- Welcome to MatraSport Forum.
Recent posts
#91
Murena / Re: Vacuum hoses - Wich are th...
Last post by matra530 - August 29, 2025, 06:14:40 PMThanks again for the informations. I found an old 10 mm T-piece in our workshop's stock. The memory and headlight control fit immediately, and to connect to the check valve, I inserted a narrower hose into the existing one (i.e. adapted it), and now everything is working as it should again. It's a shame that the detour was necessary.
#92
Murena / Re: Vacuum hoses - Wich are th...
Last post by roy4matra - August 29, 2025, 12:22:10 PMQuote from: matra530 on August 28, 2025, 06:48:28 AM
Hello Roy, thank you for your explanation. Unfortunately, the old T-piece could not be removed intact and its size could only be guessed at. Now, based on your measurements, I can confirm that the replacement part from Simon is too thick on both narrow sides and too narrow on the thick part. That's a shame, I'll have to look on eBay/Amazon etc. For the 10 mm pieces, can I also use vacuum lines with an inner diameter of 10 mm, or will that not be airtight?
Best regards,
Andreas
Here is the T-Piece at AFS:
https://www.advancedfluidsolutions.co.uk/10mm--13mm--10mm-reducing-t-piece-white-plastic-hose-joiner-barbed-connector-3-way-tee-bar-2307-p.asp
Ignore the photo which is a stock photo, as it looks like the two straight across ends are larger than the centre one, but the title and description shows it to be a larger centre connection 'reducing' to the size of the outputs.
Or here is one on eBay UK:
eBay item number 326584220799
somewhat dearer though!
Sorry that eBay URL link made the page far too wide. I've changed it to the item number now, so search for that instead.
The original rubber hoses or connecting pieces fit perfectly. I have used one of these AFS ones for some years on one of my cars.
Roy
#93
Murena / Re: Vacuum hoses - Wich are th...
Last post by matra530 - August 28, 2025, 06:48:28 AMHello Roy, thank you for your explanation. Unfortunately, the old T-piece could not be removed intact and its size could only be guessed at. Now, based on your measurements, I can confirm that the replacement part from Simon is too thick on both narrow sides and too narrow on the thick part. That's a shame, I'll have to look on eBay/Amazon etc. For the 10 mm pieces, can I also use vacuum lines with an inner diameter of 10 mm, or will that not be airtight?
Best regards,
Andreas
Best regards,
Andreas
#94
Murena / Re: Vacuum hoses - Wich are th...
Last post by Anders Dinsen - August 28, 2025, 03:37:24 AMQuote from: roy4matra on August 27, 2025, 11:04:06 AM
That sounds like they have the T-Piece sizes the wrong way around! Maybe the one they supplied was 13mm/10mm/13mm when it should have been 10mm/13mm/10mm.
The voice of an experienced mechanic understanding the nature of root causes! Thanks Roy for being so active around here
#95
Murena / Re: Vacuum hoses - Wich are th...
Last post by roy4matra - August 27, 2025, 11:04:06 AMQuote from: matra530 on August 26, 2025, 03:28:07 PM
Once the carburettor was running properly and the tension on the throttle cable was correct again, I had to tackle the vacuum supply. The T-piece (split supply vacuum control and vacuum tank) was brittle. So I ordered a new part from my usual dealer.
However, the diameter of the connections to the front and to the tank is much larger, but the connection to the check valve is much slimmer...
That sounds like they have the T-Piece sizes the wrong way around! Maybe the one they supplied was 13mm/10mm/13mm when it should have been 10mm/13mm/10mm.
Quote
So I carefully applied some silicone grease to the old vacuum lines on the T-piece and Teflon tape on the other side towards the check valve, and sealed it with a clamp.
It worked. I took it for a test drive and on the way back it started to run unevenly at idle speed. I got out and heard a loud hissing sound.
The vacuum hose couldn't withstand the increased tension and ruptured.
Now I'm considering whether to replace just that one or all of them. At the dealer, a 40 cm piece costs €10. That adds up to quite a few pieces and will probably only be available by the metre. But what is the correct designation for the right metre goods?
Many thanks for any advice.
The T-piece that has a fastening to the bulkhead, 0032602000, and has one hose to the vacuum storage tank, the opposite one to the white vacuum valve at the front of the car, and the third centre connection goes to the one way valve that is connected to the inlet manifold, has connection sizes 10mm/13mm/10mm. The 13mm connection has a short hose to the one way valve, which is the same item as the brake servo one way valve, 0030581600.
If you simply purchase a standard 10/13/10 T-Piece which can be bought for under £5, you can fasten it to the bulkhead with a cable tie. The original T-Piece fastening often breaks off anyway and has to be fastened that way in my experience. A 10/13/10mm T-Piece can easily be found on the internet or from AFS (Advanced Fluid Solutions) or on eBay, or Mercedes used to have one available which I have the part number for, if you can't find another.
Roy
#96
Murena / Vacuum hoses - Wich are the ri...
Last post by matra530 - August 26, 2025, 03:28:07 PMOnce the carburettor was running properly and the tension on the throttle cable was correct again, I had to tackle the vacuum supply. The T-piece (split supply vacuum control and vacuum tank) was brittle. So I ordered a new part from my usual dealer.
However, the diameter of the connections to the front and to the tank is much larger, but the connection to the check valve is much slimmer... So I carefully applied some silicone grease to the old vacuum lines on the T-piece and Teflon tape on the other side towards the check valve, and sealed it with a clamp.
It worked. I took it for a test drive and on the way back it started to run unevenly at idle speed. I got out and heard a loud hissing sound.
The vacuum hose couldn't withstand the increased tension and ruptured.
Now I'm considering whether to replace just that one or all of them. At the dealer, a 40 cm piece costs €10. That adds up to quite a few pieces and will probably only be available by the metre. But what is the correct designation for the right metre goods?
Many thanks for any advice.
However, the diameter of the connections to the front and to the tank is much larger, but the connection to the check valve is much slimmer... So I carefully applied some silicone grease to the old vacuum lines on the T-piece and Teflon tape on the other side towards the check valve, and sealed it with a clamp.
It worked. I took it for a test drive and on the way back it started to run unevenly at idle speed. I got out and heard a loud hissing sound.
The vacuum hose couldn't withstand the increased tension and ruptured.
Now I'm considering whether to replace just that one or all of them. At the dealer, a 40 cm piece costs €10. That adds up to quite a few pieces and will probably only be available by the metre. But what is the correct designation for the right metre goods?
Many thanks for any advice.
#97
Murena / Re: fast camshaft specs
Last post by Anders Dinsen - August 23, 2025, 06:40:06 AMGetting on the road is great. Problems show up, but I'm glad to hear your's solving it. I'm still working on getting to that point.
10 degrees on the standard cam makes sense. The period is short and there's little overlap on that cam so the fuel mixture in idle is good. You're probably running 800'ish idle? I have mine at 15 with the Holbay cam, which makes for a decent idle at 1100. It's huting a bit, but that's probably due to the high overlap on the cam and my cylinder head - it most likely short circuits a bit of fuel out the exhaust during idle. I have an AFR meter with a wide band oxygen sensor in the exhaust so I know the mixture is correct now.
I considered fuel injection years back. Most ECU's come with some sort of ignition controller and eliminate the distributor as they run wasted spark configurations with two coils. From an engine management perspective, that's a better system. They usually, however, depend on both a crank sensor and a cam sensor, so there's a bit of work involved and it will be completely custom. I'm not going that route, but staying with the sidedraught carbs. There's more performance to be gained by working on the airflow in the head, especially enlarging the inlet valve seat inner diameter. About the original distributors, in principle they can be tuned to do anything by replacing springs with other springs, but it requires a complete rebuild every time you want to try something different. The original Bosch has an advance curve that suits the original cam only (and vacuum takeoff from the original Solex carb). I have used it on my Holbay cam, but it will never be perfect, so I'm going to change eventually so that I can tune it to the cam and head.
/Anders
10 degrees on the standard cam makes sense. The period is short and there's little overlap on that cam so the fuel mixture in idle is good. You're probably running 800'ish idle? I have mine at 15 with the Holbay cam, which makes for a decent idle at 1100. It's huting a bit, but that's probably due to the high overlap on the cam and my cylinder head - it most likely short circuits a bit of fuel out the exhaust during idle. I have an AFR meter with a wide band oxygen sensor in the exhaust so I know the mixture is correct now.
I considered fuel injection years back. Most ECU's come with some sort of ignition controller and eliminate the distributor as they run wasted spark configurations with two coils. From an engine management perspective, that's a better system. They usually, however, depend on both a crank sensor and a cam sensor, so there's a bit of work involved and it will be completely custom. I'm not going that route, but staying with the sidedraught carbs. There's more performance to be gained by working on the airflow in the head, especially enlarging the inlet valve seat inner diameter. About the original distributors, in principle they can be tuned to do anything by replacing springs with other springs, but it requires a complete rebuild every time you want to try something different. The original Bosch has an advance curve that suits the original cam only (and vacuum takeoff from the original Solex carb). I have used it on my Holbay cam, but it will never be perfect, so I'm going to change eventually so that I can tune it to the cam and head.
/Anders
#98
Murena / Re: fast camshaft specs
Last post by Henk - August 22, 2025, 07:04:58 AMHi Anders,
Yes, it's starting and running great now. Before that I had a few issues with the engine. After some searching it was because of a dying alternator. When I put the spare in almost everything was solved! I had some wire connectors on the ignition coil getting loose while running the car. I change the old wire lugs with eye terminals and bolted these on the coil, problem solved.
And of course the right timing helped a lot. I found 10° advanced timing is the best. Above that doesn't work properly. I was advised 12° or more, but that's not working for this car.
For this standard engine the original ignition is fine. And I will rebuild the old alternator red so it can be used on the 2nd engine.
But most important is I can drive the car around. Because of that I found the clutch was slipping, so I replaced that. And I'm still finding little things to do.
For the spare engine injection project I think you are right to mount a 123ignition. I don't think the original will be working the best in combination with the injection and faster cam.
But first I need the injectors, all connectors, make a wiring loom and so on.
To be continued....
Yes, it's starting and running great now. Before that I had a few issues with the engine. After some searching it was because of a dying alternator. When I put the spare in almost everything was solved! I had some wire connectors on the ignition coil getting loose while running the car. I change the old wire lugs with eye terminals and bolted these on the coil, problem solved.
And of course the right timing helped a lot. I found 10° advanced timing is the best. Above that doesn't work properly. I was advised 12° or more, but that's not working for this car.
For this standard engine the original ignition is fine. And I will rebuild the old alternator red so it can be used on the 2nd engine.
But most important is I can drive the car around. Because of that I found the clutch was slipping, so I replaced that. And I'm still finding little things to do.
For the spare engine injection project I think you are right to mount a 123ignition. I don't think the original will be working the best in combination with the injection and faster cam.
But first I need the injectors, all connectors, make a wiring loom and so on.
To be continued....
#99
Murena / Re: Murena 2.2 / Chrysler 2L c...
Last post by Anders Dinsen - August 21, 2025, 07:43:04 AMThe objective of the cam is to time the airflow through the cylinder head by opening and closing the valves. There's a lot of theory and expeirence behind cam tuning, much more than I'm competent to explain, but I wanted to share these photos which Youri (Murena1400) has kindly shared with me and given me permission to post here as they show the channels the air is passing through when entering or exiting the cylinder.
The primary restriction on the 2.2 head is the inlet valve seat. The cross sectional area of the opening is simple to calculate by calculating the area of the circle inside the valve seat minus the valve stem circle area. The area of the valve opening is given by the lift of the valve multiplied by the valve seat circumference.
Increasing the inner diameter of the valve seat will increase both areas. Theory says that a restriction has effect on airflow when airspeeds become sonic as it's not possible to accelerate air molecules beyond the speed of sound. Remember that air flows into the head in pulses so the restriction can be said to "cap" the top of the pulses. Turbolence created by edges and the like also restrict a little, but generally turbulence in the inlet is desired as it assists mixing of air and fuel in the cylinder.
The pictures are of cut-throughs of an unmodified head.
Exhaust is even more limited as the exhaust valve (and valve seat) is significantly smaller. Exhaust restrictions affect performance far less than inlet on a normally aspirated 4 stroke engine.
The primary restriction on the 2.2 head is the inlet valve seat. The cross sectional area of the opening is simple to calculate by calculating the area of the circle inside the valve seat minus the valve stem circle area. The area of the valve opening is given by the lift of the valve multiplied by the valve seat circumference.
Increasing the inner diameter of the valve seat will increase both areas. Theory says that a restriction has effect on airflow when airspeeds become sonic as it's not possible to accelerate air molecules beyond the speed of sound. Remember that air flows into the head in pulses so the restriction can be said to "cap" the top of the pulses. Turbolence created by edges and the like also restrict a little, but generally turbulence in the inlet is desired as it assists mixing of air and fuel in the cylinder.
The pictures are of cut-throughs of an unmodified head.
Exhaust is even more limited as the exhaust valve (and valve seat) is significantly smaller. Exhaust restrictions affect performance far less than inlet on a normally aspirated 4 stroke engine.
#100
Murena / Re: fast camshaft specs
Last post by Anders Dinsen - August 21, 2025, 07:30:45 AMHi Henk, good to hear you finally got it reground, and also great that you have the car running again.
I notice you asked about ignition in the thread below. Have you considered converting to 123Ignition?
Classic Auto Elec in Tours, France stocks it for the Murena. It's the same distributor for all engine types, 1.6 or 2.2, you just have to choose the right distributor cap for the 2.2:
https://classicautoelec.com/en/electronic-ignition-matra/5130-6778-programmable-electronic-igniter-for-simca-1000-1200-1300.html#/180-tete_d_allumeur_a_sorties-droites/678-123_tune-non
I have run the standard 2.2 Bosch distributor on my Holbay and I've not yet converted to digital ignition advance myself, but I will since it allows tuning the ignition advance correctly to match the cam. Of course you can play with the timing springs in the distributor, but they're hard to find and even harder to replace.
123Ignition can be tuned over Bluetooth with an app on your phone.
I notice you asked about ignition in the thread below. Have you considered converting to 123Ignition?
Classic Auto Elec in Tours, France stocks it for the Murena. It's the same distributor for all engine types, 1.6 or 2.2, you just have to choose the right distributor cap for the 2.2:
https://classicautoelec.com/en/electronic-ignition-matra/5130-6778-programmable-electronic-igniter-for-simca-1000-1200-1300.html#/180-tete_d_allumeur_a_sorties-droites/678-123_tune-non
I have run the standard 2.2 Bosch distributor on my Holbay and I've not yet converted to digital ignition advance myself, but I will since it allows tuning the ignition advance correctly to match the cam. Of course you can play with the timing springs in the distributor, but they're hard to find and even harder to replace.
123Ignition can be tuned over Bluetooth with an app on your phone.