The Bridge Classic Cars team have been working their way through the 1973 Mercedes 250 as part of the diagnostic checks to find out why the classic Mercedes saloon isn’t running quite right,
Jon, one of our restoration technicians, has manually checked the valve timing to make sure that is in spec and then physically rotating the engine around until all of the relevant timing marks fall perfectly in place.
Once the timing marks aligned, Jon could begin to check the valve clearances. Whilst he found the inlet valves easy to access, the exhaust valves were difficult so Jon has had to make a special tool for this side of the valvetrain whilst making the nessecary adjustment to the exhaust side.
After getting everything correctly in phase, Jon could begin to dive deeper into the running issue by checking the tappets as well as the spark plugs themselves. The spark plugs were carefully inspected and cleaned before Jon discovered damage to the electrode on one plug which he replaced.
As part of Jon’s inspection for getting to the bottom of the running issue, he discovered an issue with the exhaust of the car. He discovered the centre section of the exhaust had developed a hole which must be repaired before diagnostics can continue.
Our fabricator Greg came over from our in-house fabrication shop to help Jon out by cutting out the affected area and replacing it with a new section to close up any of the holes. Once in place, Jon could continue his work of diagnosing the cars issue.
Jon worked on checking over and inspecting the rear carburettor on the car as he discovered the accelerator pump was not working correctly. So, Jon removed the unit from the car to strip it down on the bench and check all the components in order to get to the bottom of the issue. After rebuilding and refitting the carburettor back onto manifold and running up the car, it still had the same running issue.
