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Old 08-15-2006, 01:41 AM
Motor John Motor John is offline
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Replace it? Overhaul it? Overhaul it!

It’s been almost 8 years since I overhauled my Atomic 4, and I’d like to share some of my experiences with the Atomic 4 in my ’77 Catalina 30.

When I bought the boat the engine was on it’s last legs, it had not been maintained properly and generally looked like a lump of rust. At one time or other it had lost oil pressure and had serious main barring and crank damage. Although it still ran the oil pressure was poor when the engine was cold and non existent when warm. I checked out the options to re power with a new die$el but it would have cost more than I paid for the boat with a cut in performance.

I was told parts were impossible to come by but this did not prove to be the case. I was searching on the web for A4 parts (yes, it did exist in 1998) and came across Moyer Marine, so I gave them a call. I discovered almost anything was available and Brenda (Don’s better half?) talked me into rebuilding the engine. She said it’s quiet, powerful, you’ll love it – I was up for a challenge, so rebuild it was.

After removing the galley and disconnecting the various plumbing and prop shaft it was ready. That made it sound so easy! Some of the tools involved included a hand grinder to remove the heads of the hopelessly stuck prop shaft and exhaust bolts and a nut cracker to split the bolts off the engine mounts. Once this was done the engine could be lifted up and out right through the hatch with the help of a chunk of schedule 40 pipe and a come-a-long. We used the boom as a crane and plopped it into a dock card, into the back of the car and home it went.

Before attempting an overhaul yourself on an A4 get Don’s book, it is extremely helpful, also asses your skills as a mechanic. If your engine was in the same shape mine was it will put your patience to the test. Anything you try to remove will be rusted, stuck or all boogered up! (a technical term!) I like to use products called “Kroil” and “Mouse Milk” products used in the aviation industry and rarely seen off the airport. Also another product “PB Blaster” is an extremely good penetrating oil.

As for tools don’t chintz out, especially get the Snap-On stud remover, it’s a must have for working on the A-4, also the tools you use should be of good quality, you don’t need to go as far as Snap-On but Craftsman should do just fine. (Well, you WILL need the Snap-On stud remover.)

Once all apart I took the block to a machine shop specializing in automotive work and hot the block dunked and boiled out. This removed the scale that had built up over the years and allowed me to asses the true condition of the block, which turned out to be quite good, considering the engine had been raw water cooled it’s entire life, it was definitely a keeper.

The crank was taken to a crank shop magnafluxed to check for cracks and turned down; to my surprise we discovered that the crank was already undersized! It had been overhauled before! Since bearings are available in several over sizes; this did not pose to be a problem. Another surprise what that the crank shop knew what an atomic 4 was, it dimensions for the crankshaft was in their tables of data. Didn’t know what the engine looked like of what it was used for, but they did know how to grind the crank. It came out perfectly.

After checking the cam (okay), the oil pump (okay) I ground the valve seats and lapped in the new set of valves. One turned out to be badly burned from a lack of valve lash (so put a yearly valve clearance check on your list of things to do!)

The block all cleaned up and generally refreshed I reassembled the engine. As I was doing so I struck me that this engine was a simple and elegant design. Seriously overbuilt and under stressed it should run forever, providing it doesn’t rust out!

I pondered the option of powder coating the engine, I discussed this with Don, we didn’t know how the block would respond to the high temperatures necessary in the powder coating process. I rattle canned the engine once it was back together with two coats of primer and three coats of Krylon “Machinery Gray” paint. Came out great, still looks good almost 8 years later.

When I re-installed the engine I put a new set of engine mounts in along with all new hoses and an exhaust riser and pipe. It also was in sorry shape. I also added a new Balmar alternator and regulator.

Once in we spend a great deal of time properly adjusting the prop shaft alignment. Since we put new engine mounts we had to start from scratch. It tool many colorful metaphors but we at last got it right on. The engine started right up and ran great after we got all the adjustments properly set.

Over the last 7 years and 8 months it’s been great. It runs smooth and always starts right up.

John’s suggestions-

Keep the tank topped up with fuel treated with stabilizer such as Stabil, I mix it in when I buy the fuel in my jerry can. Then it goes in well agitated. I also installed a fuel ‘polishing” filter with a 20 micron element with a water separator.

I change the oil every 90 days, whether it needs it or not. I start the boat weekely, it’s always in the water here so that’s not a problem.

I check the valve tappets yearly; they do tend to tighten up a little at first. Also I replace the plugs and points (no electronic ignition here) on a yearly basis as well.

Every other year I replace the water pump impeller.

I don’t know if a DYI overhaul is your cup of tea, but for me it worked out great. Don took several of my calls when I had questions. To Don a great big thank you! We are lucky to have this level of support and expertise for our iron wind.
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