Author Topic: Solex to Holley conversion pictorial  (Read 2975 times)

oscar

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Solex to Holley conversion pictorial
« on: 02 December 2008, 12:41 AM »
A succesful one I might add.  8)  To be honest though it was a fairly simple conversion due to the Holley being taken off a previous conversion.  So all parts were ready to go. 

The only things I would've needed to purchase if i was starting from scratch is a square bore adapter plate, angled throttle linkage and some vacuum hose and maybe coolant hose and a few hose clips and screws and electrical wire and things  ::) .....  Check the photos to see what's needed.

We'll start with the main component, the carburettor.  The Solex4A1 I'm replacing is actually fine.  It works well and was recently raced.  But since the application is an upcoming race car I wanted to try this spare Holley I've got which (fingers crossed), hopefully helps the M110 breathe better and give it some better acceleration. 

The Holley replacement is an old squarebore 4bbl (4 equally sized barrels), 390CFM, 4160, p/n 0-8007.  The Solex on the other hand is spreadbore (2 larger, 2 smaller barrels).  The Holley pdf link says not to use a square bore to spread bore adapter.  ::)  Stiff, I haven't got a hope of fashioning a square bore out of the stock manifold due to the way it's cast and machined.  It's not one big flat surface that I can simply cut the middle from.  Anyway, the adapter is thick and I reckon there's a bit of room for the fuel/air mix to get to where it's going without too much restriction.  The adapter BTW has got "LYNX" cast into it and that's all I can tell you.  No other numbers on there sorry

REMOVAL OF THE SOLEX.






A view of the naked manifold with spredbore configuration.


HOLLEY AND EXTRA BITS NEEDED

An underside comparison of the Solex and Holley.  Not sure of the CFM of the Solex and after seeing the two together I wondered whether the conversion is actually worth it.  Seems to rev harder when given full throttle but time will tell after a full test drive how effective the holley is in providing extra power.  I wont know fuel economy as the car will be spending much of its time at wide open throttle anyway 8).


Extra bits needed-

Angled throttle linkage


A wire connected to the (+) terminal of the coil then goes to the spade terminal of the electric choke.


A self made bracket for the throttle return spring needs to be manufactured and placed where shown.


The coolant hoses need to bypass the carburettor all together.  Either by way of a short piece of copper tubing as shown or replace both hoses with a much longer one.


One squarebore to spreadbore adapter plate. This one is LYNX branded.  4 allen bolts go into the manifold and four bolts poke up through from the bottom so the Holley can be bolted down.


Some vacuum hose and a "T" piece to tap the vacuum off the manifold.  The black hose then goes off to the fuel purge valve that regualtes fuel pressure to the carby and allows fuel to flow through the return line under low load conditions. I think that's how it works  ::)



INSTALLING THE HOLLEY

Install adapter plate to soft mount that was under the Solex.


Coolant hose bypasses carburettor


Install Holley on studs and screw nuts on.  Attach fuel line.  I was unable to remove the sealing collet so I just slid the fuel line as far as it would go, slightly over the collet, then screwed the clamp up.  no leaks.


Vacuum lines to vacuum switch that provides retard at idle were plugged.  Emissions aren't a concern for this car but you could add another "T" to that other vac line I spoke of earlier.  When I find a cap I'll put it over the retard connection of the distributors retard connection.  There's another large vacuum connection off the side of the carb facing the engine that was capped some time ago and wont be used.



Vacuum line that goes to the fuel purge valve is attached running from that "T"connection I put in earlier.


Throttle linkage and return spring


Attach vacuum line to the vacuum advance port on the distributor. (middle of pic)


Lastly, don't forget to attach the electrical wire from the coil to the choke.  No pic sorry.



THE VIDEOS

The sound lags somewhat behind the footage for some reason but when it started it was really responsive.

First start attempt was a failure.  The carb was empty and the fuel bowls needed to fill which I expected but the purge valve wasn't connected to a vacuum source either.
<a href="http://www.youtube.com/v/KJkhjewIGwI&amp;hl=en&amp;fs=1" target="_blank" class="new_win">http://www.youtube.com/v/KJkhjewIGwI&amp;hl=en&amp;fs=1</a>

With the vacuum line to the purge valve connected.  Eureka!!!  But maybe the fuel bowls had filled by this time.  I don't know.  Time lapsed between first and second attempt was about 10mins.  Flooding wasn't a cause of the non start first time round.
<a href="http://www.youtube.com/v/FfilhCHfxPI&amp;hl=en&amp;fs=1" target="_blank" class="new_win">http://www.youtube.com/v/FfilhCHfxPI&amp;hl=en&amp;fs=1</a>

As the car warms up the electric choke is working, you can see it opening....slowly.
<a href="http://www.youtube.com/v/-vHl_md6WWc&amp;hl=en&amp;fs=1" target="_blank" class="new_win">http://www.youtube.com/v/-vHl_md6WWc&amp;hl=en&amp;fs=1</a>

After the engine has fully warmed up I give it one more look over for fuel and coolant leaks then  floor it a few times to check operation of the vacuum secondaries.  You can see the gate of the secondarys' axle moving.  The car needs to be under load to get them to be wide open, or I could possibly keep my foot on the pedal but not yet.  I've got a rev limiting rotor in there and whilst it's brand new and still has it's counterwieght, I'm yet to hear it have an effect.
<a href="http://www.youtube.com/v/EXBQw9lcsZY&amp;hl=en&amp;fs=1" target="_blank" class="new_win">http://www.youtube.com/v/EXBQw9lcsZY&amp;hl=en&amp;fs=1</a>




« Last Edit: 02 December 2008, 12:46 AM by oscar »
1973 350SE, my first & fave

wbrian63

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Re: Solex to Holley conversion pictorial
« Reply #1 on: 02 December 2008, 06:29 AM »
I'm not certain about MB's, but on some cars, the coil only gets 12v+ during cranking. Whilst running, the voltage comes to the coil through a ballast resistor - this is to prevent burning the points in the distributor.

Running less than 12v to the choke coil will not harm it, but the warmup cycle will be possibly too long. May not matter much on a race car...

Just thought I'd mention it.

Regards
W. Brian Fogarty

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'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

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oscar

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Re: Solex to Holley conversion pictorial
« Reply #2 on: 02 December 2008, 12:22 PM »
Not at all, thanks for that.  Like I said, I was just moving the Holley from one car to the next and copying the install.   True the choke wont matter too much on this car and I was thinking about removing it altogether.  But I might look into the documentation of the holley and see where they recommend to put that wire.   

In regards to the coil and ballast resistors, although it's been explained  before I'm clueless over the resistors.  However, on this car and the donor 280S there's only one resistor compared to all the FI models which have two.  Don't know if that makes a difference  ???
1973 350SE, my first & fave

TJ 450

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Re: Solex to Holley conversion pictorial
« Reply #3 on: 03 December 2008, 03:12 AM »
It's looking awesome, Oscar. It's quite interesting to see the workings of these carburettors. 8)

My understanding of the ballast resistors too, is that they allow the coil ~12v during cranking then ~6v or so whilst the car is actually running (this is a generalisation).
I would imagine that the coil on FI cars is of a different specification than the carby models, probably a higher output version. The fact that there is only one resistor suggests that the circuit is quite different.

FWIW, my Dad's 1976 VW Bus has the electric chokes of the twin Solexes connected to the +ve terminal of the coil. However, this is just a GT40 with no resistors.

Tim
« Last Edit: 03 December 2008, 03:17 AM by TJ 450 »
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oscar

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Re: Solex to Holley conversion pictorial
« Reply #4 on: 02 March 2009, 10:46 PM »
Finally did a 0-100km/hr test with the holley to see what the difference would be and the judges decision was - bugger all difference. 

With the solex you could feel the secondaries open up due to its larger secondaries but with the holley's squarebore vacuum secondaries there was no kick in the back of any description but that's a good thing I suppose.  Smooth as transition.  Performance wise 0-100km'hr was a touch over 10 seconds.  Pretty much the same as the Solex.  I really wanted to break the 10 second mark but whilst I was easy on the 2nd and 3rd gears the engine really struggles to develop power at speed, hecne the non redline changes.  The chain is stretched but the next thing I'll do is replace it and play with cam timing to get some top end power.  I'd like to convincingly break 10 seconds and have some more power to get a decent higher top speed in much less time.  In the vids, the car could've gone faster.  I got to just under 160km/h on both runs but I got bored waiting for it to go faster.  Took too long.

BTW, I also put a cheap 14" air cleaner on and had to build up the gasket out of cork and modify the throttle linkage where a kickdown linkage would go if I had an auto.

<a href="http://www.youtube.com/v/uDgAjyhAE_Q&amp;hl=en&amp;fs=1&gt" target="_blank" class="new_win">http://www.youtube.com/v/uDgAjyhAE_Q&amp;hl=en&amp;fs=1&gt;</a><a href="http://www.youtube.com/v/uDgAjyhAE_Q&amp;hl=en&amp;fs=1" target="_blank" class="new_win">http://www.youtube.com/v/uDgAjyhAE_Q&amp;hl=en&amp;fs=1</a>




1973 350SE, my first & fave

Zuendfolge

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Re: Solex to Holley conversion pictorial
« Reply #5 on: 03 March 2009, 02:43 AM »
Hi Oscar.

Nice conversion and nice to get some more understanding of carburettors!

I think it will be hard to break the 10 seconds to 100 km/h. Even a SE couldn't really break that mark. The only possibility is to lower the car's weight.
Maybe take out the Fan, take out the power steering or mount smaller diameter wheels (or a 1:4,09 rear axle from a W115).

That Solex is already a hell of a big Carb isn't it?

The resistants before the ignition coil are there to lower the voltage on the coil. When the starter is applied 1 resistance is bridged to compensate for the dropping voltage because of the starter engine. MB used different coils with different voltage needs. Blue is usually for the SE models (they had electronic ignition from the start).

Good luck with your cars, it is very interesting!

Zund

oscar

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Re: Solex to Holley conversion pictorial
« Reply #6 on: 03 March 2009, 06:58 PM »
Hi Zund thanks very much.  Not sure if I've posted pics or not of the interior but it has been stripped.  Air con has gone, fan replaced with electric, tow bar removed, alloy wheels on.  I'd hate to take the bumpers off but they might have to go too.  Shedding weight is a must and there's further weight reduction planned.   So with that in mind I'm not far off breaking the 10sec but I'm really looking forward to see the difference cam timing adjustments will make and further mods down the track.  I wanted to whack a turbo or supercharger on there but I'd like to see what I can do to a naturally aspirated m110 first.
1973 350SE, my first & fave

chinny4290

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Re: Solex to Holley conversion pictorial
« Reply #7 on: 03 March 2009, 07:32 PM »
Your engine sounds so much awesomer than mine  :(

Would you be able to tell my why mine sounds like it has a waaaaaahooooooo wailing/buzzing/sort of noise when I give it some juice?

http://www.youtube.com/watch?v=tkKJysU82ts

I don't mean to jack your thread :)
« Last Edit: 03 March 2009, 07:43 PM by chinny4290 »
1975 W116 280S Hobby/Restoration Project/ Future Daily Driver woot!
1994 W124 E320 Coupe My first car/love...what can I say?

oscar

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Re: Solex to Holley conversion pictorial
« Reply #8 on: 03 March 2009, 08:02 PM »
Yeah I was only watching yours again the other day when I heard that lawn mower sound and all I can think of is that it's your fan which should also have a shroud.  Not sure if a shroud would eliminate the sound but it might. Have you got a smog pump too? Not sure if any 280S had them and I've never heard one operate but I wondered if a faulty one of those could be the culprit.  But I still reckon it's just the fan.

My exhaust sounds completely different mainly because of two pipes coming down from the two exhaust manifolds through to the centre muffler.  Sounds a bit sportier but there's no "y" piece or anywhere else where two pipes go into one although I'm sure the center and rear mufflers are open.  I was going to post in your exhaust thread and might just do that.  There's two kind of manifolds, an early type that requires this "Y" pice and then there's the later style where two individual piipes come down then go into a single pipe for a bit.  I'll take photos and get back to you in that thread later today.
1973 350SE, my first & fave

chinny4290

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Re: Solex to Holley conversion pictorial
« Reply #9 on: 04 March 2009, 07:08 PM »
Interestingly it doesnt sound like its the fan. The primary fan gets a low woosh like it should.

But the leaf blower sound seems like its coming from the carb/intake manifold area. One of the small vacuum lines on the carb is rotted and needs replacement. COuld it be that?

Also I dont know if Ihave a smog pump. This car never saw the West coast (suggesting Cali) since Cali cars I'm sure required smog pumps or extra requirements for emissions.
1975 W116 280S Hobby/Restoration Project/ Future Daily Driver woot!
1994 W124 E320 Coupe My first car/love...what can I say?

oscar

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Re: Solex to Holley conversion pictorial
« Reply #10 on: 04 March 2009, 08:56 PM »
Hmm, it's a tough one.  I'd say take off the air cleaner housing and see if the sound changes like gets louder or even goes away just to see whether it is intake related.

I see you've got a charcoal cannister which is that long cannister sitting vertical behind the drivers side of the radiator with three hoses angled out the top.  Not sure if this means you have a smog pump or not but if you have got one it sits directly below the power steering pump.  Below is a photo of a pump on a k-jet 280, left of screen.  It's seized and is why the fan belt was removed.  If you do have one I'd try removing the belt and rev the car to see if the sound stops.  I really can't think of anything else it could be.

1973 350SE, my first & fave

chinny4290

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Re: Solex to Holley conversion pictorial
« Reply #11 on: 05 March 2009, 12:29 AM »
you mean this thing?

1975 W116 280S Hobby/Restoration Project/ Future Daily Driver woot!
1994 W124 E320 Coupe My first car/love...what can I say?

oscar

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Re: Solex to Holley conversion pictorial
« Reply #12 on: 05 March 2009, 01:10 AM »
Yep that's the charcoal cannister.   I saw that and wondered whether you had the smog pump as well
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oscar

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Re: Solex to Holley conversion pictorial
« Reply #13 on: 24 March 2009, 05:55 AM »
Hey chinny, that noise, did your mechanic replace the timing chain recently?

I just finished mine and now there's a whirr that sounds like a twin screw Eaton supercharger.  Although I tightened the tensioner up to specs I reckon it's too tight but the result is this whirr sound that I've never had before.

<a href="http://www.youtube.com/v/qW82OcrC6Ko&amp;hl=en&amp;fs=1" target="_blank" class="new_win">http://www.youtube.com/v/qW82OcrC6Ko&amp;hl=en&amp;fs=1</a>
1973 350SE, my first & fave

chinny4290

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Re: Solex to Holley conversion pictorial
« Reply #14 on: 24 March 2009, 03:38 PM »
Hey chinny, that noise, did your mechanic replace the timing chain recently?

I just finished mine and now there's a whirr that sounds like a twin screw Eaton supercharger.  Although I tightened the tensioner up to specs I reckon it's too tight but the result is this whirr sound that I've never had before.

<a href="http://www.youtube.com/v/qW82OcrC6Ko&amp;hl=en&amp;fs=1" target="_blank" class="new_win">http://www.youtube.com/v/qW82OcrC6Ko&amp;hl=en&amp;fs=1</a>

I have had no work done with the timing chain at all. I don't know about previous owners.

But I have no reason to really suspect the timing chain because the car only has 82k miles on it. Also, the sound is more of a leaf blower noise and really isn't close to the supercharger sound. I wish I had a supercharger on it though  :D
1975 W116 280S Hobby/Restoration Project/ Future Daily Driver woot!
1994 W124 E320 Coupe My first car/love...what can I say?