Removing the needle seat from a Solex... Log Out | Topics | Search
Moderators | Register | Edit Profile

Australian RR Forums » Silver Shadow Series » Removing the needle seat from a Solex 4A1 carburettor « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 57
Registered: 02-2015
Posted on Tuesday, 17 March, 2020 - 13:17:   Edit PostDelete PostView Post/Check IP

I am working on the Solex 4A1 carburettor from my 1978 Rolls-Royce Corniche DRH32489. As part of the job I have replaced gaskets etc since I had a air leak and found some damaged parts of gaskets. I was trying to remove the needle valve seat. It is free to rotate on its axis but can't be pulled out. The photos show the new seat, which suggests a straight removal and replacement. Does anyone know how to remove the old seat? Weird! I can't see any retaining clip or any device preventing its removal. I am rather stuck for ideas - help much appreciated.


Solex 1

Solex 2

Two views of the new seat
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 58
Registered: 02-2015
Posted on Tuesday, 17 March, 2020 - 13:23:   Edit PostDelete PostView Post/Check IP

I have just looked closely at the existing seat. It looks like the base in which it sits has been centre-punched twice to keep the seat in place. Any thoughts on getting rid of the tiny little metal bits that has been pushed out over the lip of the seat?
Top of pagePrevious messageNext messageBottom of page Link to this message

David Gore
Moderator
Username: david_gore

Post Number: 3630
Registered: 04-2003
Posted on Tuesday, 17 March, 2020 - 15:24:   Edit PostDelete PostView Post/Check IP

A Dremel Multi-Tool with an appropriate cutting/grinding bit together with a magnifying desk lamp would be my choice for this task.
Top of pagePrevious messageNext messageBottom of page Link to this message

Graham Phillips
Frequent User
Username: playtime

Post Number: 239
Registered: 03-2019
Posted on Tuesday, 17 March, 2020 - 15:26:   Edit PostDelete PostView Post/Check IP

G'day everyone,....


Very fine needle grinder aka: dremil tool or similar?

Have access to a dentists drill type?

That should be able to clean off the burr's,....


Graham.
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 59
Registered: 02-2015
Posted on Tuesday, 17 March, 2020 - 16:02:   Edit PostDelete PostView Post/Check IP

Thanks, David and Graham. Just before I went to the dentist this afternoon, I tried a couple of fine Dremel-type bits but not much luck . I used a larger Dremel bit to destroy the top part of the seat (ie where the main body of the needle valve sits in). I can see things a bit clearer now. Some more work with the Dremel and/or emery to trim things a bit might do the trick. Almost time for happy hour, so I will be back on it tomorrow.

Cheers, John
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 60
Registered: 02-2015
Posted on Wednesday, 18 March, 2020 - 18:05:   Edit PostDelete PostView Post/Check IP

I have had no success. I found some drawings on the net which didn't have sufficient detail to understand how the needle seat was located. I finally talked to a carby expert on the Sunshine Coast, and he said that his carby gasket kits he received never have a needle seat in them. This is true for the Mercedes Solex 4A1 gasket kit I got.
He said that the seat is never removed and he has never done one. So it is rather weird that IntroCar sent me a kit with a new seat. The truth is that I should have listened to the old adage "If it ain't broke, don't fix it". Strewth! All I was doing was to replace the "easy" things like the needle and seat. A big lesson for a dubbo like me.
The upshot is that I am taking the Solex 4A1 carby up to the Sunshine Coast tomorrow and hopefully we will work out what is the problem and eventually instal the new seat.
Fingers crossed.
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 61
Registered: 02-2015
Posted on Thursday, 19 March, 2020 - 17:56:   Edit PostDelete PostView Post/Check IP

I took the Solex 4A1 to the Sunshine Coast expert today. We discussed the problem, and he used an ezy-out and started turning the seat and pulling at the same time. It eventually came out!! Thank goodness. He is a lot younger than me and had a bit more strength which helps as well.

It looked like the work with the Dremel had removed most of the metal which was overhanging the lip, but the main carby body might have been distorted slightly which prevented the seat being removed easily.

I had some correspondence with IntroCar over the past couple of days, and they have absolutely zero information on the Solex float needle seat, despite it being in their carby repair kit. Even the Heritage Bentley site has nothing on it. Surely someone in the world must have a drawing of the seat, since it has been made.

I have found a cross sectional drawing of the Solex 4A1 from a German site which actually shows the seat in position, but no details about how it is fastened in position. I suspect the drawing is taken from the Solex factory manual which I have been unable to find. I will scan the drawing and put it in the next posting.

I will keep all informed
Top of pagePrevious messageNext messageBottom of page Link to this message

David Gore
Moderator
Username: david_gore

Post Number: 3634
Registered: 04-2003
Posted on Thursday, 19 March, 2020 - 18:52:   Edit PostDelete PostView Post/Check IP

John,

Any chance it might be a shrink fit?

If the seat cannot be inserted at room temperature, try putting it in a freezer for an hour or two and then see if it will drop straight in.

As the seat comes back to room temperature, it will expand and hopefully this will keep it in position by compression without requiring punching a retaining lip on one of the items.
Top of pagePrevious messageNext messageBottom of page Link to this message

Patrick Lockyer.
Grand Master
Username: pat_lockyer

Post Number: 2276
Registered: 09-2004
Posted on Thursday, 19 March, 2020 - 19:03:   Edit PostDelete PostView Post/Check IP

And I thought the Solex was Diecast!
Top of pagePrevious messageNext messageBottom of page Link to this message

Jim Walters
Frequent User
Username: jim_walters

Post Number: 299
Registered: 01-2014
Posted on Friday, 20 March, 2020 - 03:25:   Edit PostDelete PostView Post/Check IP

John, if it's not a tight press fit now red or green Loctite would keep it in place forever. Rough up the contact surfaces with 280 grit emery and degrease before installing.

SRH8505 SRC18015 SRE22493 NAC-05370
www.bristolmotors.com
Top of pagePrevious messageNext messageBottom of page Link to this message

Omar M. Shams
Prolific User
Username: omar

Post Number: 1958
Registered: 04-2009
Posted on Friday, 20 March, 2020 - 05:47:   Edit PostDelete PostView Post/Check IP

Many Corniches were converted to SU carbs due to the fragility of the Solex Carburettors. Many of these carb bodies have suffered at the hands of ham fisted mechanics in the past. It does not take much torque on the hold down bolts to twist the bodies. If that has happened to your carb John then you will have to apply engineered solutions as have been suggested above. Also machining the mating face to the manifold to ensure a flush fit will also be a good thing.
Good luck
Top of pagePrevious messageNext messageBottom of page Link to this message

gordon le feuvre
Frequent User
Username: triumph

Post Number: 332
Registered: 07-2012
Posted on Saturday, 21 March, 2020 - 18:36:   Edit PostDelete PostView Post/Check IP

John, when your car was new there were issues of the seat moving down under hot soak conditions and blocking off supply of fuel into carb. factory fix was slightly oversized seat supplied with machined mandrel to tap it (hit) it into place. So, historically an issue. Sounds as if someone on your carb had come across issue and decide to just "peen" edge carb to stop seat dropping out after they had pushed it back in place presumably after a "failure to proceed" incident caused by fuel starvation into float chamber.
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 62
Registered: 02-2015
Posted on Sunday, 22 March, 2020 - 14:55:   Edit PostDelete PostView Post/Check IP

Thanks for the information, gentlemen.

Gordon: Sounds like a good explanation of why my Solex was like it was.

I couldn't get a decent scan or copy of the drawing of the Solex cross section to post, but the link is patrykrebisz.com/w114/solex_diagram_all.html

I will talk to the expert who is working on the carby about a means for holding the seat in place and refer him to everyone's comments.

Most of the RR mechanics I know in Queensland, have the opinion that I should replace the Solex with SUs, but I really want to keep the Corniche as near to original as possible. In a week or two, when the Solex is back in the car, I will be able to let you know if the work was successful.
Top of pagePrevious messageNext messageBottom of page Link to this message

gordon le feuvre
Frequent User
Username: triumph

Post Number: 334
Registered: 07-2012
Posted on Sunday, 22 March, 2020 - 17:30:   Edit PostDelete PostView Post/Check IP

John, we recovered the car in question from France having taken parts with us. Never had another issue. I would say Jim Walters idea of Loctite is as good as you will get. You can of course search through Service bulletins of Bentley Heritage in hope of finding part number for oversized seat, but you can bet that it is not available. back to Jim's idea
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 63
Registered: 02-2015
Posted on Friday, 27 March, 2020 - 15:45:   Edit PostDelete PostView Post/Check IP

I have now got the Solex back from Mike Bushnell of Advance Diaphram Options in Caloundra, Qld. Mike did a great job and replaced virtually everything that was in the carby gasket kit I purchased from IntroCar. The needle seat was a very close fit as expected and he used a Loctite-type material to keep it in place as well as a little bit of peaning of metal over the little lip at the bottom of the seat using a small screwdriver.
I popped the Solex back in DRH32489 this afternoon and she started with some hesitation, and coughed and spluttered a bit.
This was a little disconcerting, and I took the air cleaner off to see what could be the matter, but I couldn't see anything astray. I gave it another couple of starts and by the third short run, the coughing and spluttering disappeared and the car seemed to run well. It may have taken a little time for all the channels in the carby to fill up with fuel and allow it to operate normally.
It is raining at the moment, so I will get the Bentley Special out of the way tomorrow and take the Corniche for a real test, provided the rain stays away.
I found another drawing which had a cross-section of the Solex which showed the seat, but no real indication of the fastening method. It was right in front of my eyes - Figure K47 in the Silver Shadow Workshop Manual which is readily available on the RROCA website.
Hopefully I will be able to report in the next day of two about the road test.
Thanks for all your comments and thanks to Mike who also filed down one of the warped faces where some air was getting through.
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 64
Registered: 02-2015
Posted on Saturday, 04 April, 2020 - 14:22:   Edit PostDelete PostView Post/Check IP

I finally got to do a road test, but the idle was still rough. Steve Sparks of NBS Services suggested I test the gearbox modular valve by blanking off the connection at the carburettor. This quickly showed no change.
Steve also suggested that a leak at the inlet manifold was a possibility, and he suggested that I spray carby cleaner around the manifold - if there was an air leak, the spray would cause the engine to speed up by enriching the mixture and the engine to run smoother.
I subsequently sprayed around the 4 connecting arms of the manifold on the heads, and when I sprayed the left hand front section of the manifold connection the engine speed increased and it ran smoother for a short time.
I had noticed that there was not a collection on gunk for about a 35mm section of the interface between the manifold and the head. I cleaned all the areas up and it was evident that the gasket material was missing in the area. I sealed the spot with silastic and allowed it to set overnight.
Today I started the car easily and it was as smooth as one would expect. Obviously a significant portion of the manifold gasket had disappeared. A rapid loss of this gasket section would explain why I suddenly got rough idling before last Christmas. I have now ordered the replacement gaskets and O-rings. I will let Steve replace the gaskets as it looks like an awful job for a rank amateur like myself.
By the time I have finished this I will have replaced the distributor internals with the Petronix Igniter, replaced the coil with a Petronix Flame Thrower coil, replaced all the HT leads, spark plugs and refurbished the Solex 4A1 carburettor.
With some luck I will then have fixed all possibilities for rough idling after getting the timing and idle mixture correct. Fingers crossed anyway.
Top of pagePrevious messageNext messageBottom of page Link to this message

Omar M. Shams
Prolific User
Username: omar

Post Number: 1975
Registered: 04-2009
Posted on Saturday, 04 April, 2020 - 14:48:   Edit PostDelete PostView Post/Check IP

This is fascinating John.
I wonder how many of us are driving our cars with leaking manifold gaskets?
The Solex is particularly sensitive to this failure whereas the SUs are more forgiving.
If you have any photos - these would be most welcome.
Thanks
Omar
Top of pagePrevious messageNext messageBottom of page Link to this message

David Gore
Moderator
Username: david_gore

Post Number: 3657
Registered: 04-2003
Posted on Saturday, 04 April, 2020 - 16:36:   Edit PostDelete PostView Post/Check IP

John,

Make sure your mechanic checks the flatness of the exhaust manifold mating face with the engine block as it is common for distortion to occur after gasket failure due to uneven heating of the cast iron manifold.

I had the manifolds on DRH14434 surface ground before reinstalling them for this reason on advice from my long-time US friend who is an experienced car restorer and was visiting at the time.
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 65
Registered: 02-2015
Posted on Sunday, 05 April, 2020 - 12:32:   Edit PostDelete PostView Post/Check IP

Thanks Omar and David. The manifolds and head will be certainly inspected carefully when the manifolds are removed.
I have some photos below.
Recon Solex
The reconditioned Solex 4A1 Carburettor.

The inlet manifold appeared to be damaged from a grinder or rasp?? There are a couple of places on the head where this sort of damage is apparent. Hopefully the head proper is OK.
The gasket can be seen here.

Damage to head
Inlet manifold showing damage to the head.

The position where the gasket is missing. In other sections of the manifold, the gasket can be seen clearly protruding a mm or two. See previous photo.

missing gasket
Inlet manifold where gasket is missing.

Silastic seal
The manifold sealed with silastic

Hopefully all will be perfect in a few weeks time when the new gaskets are installed and any damage repaired.

Cheers, John
Top of pagePrevious messageNext messageBottom of page Link to this message

ross kowalski
Prolific User
Username: cdfpw

Post Number: 1348
Registered: 11-2015
Posted on Sunday, 05 April, 2020 - 22:47:   Edit PostDelete PostView Post/Check IP

John,

Good diagnosis and great results. You could certainly do the manifold yourself, but the proper fitting of everything you need to pull in order to gain access is fussy. The job would be very satisfying and educational though.

The postmortem on the original gasket and mating surfaced will be interesting to see.

It might Also be good to check the manifold vacuum at this point. The shadow should read a high steady 22~23 in/Hg at idle.

Luck to you.
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 68
Registered: 02-2015
Posted on Monday, 20 April, 2020 - 10:37:   Edit PostDelete PostView Post/Check IP

Steve Sparks has removed the inlet manifold and sent me the following photos.

LH rear
Corniche LH Rear Gasket - Inlet manifold

LH Front
Corniche LH Front Gasket - Inlet manifold

The front gasket obviously has a significant portion of it missing. The rear gasket looks like it is missing a proportion of the gasket, but not as bad as the front gasket.

Steve has now cleaned up the manifold and the head and the surfaces are perfect. There is no need for machining, thank goodness.

The score marks at the side of the head appear to be just original machining marks.

.
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 83
Registered: 02-2015
Posted on Monday, 22 June, 2020 - 18:39:   Edit PostDelete PostView Post/Check IP

I got DRH32489 back from Steve Sparks a few weeks ago with the new inlet manifold gaskets replaced. As well as doing this job, Steve found numerous hoses were old and brittle and needed replacement. The hydraulic system was filthy and needed lots of work. In addition the alternator had to be rebuilt. He also did a full service including work on the gearbox which revealed that some time in the past some naughty things were done - now all remedied.
The Corniche now starts first try - this is the first time in the 6 years that I have owned it that the starting is so easy when starting according to the manual. Last weekend we went down to NSW and stayed with old friends at their farm south of Ballina, and the car ran beautifully. It was effortless cruising with the cruise control set on 110 km/h on the highway. Sometimes it is hard to believe we are driving in a 42 year old vehicle - it was almost like driving along in my everyday drive with all the modern gizmos, but much more fun. The only problem was that SHMBO insisted on the roof being up due to the chilly weather.
Top of pagePrevious messageNext messageBottom of page Link to this message

John Rowney
Experienced User
Username: johnrowney

Post Number: 84
Registered: 02-2015
Posted on Monday, 22 June, 2020 - 18:41:   Edit PostDelete PostView Post/Check IP

Sorry, I meant SWMBO - She Who Must Be Obeyed

Add Your Message Here
Post:
Bold text Italics Underline Create a hyperlink Insert a clipart image

Username: Posting Information:
This is a public posting area. Enter your username and password if you have an account. Otherwise, enter your full name as your username and leave the password blank. Your e-mail address is optional.
Please quote Chassis Numbers for all vehicles mentioned.
Password:
E-mail:
Action: