Time to do some repairs

[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.

/Anders

[Moes]

Hi Anders

Thank you very much for you reply!    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  

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 80´s 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 70´s for Bagheeras and other models, and it states that the Simca gearbox were build on a 60´s 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      



      

[Moes]

I have been talking to a local metal surface treatment company. I heard about the company from a fellow Matra owner some year ago. He had a good experience with having door brackets and other steel parts for he's Murena given a new surface treatment at this place.

I got the idea that it would be much more satisfying to have all the bolts for the gearbox, differential and engine, cleaned and given a new anti corrosion surface, now when I got it all taken apart anyway 

Then I thought maybe they can also do surface treatments of aluminium. They told me that they could do surface treatments of aluminium, but there can not be any steel bushings or any steel parts left on the aluminium parts, because the treatment of aluminium will damage the steel. I was hoping to get the complete gearbox and differential housing treated, but I am not able to get all the small steel bushings out of the lid for the gearbox gear selection mechanism (without damaging them), but I think I can have all the other parts treated. I will drop by company next week with the parts

I have also startet to remove the old paint from the crank case. I startet out with a paint removing gel (Nitro Mors), it does not work that great on a rough surface like cast iron.. but it does make the paint soft like rubber, and then it is rather easy to remove the paint with a wire disc brush. 

 - Frederik

[Moes]

Today I had an hour to kill, and I got one side of the crank case primed; it feels good to do some work that is going to remain unlike most of the work I have done so far; disassembly, sanding and cleaning.  

Yesterday I started to remove rust ans loose paint on the frame and in the engine compartment. I hav not got very far with it yet, but the dust mask says otherwise    I think I will change it out with a full face gas mask the next time.

I have also ordered a set of welsh/core plugs. The first time I started up the engine 10 year ago one of the plugs was rusted, and cooling water was suddenly everywhere, back then I only changed the one plug because it was difficult to get the new plug in place while the engine was in the car.     

- Frederik

[Anders Dinsen]

Greenish-yellow primer - what colour will it become? Awesome to see your progress

[Moes]

Hi

The colour..  It will be a surprise   At first I was going with a conservative colour choice, but them I thought.. No..  be bold!   You will have to be under the car to appreciate it anyway      

Yesterday I delivered all the bolts and nuts + some steel brackets, and the gearbox and differential housings for surface treatment at a place called Værløse Galvaniske (In Denmark), they will do a Plasma electrolytic oxidation surface treatment of my aluminium parts, and some sort og dual layer black electrolytic zink treatment of the steel bolts and brackets, which should be four times as strong than the white electrolytic zink treatment. I am very excited to see the result, I am not completely sure what to expect, they said the result (and colour) on the aluminium would depend on the quality of the aluminium, but I should expect it to be darker in colour; they could also do more funky colors like screaming red or blue, but I told them to do it colorless.    
I have also delivered all of my larger steel parts for sandblasting and black powder coating.

 - Frederik      

[Anders Dinsen]

It all looks absolutely fantastic. I'm always impressed with your work - you're really doing a serious job. Let me guess about the colour... a chromed engine block would be bold, but would require a full stripdown, so probably not what you're doing. I think you'll paint it purple, that will go perfectly with the orange

Looking forward to seeing your parts. Unfortunately won't have time the coming weekends to drop by

/Anders

[Moes]

Thank you, Anders!

I have received some new parts, a crank case gasket and oil seal set, and a lot of smaller brackets and p-clips, but no parts back from surface treatment or powder coating, and no welsh plugs yet..

At some point I will have to continue the work on the chassis, it is just no the most fun part of the work I will have to do.

Yesterday I stopped by the local metal salvage yard, and found a lovely sheet of stainless steel, from which I cut out some pieces to rebuild the tank straps which I recently bought. A metal worker seeing me weld stainless steel and mild steel together would probably laugh or cry, but I do not have access to a TIG welder, and I am sure they will last longer than the originals anyway.

 - Frederik

     

[Moes]

This weekend I got to do some work on the chassis.

I am looking very much forward to being done with stripping the loose paint and rust, the dust is everywhere,  my garage will need a thorough cleaning afterwards, so I better get it over with..

I have chosen to close the rust hole in the engine bay air duct with a rigid aluminum sheet, which I hope will work as a heat shield. I can see on the old piece I cut out, that this place has been repaired at least three times before. The heat from the exhaust manifold seems to be the sinner.

When I bought the car there were no good exhaust manifold with it; I bought a new one from Simon-auto made from tubes, but of cause it startet to rust almost immediately, there are probably not many paint types that can handle the heat and the tension from being heated and cooled time and time again; but I have bought some gray 1-component Por-15 manifold paint. I am curious to see how long this will last?      

 - Frederik      

[Anders Dinsen]

The manifold looks good painted. It will indeed be interesting to see if it can keep the rust away for a while. It looks like it's made of thick gauge tubing so it probably isn't going to rust through. Did the bagheera have a special manifold compared to Simcas with the same engine?

Someone warned me against using aluminium on steel, but it looks like a good idea. Would be interesting to hear what other bag owners have done with this air duct. Looks by the way like its corroding from the inside (which would make sense).

Anders

[Moes]

Hi Anders

The original Bagheera exhaust manifold is a standard Simca cast iron. Actually I did get one with the car, but it was cracked. I asked around, but nobody would weld it, they told me that a weld on cast iron would not last. Back then I did not know much about the cars heritage, so I could not find a used manifold at any scrap yards; had I known that it was the same used on other Simcas and Talbots I probably would have found one. So I ended up buying a new production manifold from Simon-auto.

The manifold paint will have to cure for 24 hours at 20 degree Celsius, and then the manifold will have to be heated up to 150-200 degree Celsius for 2 hours to fully cure, so it is going in the oven  

I have also heard that mixing mild steel/aluminum or mild steel/Stainless steel is a bad idea due to galvanic corrosion, but I will be testing it out    The best solution would probably have been to weld in a sheet of mild steel, and make a separate aluminum heat shield, or to paint the air duct inside and out with a heat resistant paint, but it is very hard to do a propper paint job on the inside, and coating the inside with under body sealer would not work with the heat in this area.  

 - Frederik    

[Anders Dinsen]

Sounds like a serious paint job you're doing there. You're lucky it's no bigger than it is so it fits your oven

If you clean and paint both the aluminum and steel well so the two metals will not get in contact with each other, you should be all right, I think Otherwise a steel plate could be painted and then riveted on. Just thinking 

[Moes]

Today on my way home I picked up my pieces from sandblasting and powder coating   And when I got home the new core plugs had arrived!

And I managed to prime the rear brake parts, so they should be ready for a nice red top coat; and get the new core plugs in.

 - Frederik

[Anders Dinsen]

Wow, that oil pan looks like it's new! The other parts look great too. Beautiful pictures

[Moes]

Hi

Thank you, Anders!  I love getting parts back in "ready to install" condition 

Today I went by the surface treatment company because I had not heard from them yet. The steel parts and bolts were done, not quiet as we agreed upon, but I think it looks very good. They had not been treating my aluminum parts yet because they had not been able to clean the parts as well as they thought they could, by leaving them in some kind of cleaning tub, so I will have to do some more preliminary cleaning or maybe glass-/ or soda blasting before they can get the surface treatment.

 - Frederik