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 on: January 06, 2020, 11:48:27 am 
Started by Colin - Last post by Matraman
Herman, I've also found that the L shaped pivot is too stiff, but I'm struggling to get it off. There seems to be a circlip hiding at the bell housing end of it, which I can't get to. Any special tricks to release it? I notice in your photo a tiny screw driver, did you use that as part of the trick of removing it?

 on: January 06, 2020, 11:13:56 am 
Started by Matraman - Last post by Matraman
Thanks Ian. The disc was in good condition and a very tight fit when I tapped it back in, so hopefully it'll stay there. I'll try your leak check idea, maybe a bit of thinner oil would be closer to warm transmission oil for cold leak checking?

I count myself lucky that the drive shafts came out OK. My biggest problem was hub nuts, but I won in the end!

 on: January 06, 2020, 09:39:35 am 
Started by Moes - Last post by Moes
Hi Anders

Thank you very much for you reply!  Smiley  I really appreciate it. It has helped me to see things in the right light, and to make my decisions on what to do, and how far to go with my repairs  Grin

It would be a lot of fun to get the car on a rolling road after doing all the work you mention, but I would like to have the car back on the road this spring, so I am going to keep it all original, and keep the crank case with cylinder head and cam as it is; I might take off the timing chain, and do some measuring, to see how worn it is.

I was expecting most of the work you mention, if I choose to change the camshaft, but it is good to see a more complete picture of the work that would be needed in writing. I am thinking (dreaming) of having an engine tune-up project alongside a running car. So i might bye an 80s 1600 cc Talbot engine (Murena crankcase), and rebuild it with a little more kick, to fit my Bagheera; and with a more modern style gearbox. I have found an article about the gearbox Simca used in the 70s for Bagheeras and other models, and it states that the Simca gearbox were build on a 60s Porsche design and patent (with compression-synchromesh rings). After reading this article I found a very nice rebuild-guide for a similar Porsche gearbox, which also explains wear and tear on these types of gearboxes: http://porsche.wikidot.com/how-to:porsche-915-transmission-repair-tutorial-part-ii

On Saturday I bought a Bagheera gastank without any damages, and a set of gastank straps. I have been removing a Kg of old underbody coating from tank, and it is looking better and better. I was quite disappointed with the tank straps; they should be original (I can see that one out of four parts is home made), but the original pieces has been welded on to the brackets in the engine compartment (from the factory), and not boltet on as I through when looking at the brackets on my car. Because of this i have chosen only to reuse a few parts for the straps, and make new ones, that kan be boltet on the the existing brackets.

The gastank came from a car that had been stranded for 10-20 year in a field, and it contained app. a liter of.. water! and not a hint of gas. So all metal parts in the tank (suction pipe and level transmitter) had turned into rust residues.

Best regards Frederik      


 on: January 05, 2020, 09:13:58 pm 
Started by Matraman - Last post by MatraIan
Good job done.
Just saw your second post as i was replying as i had to do this on my car.
Although you have tapped it back in i would suggest putting the shaft in a vertical position with some oil in to check if it has re-seald properly as it has been disturbed and as you will have seen it is an inteference fit.
If it leaks and you need to replace it, it is 30mm in diameter.
Peugeot Citroen part number 3111.11 is the one I used to replace mine.
I had advice and help from Roy Gillard to remove my engine and I could not get my short drive shaft out. I had to take the shaft and the diff off together and separate on the bench. I had to unbolt and dismantle the diff to get at the core plug and it was removed by forcing a screwdriver into it to distort and then prise it out.
I stripped the diff down to clean and check whilst it was apart.


 on: January 05, 2020, 08:53:54 pm 
Started by Matraman - Last post by Matraman
I managed it! I had to undo the 12 bolts on the main gear in the diff, remove the bearing from one side then slide the planet gears out of the way then I could access where the disc came from and tap it back in. Everything else looked good inside there with no chunks of metal, just a small amount of swarf on the magnetic drain plug. I hope the gearbox is as good because Ive never been able to use it yet, so an oil change is all that itll get with a couple of new linkages and top hat bush.

 on: January 04, 2020, 04:29:21 pm 
Started by Matraman - Last post by Matraman
In checking over the gearbox and bell housing, which is out of the car and on the bench, I noticed that inside the differential, where the left side drive shaft is inserted, there is a loose 2cm disc. I suspect this is what stops oil leaking out past the drive shaft splines and it probably fell out because I gave it a tap when trying to extract the right hand drive shaft. Oops!

I've removed the differential casing and lifted out the main gears in one piece, but I still can't get access to this disc. Can anyone suggest the next step please? I guess it's some kind of push fit, but I need to get to the inside surface of it to get it back. The options seem to be to remove the bearing from the spline tube, or remove the 12 bolts on the diff to dismantle it further. I don't want to go any further until I've checked with you guys further.

 on: January 04, 2020, 11:29:21 am 
Started by Matraman - Last post by Anders Dinsen
Glad to hear you've been finding inspiration in my posts Smiley

The "right thing to do" is to replace both with new ones remade from scratch. That said, they sell them one by one, as far as I know. Simon too. I have also heard of people welding them up successfully, as you're thinking about. It can probably be done so it won't be noticed, though it wouldn't be legal (at least not here). Suspension components should generally be replaced, not repaired.

That said, however, I think the arms are over-dimensioned, and especially the outer part is less critical part of it from a strength point of view. I haven't made any calculations (semi-trailing arm physics is hard...), but the upwards load is obviously on the spring/damper joint, and the lateral load on the inner joint. The outer joint is only there to control the suspension movement. You can see this by the fact that the inner joint has a face on which it's running against the chassis, whereas the outer is just a bolt running through the holes, so it's by the inner joint that the lateral forces on the outer wheel (which is carrying most of the weight of the car during cornering) are transmitted to the chassis. Also note the bar under the engine that connects these two points on the chassis to further strengthen that and ensure the lateral forces are transmitted through the chassis to the opposite front wheel to stabilize the car during cornering (the job of the roll stabilizer).

Matra knew what they were doing with the chassis. It's a pity they decided to save some money on the trailing arms... An aluminum design (as on the Bagheera) would have been much better for us now.


 on: January 04, 2020, 11:12:14 am 
Started by Moes - Last post by Anders Dinsen
Hi Frederik,

I wouldn't expect you to go wrong with Politecnic. They have experience.

Remember that you'd need to rejet your carburettors, and preferably set it up on a rolling road, so consider that too when you think about cost. A new/better exhaust manifold will probably be needed too.

A number of parameters define the performance of a cam, but it always depends on the engine: Cam development is to my knowledge as much an art as a science. However, the basic parameters are the ability to increase the amount of air being drawn into the cylinder and the ease with which it is blown out.

That depends on lift and period, of course, but there's more: E.g. the exact timing, the envelope (how quickly the valve is opened and closed), the overlap during which both the inlet and exhaust valves are open, and the exhaust and inlet manifolds. All these parameters determine more of the dynamics of the cam, i.e. how the engine performs at midrange to high RPM.

For example, at high air velocity, the vacuum developing on the back side of the exhaust "bubble" as it moves down the exhaust manifold can be used to initiate the draw of air in through the inlet valves early. That's why fast cams have overlap where both valves are open at the same time.

Remember that air has a mass, so getting it moving and accelerating it is important. Also, once the air through the inlet has accelerated, it will generally keep moving through the valve even as it closes, so at mid range to high RPM, the air will continue to fill the cylinder even as the piston starts the compression cycle, so you want the cam to stay open longer on a fast cam.

Now, I can't claim to be an expert. This is just to explain some of the dynamics that experts are working with when they're designing cams.

If you're interested, I suggest you contact Politecnic and inquire them about what kind of performance you will be looking at for the Gr.2 cam and what other changes will be needed. I would expect as a minimum the exhaust manifold should be changed from the standard cast iron manifold to a tubular design and the carbs should be rejetted. The flywheel should probably also be lightened.


 on: January 04, 2020, 09:25:14 am 
Started by Matraman - Last post by Matraman
Hi Anders
Ive read your thread with great interest over recent weeks since I bought my Murena 2.2 project. It has helped me to see what is possible with a single garage, which you and I both have. So while reading through it I saw your new trailing arms, very nice! Do they have to be ordered in pairs, or could I just buy one?

My trailing arms have been treated internally through some drlled holes at some point, the previous owner was very keen to tell me that it was done regularly. It seems to have been effective on the RHS but not on the LHS for some reason. I plan to give the RHS a good blast with Waxoyl inside, but Im not confident about the strength left in the LHS. The consequences of it collapsing could be severe!

So if I could just get hold of a left one for now it would be another step towards getting it back onto the road after 20 years of sitting in a garage.

 on: January 03, 2020, 08:27:27 pm 
Started by Matraman - Last post by Anders Dinsen
Been there... http://www.matrasport.dk/forum/index.php/topic,3311.msg24428.html#msg24428

I ended up ordering two new ones from Politecnic as they tend to corrode from the inside. The LHS is fitted now and I'm now going to start on the RHS. I'll be sending the old hubs back to Politecnic so they can be used for new ones.


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