested. After a marathon weekend of work, I got it running yesterday and took a couple of test drives. I had ended up with just under 1/4" clearance (about .240) between the rear carb and the steering column and figured that was enough. I put 6 layers of masking tape on the column under the carb and, so far, no marks in the tape.

As an initial set-up I am using CV needles and yellow, 8oz springs. Tops of jets are now set at about .030 below the bridge and the mixture seems good.

My motor is well balanced, +.040 over, lotta head work, cam is 283 deg at 0 lift but not enough lift to need pockets in the block. I have headers that are 3 into 1 and I have oxygen (Lamda) sensors in each collector and a Stewart-Warner gage with a switch to go from one to the other (front 1/2 vs rear 1/2 of motor).

On my test drive, I had no lean spots and generally was a bit rich, if anything, and richer is always safer than lean.
It starts and idles very nicely and the throttle response is very crisp. And power 1s way up, particularly in the 5-6000 range. And I suspect it will get even better as I continue to fine-tune it.

Again, this was my first experience at using a 'forum' of any kind and I am very appreciative of all the help.

If nothing else, it's reassuring to know I'm not the only nut out there.

Thanks
Dave Phillips