A4 to M-35 on C 30 ?
- Thread starter pdevlin
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Welcome to the forum!!
So you want to replower a Atomic 4 30 hp gasoline engine with a Universal M-35 30 hp diesel engine? Some considerations include dimensions, including footprint, exhaust system, transmission, ignition system, etc. Suggest discussing the conversion with your local marine engine mechanic to assess the work scope and costs. Once you do, please let the forum know the feasibility, work scope and cost so others can learn form your experience. I am sure the forum will plenty lots of sound advise, besides asking why you plan a repower and if you've considered rebuilding the Atomic 4 engine, but I will leave that discussion to others.
So you want to replower a Atomic 4 30 hp gasoline engine with a Universal M-35 30 hp diesel engine? Some considerations include dimensions, including footprint, exhaust system, transmission, ignition system, etc. Suggest discussing the conversion with your local marine engine mechanic to assess the work scope and costs. Once you do, please let the forum know the feasibility, work scope and cost so others can learn form your experience. I am sure the forum will plenty lots of sound advise, besides asking why you plan a repower and if you've considered rebuilding the Atomic 4 engine, but I will leave that discussion to others.
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I have a friend who repowered his Pearson 30 from an A4 to an M25. Not an M35.
Two major things, in addition to all the subsystems like fuel that sail sfbay covered:
1. Fit. You can find the manuals and physical dimensions of the engine online. They might be in the links here:
c34.org
2. Transmission and prop. IIRC, the A4 has a different ratio in the transmission than either diesel would require.
Without checking, my gut feeling is that it would be a tight, very tight, fit. Why? Because our C34s came with M25s, and eventually M35s. The M35 was a tight fit in what is a much larger engine bay, although I am not an expert on the C30 engine space, I do know it's under the settee forward of the galley, while the C34 is under the companionway steps. Big differences.
Good luck.
Two major things, in addition to all the subsystems like fuel that sail sfbay covered:
1. Fit. You can find the manuals and physical dimensions of the engine online. They might be in the links here:
Manuals - c34.org
2. Transmission and prop. IIRC, the A4 has a different ratio in the transmission than either diesel would require.
Without checking, my gut feeling is that it would be a tight, very tight, fit. Why? Because our C34s came with M25s, and eventually M35s. The M35 was a tight fit in what is a much larger engine bay, although I am not an expert on the C30 engine space, I do know it's under the settee forward of the galley, while the C34 is under the companionway steps. Big differences.
Good luck.
Well I thank You for the welcome and all of Your responses and inputs after dealing with this project I picked up to keep busy during pandemic all sorts of alternatives came to mind I don't know if any of Your baby's diapers had ever been this dirty and the further I tore down the more the complete M-35 in my mind would fit and it actually is not that far off but I'am a stubborn Irishman and cannot let this A4 beat me at this point and follow through putting her back together especially since I have already bought almost all kits possible and I think assembly will be a lot more pleasant than the teardown and maybe I'll be Sailing by summer. Thanks again Take Care Be Safe Patrick Who lets an engine get this way???
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You might be able to replace engine with a smaller, lower hp engine. You might find this article helpful: Repowering Your Sailboat (l-36.com)
Your boat is limited by "hull speed" that is the theoretical maximum speed your displacement hull will go. If you put too big of an engine in your boat then when reaching hull speed you will be running your motor at too low of an RPM. The C30's I've sailed on all had M-25 motors as does Stu's C34 and my O'Day 35. That is plenty of motor for the C30. But if thinking new motor you should look at the Beta 25 or the Beta 20
Yea I know about "hull speed" I wasn't looking to go faster the only reason I wondered if the M-35 would work is that it is readily available locally at a great price without a thousand hours of hard labor like my A4 but I didn't think about the low Rpm I'd be running So thank You for pointing that out and at this point finishing my rebuild seems to be the most logical a affordable way to go and besides it is a Sailboat I need to remember that Thank Y
ou all much
ou all much
I will also add........make sure the larger engine is maintainable, i.e., ease of access. A friend bought a sailboat that was repowered with a much larger than the stock engine and he found imaintenance access limited so had to hire all that work out.
Greetings,
We did an engine swap about 5 years ago on the family boat. We started on a conversion from a 2 cylinder 18 hp to the M35. We started by measuring the space occupied by our old 18hp, loaded the measurements for the M35 from the engine manual to compare, then measured the actual space in the boat avaialable. Once you download the manuals its pretty easy to build a chart for size comparision.
We found our boat would take an M25 and M35, but the M35 was about 3"longer than our existing, meaning we would have to push out the engine cover out to accomodate the engine. The fuel line locations and filters were fine as is, and the forward motor mounts needed to be moved 1.5 inches forward. We saved a lot of money because we knew what needed to be modified to make the change out work properly.
You can get the actual dimensions for your A5 and your M35 fairly easily from the internet, just like we did, then compare with the space you actually have in the boat.
Good luck
We did an engine swap about 5 years ago on the family boat. We started on a conversion from a 2 cylinder 18 hp to the M35. We started by measuring the space occupied by our old 18hp, loaded the measurements for the M35 from the engine manual to compare, then measured the actual space in the boat avaialable. Once you download the manuals its pretty easy to build a chart for size comparision.
We found our boat would take an M25 and M35, but the M35 was about 3"longer than our existing, meaning we would have to push out the engine cover out to accomodate the engine. The fuel line locations and filters were fine as is, and the forward motor mounts needed to be moved 1.5 inches forward. We saved a lot of money because we knew what needed to be modified to make the change out work properly.
You can get the actual dimensions for your A5 and your M35 fairly easily from the internet, just like we did, then compare with the space you actually have in the boat.
Good luck