MatraSport Forum

Hi everyone !
I had to remove my 230hp turbo engine from my car (thanks to new french tech control  :'( ) and I'm working on a "near genuine but spicy" 2.2 engine  8). Sooo, I'm looking for a good camshaft.
 Everyone is talking in great worlds about Holbay 58C one, but it seems that no one can sell it now ...
 I have most of sport camshaft specs ( S, Politecnic, Sodemo Gr4, .....) but not this one's  !
Is someone can tell me the specs of this camshaft ? I think it would be the best choice for my car ...

Hey there! Welcome to the forum. Sad to hear about your contrôle technique experience. I have the following specs on file:

Specs:
Std:    Lift 6.5mm          Timing 19°12' 56°48' 54°48' 13°12'
Period (Inlet) 256° (Exhaust) 248°       Overlap 32°24'
Valve clearance (Inlet) 0.2mm   (Exhaust) 0.3mm

'S':    Lift 7.4mm          Timing 27° 72° 69°30' 29°30'
Period (Inlet) 279° (Exhaust) 279°       Overlap 56°30'

Holbay: Lift 7.06mm         Timing 39° 77° 79° 37°
Period (Inlet) 296° (Exhaust) 296°       Overlap 76°
Valve clearance (Inlet) 0.25mm   (Exhaust) 0.3mm

Sodemo gr 4:   Lift 7.75mm  Timing 30° 86° 78° 42°
Period (Inlet) 296° (Exhaust) 300°       Overlap 72°

I agree, the Holbay is a great cam shaft. Although it has less lift than the S-cam, the overlap helps the airflow and the performance might be even better. Also, it runs very well with the standard Solex 34CIC carb.

There was a few made recently. Contact Roy at roy@matraclub.org.uk as I think he knows who has the tooling for it.

thanks for this so fast answer !!! Do you think this camshaft is only good for a single carb use (and maybe 2x40ADDHE), and sodemo better for bigger carbs with high revs ?

You're welcome :) No I think it's fine for a set of twin carbs, but if you want to convince the car is standard, why not use the single double barrel Solex? I'm running a Holbay on a pair of Weber 40DCOEs

I will use a genuine carb for the moment ... but I'm working on a exact "S" replica manifold  3d printed made of ULTEM material ... next level ...  ;D

That sounds VERY interesting! :)

3D modeling from an original manifold is on the way ( near finished), and Ultem is loaded  ;D
I will be able so cast in aluminium too (with lost PLA method), but first step will be to print the prototype .... validate it, and go to Ultem.
I also made a "Matra Sport" camshaft cover for 2.2, the prototype is validated and ready for aluminium casting (casting sand method).

Do you think a camshaft with all Holbay specs, but with a little bit more lift (maybe 7.2 between holbay and "S") would be better ?

I have a genuine 2.2s but it had been changed to a single Solex by a previous owner. (who hadnt kept the original carbs manifold or airbox - Arrrggghhh). trying to get original replacements is almost impossible.
I bought one of the 4 new cams that Roy had made to a new spec, trying to get the best of all the previous versions.
Mine is installed but not running yet . There is only 1 running i know of so far and i believe Roy has driven it and that he has previously owned both standard and Holbay versions so would be a good person to ask his opinion.
Like you I wanted revert to original ‘S’’ but also it be reliable. I believe the Dellorto is a better set up and more reliable than the Solex so that is what I will be fitting. I have also made a reasonable attempt at a new inlet manifold, made from flat plate and tubular alloy. I had four of these and I think Roy still has a spare available. They were fairly cost effective and simple just not quite as curvy as original. i will try and get a picture over the weekend.
Ian.

Hello philiping,  The first thing you need to realise is that the Matra marketing department lied about the horsepower of the original engines.  The engines were tested by the factory for the original specifications and these figures were in kilowatts as is normal in France.  A standard 2.2 produced 84.32 kw, the 'Prep 142 ' was rated at 101.4 kw and the genuine 'S' was rated at 100 kw. (Check the certificates of Conformity)  However the marketing people then used a 1.4:1 conversion factor for horsepower to kw which is wrong and this gave misleadingly high horsepower figures.  Also they did not state whether this horsepower was PS or bhp, but since they generally talk of horsepower DIN, that is PS... NOT bhp.

If you convert the original kilowatt figures recorded to bhp correctly, then the standard 2.2 produces 113 bhp, the 'Prep 142' uprate gives 136 bhp and the genuine 'S' produces only 134 bhp.  All this has been on my website for some years.

The Holbay reprofile gives a lovely camshaft which easily produces as much performance as a genuine 'S'  and on the road is better.  I know, as I have driven both for many years.  Furthermore the Holbay reprofled cam can be used with either a 'twin-choke' down-draught carb. or two twin side-draught carbs. and the only real difference is the fuel consumption.  On a down-draught carb. it will easily top 31 mpg on the open road, and not generally drop below 25 mpg even around London!  (that is where I live so I have proof if anyone needs it)  With two twin side-draught carbs. the consumption will always be slightly less on the open road, but around town it can drop below 20mpg!

I once roller tested my Murena with Holbay 58C cam still using the down-draught Solex, and it gave 140 bhp, so you can see it slightly out performs even the 'Prep 142'.  Unfortunately Holbay no longer exist, which is why you cannot get a Holbay reprofile from them, but that is not to say you could not get a similar reprofile from someone like Piper or Kent cams.  It is simply a 'fast road' camshaft reprofile.

I did not like the 'S' profile as it has more lift but less duration which means the ramp angles are steeper, and since the lower lift but longer duration Holbay profile produces more power I decided a better cam would have more lift as well as longer duration.  Working with Piper we came up with a high lift long duration profile fast road cam which produces a superb engine as I know from having driven the first one I built.

I should also point out here that the Politecnic 'maxi-route' profile which originally appeared to be a Gr.4 cam in their leaflet (of which I have a copy somewhere) is unlikely to be as good as it has a similar duration but less lift.  (7.75mm lift compared to 8.30mm lift for our Piper and 296 inlet/300 exhaust degree duration compared with 298+ degree for both inlet and exhaust duration on the Piper, which they measure from 10 thou open to 10 thou before closed)

Again, I have driven a Murena with the 'maxi-route' cam which is stamped 150cv suggesting it is actually rated 150 horsepower but with optimum set up can give around 155 bhp, and the Piper is better.  This is with both using the standard valves.  To get a true 184 bhp Piper say the engine would need to have a lot more lift (maybe 9mm cam and over 12mm valve) and bigger valves or 4 valves per cylinder, higher compression, combined with optimum fuel feed from big carbs. or fuel injection and unrestricted intake, and even those special ROC engines only gave 200 bhp with a £2,000 special cast twin cam cylinder head and race build and preparation!

Finally, if you have a standard 2.2 engine, then you should get the flywheel lightened as it is too heavy for the Murena because it has the standard Tagora 2.2 flywheel!  The lightened flywheel improves pickup noticeably.

Roy

wow ... and 8.3 lift does not make  piston/valves interferences ?
So my idea to make a cameshaft with all the Holbay specs, but a little bit more lift (7.3) is not so bad ?
I've already worked on my flywheel : now it's 8.2kg and balanced with all rorating parts. As you said, it's a must do for this engine !

Has anyone here rebuilt a 2,2 engine with a sportcamshaft and instead of single or twin carburaters used manifold from Peuget 505 turbo engine together with Bosch LE jetronic injection or similar simple system?
If I compare with experience from Opel CIH engines in GT,Manta Ascona there is a big difference when the engine has fuel injection system. More quiet and smooth behavior, save fuel and always starts with warm engine.

//Mattias

Would love to see a picture of the "Matra Sport" camshaft cover when it is finished.

I have a "Politechnic" camshaft cover which is O.K.  but a bit "agricultural"

Here is an old article for your interest/inspiration with some piston/valve interferences mentioned during an engine rebuild carried out by Roy previously for me. (Using the Camshaft stamped 150 CV from Politechnic).

Keep us posted of developments......................

I have the only car running with the Piper cam in it, unless Graham has been busy...? (do you have any events planned for next year with the Murena Graham? I am yet to see it in action...) It is good, very good, everyone who has driven it (who all have more experience of driving various Murena then me) says how good it is.
Here are some videos of it...
https://www.youtube.com/playlist?list=PLkkcMOq03tEgbCE2AzitiB7zyv-57QC0H

No, I originally measured the clearances between the valves and pistons when rebuilding Graham's engine some years ago, so we knew we could go with more lift when we had the Piper cams made.  The Murena 2.2 engine now rebuilt in Colin's car has our new Piper camshaft with 8.3mm lift (11.37mm valve lift) and still has some clearance when running, and as can be seen and heard on his youtube videos, it goes well and sounds really good. :)

Roy

Hi Colin, no I have not fitted the Piper Cam as per your engine yet. Too mean to replace the Mecapart Head Gasket again £££££ Hah!
Another "no" I'm afraid as nothing planned for next year as yet.  A few other distractions/responsibilities have popped up.
Keep you posted when it does happen though?

Graham

2020 Update:

I have now found my Politecnic brochure and the above specifications are not quite correct, so I would like to correct them for anyone else who is wanting to uprate their 2.2 engine, and is reading this thread.

The camshaft specification Anders lists above as the Sodemo Gr.4 cam is actually the data for the Politecnic Maxiroute camshaft and will only produce around 150-155 horsepower and cannot be a Group 4 cam producing 184cv.  The Group 4 Politecnic-Danielson kit which was supposed to produce 184 cv also had bronze valve guides and special sodium filled exhaust valves (for cooling) with twin concentric valve springs and special aluminium retainers. Whether these valves were larger and the head had a higher compression it does not say, but I suspect it did and also had a special high lift cam, higher than even the Piper 3777 because having spoken to experienced racing engine manufacturers, for this naturally aspirated 2.2 engine, the valves would need to be lifting over 12mm to produce around 185 horsepower.

We know that the Piper 3777 cam with 8.3mm cam lift and therefore 11.371 valve lift, plus wider timing will not produce more than approx. 160bhp so there is no way the Maxiroute cam with less lift could produce that claimed 184cv (181bhp) without extensive other modifications.  But the original Politecnic brochure does not claim the Politecnic-Danielson kit uses the Maxiroute cam.  The brochure simply lists what was available from them at the time and the options were:
1) Maxiroute reprofiled camshaft priced at 1,990 FF in exchange for your old cam.
2) Politecnic-Danielson complete Gr.4 kit priced at 7,500 FF.  (yes French Francs which shows how old this brochure is!)
You can see from the price difference here, that the Gr.4 kit contained a lot more as it cost approx. 3.5 times as much as the reprofiled Maxiroute cam!

Roy

I have the correct information on this matter.

The Politecnic Gr.4 set consisted of a special hemispherical head, with bigger valves, double springs, modified intake ports, small spark plugs and a wider exhaust.
It was delivered with a special camshaft, which was available in two stages, 184cv and 200cv. (these figures are real figures as on bench tests).

A few of these heads were made for the Rallye Monte Carlo cars, and later for some rallyecross operations.

Whatever was left they put for sale on their brochure, (in numbers not more than 2 sets). The last set was bought by us in 2001 and put on a Murena S.
(The photos of the engine bay of a Murena S with double Dellorto's is in fact our car).

These are really potent kits and are not comparable to whatever is on the market today.

Thank you for your reply and the confirmation of the true facts.

When you say the photos of the engine bay are of your car, what photos?  I see no photos here, or are you referring to the photos in that an old Politecnic brochure?

Roy

Roy,

The photographs of the Murena S engine bay on the Politecnic website are in fact of our Murena.

But it seems the photograph is gone, there are still some photo's on the "Moteur complet" page (the right one, with the carburettors, it is the special head.)

Hello,

I'm Henk Scholte from the Netherlands. I am restoring my Matra Murena 2.2 from 1983 which is almost done. I had a donor car so lots of extra parts and therefore a spare engine.
This one will be repaired. The camshaft looks quite good, and I want it machined to the Holbay specs. I allready found a machine shop for this. As I understand the Holbay will work fine with the standard Solex carb.

What i'm unsure about is the ignition. Will this have to be changed also, or is adjusting the timing enough?

Thanks.

Henk

Hello Henk,

No, the ignition doesn't need to be changed, it is fine just as it was originally.  You don't even need to adjust the timing.

I have run a Murena 2.2 for many years and many thousands of kilometres with a standard Solex 34 CICF carb. a standard camshaft reprofiled by Holbay to their 58C profile, commonly named the Tornado cam, a four-into-one gas flowed exhaust manifold and stainless steel silencer with one tail pipe on the left like the original. It has the original Bosch distributor, standard electronic specification 12v coil, standard amplifier, and standard 10 degree BTDC static timing, using NGK BP6ES plugs and it runs fine. It also has a lightened flywheel. It produces around 140 genuine bhp. The Murena 2.2S was rated at 100 kW on the Certificat de Conformité and that, when it is correctly converted to bhp, is only 134 bhp. The claims of 142 bhp are erroneous as the incorrect conversion factor was used in all the Matra advertising. This has all been detailed on my website for years.

I have owned a genuine 'Prep 142' and driven a genuine 'S' and I know mine is slightly quicker as well as being better on fuel economy since the 34 CICF down-draught carb. is more economical than two twin side-draught carbs. in normal fast driving, and I get between 10 litres per 100km (worst) and 7.1 litres per 100km (best) (that is between 28 mpg and 40 mpg!) and I mostly drive fast but I do have the high 5th gear fitted which I pioneered! I would normally easily achieve 8 litres per 100km or say 34-35 mpg on a run. Even before I fitted the high 5th gear I would easily get 8.7 litres per 100km (33 mpg).

Roy

Sounds great Roy!

What I want/need to do is first get the Murena driveable, get the gas installation removed  from the carregistration and then the APK (MOT in England). Then the car is road legal. This is almost done!

In the main time I will revise the second cilinderhead and fit it with the Holbay cam. Make a good exhaust and get the 2nd flywheel machined. When all that's done exchange the original with the revised one, and off course fit the new flowed exhaust and lightened flywheel. This will take a couple of months. Enough to get used to the Murena and notice a difference in performance.

Thank you very much!

Henk

I've send the cam to the machineshop last week for regrinding it to the Holbay specs. I noticed one of the camlobes is badly worn, as is clearly shown in the picture. Only one, the others are fine. How is that possibl.... So not a moment to soon. I expect the cam back in a few weeks. Before it's back I will clean the engine and prepare everything so I can fit the faster camshaft quickly.

That does not look particulary good, when you fit the new/reground cam you will need to fit either new followers or get the existing ones refaced(if they are in good enough condition). I would also check that valve and spring assembly to make sure that there is no undue stiffness or sticking to cause that amount of wear also do not be surprised if there is not enough of that cam lobe left to allow a regrind.

Good Luck
John

First thing Henk, have you removed all the rocker arms and kept them in order so you know exactly which position they came from?  Have you checked that all the exhaust rocker arms are the ones with oil holes on the underside as this lubricates the system on that side?  The inlet rocker arms don't, or should not, have an oil hole on their underside.  They have oil fed from the rocker shaft internally.  Having both sides correct is very important.  Over 90% of all the engines I have stripped, with cam wear on various lobes, have been previously rebuilt by someone who did not keep them in the correct place and there were arms with oil holes on the inlet side and some without on the exhaust side!

With that amount of wear even on only one lobe and rocker arm - and that rocker arm will be bad and should be replaced too as I doubt it can be refurbished, but if they do manage, it will certainly need the case hardening to be redone.  I have seen this so many times and it shows how many people overhauling engines don't really know how!  Also with that amount of wear, all the material that has come off will have circulated with the oil and you need to check everything for wear now.  Particularly the oil pump, and all bearings on the crankshaft, as well as totally cleaning out the oil system to get rid of the abrasive oil and metal swarf mix.

As JL has already said, I would be surprised if they can recover that cam because of the amount of wear on that one lobe, but if they have rebuilt it up and reground it, they must have also redone the case hardening.  Make sure they have done that to all the lobes.  But you must not rebuild this now without refurbishing all the rocker arm pads.  You do not use worn rocker arms against a newly reground cam, because it will not last if you do.  I know at least two owners that did that and the cams were shot in less than 10,000 km.

Roy

Thanks for the input guys.

Thanks to this site I am aware of the order of the rocker arms. These were mounted in the right order. I removed and cleaned them and I will put them in back in the correct way. The rocker arm of the worn lobe was also damaged. This was not as bad as the lobe and it could be salvaged by a light regrinding, hardening and polishing. The other arms will be regrind also. All valves are cleaned and polished, and the springs are alle fine. I also refurbished the waterpump, again with help to the info on this site.

But I found this cilinder head wasn't original. The upper engine mount mounting points are welded on, so it's probably from a Tagora or 180. The head of the 2nd motor however is original. This one is also been totally refurbished (as above) and is as new.

Further the oil has been removed, engine and pump cleaned and new oilfilter mounted. I found no pieces of metal in the old oil. Hopefully the filter caught the particles. I will change the oil and filter after a few rides, to be sure.

The cam itself is now at a specialist who will be welding the worn lobe, than regrind it to the Holbay specs and give it a hardening treatment.
I expect to have it back in a week or 2. Can't wait to put it in the car.