Universal Atomic 4 Improvements

[jgmartis]

I am restoring a 1961 New Horizons, The Atomic 4 only has 1055 hours on it and the compression is good. It has never been updated and is in the orginal condition. I am planning to update it with a rebuilt carb, electronic ignition with new wires and plugs, electric fuel pump, rebuilt starter and generator.

Question is am I missing anything? What should i be doing to the transmission? Do you use Marvel additive?

[bonnelaine]

get with the link

Moyer marine.com the guru of atomic fours great engine have a 1977 in my pearson 323 and it is bullitt proof if taken care of .good luck but def contact moyer marine
lake ontario

[AventuraII]

Moyer marine has been a great help to me- I've got a 33 year old A-4 and love it!

[SEMIJim]

Check the Moyer Marine. Pretty much all you could ask for or need for your A4.

I don't use MMO, but both Don Moyer and many others swear by it.

Jim

[sailhog]

Paint the engine with the A-4 spray paint. Get the new grease cup-less water pump from Moyer if the old one isn't perfect. New hoses. Make sure you mix fuel stablizer in your gasoline.

[floatsome]

Find the "A few critical suggestions" thread on Don Moyer's website.

[Valiente]

I've rebuilt one and parted out three.

They are quite durable and worthy of continued care and feeding. A couple of suggestions you haven't listed: If you are removing the engine for cleaning/paint job, consider tapping an elbow into a low spot in the oil pan and adding a stopcock in front of that. It makes oil changes much cleaner and easier: simply run the engine until the oil is warm (15 minutes at idle at dock) and then switch off, pump out and refill as per normal).

Consider getting the PCV (positive crankcase ventilation) device from Indigo (I think). Consider getting Moyer's rebuild kit. Consider using RJ12C gapped to .040 rather than the stock RJ8s (Champion: equivalents are online). Consider "refreshing" the gaskets and make sure the water pump impeller is good every season. Consider putting a filter basket between the water pump and the side of the block: you can see if gruesome stuff is getting minced in the impeller and can remedy the situation WITHOUT getting goo in the block. Consider rewiring the A4 panel entirely (you can order a new wiring loom) and getting rid of the easily corroded glass fuse holders. Consider checking the squirrel cage blower for intactness and consider an Atwood-style blower in the engine compartment itself for reasons of easier access. Mount it aft of the carb side.
Consider also getting a plastic VETUS style "waterlock" instead of the old "soupcan" waterlifts, which can corrode and fail. The single biggest issue I have had with marine engines is failed or compromised cooling and/or exhaust systems, leading to water in the block and hours of unhappiness.

Lastly, put a spin on Aquapro or Quicksilver-style fuel-water separator inline before your fuel pump, and make it a habit to shut off both the seawater intake seacock and the fuel line **** (which is best put above and to the left of the engine away from both the carb side and the coil, if the coil's still there.

[SEMIJim]

One thing that is undoubtedly an exceedingly useful upgrade is Moyer's oil change kit. That, coupled with the Moeller Fluid Extraction Kit (available at West Marine) makes oil changes a breeze. When I first read about the oil change process on sailboats I dreaded the prospect. I installed Moyer's kit and bought the Moeller pump, and no problem .

If you're going to be relying heavily on your A-4's alternator to charge the batteries and you have more than a couple Group 24 batteries, you'll probably want to consider an alternator upgrade. The A-4's stock Motorola alternator is only 35A. Moyer sells an API 55A alternator that's basically a drop-in replacement, and I've been told a 55A Mando is a drop-in replacement. You can go bigger, but the A-4 has only so much HP, and you may have to do more extensive work to get the pulleys to line up, etc.

Jim

[JimsCAL]

I see you are already considering an electronic ignition. All the A4 owners I know say this is a great addition. Also consider a fresh water cooling kit if you operate in salt water. It will really extend the life of the engine and avoid corrosion and scaling problems down the road.

[Valiente]

Originally Posted by SEMIJim

You can go bigger, but the A-4 has only so much HP, and you may have to do more extensive work to get the pulleys to line up, etc.

Jim

While I have heard of bigger alts on Atomic 4s, my strong impression is that 55 A is about the useful limit before you either begin to wear the accessory drive or siphon off power to the propshaft. I have seen, however, PTO mounts on the flywheel that allow either a second alternator or a compressor to be run, but not outside of an old drawing from an A4 accessory catalogue.

By contrast, I have seen 125 A alts on 50 HP diesels, but my "stock" alt is 55 A on a 52 HP diesel, and I would probably use the PTO to mount a second 55 A or a 75 amp rather than going with one larger alternator.