Re: 1985 V4 Crossflow T-Stat install
Running a high performance engine (yours) on a flushette requires that the hose water pressure be on full force. Low water pressure results in gaps in the water supply.
The working end (long end) of the thermostats face the thermostat housing, not the engine. Although it is near impossible to install them backwards, I've seen it done a couple times. No insulting reflections aimed at your intelligence... just a note of what something encountered over the years.
The thermostat(s) open at about 148? resulting in the engine running somewhat hotter than that of course. This heat range allows you to hold your hand/fingers on the large exhaust baffle plate or the cylinder heads for a time but not indeffinitely.
Notice the holes/slots at the rear section of the lower unit, just above the cavitation plate. Those are the water outlets for the thermostat water flow. When cold, there is no water flow out of those holes, but when the thermostats open...... water should flow out of those holes immediately.
Thermostats in that engine is a must.
(Thermostat Purpose)
(J. Reeves)
Many engines are considered high performance engines and demand a thermostat(s), and many smaller hp engines also require a thermostat for the following reason. The pistons actually distort/twist off round when running. The thermostat is required to keep the outer wall surrounding the steel cylinder, and the cylinder wall itself at a temperture to compensate for the distortion.
With the thermostat removed, the difference in temperture between the inside the cylinder and the water jacket quickly reaches a point whereas (in effect) you have a oblong piston running up and down a round cylinder, or vice versa. Bottom line is without the thermostat, the piston and cylinder wall could be damaged in a short period of time.
The thermostat in your car isn't there simply to have the heater function properly..... think about it.
If the water deflectors have never been replaced, and you haven't inspected them when the heads were off, they may be a source of overheating.
(Water Deflectors)
(J. Reeves)
Water deflectors are actually lengths of 3/8" outside diameter rubber hose, installed between the top cylinder and any cylinder beneath it, and also between the bottom cylinder and the block. The purpose of the deflectors is to have the water follow a definite path around the cylinder walls. Unfortunately the deflectors between the cylinders will at times swell sideways due to either a previous bad overheating problem, or simply due to age and salt corrosion. This causes a water flow restriction which usually allows the water to cool sufficently at low rpms but not at the higher rpms.
This hose material can be purchased reasonably at any automotive parts type store if you care to make your own, or you can purchase individual deflectors at any Evinrude/Johnson dealership at a somewhat higher cost.
Removing and installing them can be a hassle at times, but not always. I use a sharply pointed scribe with about 1/4" of the tip bent at a right angle whereas I can reach in, jab the tip sideways into the rubber, then yank it out. It's necessary to clean the seating surfaces where the ruber contacts the block with a small rat tail file to eliminate salt deposits etc. When installing the new rubber deflector, coat the deflector and the metal surfaces with WD40 which will act as lubrication to allow it to go in as easily as possible.
Make sure that you insert something into that deflector area before cutting and installing the deflectors if you make your own so that you will be certain that they are the right length and also that they will be seated properly. Usually a very small amount will be left extending about the block sealing area..... simply cut the excess off with a single edge razor blade.
