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Author Topic: Newly re-profiled Murena 2.2 cams  (Read 75 times)
roy4matra
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« on: June 18, 2025, 10:23:41 am »

Hello all, as you know the Murena 2.2 was originally fitted with the standard Tagora 2.2 engine with no performance modifications at all, and as such was not very powerful as a consequence.  The main problem was a very mild camshaft profile, which was reasonable for a heavy 4 or 5 seater saloon car, but definitely not ideal for a light mid-engined sports car!

At that time Holbay were a well known excellent engine tuning company that tended to support Rootes (and later Chrysler Europe) cars and I'm sure most of us older owners remember the fast 998cc Imps and Rapier H120 (Holbay 120 horse power) fast Rootes road cars as well as in circuit racing it was often the Holbay tuned FF and F3 cars that were the best.  So it was Holbay that produced a re-profiled fast road cam for the Type 180 engine that is in the Murena 2.2, and this gave it some much more suitable performance, without any other modifications necessary.  This re-profile was called the Tornado or the 58C profile.  Unfortunately as you know, Holbay no longer exist.

However, I have contacted Piper Cams who made the brand new 3777 high performance cams for a few of us a few years ago, to see if they would re-profile some standard cams at a much lower cost, with a similar fast road profile to those Tornado cams, and they are willing to do that.

So if any of you Murena 2.2 owners still have an original 2.2 Murena cam in good condition, and would like to increase your Murena's performance for less than half what it would cost to buy something like an 'S' cam, and also not requiring any other costly alterations, now is the time!  If they do several cams at the same time they only have to set up their equipment once and so they can offer a slightly reduced cost.  Obviously if the cam is still in the engine in the car, you will have to remove the cylinder head to remove the cam, and you will need to refurbish the rocker arm pads too, so there will be some additional costs, but the re-profiling will be in the region of £250 or less and therefore a lot lower than the normal cost of a better cam from the usual European Matra suppliers such as Politecnic, Carjoy, etc.

I currently have 4 standard cams which I will be taking when we are ready, so if anyone else wishes to join us, then let me know as soon as possible please.

Roy

« Last Edit: June 18, 2025, 10:37:21 am by roy4matra » Logged

Grapes
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« Reply #1 on: June 18, 2025, 05:17:31 pm »

I know there's a bunch of 2.2 owners in the Netherlands who are in some sort of a Matra sports club WhatsApp group. I never really used WhatsApp so I don't know if anyone can just join and how but you probably will find more interested parties through there as well.
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Murena1400
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Posts: 20


« Reply #2 on: June 19, 2025, 03:02:50 pm »

This is a job that I just finished. Reprofiling the camshaft is not the issue, but figuring out what profile to use is.
After some research, calculating and talking to people that worked on these engines in the 70s, I settled for a camshaft profile that follows the "Simca Challenge 74" Specifications.

To what specifications will these camshafts be ground?
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roy4matra
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Posts: 1225



« Reply #3 on: Today at 05:47:21 pm »

This is a job that I just finished. Reprofiling the camshaft is not the issue, but figuring out what profile to use is.
After some research, calculating and talking to people that worked on these engines in the 70s, I settled for a camshaft profile that follows the "Simca Challenge 74" Specifications.

To what specifications will these camshafts be ground?

At this time nothing has been decided.  I am in consultation with Piper, who as a long time camshaft specialist, know how to produce a fast road cam, so I have supplied them with the Holbay specifications that were given to me at the time, and I will leave the rest to them as I trust them to know what they are doing, just as they did when producing the 3777 cams for us.  I gave them the details of what we wished for from those high performance new cams, and what they produced has been spectacular, both in power output and the sound they produce. (although I know that the exhaust has a bearing on the sound too)

I don't know what that 'Simca Challenge 74' specification is, but it sounds like a racing series engine, so do you know what the power output and details are exactly?  Obviously it would be for the Chrysler Type 180 engine but probably the 1812 or 1981cc engines as the 2156cc engine did not exist at that time.  Is it suitable as a fast road car engine cam with absolutely no other modifications required, or is it a peaky cam which needs some carburation and/or other engine changes?

Most cam manufacturers or engine tuners consider their work secret and won't release full details of their work as they are in competition with other engine tuners, so I'm surprised if you got all the profile details for that Challenge 74 cam, but well done if you did.

Have you had yours reground and it's back in your car now?  How does it perform?

If you have not had it done yet, is it already planned to do soon?

Contact me by direct email please for more on this, thanks.

Roy
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