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Quotes - Engineering - Sales6LY, 6HY and 6AY
Leisure and commercial ratings
Yanmar marine engines split fairly cleanly into leisure and commercial families, and the coolers follow that split. The 6LY range broadly covers about 300 to 480 horsepower in fast pleasure and light commercial use, the 6HY and 6AY families run heavier commercial duty from roughly 400 up to around 900 horsepower, and the smaller four cylinder engines sit below with compact frames. Each is sized from the heat rejection published for the specific rating.
Yanmar installations tend to be neatly packaged, which is good news for reliability and awkward news for replacement. The original exchanger is often part of a marinising arrangement built around the engine, sitting in a defined space with fixed connection orientation. Replacing it means matching the envelope as carefully as the duty, so the measurements matter as much as the rating.
The build is the standard marine option set: seawater on the tube side in copper-nickel tubes, coolant or oil on the shell side, bronze bonnets and brass tubesheet with replaceable zinc anodes. Metric and BSP connections are usual on these engines and adapters go on the quotation. Send the engine model, rated output and rated speed with the old unit dimensions to Sales@HeatX.com.
Commercial Duty
Compact Fit
CN Tubes
Oil Coolers
Selecting for a Yanmar
Packaged installations need the envelope defined as precisely as the duty.
Duty Inputs
- Engine model and rated output
- Rated RPM and duty rating class
- Heat rejection from the engine data sheet
- Connection sizes, forms and orientation
- Length, diameter and mounting centres
What We Supply
- Compact and mid HC frames
- Copper-nickel or titanium tubes
- Bronze bonnets with zinc anodes
- Adapters for metric or BSP piping
- Lube oil and gear coolers
Duty Profile
- Commercial fishing at sustained load
- Warm coastal and tropical water
- Short raw water pipe runs
- Neatly packaged engine spaces
| MODEL / RATING | HORSEPOWER | DUTY | TYPICAL SELECTION |
| Four cylinder marine blocks | About 40 to 250 hp | Jacket water | B Series small frame |
| 6LY family | About 300 to 480 hp | Jacket water and lube oil | HC Series with CN tubes |
| 6HY family | About 400 to 700 hp | Jacket water, oil, gear | HC Series plus lube oil cooler |
| 6AY family | About 600 to 900 hp | Jacket water, oil, charge air | HC Series larger frame |
| Auxiliary generator variants | Call for rating | Constant speed jacket water | AB Series or B Series |
Orientation Matters
Connections in the right places
On a packaged installation the hoses have almost no slack, so a frame with connections facing the wrong way is as useless as one that is too long. Record which way each connection points relative to the mounting, and whether the raw water enters at the top or the bottom. A sketch beats a description every time.
Where the available frames do not offer your exact orientation, the choice is between reworking a short section of hose and shifting the mounting. We will tell you which is involved before you order, and in most cases the answer is a length of hose rather than any structural change.
6HY and 6AY service life
Commercial Yanmar boats accumulate hours fast and the raw water side sees the consequences. A bundle in a fishing boat working warm coastal water may need cleaning annually, and after two or three cleanings the tube wall no longer supports the original pressure rating. Track cleanings rather than counting on the gauge.
Where the cleaning interval has fallen below a year, look at the strainer for bypass and at the frame size for adequacy before ordering the same unit again. Send the service history with the enquiry and we will review the selection instead of simply repeating it.
Related
ENGINES • OTHER MARINE
Mitsubishi
The larger Japanese commercial blocks and their cooler duties
+ Learn More
APPLICATIONS • OIL COOLING
Lube Oil
Sizing oil coolers on load, grade and pressure drop
+ Learn More
ENGINEERING • MATERIALS
Copper-Nickel
What the alloy tolerates and where its velocity limit sits
+ Learn MoreCommon FAQs
Broadly around 300 to 480 horsepower depending on the variant and duty rating class. Size from the engine plate rather than the range, since the jacket water and lube oil heat rejection published for your specific rating is what sets the frame and the pass arrangement we select.
Yes, on a packaged Yanmar installation it often matters as much as length. Record which way each connection points relative to the mounting and whether raw water enters top or bottom. Where the frame available does not match, usually a short hose rework solves it rather than moving the mounting.
Possibly, or the strainer is bypassing. Check the strainer first, then look at whether the frame is marginal for the rating in warm water. Send the cleaning history and the engine rating and we will review the selection rather than just supply the same unit again.
Yes. Gear coolers are sized on gear heat load, oil grade and allowable pressure drop rather than on engine horsepower. Send the gear model and the oil grade with the engine details and we will quote it alongside the jacket water and lube oil units on one order.
Often, where warm water and high flow have already shortened a copper-nickel bundle. Titanium removes the velocity limitation on the raw water side and tolerates polluted harbour water. It is an option code on the frames we select from, and ratings on titanium builds are set per duty, so call for a rating.
