Add the flywheel bolt lengths to that list of items that must be watched out for when working on the Ford Y or for that matter, most engines in general.
With over half a century now elapsing since the Ford Y has been offered in a vehicle, not many of those engines are still around that have not been worked on at least once during that time. The flywheel bolts are often changed when transmissions and/or engines are swapped out in the vehicles which leaves open the possibility of the incorrect length bolts being used. The Ford Y family of engines does not leave much latitude in the flywheel bolt lengths as the space between the flywheel flange and the block is minimal to say the least. Said another way, there’s not much room for a bolt that’s protruding through the end of the crankshaft flywheel flange and not to create interference at the back of the block. In some of those instances, the bolts are too long just to the extent that they lightly score the seal retainer and the back of the block and engines still run. In other cases, those bolts are so long as to cause quite a bit of damage including destroying the thrust flange on the main bearing and/or the thrust surface on the crankshaft. In some instances, the seal retainer is destroyed to the point that the crankshaft rear seal no longer keeps the oil in the engine.
With the number of different combinations of both standard and automatic transmission flywheel combinations for the Ford Y, there is not a single fit all for the flywheel bolt length. The flywheel flange thickness as well as the crankshaft flange must be measured and the appropriate bolt length applied.
With all that being said, here are pictures of some Ford Y rear seal retainers that have had flywheel bolt interference issues.
So there you have it. Flywheel bolts being too long is just one more nuance that can prove to be disastrous if not watched out for. And this bolt problem can occur on almost any engine, not just the Ford Y. As always, consider this just food for thought. Until next time, happy Y motoring. Ted Eaton
Note: This article was originally published in The Y-Block Magazine, issue #168, Jan-Feb 2022.