Side Housings - Information

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This is just a sample of a typical side housing as it comes out of an engine.
The greatest wear is usually opposite the intake port - in the area of where the lines in the image are converging.
This is a close up of the above shot. The depth of the vertical wear groove (from the corner seal) is what determines how much material needs to be lapped off. Very deep grooves make the housing not usable.
A fair amount of material can be removed from the housings - the problem is that it is cumulative. Both in the total per housing (how many times have they previously been cut ?), and the total of cuts done on all FOUR surfaces. You can actually end up with an engine that is so "short" the manifold holes need to be ovaled. The actual limit (which is virtually impossible to measure) is the radius of the end of the stationary gear hitting the radius of the eccentric shaft rotor bearing journal.
This image, (and the one below), are the main reason for making this page. These images illustrate the dreaded "unknown water leak" in '86 and later engines. The casting is weak in the water seal groove area, and the edge of the seal support breaks away.
This crack lets the water seal slide out of place, and is VERY hard to diagnose. We fought this car for 6 months - was just gradually using water. We had to leave the water system heavily pressurized for over 48 hours before we finally got a little water into the combustion area. This crack is what we found.
The fault can be anywhere around the seal, but is usually in the lower half. We have found a number of housings with the piece gone already. We check all the side housings we use VERY carefully before using them. Worst case is to miss one that is just cracked, but has not moved out of place yet !!
Burned Housing This is an image of a "burned" housing. These ones have "blued" areas on the face from overheating, usually due to lack of oil. They are NOT usable! The metal is hardened, because it is actually shrunken down in that area.
An example of what they look like after lapping (and a LOT of cleaning!).
Just a shot of our big, ugly, dirty, noisy lapping machine. The 48" table does four surfaces at a time. We have it stuck in its own corner, to confine the mess. Normal procedure is to dedicate one person for one full day to do all we need for the next time period. We prefer keeping that lucky person confined to the area for the day, and just throw food and drink in as needed.

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