Home > 1974 SM IE > Drivetrain (page 1)

FRANÇAIS

NEXT PAGE   Drivetrain April 23, 2007 Here is the engine compartment when the car arrived at my home in April 2007 Everything is here, I believe... ...but we can't say that it's clean Air filters are ugly

Servicing Program April 23, 2007 - Fix the engine coolant leak around the water pump - Fix the alternator belt breakage problem - Replacement of the spark plugs - Installation of an electronic ignition device - General cleaning of the engine compartment - Check tension of the secondary timing chains - Fix the idle level when engine is hot

Engine Cooling Circuit Problems April 23, 2007 After a temporary repair just to bring the car to my home, I have to seriously fix the coolant leak located on the exit duct of the water pump. This duct is usually in very bad shape and its age is often the age of the car. I have to work outside so I work on the problem when the weather allows it. Before starting fixing this problem, I discover another leak, on the front of the car, probably from the radiator. It's a good start ;-) I choused to have a second SM instead of a DS to eventually take benefit of the parts I already prepared for the restoration of the first SM and because I begin to know quite well the SM. So I quickly apply the idea by replacing the leaking radiator by the one I had redone for the carburetor SM. I begin by working on the ail filters. Immediate sandblast and paint, so they'll have plenty of time to dry while I work on the other issues. Ugly, I told you! After a few hours of sandblast, finishing in my amateur painting cabin with the original AC140 gray Then I switch to the cooling circuit It's not the moment to open the air conditioning circuit, so I lay down everything the best I can Cooling fans are not easy to remove, but after many tentatives, I find a way to have them out The radiator finally goes out also. I thought I would have to remove the front grill, but fortunately, it's not necessary Another sad discovery when I removed the left side cooling duct. One more part of my other SM will come to help The new radiator is in Again, cooling fans are not easy to put back Of course, I take the opportunity to replace the cooling ducts and their clamps I put back the air conditioning condenser, trying not to damage the new radiator ;-) The new radiator is wider than the original, so I have to put spacers (I used bolts) to put back the cooling fans (they are now very close from the gearbox supporting bar) That's not all, I have now to deal with the little cooling duct at the exit of the water pump and also the thermostat cover that is in very bad shape. First issue: thermostat cover, dead To work on the next issue, some space has to be made Once the cooling manifold out, I finally see the damn cooling duct Second issue: water pump exiting cooling duct, dead Preparation of the manifold and its cover, after a little cleaning of course. The new cooling duct is made from a modern car hose, cut to fit The cooling manifold is back. Patience and cigarettes required to not get mad ;-) The manifold is ready, with new gaskets and a new thermostat Everything is closed. I use a plastic clamp, but it's temporary, I promise ;-) Another new cooling duct, on the radiator, it should be ok there from now on I put back the air filters. It's not a fantastic paint, but it's clean Here comes the moment of truth. I turn on the engine to see if everything works No leaks! I waited until the cooling fans go on while filling the circuit with coolant After these operations I went test driving the car. The cooling circuit seems ok (to be confirmed in regular driving conditions) but I confirmed two bad impressions I had when I first brought the car to my home: there is a strange noise somewhere on the front of the car and the throttle doesn't go back correctly (or at least, the engine revolutions don't drop as they should). There is more work to do before hoping to pass the official technical inspection.

Timing Chains Tension May 26, 2007 The engine is noisy and this noise is, I think, coming from the secondary timing chains. The professional mechanics who could fix this problem are not available, so I decide to check myself the timing chains tension. I can easily do it myself, and that way I will know how. One more time, I prepare this work with the forum of the SM Club de France. I ask questions to this forum experts because I have a doubt about how exactly doing it, even if I have all related documentation. I'm told to use a torque wrench to apply to required tension. As usual on a SM, the longer step is to remove everything needed to have a correct access. Is this case, the intake manifolds have to be removed to gain access to the head covers. I leave the fuel hoses and injectors in place I take pictures to help me putting back everything if needed I'll take the opportunity to do a little cleaning About 1.5 hours to remove the two intake manifolds. Next time it will be faster ;-) Here is how it looks like when removed, it's like a carburetor SM It's not very nice On the right side, access is even more difficult, because of the fan assembly and the handbrake cable Here is the first head cover removed. With such an easy access, I replace the spark plugs I turn a wheel by hand to reach the Top Dead Center (piston 1 for the right side and piston 6 for the left one) as best as I can and I apply tension with the torque wrench A little cleaning of the head cover, a new gasket and one more torque wrench application to tighten back the cover Same work for the right side but more difficulties because of limited access (the head cover is difficult to remove) I put back all parts, here the two intake manifolds After 5 to 6 hours of work, everything is back With clean intake manifolds and head covers, it's nicer I checked multiple times that I didn't forget something and I confirmed my doubts with the pictures I took I start the engine. Everything goes well first, but the alternator belt quickly brakes After a full day of work, not so much results. The timing chains tension didn't eliminate the engine noise and the alternator belt is making troubles again. I'll have to investigate deeper this engine noise. It could be the main timing chain, if its tensioner or limiter is damaged. The main problem is that it's almost impossible to access this main chain. The engine should be removed but that's very difficult because my garage is not available, my other SM is in it, and I cannot do this work outside. There is a way to inspect the main timing chain by the lower engine, removing the oil pan, that's what I'll have to do as a first step. About the alternator belt, it's not so bad and I knew I had to do something. It seems that when the battery is in good shape, this belt is not working so hard so she's fine, but when a bigger load comes she can't handle it probably because of a bad alignment. During my work on the timing chains, I left the trunk open (to cool off the interior) thinking that the trunk inside light was not working, but this time the light decided to work and it eventually weakened the battery. So I did my best to realign the alternator, without actual alignment tool, to have a better looking alignment. We'll see if it works.

Replacement of a Drive Shaft... to try August 20, 2007 By the summer of 2007, I frequently use the car, I drove about 2500 km from May to August, but I still have a very bad noise coming from the front of the car. I think about 3 possible causes: the anti-roll bar, a drive shaft of a ball pin. I begin by greasing everything I can around the front axle, the anti-roll bar for example. It doesn't fix the problem. During this greasing operation, I discover that the rubber sleeves supposed to keep the grease of each ball pin are damaged, so I guess that ball pins could be the cause of my noise, it's logical. But I can't replace the ball pins myself because special tools are required. While waiting that my mechanic is available one day to change the ball pins and adjust the valves, I decide to try fixing my noise problem by replacing a drive shaft to see if, by chance, the noise could be caused by a damaged drive shaft, and because I can do it myself. So I'm going to replace the left drive shaft by one belonging to my other SM. I work in the street, because it's flat (my driveway is not) Here the damaged rubber sleeve of the upper ball pin I begin by turning upside down the dust cover (which has been repaired some day) On the gearbox side, I loosen the drive housing, that's not easy because there is not so much space Then I pull out the drive shaft Here is the empty pivot And here is the drive shaft I clean and put some grease in the drive housing and I put it back with its balls but with a drive shaft of my other SM Operation's result: no change, this damn noise is still there. I was pretty confident that it will be the case, but this test was not totally useless. I also put so much grease in the drive shaft that when driving the car again, grease went all around the wheel arch and into the rim. Congratulations ;-)) So the noise is certainly caused by damaged upper ball pins, whose rubber sleeves are cut. So I have to wait for my mechanic's willing or I can try to find a solution to replace the ball pins myself. I'm waiting for more than 2 months now.

Valve Adjustment and Suspension Noise November 25, 2007 During September 2007, my mechanic can finally work on the car. The goal is to adjust the valves, replace the secondary timing chains and track and fix the annoying suspension noise I have for a long time now. It will be a good occasion to do an interesting diagnostic. The valve adjustment brings a few comments: the valves actually needed adjustment, one camshaft was lose (the adjusting gear) and some cam bearings were lose also. This maintenance was needed! The problem is that once the valve adjustment completed, the mechanic spent about 20 hours to search why the engine didn't want to work anymore. After a lot of search and 2 weeks, he found that a ground wire in the injection wiring harness was defective. This defect caused the fuel pump to not work anymore. Dominique and Claude searching for the electrical defect The injection wiring harness is not very dependable A good cleaning has been done on the relays plate A good part of the ignition wiring and connections has been restored The main conclusion is that the injection wiring harness is globally in bad shape. The main wiring harness is not very nice either. It's worse than I thought. On the forum of the french SM Club, I'm told that a german electrician is manufacturing new wiring harnesses for the DS and SM. It's a good opportunity, I order a new injection wiring harness, it will make this part of the electrical installation much more reliable. Once this problem fixed, the mechanic works on the suspension noise. This one is a lot quicker. After a few greasing operations and an inspection of the ball pins supposed (by me) to be the cause of the problem, he discovers that the noise is due to lose suspension arm holders. A few bolts are so lose that they can be turned by hand ! That's crazy. When I disassembled my other SM's arms, it was very difficult as these bolts were tight and rusty, but on this car the same bolts are lose. So it was a big step forward. The engine is working fine, I'm more confident now that valves and camshafts have been inspected and adjusted. The suspension noise finally disappeared, no more cracking noise like a wreck car. Finally, the electrical problem has been a good opportunity to do a maintenance on the electrical circuit and plan to replace the injection wiring harness. The car is out of the garage early October, but winter is coming and I have to store the car soon, after using it for only 50 kilometers. See you next spring.

Replacement of the injection wiring harness June 21, 2008 Following the electrical difficulties I had in September 2007, I ordered a new injection wiring harness. So here comes the moment to install this new wiring harness, this is early June 2008. Here are the two parts of the wiring harness. The first part starts from the calculator and goes to some valves and connectors for the second part, which connects to the injectors and other valves and sensors I start by removing the right front fender, to gain access to where the wiring goes right through the body Here is the calculator, located at the passenger's feet, behind the carpet and a protecting plate I start moving the old wiring out of its location and I prepare the new one (the clean one) Here both wiring harnesses. I gradually install the new one The new wiring is now going right through the body I connect it to the calculator Everything here is still disconnected, like the injectors, the water temperature sensor... ... and here the throttle spindle connector and the air temperature sensor Connection of the full load switch. The wiring then goes through the left side of the engine compartment Connection of the injectors, with the second portion of the wiring harness Here is the junction of both portions. It's now clean and reliable Special attention for waterproofness is needed here... ... I use an automotive seam and joint filler, I hope it will be ok, but it's not very nice One portion of the old wiring. It was in poor condition And here is everything back together This intervention took me 4 or 5 evenings of work. I complete this work on a friday night and the day after I plan to take part to an event organized by my antique car club. So I crank, the engine quickly starts but it doesn't work properly. On idle or at constant revs, it doesn't work well but it seems ok under acceleration, if the car is stopped or when driving it. I don't have time to fix the problem. The can be driven so the day after I drive it for about 30 km to go to the planned event. The engine still doesn't work correctly but I reach my destination. The problem occurs when I try to go back home late the same day. The engine doesn't want to start at all! I try to investigate a bit, I discover a disconnected vacuum hose because of a broken T-shape union, but I have nothing with me to repair so I go back home with a cab. The day after, Sunday, I call a towing to bring the car back home. The disconnected hose, still with the broken T-shape union part attached Here is what's left of the union with the other two hoses attached. The two inlets that we see are a smaller diameter than the outlet part that's broken It was not easy to find a replacement part. I finally found this plastic union on which we can select different diameters by cutting at the right place I secured the connection to the low pressure transmitter because it had tendency to easily disconnect when I was "playing" around The vacuum hose should go to the low pressure transmitter. This problem perfectly explained why the engine was running odd, the mixture was way too rich because the pressure transmitter was not receiving the right vacuum information. But, as nothing is as simple on a SM, when I connected back the vacuum lines, the engine didn't start better. In fact, from Sunday to the next Thursday, I spent hours trying to have the engine back in running condition. Of course, as I just replaced the injection wiring harness, I thought the problem was directly linked to this new wiring. So I spent a lot of time checking all the fuel injection devices I could check, I even temporarily put back the old wiring harness, but everything appeared to be just fine on this side. The ignition was creating sparks that I found fine also. The fuel tank was not empty, I even added more fuel to be sure. But it was still not working. On Thursday I seriously begin to be discouraged and I have more and more pressure because I have to go to the annual Citroen Rendezvous in Saratoga Springs on Friday night or Saturday morning the latest, with a drive of about 350 km. I eventually decide to remove the intake capacity boxes because I discover traces of fuel inside them. I plan to replace all spark plugs because access is ideal at that moment and to eliminate any doubt about these plugs. After putting everything back together, I give the engine a try and it starts right away. Yes! It's around 10 PM. The engine is running and evacuated a good quantity of soot (or let's say black residue). So here is my understanding of the problem: when I replaced the injection wiring harness, I moved almost everything, so I certainly and without seeing it finished to brake the T-shape union from the circuit going to the pressure transmitter, this union was certainly already damaged. This problem caused the engine to run with a very rich mixture. As I drove the car with this problem, I certainly sooted up and even damaged the spark plugs, and it eventually caused the engine to not start any more. Then, the numerous tries I made to start the engine during my evenings of check and repair finished to soot up and flood the engine. The day after, Friday, I take the SM to go to work and she works just fine. Later the same day I join Marcel and Othello (visiting Québec) and we make a part of the trip to Saratoga Springs for the famous annual meeting. They also had pressure finishing Marcel's SM. A few days before, following a complete paint job, they had to put the car back together, a huge work done in record time. Visit Othello's web site here to see (much) more details about that work (french text but many pictures). Saturday morning, we just arrived in Saratoga. Marcel and Othello were not able to put back the headlight glasses of the black SM, so she runs without them On the trip back on Sunday, Marcel's SM found back its headlight glasses Othello had the very good idea to take some pictures of my SM on the road. A big thank to him What a style! The Saratoga meeting has been very friendly, as usual, and it was finally the occasion to meet Othello, who I thank for his friendship and for visiting us. Visit his website because he did a great page about his trip to Canada and United States, it's here. Marcel's SM and mine, which were ready only at the last minute or so for this trip, both worked just fine during this week-end. Air conditioning in Marcel's car was also working fine but it doesn't work on my car so it was very hot inside. So I decided that the next intervention on this car will be to put the air conditioning back in running condition.   NEXT PAGE