Hi - just purchased a 1974 irwin 28 mkII. the previous owner had removed the volvo motor and was going to replace it with an atomic 4. the atomic 4 came with the boat. does anyone have any experience or knowledge of doing this? any info would be greatly appreciated. Thanks
volvo mb10a to atomic 4 changeout
- Thread starter ctalmage
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IMHO, it depends on how much prep the PO did for
the swapout. If all fuel system components have been converted for gas, then *maybe* I'd proceed with the conversion. This includes tank cleanout, fuel lines, filters, compartment ventilation (Big) and bilge blowers (Very Big). If these have not been done, I would seriously consider putting a diesel back in your boat. Either have the Volvo completely rebuilt (is it still in the boat?)or replace with a Beta with the correct mounting brackets. etc. You should be able to recover some of the costs by selling your A4 as a unit or as parts.
the swapout. If all fuel system components have been converted for gas, then *maybe* I'd proceed with the conversion. This includes tank cleanout, fuel lines, filters, compartment ventilation (Big) and bilge blowers (Very Big). If these have not been done, I would seriously consider putting a diesel back in your boat. Either have the Volvo completely rebuilt (is it still in the boat?)or replace with a Beta with the correct mounting brackets. etc. You should be able to recover some of the costs by selling your A4 as a unit or as parts.
Perhaps the biggest change that happens in a
modification like this is the engine beds. I went the other way removing the A-4 and installing a Volvo. Many things changed. The engine beds had rotted, the packing gland had chafed the shaft and both were ruined, The transmission angle on the Volvo is not the same as on the A-4. Of course the fuel systems changed as did the exhaust and the engine cooling water system. The engine controls and instrument panel are completely different. So it gets back to the question , How far did the PO get before he quit?
modification like this is the engine beds. I went the other way removing the A-4 and installing a Volvo. Many things changed. The engine beds had rotted, the packing gland had chafed the shaft and both were ruined, The transmission angle on the Volvo is not the same as on the A-4. Of course the fuel systems changed as did the exhaust and the engine cooling water system. The engine controls and instrument panel are completely different. So it gets back to the question , How far did the PO get before he quit?
consider this....
the Atomic 4 is old outdated technology. It's dangerous in the fact that it a gasoline engine, hard to get parts and service, and would be a waste of time and money to reinstall. Put your time, money and energy into repairing the Volvo diesel, installing a new Beta diesel and transmission (possibly even the saildrive unit) or simply adding outboard on the back. Decisions such as this depend on what your boat is worth, how long your are going to keep it, how much money you have available, and finally how you're going to use the boat. Good luck.
the Atomic 4 is old outdated technology. It's dangerous in the fact that it a gasoline engine, hard to get parts and service, and would be a waste of time and money to reinstall. Put your time, money and energy into repairing the Volvo diesel, installing a new Beta diesel and transmission (possibly even the saildrive unit) or simply adding outboard on the back. Decisions such as this depend on what your boat is worth, how long your are going to keep it, how much money you have available, and finally how you're going to use the boat. Good luck.
A-4
I gotta disagree, respectfully of course, with Landsend. The A4 is a fine engine and not dangerous when one takes a few simple precautions. Parts, and advice, for the engine are readily available at Moyer marine in Pennsylvania. In fact, parts are easier to get today than when the engine was in popular use I would rather have a diesel. My last boat, an Irwin 32, had the A4 and it worked just fine. My present boat has a 3QM Yanmar and I like it much better.
I gotta disagree, respectfully of course, with Landsend. The A4 is a fine engine and not dangerous when one takes a few simple precautions. Parts, and advice, for the engine are readily available at Moyer marine in Pennsylvania. In fact, parts are easier to get today than when the engine was in popular use I would rather have a diesel. My last boat, an Irwin 32, had the A4 and it worked just fine. My present boat has a 3QM Yanmar and I like it much better.
Gasoline is a perfectly safe motor fuel
as long as you don't let it get lose. There are millions of cars that are parked in garages each night and started each orning without blowing the owners to kingdom come. The danger comes when the gasoline escapes captivity and finds a spark.
as long as you don't let it get lose. There are millions of cars that are parked in garages each night and started each orning without blowing the owners to kingdom come. The danger comes when the gasoline escapes captivity and finds a spark.
I can understand keeping an existing Atomic 4
running, but putting one in!!!!! Not a good idea. Gasoline engines for axuilliary sailboat power is obsolete. There are no small gasoline marine engines being produced now. What does that tell you?
running, but putting one in!!!!! Not a good idea. Gasoline engines for axuilliary sailboat power is obsolete. There are no small gasoline marine engines being produced now. What does that tell you?
Haven't we been here recently?
The Atomic 4 was undoubtedly an OK engine way back when it was pieced together. It must have been OK because there are about a bajillian of their relatives out there working their little two main crankshafts out in fork lifts as Continental engines. Not great engines but probably OK. Back in the day guys were willing to accept them because that's about all there was. However, it just seems kind of silly to me to re-modify the engine room just to stuff an OLD one back into the boat. It just doesn't make any sense, even if you have less ready cash on hand than Patric of "Free Bout Morgan OI 33" fame. I think I'd rather see an outboard slapped on the stern. Might just be a whole passle less aggravation in the long run. As to the safety of gasoline, the problem lies in the equipment that handles the gas. Rubber hoses crack, come loose, fray and chafe. With gas comes carburetors. They have floats. Floats sometimes cease to float, causing large amounts of gasoline to dribble and squirt out into the general environs. Crap gets stuck between the float needle and it's seat. Same dribble and squirt. (No, this is not a flomax commercial.) I've had it happen on cars and motorcycles. SUs and Amals, rarely Mikunis, frequently Rochesters, Carters and so-on.) The big difference in cars and bikes is that the fumes, the really dangerous part, drops down and out through the open area below the engine (the environs) to where it can drift or be blown safely away. On a boat however, that area below the engine is enclosed by that device that keeps the water out; the hull. You get gas squirting or dribbling in there, the fumes drop down into the bilge, mixes with abundant but enclosed air and you get perfect conditions for very fast combustion, which we call an explosion. An old coil or plug wire carrying a spark on it's surface, (YES it does happen.)A bare wire, even a steel tool dropped against the metal of the engine? Ka boom. (Did I spell that right?) Nowadays we don't have to accept the Atomic 4's archaeic technology and shortcomings because there are so many better alternatives. Like diesel.
The Atomic 4 was undoubtedly an OK engine way back when it was pieced together. It must have been OK because there are about a bajillian of their relatives out there working their little two main crankshafts out in fork lifts as Continental engines. Not great engines but probably OK. Back in the day guys were willing to accept them because that's about all there was. However, it just seems kind of silly to me to re-modify the engine room just to stuff an OLD one back into the boat. It just doesn't make any sense, even if you have less ready cash on hand than Patric of "Free Bout Morgan OI 33" fame. I think I'd rather see an outboard slapped on the stern. Might just be a whole passle less aggravation in the long run. As to the safety of gasoline, the problem lies in the equipment that handles the gas. Rubber hoses crack, come loose, fray and chafe. With gas comes carburetors. They have floats. Floats sometimes cease to float, causing large amounts of gasoline to dribble and squirt out into the general environs. Crap gets stuck between the float needle and it's seat. Same dribble and squirt. (No, this is not a flomax commercial.) I've had it happen on cars and motorcycles. SUs and Amals, rarely Mikunis, frequently Rochesters, Carters and so-on.) The big difference in cars and bikes is that the fumes, the really dangerous part, drops down and out through the open area below the engine (the environs) to where it can drift or be blown safely away. On a boat however, that area below the engine is enclosed by that device that keeps the water out; the hull. You get gas squirting or dribbling in there, the fumes drop down into the bilge, mixes with abundant but enclosed air and you get perfect conditions for very fast combustion, which we call an explosion. An old coil or plug wire carrying a spark on it's surface, (YES it does happen.)A bare wire, even a steel tool dropped against the metal of the engine? Ka boom. (Did I spell that right?) Nowadays we don't have to accept the Atomic 4's archaeic technology and shortcomings because there are so many better alternatives. Like diesel.
Go for an outboard on a liftable mount
A new diesel would be superb but here are some advantages of an outboard over a gasoline inboard. It will be new and have a warranty. If you are on a trip and it breaks down, you could drive the motor to a repair shop. If you ever had to replace it, you could do it in an hour. you would be getting a new tranny at the same time. The outboard and a full keg of beer would probably still weigh less than an inboard. You can use the pivoting engine and prop blast to steer the boat in tighter circles when docking. The boat will seem much quieter to anyone who is down below while underway. You can tilt the motor out of the water when sailing, loss of prop drag will make you sail faster than similar boat with inboard. The space from removed inboard can be used for storage, say for a keg of beer. You will have breakerless ignition. In the long run it will cost less and demand far less attention.
A new diesel would be superb but here are some advantages of an outboard over a gasoline inboard. It will be new and have a warranty. If you are on a trip and it breaks down, you could drive the motor to a repair shop. If you ever had to replace it, you could do it in an hour. you would be getting a new tranny at the same time. The outboard and a full keg of beer would probably still weigh less than an inboard. You can use the pivoting engine and prop blast to steer the boat in tighter circles when docking. The boat will seem much quieter to anyone who is down below while underway. You can tilt the motor out of the water when sailing, loss of prop drag will make you sail faster than similar boat with inboard. The space from removed inboard can be used for storage, say for a keg of beer. You will have breakerless ignition. In the long run it will cost less and demand far less attention.
Atomic4 vs Diesel My 2c
This old topic has been hashed over at least a dozen times on this board and others. You got your pro atomic 4 guys who I guarantee you are all good ignition men. The atomic 4 was a piece of junk from day 1. everyone keeps talkin about the dangers of gasoline. Thats not going to be your main worry. Your biggest problem is the zenith updraft carburetor. You splash a couple of drops of water on it from the bilge and the thing is not gonna start when you need it the most. Not to mention wet or oil soaked plugs and points that are out of sync. I had 2 of them in boats I owned and they both ended up as moorings. They are just not dependable. Thats why they stopped using them in new boats about 25 years ago. The diesel is a better Idea because it is dependable. If you got a battery and fuel its gonna start and probably run with a lot of things wrong with it. The problem with the diesel by the time its in with bed adjustments, shaft prop and labor its going to run a minimum of $10000. If you cruising very far and the boat displaces under 8000lbs go for the outboard.
This old topic has been hashed over at least a dozen times on this board and others. You got your pro atomic 4 guys who I guarantee you are all good ignition men. The atomic 4 was a piece of junk from day 1. everyone keeps talkin about the dangers of gasoline. Thats not going to be your main worry. Your biggest problem is the zenith updraft carburetor. You splash a couple of drops of water on it from the bilge and the thing is not gonna start when you need it the most. Not to mention wet or oil soaked plugs and points that are out of sync. I had 2 of them in boats I owned and they both ended up as moorings. They are just not dependable. Thats why they stopped using them in new boats about 25 years ago. The diesel is a better Idea because it is dependable. If you got a battery and fuel its gonna start and probably run with a lot of things wrong with it. The problem with the diesel by the time its in with bed adjustments, shaft prop and labor its going to run a minimum of $10000. If you cruising very far and the boat displaces under 8000lbs go for the outboard.
This points to an area where some aptitude and knowledge
can be very valuable. A prop shaft costs about 200 dollars and an engine by Beta can be bought for less than 7k so for 2800 dollars a mechanic will install it for you. Learn, buy the tools and do the work unless you make more per hour than the yard charges.
can be very valuable. A prop shaft costs about 200 dollars and an engine by Beta can be bought for less than 7k so for 2800 dollars a mechanic will install it for you. Learn, buy the tools and do the work unless you make more per hour than the yard charges.
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