The wealth of knowledge held in our workshop is incredible. Centuries almost of combined experience allow Bridge Classic Cars to look into a wide spectrum of issues on classic cars.
Take for instance this 1971 Jaguar XJ6. Recently it had its fuel tanks replaced with us but during the setup, our in-house restoration team noticed that it had a pretty bad misfire. This needed to be looked into more in-depth. Dave, one of our most experienced technicians, began to dive deeper into the straight-six.
Dave had noted that the HT leads and the coil was arching to the closest metal object. So, with that and his experience he elected to replace the leads and the coil as the first port of call. However, after startup, the misfire was still prominent. At that point, it was decided to perform a compression test. 5 out of the 6 cylinders were all within spec. However, 1 of them was suspiciously low. With the classic cars, it can be a myriad of things that can cause this.
Dave then pulled the rocker cover off of the intake side of the engine to gain access to the rockers and more importantly the valves. With the help of our in-house engine builder Ady, Dave checked each of the valves for the correct lash. Originally they would have been between 10-14 thousandths of an inch but on Ady’s guidance, he is happy to see them between 8-10 thousandths with a vehicle of this age and mileage. All of the valves however fell within those guidelines. Nothing was noticeably out of place.
With that, Dave then found the leads had begun to arch again. This time through a set of pliers and straight to the cylinder head, which was worrying. So, Dave is going to rebuild the distributor with new points and condenser along with a completely new set of HT leads again.
Expect to see more of the progress of diagnosing the misfire on the 1971 Jaguar XJ6 at Bridge Classic Cars very soon on the News Page.
