Top marks for perseverance Ken.
Its difficult to help without being hands on, but great to see so many wanting to pitching in anyhow. Troy turned up, just as you posted last night. He is CR mad with five CRs from 85 to 89.
one reason for requesting pics was;
*I thought Smed had it for a moment, but indeed CR and RMs is right, the 84 has the type of
pump cover that doesn't use separator plate and you have the correct type to be used without a plate Ken(there is a major difference, between the two).
The separator plate is named in reference to its main intended purpose, that is, to separate the flow of the
inlet channel to the pump impeller from that of the
outlet flow channel. In the 84's case the flow channels are separated by a division "cast into" the pump cover. That division separates the two flows from instantly recirculating in the pump.
*Troy has also clued me that there is no thermostat in any of his CRs.
*I think it is safe to assume by now, that
-you have new radiators, with hoses correctly routed?
-you have a top end with gasket correctly positioned and that it contains and isolates combustion gases from the cooling jacket?
-you are not producing excessive heat from a combination of incorrect fuel, timing or a lean fuel/air mix.
If the above is sorted, then it is time to
-
verify and prove that cooling system containment pressure meets the figure as stated by Honda at 28.4 PSI test, indeed the cap requirement is not to crack until between 15.6 - 19.9 PSI.
- verify that the cap tests to its rated pressure before it cracks. look at the pressure that this system is required to run at. The main reason for increasing pressure containment of a cooling system way above atmospheric, is to be able to increase the boiling point of the fluid in it. Obviously system pressure is limited and controlled by the rated crack pressure of the cap. If your system is incapable of maintaining that rated 19.9 PSI? It will reach boiling(steam) point premature of prescribed engine running temp. I might add, 19.9 psi is a demanding requirement, no doubt a clear indication of engine running temp spec.
When you have achieved the above,,,,,You need to verify the impeller face clearance is
correct in relationship to the pump cover Ken.
It looks as though there is a long history of work around the impeller shaft and gasket thicknesses? etc. All of which can effect the optimum impeller face clearance. Acceptable clearance for many is usually achieved by accident, simply by using only correct genuine parts from from Mr Honda, assembled as per his expoded views.
That clearance is super critical to the performance of open face impeller pumps. Through-out industry I have achieved amazing differences in energy requirements or pump head performances, by simply varying that clearance. It may be as easy to repair as just to fit a shim spacing washer of the required thickness behind the impeller to bring it out closer to the cover face, but you first need to calculate that requirement by taking a measurement of the existing clearance.
The impeller face is machined to a tapered profile, as is the mating shear surface in the pump cover. The easiest way to take a measurement is, "crush test" it. It may simply be the case that a thicker gasket material has been used, or impeller shaft set-up has opened the clearance.
I would aim at 0.008" assembled clearance. Don't forget to take into account any measurable impeller shaft end float. I imagine there wouldn't be much, but it would be prudent to check.
pS; I am pretty sure I can help with all/most of your gasket needs. I am off for a day or two now, when I return I will look for a box half full of opened CR gasket sets. It has heaps water-cooled CR head gaskets in it(unlabelled though). I will send you my address. Slip one of those old head gaskets into a freezer bag, then envelope and post it to me as a sample please.
