Reinstalling the Engine and Transmission

Forgive me Father for I have sinned. It's been a long long time since my last blog entry. Fortunately, that does not mean I have not worked on the SM, but rather that I did not find the inspiration to put it down in print.

Engine Updates

After installing the clutch package using a generic "cone" centering tool from Harbor Freight, I tried mating transmission to engine on the floor in my garage. It did not work, despite all the jiggling and tilting I could muster. Time to talk to David again. He said, it would not work with generic and sent me an old shaft from a DS transmission. I re-centered the clutch using it and had the two units mated less than 5 minutes later. Again, the voice of experience thrumphs rational thought and preparation.

The engine I bought came with carbs, but without water pump impeller, engine mounts and rear cooling bridge between the heads, also containing the thermostat housing.

Installing the carbs, a new thermostat and its housing was easy.

The engine mounts must be measured and adjusted. The left side should have a different height than the left.

As I am assembling things, I take my time, trying to look at pictures I took before disassembly, the Citroen manual and whatever I can find on the Sports Maserati List archives and the web. I find a lot of pictures and text in French text on the CitrOthello site in Switzerland. Oh, how I wish I had paid attention to my French teacher in middle and high school.

I also wanted to include an update to the impeller, a new wear surface made from polished ceramics. The idea had been conceivedby Andrew Brodie to combat the wear on the relatively soft bronze impeller surface. Andrew made a batch of seals and they were tested and showed great promise, reducing leaks both from wear and a better sealing surface.

The original seal was sourced from a complete mechanical seal assembly, meaning that you threw away expensive parts you did not use, making the parts used (seal ring) unnecessarily expensive. Thus, Andrew commissioned a batch of purpose made ceramic seal rings. The modified version was of slightly smaller diameter, but a lot cheaper. To fit this seal, the impeller had to be grooved. A local machine shop took on the job, but either did not understand my instructions or interpreted them differently than I intended. At any rate, they did not cut a groove for the seal ring but instead cut the whole center out. To make matters worse, I had TWO impellers modified at the same time. When discovered, they rectified their mistake by brazing on a new bronze center ring and machined it back. I gave them the jackshaft so that they could ensure a good fit. You can see the result in the picture below.

John Titus, an early tester of the ceramic seal, and Andrew, the inventor, advised me that the seal should be mounted slightly below the surface plane of the bronze face. The center ring has to be proud of the ceramic seal surface so that you do not crush/crack the seal when torquing the impeller down with the acorn nut.

The machined impeller with the ceramic seal. The seal is then mounted with hight temperature silicone , applying even pressure until silicone "sets up" to ensure a level seal surface.

After verifying this setup, I discovered that my seal, a JBM after market seal, which has slightly different diameter and edge chamfers, was just a tad larger the OEM seal and thus only had a little clearance against the outer, proud edges of the bronze outside of the ceramic seal. The JBM seal, like the original is slightly cone shaped, with the smallest diameter at the face of the seal, and diameter growing as you move up the seal's rubber collar. This means that, as the surface of the spring loaded seal wears down, the surface mating against the ceramic seal would increase in size and possible rub against or "hang" on the slightly proud bronze surface outside the ceramic seal. In turn, this could be wearing the seal bellow or result in leakage. The original seal did not have this problem, being of slightly smaller outer diameter than the aftermarket JBM seal. Luckily, one of the list members had an original seal for sale at reasonable cost , so I could avoid this issue.

What I learned from taking 4 trips to the machine shop, was to ALWAYS, give them a sketch, even when they nod in understanding to your verbal instructions, even though the task seems simple. Also, you should have the surface outside of the OD of the Ceramic seal machined slightly below the plane of the seal. This will allow you to use both OEM and JBM seals with no problems!

Left OEM seal, right: JBM seal, which has a slightly larger face diameter (the side facing the bench top in this photo) and is also taller than the OEM

Transmission

The original 5 speed transmission from Citroen is very sturdy and reliable. It is essentially the same unit as the DS with modification to the housing for the speed sensitive steering unit and mountings, which are different on the SM.

Always check the torque of the 1/2 shafts, as these bolts can become lose over time.

I finally installed the engine and gear box package in the fall of 2010. Apart from this, I only modified the the differential housing vent. This vent in original design is a M7 bolt with a 1-2 mm center hole. Due to its location, any fluid, such as coolant or when doing an engine room cleanup, can easily enter and end up contaminating the gearbox oil. As little as .1% water in oli reduces the bearing life by 75 %. so this is important. The new vent prevent this scenario. The vent was conceived by Richard Batchelor in Arizona. I simply copied his design concept. See picture below.

The new vent (center of picture) with trimmings. The vent is manufactured from a M7 citroen bolt with about 10mm length, drilled to accept a flared Citroen hydraulic line end. The end was brazed into the nut and the metal tab's smaller end is placed over the fitting after which the square end of the hose is pushed on all the way down. The new breather is now fastened to the transmission with the copper washer. The pointed end of the hose is inserted through the remaining hole in the metal tab to protrude about 10 mmm or so. The hose now forms a loop with the opening facing down, thus eliminating an involuntary entry of any foreign material, yet allowing for better air exchange (larger hole).