Weber conversion

Printed from: Sunbeam Rapier Owners Club
Topic URL: http://www.sunbeamrapier.co.uk/forum/topic.asp?TOPIC_ID=880
Printed on: 08 Jan 2025

Topic:

Topic author: UMU
Subject: Weber conversion
Posted on: 15 Jan 2013 10:27:02
Message:

It seems like ive had this set of weber 40s for ages now, so its time to get them on - Thanks for the nudge Jason.
Im missing some bits though and although i could buy new, id like to avoid this if poss to save a bit of cash.

Im after
4 - 32mm chokes
4 - Trumpets (must be shiney)
Either the origional air box assembly or aftermarket filters.
Also i have a distinct lack of cables, linking bars, etc.

If anyone has any of the above, please let me know

The pics show what i have -

Replies:

Reply author: JPSH120
Replied on: 15 Jan 2013 10:55:07
Message:

Good man, you know it makes sense!

Set of trumpets here;

http://www.ebay.co.uk/itm/Weber-40-DCOE-Ram-Pipes-Trumpets-/140905423695?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item20ce9e234f

Cables you should be able to get hold of easily enough, although choke cables are for show only as the choke is a waste of time in my experience. You need a connecting rod between the carbs and cable mount (black bracket thingy) which again should be easy to find.

Your hardest job will be finding the fibreglass air box & saucepan airfilter housing. I may have a spare air box but the filter housings are like rocking horse poo (I will double check but don't think I have one spare). You might have to settle for after market filters until you can find what you need.

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Reply author: andyb
Replied on: 15 Jan 2013 11:21:48
Message:

just fitted webers to my fastback
managed to get the whole lot inc airbox but no filter housing

strangely enough i inadvertently threw out a filter housing that came with the car as i didn't recognise it as a rapier item doh !





sometimes nothing can be a real cool hand

Reply author: JPSH120
Replied on: 15 Jan 2013 11:28:25
Message:

quote:

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Originally posted by andyb

strangely enough i inadvertently threw out a filter housing that came with the car as i didn't recognise it as a rapier item doh !

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Reply author: UMU
Replied on: 15 Jan 2013 11:52:12
Message:

Thanks.

Im happy to fit aftermarket filter things, i like the look of them so dont worry too much. But of course if an air box etc come up ill be interested

Andy, how does your car run now?
Any issues?

Reply author: UMU
Replied on: 15 Jan 2013 11:53:36
Message:

Jason, thanks for the link.
I have a set of those, but dont know how they fit on??? So figuered theyre the wrong ones, no im not sure

Reply author: JPSH120
Replied on: 15 Jan 2013 11:56:19
Message:

They are held on with little lugs, like these;

http://www.ebay.co.uk/itm/WEBER-40-DCOE-RAMPIPE-TAB-NEW-SET-OF-8-PN-52150-012-/360493456232?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item53ef159b68

By the way, what are your plans for Shepton Mallet this year, is your car available if required?

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Reply author: UMU
Replied on: 15 Jan 2013 11:57:12
Message:

Reply author: UMU
Replied on: 15 Jan 2013 11:58:27
Message:

YES please, id like to be there if u have room for me

Reply author: andyb
Replied on: 15 Jan 2013 12:22:51
Message:

It needs setting up as spits and farts when cold but smooths off when engine warmed up

it will also require a cable sorting out, the guy that rolling road tunes our cars will probably want to put a new cable/linkage on it but thats not a problem

need to get a few other jobs sorted than it can go
i just wonder if it will be ok ref the difference in port sizes



sometimes nothing can be a real cool hand

Reply author: JPSH120
Replied on: 15 Jan 2013 13:22:30
Message:

quote:

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Originally posted by UMU

YES please, id like to be there if u have room for me

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Reply author: UMU
Replied on: 15 Jan 2013 13:47:22
Message:

Thats fine Jason, just let me know when you do.

It looks like the ram pipes fit in the intake side of the webers, but only if i remove the venturis.
So I guess the trumpets i need are the external bolt on ones.

Andy, if you could put a few pics on of your set up for me too follow, id really appreciate it

Reply author: JPSH120
Replied on: 15 Jan 2013 14:04:22
Message:

Have a look at the picture on this listing;

http://www.ebay.co.uk/itm/Single-Webber-Weber-40-DCOE-34-Carb-Carburettor-Italian-Made-/281049863662?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item416fe095ee

You can see the little lugs holding the edge of the lip that is on the ram pipes. The venturis go inside the inlet side of the carb and then the pipes go in after.

Looks from the picture that having no backing plate is not a problem.

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Reply author: 1922
Replied on: 16 Jan 2013 08:42:24
Message:

And - if you fit K&N filters or similar you will probably need to use bigger main jets.
Long ago Holbay used to do a kit with filters and jets.

Reply author: 1922
Replied on: 16 Jan 2013 08:50:35
Message:

Oh yeh - and if you are replacing the chokes. You need the correct type with the extended auxiliary venturis - it won't run properly without them.
Unfortunately I can't find my Weber tuning book at the moment to explain why - it was something to do with pulsing of the airflow.

If you can get yourself a copy of Weber Carburettors, Part 2: Tuning & Maintenance by John Passini - very informative and quite funny. It even mentions the H120 a few times.
http://www.amazon.co.uk/Weber-Carburettors-Tuning-Maintenance-v/dp/0851130607/ref=sr_1_fkmr1_1?ie=UTF8&qid=1358326664&sr=8-1-fkmr1

Reply author: UMU
Replied on: 18 Jan 2013 10:47:35
Message:

Derek, thanks for the link and the advise. The guy I got the carbs from has his on a 17.25 engine in a small alpine. I'll give him a shout and see what he says, hopefully he will give some pics too

Reply author: did60
Replied on: 19 Jan 2013 09:49:54
Message:

I also have 2 webers on my alpine ... you can see the link below on the club forum where I explain my assembly ....
http://sunbeamania.purforum.com/t107-quel-weber-pour-ma-sunbeam

Reply author: UMU
Replied on: 21 Jan 2013 20:49:00
Message:

Ive now seperated my stromberg manifold from the head and was hoping to find its a H120 head as i have the 4 branch exhaust fitted, but its not.
In case anyones interested, ive been speaking to a really helpful and knowledgable chap called Chris Draycott, who (if you dont know him) specialises in modified/ tuned rootes engines and webers.

Hes going to make me a manifold to fit and take advantage of increased air flow as well as any other bits i need along the way. He can also tune the car for me, but thats not practical as hes not local.
(this also means i now have a H120 manifold for sale)

Reply author: JPSH120
Replied on: 22 Jan 2013 13:39:21
Message:

Martin,

Here is an air box/filter housing taken from one of the later H120's, not as nice looking IMO as the earlier version but it is OE.

Might be worth getting if the price is right?

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Reply author: arrocuda
Replied on: 22 Jan 2013 16:26:19
Message:

Chris Draycott sent me some valve timing data a few years back. A very knowledgeable and most helpful guy. What will the final spec' of the engine be? Do you plan to swap the camshaft out?

Interesting stuff!

Here's the link to the air box that Jason forgot to post.....
http://www.ebay.co.uk/itm/HILLMAN-HUNTER-HOLBAY-GLS-AIR-FILTER-BOX-/181066871762?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2a286d33d2

I'm assuming that it's the same one.... but if not is another one to try for.

Is also a pair of Webers complete with trumpets on 'the bay of interesting tat' right now if anyone's looking for some.

http://www.ebay.co.uk/itm/weber-twin-40-Carburettors-Form-Holbay-Sunbeam-Alpine-Escort-Race-Car-/181066844732?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2a286cca3c








Building the 'Mark II' fastback Rapier ('Arrocuda').

Reply author: arrocuda
Replied on: 22 Jan 2013 16:38:25
Message:

Forgot to mention that Didier (did60) was asking if anyone had a Holbay manifold going spare in the 'parts wanted' section recently.

Building the 'Mark II' fastback Rapier ('Arrocuda').

Reply author: UMU
Replied on: 22 Jan 2013 19:58:16
Message:

Thanks guys.

Reply author: JPSH120
Replied on: 22 Jan 2013 23:51:40
Message:

Oops, thanks for adding the link Tim!

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Reply author: UMU
Replied on: 05 Feb 2013 19:29:08
Message:

I've now made a little progress. First ive sold the manifold that I dont need and I've bought all the parts.

Its like Christmas as there all arriving, today I received the manifold gaskets and foam socks

Reply author: UMU
Replied on: 07 Feb 2013 07:37:27
Message:

Refurb kits arrived yesterday and both carbs have been stripped, cleaned and rebuilt.

I have a little issue though, one of the lugs that support one side of a float have snapped off. Thinking about soldering back on. Any ideas?

Reply author: UMU
Replied on: 08 Feb 2013 17:06:50
Message:

I've now got all the parts, except the manifold but that will come. I think I have also found someone who will weld the broken bit up for me on Monday.

so basically they are ready to go.

Next stage is fitting and getting them hooked up

Reply author: UMU
Replied on: 26 Feb 2013 20:53:25
Message:

So I've had my Weber repaired and have completely rebuilt them whilst cleaning and installing the gasket kits.

ill put some pics on very soon too

Reply author: UMU
Replied on: 28 Feb 2013 20:49:33
Message:

Heres a few pics of the webers

Reply author: UMU
Replied on: 13 Mar 2013 23:42:48
Message:

I now have virtually all the parts for the conversion, but im in need of hoses too replace the standard ones - the one for the heater matrix loop and the two to the h120 manifold.

also if anyone could post a pic of their h120 engine bay for me to follow, that would really help.
And any ideas where i might get the pipes I need.

Will be fitting the manifold and webers tomorrow

Reply author: JPSH120
Replied on: 14 Mar 2013 07:24:39
Message:

Hello mate!

If you get some servo/vacuum hose that will be what you need to go from the servo to the 2 connections on the manifold, you also need a plastic tee piece.

Heater hoses I have some 2nd hand ones if you need them, you know where I am

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Reply author: bigt80
Replied on: 14 Mar 2013 18:40:19
Message:

Yes, the 34/35's were specially made by Weber for the H120. I think those venturi's were added to try and get over the flat spot they suffered from in the 1800 - 2200 RPM band. Never really worked successfully tho!

Reply author: UMU
Replied on: 15 Mar 2013 19:56:40
Message:

I've fitted the webers! And well chuffed with how the engine bay now looks.

However I haven't finished the task as still have to connect the fuel pipe (need a 't' piece) and the vacuum for the servo (again a 't' piece is needed).

And the accelerator cable is wrong, so will be looking out for a H120 one (mine has the wrong end bit and the protruding cable is too long)

Hope to be in a position to start it this weekend, fingers crossed

Reply author: 1922
Replied on: 18 Mar 2013 11:15:04
Message:

Small gas pipe compression fittings work well as the fuel T-piece. Had one on mine for years.

Like this http://www.cotswoldengineeringsupplies.co.uk/Wade%20Brass%20Compression%20Fittings/brasscomprimpmet.php?item=Equal%20Tee&inthere=&line=Brass%20Compression

Reply author: UMU
Replied on: 18 Mar 2013 20:03:30
Message:

Ive now completed the job - the car doesnt run too well, but its booked in for a day on a rolling road to sort it out.

The last time it started was in Jan, and tonight it started with the webers first time and sound so so good. It idles very well to, just wants to die under acceleration.

Anyway enjoy the photos and thanks for all the advice guy!!!

ps a holbay rocker cover will be on as soon as i find the right fixing bolts!

Reply author: retro68
Replied on: 18 Mar 2013 23:18:00
Message:

Looks great,good work, I luv the cars but not so mechanically minded, hope you get the running sorted, cheers Andy.

Reply author: arrocuda
Replied on: 19 Mar 2013 09:30:41
Message:

I notice from the pic' that you're still running with the vacuum dizzy Martin. As I recall from the time I was doing the research that Chris provided me with the valve timing data for, the mechanical (H120) dizzy has a slower advance curve so as to allow the piston to travel higher up the bore, increasing the compression before the spark. Even at maximum advance, (high revs), they run around 10 degrees less advance than the vacuum unit.

Could be worth trying to slow down the ignition advance by putting a slightly heavier spring on the advance mechanism if you don't have a mechanical dizzy.



Building the 'Mark II' fastback Rapier ('Arrocuda').

Reply author: UMU
Replied on: 19 Mar 2013 18:56:33
Message:

Well noticed, thank you. I have also heard that the H120 doesn't have a vacuum dizzy and have tried mine with the vacuum connected to the servo vacuum and also with it blocked.
Neather make any difference so might be worth trying a different dizzy.

I've tinkered today and adjusted the 4 screws, which seem to have to be turned out 1 1/2 turns to run smoothly without much pinking.
I've also tried running the engine without the inspection caps to avoid starvation of air and still no difference - it idles ok, but won't accelerate

Might have to get it towed to the rolling road.

Reply author: UMU
Replied on: 19 Mar 2013 18:59:11
Message:

Ps, Andy thanks for your comment:-)

Reply author: Fastback Thomas
Replied on: 19 Mar 2013 20:06:47
Message:

Hi Martin,
Looks so good with the webers!!! (I'm jealous!!!!)
Hope you get it running and accelerating nicely!
Just a thought we had the same problem with our triumph MKI not accelerating properly.
It turned out to be a very hard vacuum line causing it to leak.. new vacuum line cured it and it's now running better then ever!
The tubes look new so I'd say check the T-piece and the other connections...

Hope it helps mate!


'68 sunbeam rapier fastback {B341006846 OD/LHO}
I like a car that looks normal but really knocks your socks off!!

Reply author: UMU
Replied on: 20 Mar 2013 20:32:09
Message:

Thanks Tim ill replace hoses, as they are very stiff and also remove the dizzy vacuum for good.

Does anyone have any spare holbay rocket cover bolts going or know where I might find them in good nik as im now wanting to crown the engine

Reply author: UMU
Replied on: 20 Mar 2013 20:33:09
Message:

Typo - thanks Tom :-)

Reply author: JPSH120
Replied on: 20 Mar 2013 21:29:57
Message:

quote:

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Originally posted by UMU

Thanks Tim ill replace hoses, as they are very stiff and also remove the dizzy vacuum for good.

Does anyone have any spare holbay rocket cover bolts going or know where I might find them in good nik as im now wanting to crown the engine

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Reply author: 1922
Replied on: 21 Mar 2013 12:54:45
Message:

I assume they are the same as the series cars that have the alloy rocker cover - such as the Alpine sports cars.

So Alpine West Midlands might have them, or Speedy Spares in Brighton.

Reply author: Fastback Thomas
Replied on: 21 Mar 2013 18:23:55
Message:

No problem Martin,

it's just that it really makes a big difference!!! and I hope you get it solved mate!

'68 sunbeam rapier fastback {B341006846 OD/LHO}
I like a car that looks normal but really knocks your socks off!!

Reply author: Jon
Replied on: 23 Mar 2013 14:39:55
Message:

quote:

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Originally posted by UMU

Well noticed, thank you. I have also heard that the H120 doesn't have a vacuum dizzy and have tried mine with the vacuum connected to the servo vacuum and also with it blocked.
Neather make any difference so might be worth trying a different dizzy.

I've tinkered today and adjusted the 4 screws, which seem to have to be turned out 1 1/2 turns to run smoothly without much pinking.
I've also tried running the engine without the inspection caps to avoid starvation of air and still no difference - it idles ok, but won't accelerate

Might have to get it towed to the rolling road.

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Reply author: UMU
Replied on: 28 Mar 2013 13:10:27
Message:

Jon, thanks for the message. I intend to work on the setting up this weekend.
With your advise and previous advise i actually have a chance of sorting things out.

Do you know the kind words and advise is so appreciated and is partly why i enjoy my sunbeam and being part of the club. It really makes a difference to know that we selflessly help eachother.
Thank you!

Reply author: UMU
Replied on: 09 May 2013 11:34:49
Message:

So good news
Yesterday evening I had a friend of mine come round, who is a mechanic and we worked on the engine for an hour or so.

She now purrs well and pulls off...
Still hates it between revs 1500-2000, but once over that, WOW its like a racing engine, revs, pulls and sounds awesome.
The power increase is pretty dramatic, rear wheel spin is now something to be aware of to.

I've ordered a H120 electronic dizzy and new coil to boot, which should sort the remaining problem, as I've learnt it gives the different advance curve that the webers like.

Also the Holbay rocker cover is on

Reply author: JPSH120
Replied on: 09 May 2013 11:39:25
Message:

quote:

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Originally posted by UMU


Still hates it between revs 1500-2000, but once over that, WOW its like a racing engine, revs, pulls and sounds awesome.

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Sunbeam Rapier Owners Club : http://www.sunbeamrapier.co.uk/forum/