7. How important is the internal fitting on the block side plate, the one directing coolant flow to the rear of the block?

This is a good question, and I suppose the answer depends on which expert you ask.

Universal, of course, felt that it was important, since they installed the cap in first place. However, there is a consensus among the current generation of experts with whom we network that the factory configuration might have been a bit of an overkill.

Historically, early model engines had side plates with three 1/4" holes which directed the incoming water somewhat evenly into the block with respect to fore and aft distribution.

The concern now is that by directing all of the incoming cooling water aft in late model raw water cooled engines, we may tend to give the rear cylinder a "cold shower". This same rationale is used to explain the fact that the number 4 cylinder (on many engines) tends to have sootier plugs than the other three.

In our own rebuilding operation, we provide a cap with the factory recommended hole facing aft, plus a 1/4" hole facing toward the manifold, so that some of the incoming water flows through the space between the center two cylinders, and over to the valve side of the engine (which is also the hottest side). We believe that this second hole provides a more even and more effective distribution of incoming raw water.

It should be pointed out, however, that this concern relates mostly to raw water cooled engines, in which case, the incoming water is cold. In the case of freshwater or "enclosed loop" systems, the incoming water is already partially heated, so the factory configuration is much less of an issue.

Finally, if you're asking this question out of a concern that your distribution cap might be clogged and causing overheating and you're trying to claw another week or two out of your sailing season, we recommend that you unscrew the "T" fitting, let the cap drop to the bottom of the cooling jacket, re-install the "T", and then press on to enjoy the rest of your season. In the meantime, having all the incoming water directed toward the center of the block is not likely to create any ill effects for this short period of time. The side plate can be removed later as a winter project. - Updated: November 13, 2003