I have just replaced the coils on my 90 XJ-S. The new coils are BAE504-DK8M. The old coils are BAE504-DK8J. The “neck” of the new coil is about a quarter inch longer than that of the old coil. When I shove the coil wire on as far as it will go, it appears that, based on measurements I have taken, the coil wire is not contacting the connection in the coil. I calculate that there is perhaps a quarter inch gap between the two contacts. The engine starts and seems to run fine.
Should I be concerned about the gap?
By the way, the coil cable has the same female fitting at each end, such as would connect to a spark plug. The coil contact appears to be a flat disc filling the “neck” base completely and unable to accept a female fitting. Do I need a different cable?
Thank you in advance for your help!
Hello Michael - since you state “the engine starts and runs fine”, it would seem that either the “gap” is very small, or contact is being made, at the coil connection with the HT lead - try this: remove the HT lead end from the coil; push the wire through the “cup” end until the connector is visibly at the end of the cup; while holding the female wire connector on to the “disc” at the end of the coil connector neck, push the HT lead cup down onto the coil neck to secure the HT lead connection - this should work fine until you are able to get another coil that does not have the filled neck, but has the connection recessed within the neck thereby minimizing the chance of the HT spark jumping to a ground -Tex Terry, II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - sent 9/11/2020 1505hrs. EDT USA.
Big Mike, are you asking regards a 6 cyl or v12? It seems that perhaps what you received is a successor to the earlier part number. But I would double-check with vendor you bought it from to make sure you received the correct coil for your year. Make and model
When I said the engine was running “fine” that was just my subjective opinion, based on nothing more than the fact that it would start and seemed to run smoothly. Whether or not it is performing at an optimum level I can’t say for sure. One issue that concerns me is that when I disconnect the coil cable from the distributor and check for a “fat blue spark” when I turn the engine over, all I get is a fat yellow spark. I have now installed new spark plugs, spark plug cables, coils, distributor cap and rotors. I believe all that is left to replace is the amplifiers and I have heard they rarely fail.
Regarding the coil/cable end gap, the cup on each end of the cable is pre-formed into a 90 degree angle and I cannot pull the cable any farther through it. I have since found a bolt that is the same diameter as the inside diameter of the female fitting. I cut two pieces of the threaded part to the length I calculated to give me the extra quarter inch I needed to get the cable connector to to make contact with the disc in the coil neck. It feels like a very good fit now. The test spark is now a little brighter and even has a hint of blue in it,
Thank you again for your help.