Moyer thermostat???
 

On my new (to me) A4 I see that it has the Moyer thermostat housing spacer and the fancy stainless nuts. Does that mean that it has an MMI thermostat or maybe the spacer is just there because of bad sealing surfaces? The engine has almost no rust and was said to have been only run in the Great Lakes. No other mods to the engine that I can see. Grant.

The 1/4" spacer plate was necessary to fit the available replacement thermostat after the original Holly three spring stat was no longer available. Recently Moyer Marine has developed their own thermostat that is an improvement over the original Holly and does not require the spacer. The fancy fasteners accommodate the spacer without replacing the studs.

Thank you, I am going to convert to a heat exchanger anyway, so I probably will need to change the thermostat again. Grant.

You'll be pleased with the result. I have FWC with an electric coolant pump and the new MMI thermostat. My engine runs rock solid at a hair over 160° gauge temp. To get the best performance from the new stat design the condition of the port in the center of the thermostat housing dome becomes important. I recommend buying a new housing at the same time as the thermostat. There's little point in asking a newly machined bypass spud to do its job efficiently in a deteriorated port. The two have to work in concert.

It is interesting that the new MMI thermostat is bronze and looks much better than the other thermostat sold here, yet is $40 less. I will probably go with the new style. The fwc is required by the Admiral for a water heater. The only other mod I plan to do with the engine is the Indigo oil filter. I think this will work out fine. Thanks for the info. Grant.

I am touching up a little paint so I removed the starter, alternator and distributor and discovered that it has the electronic ignition, but I didnt get the module with it. I dont know if I should buy the module or just use a regular points system. I have several distributors, so I have options. I also took off the side plate and found very little rust or crud. I am happy about that. I seem to remember reading something about drilling an extra hole in the diverter that is on the inside of the side plate. I am going to FWC so would it be wise to put another hole in the diverter to more evenly distribute the cooling water? I am sure I will have many more questions. Thanks, Grant.

Please provide a picture of your electronic system. Some have an external module (typically optical systems such as Crane) and others don't (Pertronix and HotSpark are examples).

Please see this Tech Tip from our host:
https://moyermarine.com/techtip001-2-2/

That tech tip is what I had read before. It seems to make sense to drill the extra hole. My steel diverter piece is still in good shape, so I will drill it rather than put a brass one in. It might be a couple of days before I can photograph the ignition parts. Thanks for the link. I had forgotten about the tech tips. Grant.

I looked at one of my extra distributors and discovered that it also has the electronic ignition. I will get them both together tomorrow and see if I can figure out how to post photos. Grant.

No photos yet but one of the distributors has a Petronics Ignitor with 210-V2 on the top of it and the other is also Petronics with Lot#9 AK NV5M on top of the ignitor. Re-reading the earlier post , it seems that the Petronics doesnt have an external modual so I guess I have two electronic systems. The tag on the coil is too worn to show what the resistance is. I am learning something everyday. Thanks. Grant.

Get a multimeter and measure the resistance yourself. You should be doing that anyway because actual resistance is often different than spec and it can affect the current calculation. My experience is the variation range can be +10%/-0.

Six bucks at Harbor Freight
https://www.harborfreight.com/7-func...ter-63759.html