Atomic 4 basket case

[billdodr]

Hi,

I have the opportunity to purchase an Atomic 4 basket case.
Supposedly the motor is a 1976 model. It was removed from a boat, disassembled and then owner decided to do something else. Also it was supposed to have been in "running condition" when removed from the boat. The "basket" includes "all the parts" including alternator, transmission, fuel pump, water pump, carb....etc.

My son wants to rebuild a motor and I think this could be a good project for him.

What should I look for to make sure that this A4 motor is viable for rebuilding/restoring at a reasonable cost?

Thanks for any advice!!!

[roadnsky]

Welcome to the forum!

There is some really good A4 info to read up on here...

http://www.moyermarine.com/faq/index.htm

This info is from our host (Don) in the FAQ section:

18. Things to look for when buying a boat with an A4
Marine surveyors often refuse to make any evaluations regarding the engines. On the bright side, it is clear from our own customer feedback that there are many more well maintained Atomic 4's in today’s market than there were ten years ago, and many of these engines are fresh water cooled. In the early 90's, the majority of our first-time callers reported that they just bought a boat with a “basket-case” Atomic 4, and they had to spend the next year bringing the engine back to health. Today, at least half of our new owners are simply calling for parts or advice on how to best maintain their well-running engines.

Here are a few things that you can look for:

1) It is obviously very important to check on the maintenance history of the engine if one is available. The maintenance history, along with the ability to talk with the prior owner, can add insight to the findings of the following checks.

2) Check the exterior of the engine for signs of deep rust or scaling. Be especially critical of the alternator side of the block. In some cases, seals around water jacket side plates develop leaks, and given the limited access to that side of the engine on many boats, these leaks can go undetected for long periods of time, and deep scaling can result. In a few cases (fortunately very few), blocks have had to be scrapped due to this scaling extending all the way through the block and into the crankcase.

3) The engine should be started and brought to a normal operating temperature of 160 to 170 degrees for raw water cooled engines, and approximately 180 to 190 degrees for fresh water cooled engines. It is best to run the engine in “forward” and under load. If you are checking the engine in the slip, it’s OK to simply pull against the dock lines. Check for any unusual noises. Atomic 4's are known for running rather quietly and smoothly.

4) Check for fluid leaks. Be especially critical of any evidence of gasoline around the carburetor or fuel lines.

5) Check for normal oil pressure of 30 to 40 psi by around 1500 RPM and 20 psi, or above, at idle.

6) Run the engine for a short time at maximum power to check for any unusual sounds, excessive smoke out of the exhaust, or fumes from blow-by in the cabin.

7) In neutral, the engine should accelerate quickly as you flick the throttle from idle to full throttle without hesitation. It’s important that you do not allow the engine to actually reach full RPM during this check. This is simply an acceleration check. The RPM never needs to go much above 2000.

8) Shut the engine down and check the compression as soon as you can remove the spark plugs without burning your fingers. The combustion chamber volume in the heads of in-service Atomic 4's vary considerably, and compression can therefore vary from as low as 85 psi to as high as 120 psi, with the average being around 100 psi. Compression readings should have a maximum spread within 5 or 10 psi.

9) While the spark plugs are removed, check for excessive carbon build-up or oiliness. Do not be too critical of a black velvet sootiness as long as the plugs are dry.

If you are buying a boat without the opportunity to actually run the engine, perform as many of these checks as possible.

1) With a cold engine, compression readings can be expected to vary much more than in a warm engine, and if the engine has not been run in quite a while, valves might be a bit sticky, which will affect compression. These conditions are frequently not serious, and will clear up after the engine is started and given a Marvel Mystery Oil treatment (5 or 6 squirts of oil in each spark plug hole).

2) With the spark plugs removed, run the engine on the starter and check for oil pressure. Oil pressure at starter RPM will usually be around 20 psi

[joe_db]

What is the price?

Hi,

I have the opportunity to purchase an Atomic 4 basket case.
Supposedly the motor is a 1976 model. It was removed from a boat, disassembled and then owner decided to do something else. Also it was supposed to have been in "running condition" when removed from the boat. The "basket" includes "all the parts" including alternator, transmission, fuel pump, water pump, carb....etc.

My son wants to rebuild a motor and I think this could be a good project for him.

What should I look for to make sure that this A4 motor is viable for rebuilding/restoring at a reasonable cost?

Thanks for any advice!!!

[billdodr]

Hi,

Asking 100.00

I looked at the FAQs and many other posts on the site.

I know that the cylinder walls can be thin from corrosion in the water passages.

Thanks for any suggestions!

[joe_db]

For $100 you can't go wrong even if you end up buying another one too.

[Al Schober]

For $100 I'd jump at it. There's gotta be something in that pile worth $100!
In the cost of rebuilding an A4, $100 doesn't get you much. That's the price of a gasket set.
The trick is going to be spending your overhaul money wisely, rather than just pouring it into a Fla sinkhole. First step should be stripping the block and getting it to a shop for a magnaflux check for cracks. If that passes, you can have the shop skim cut the top of the block and also grind the valve seats. I used a new shop (to me) for my last block, and they installed hardened inserts for the exhaust valves - no extra charge.
FWIW, I have yet to see an A4 block with the cylinder walls corroded thin. I've also never seen one with much of a ridge at the top of the walls. YMMV
As for your son doing it, it depends on the son rather than the age. I know one son who's 40, and I wouldn't trust him with a socket set. But then I know 10 year olds that would read the book (Moyer's), ask questions, and then go to it. I'm helping one (not mine) build a storage chest/seat. I'm doing the table saw & router stuff - he's doing the rest (with guidance).

[romantic comedy]

Hi Bill,

I might offer a different opinion. It depends.

How old is the boy?

If i was going to show a youngster about engine rebuilds, I would pick a more current engine type. It is just a consideration that is all.

[HalcyonS]

[QUOTE

If i was going to show a youngster about engine rebuilds, I would pick a more current engine type. It is just a consideration that is all.[/QUOTE]

dunno, you can't beat the A4 for an introduction to the _basics_ of 4 stroke internal combustion engine

[joe_db]

Agree 100%. The A-4 is an excellent teaching aid for engines