Cylinder Head and Bellhousing Interference


The Zetec cylinder head was clearly going to be wider that the single overhead motor it was replacing. The surprise was that it was also longer than the block it was bolted to. By half an inch or so.


I thought that the problem might have also been coupled with the fact that the rear oil seal housing on the Zetec motor was just a little bit different from rear oil seal housing on the older single overheard cam motor, causing interference with the ¼ inch aluminum plate that was sandwiched between the bellhousing and the engine block (and then through- bolted to the lower chassis rails). But just a little jig saw and file work resolved that discrepancy. Then I was able to resolve the head/block clearance issue by simply adding a couple of washers to that aluminum plate as shown in the above photo. This now provided sufficient clearance. I thought I’d solved the problem. I was wrong. There was an additional complication.


And the additional complication was that it would no longer be possible, even with the added washers, to use the existing water outlet/thermostat housing location. So some sort of surgery was required.

Dennis Etcheverry, primary fabricator and welder for the Norman Racing Group in Berkeley, determined that the cleanest approach was to notch and then re-weld the bellhousing.


Initial notch. Wide enough to clear the head. Note initial layout for the water outlet clearance.


Dennis tack welded in new back-up plates.


This surgery resulted in sufficient clearance not only for the cylinder head but for the water outlet/thermostat housing as well.

Total time expended was 3 hours.