NEW R-21 Revised Engine Box

[LADY JANE]

The New R-21EC Engine Box has been revised to include an installed Chrome Vent, into the Box' fwd pnl. Check it out. This very practical upgrade would be an excellent customization project for any ol' R-21. A printout of the Eng Box front cutout dimensions would be a great input here. Maybe the new owner of a new Fwd Vented Eng Box could give us the single measurement we need, from the vent top edge to the BoxTop or BoxBottom. Also, Is there an available P/N for: "Engine Box Fwd Vent Kit"? That would include the Chrome Vent, a cutout loc.Printout, and correct Hardware. Maybe not. Does anyone have the new Chrome Vent P/N? It's more than likely identical to the side vents... ..
BB+

 

[baz]

As I have just received our new 2016 R-21EC I will check and post back later. 🙂 I'll include a pic if I find the new front mounted vent. There's also a hole to poke a fire extinguisher nozzle into if I recall.

[EDIT]

Here you go... There are three chrome vents (all identical and centered on the horizontal). The one on the front is just above the box lift handle and I placed a measure tape in the photos so you can see its precise location. The other two are on either side in the center. I will look for a part number, but as the front vent is identical to the side vents you can look for the P/N if you want.

Add 3" to the tape marking as the measuring tape dispenser has a 3" flat. So the 9" is actually 12" and the 7" is actually 10". 😉

This one shows the Fire port hole.

 

[SGIDAVE]

Here is a similar stainless steel vent at Defender if you want to add more ventilation to your engine box.

dave

 

[LADY JANE]

Dave, That "Defender" mail order Marine Supply site is incredible. It's got West Marine stuff, ON SALE!!! :idea:

 

[SGIDAVE]

Dave, That "Defender" mail order Marine Supply site is incredible. It's got West Marine stuff, ON SALE!!! :idea:

Hello Bill,

Indeed - WM stuff and then some. Everything except Garmin stuff, that is.

dave

 

[LADY JANE]

baz, Nice photos of your brand new engine box vent. This additional vent is really needed for a cooler engine atmosphere. The engineers came through again with a small revision making a big difference.
BB+theLadyJane

 

[REO6205]

Thanks for the idea on the extra engine box vent. That's one more item on the "to-do" list.

 

[LADY JANE]

First, our 2014 R-21EC engine has heat accumulating inside the box with only 2 vents. Then there's the engine noise that is being supressed inside the box. Another small vent has been added now to the front of the 2015 engine box to dissipate more engine heat. But how much louder does that make it, out front of the engine box? Or does it make any difference at all in that respect?

 

[tlkenyon]

When we first got our R21 Classic, I was very concerned about the heat in the engine box. I put a remote thermometer in the box and saw up to 120F on a hot day. I consulted a friend that is an automotive engineer and he scoffed at the temp readings, with the claim that your engine compartment in your car gets lots and lots hotter. I tried running with the box open to see that impact that had on engine temps and saw none....lust lots and lots noisier. Note that all the air for the combustion comes from air entering sucked into the box, kinda a built-in fan. More vents=more noise.

 

[LADY JANE]

Great info TLKenyon. The chrome vents installed around the D1-30 engine box allow plenty of ventilation for this little 3-cylinder engine. We should be able to muffle that extra amount of "engine noise" (as my Wife calls it) by adding a small strip of insulation to the inside lower half of each vent. That should cut down on the escaping engine sound in-half, from 4 to 2 slots per vent, and still get plenty of box ventilation. Might even run the insulation vertically, for a half-vent with 4 short slots. Am getting some Approved fireproof, waterproof, soundproof hood insulation at the auto parts store & will update this post when the temp results are in.
-Bill

 

[harry ames]

Yanmar folks I talked to about the "sealed" engine box on Poopsy, R21 Classic, told me that the engine and systems are designed to be in a closed area as long as intake air is available. The engine and exhaust systems are designed for the heat generated. In addition, as I explained the installation on Poopsy to them, they said that the engine intake is pulling in the heated air around the engine with external air and that would keep box temperatures inside easily below anything that would be a hazard to the engine system.

None of the hoses and other rubber parts on the 800 hours engine seem to be hardening or cracking as one might expect if the box temperatures were excessive for the engine and components.

So, as attractive as it seems to me as well as others to add ventilation, apparently it is a feel good move rather than a "better" thing. Also, my 21 is noisy enough with no other ventilation other than that provided by the intake air pulling in ambient air from outside.

 

[LADY JANE]

Those with an R-21EC engine box with a foreword-center "Engine Noise Outlet Vent" might want to consider spinning the eng box around front to back. A Tugnut previously suggested: 'Remove the 2 half-hinges from the back of the engine box and reinstall them to the other box-end'. That way, the engine box dual cup holder will be in front of the engine and the sound of the engine revs will be directed toward the stern, instead of directly at the cab. Also, the hood-handle needs to be removed from the vent end and installed below the cups holder. This engine box modification will alleviate a noticeable amount of engine db's from the cabin/pilot house.

- Bill -

 

[MichaelStrotz2]

I doubt turning the engine box cover around is a good idea, as the rear end-wal of the box has two hinges attached. Inspection of the rear wall of the engine box cover will show that it is much thicker in areas where the hinges attach. This is reinforcing to secure the hinges to the reinforced rear wall of the engine cover.

 

[Newf]

This was an old thread (2015-2016) but for those with the D1-30, keep in mind that these engine were designed to run hot as the thermostat does not even start to open until 194F and not fully open until 221F I believe. In my opinion (not an engineer) the amount of air drawn into the engine box is limited by the size of the inlet on the breather box at the back of the engine. The two side vent and the two holes in the "trough" below the engine is more than enough for engine air intake so adding an extra vent does nothing or very little to help cool the interior of the box. The breather box/air filter controls how much is sucked in unless you add a suction fan inside the engine cover but maybe I'm missing something. 2 side vents and 3200hrs on 2014EC and no issues that I'm aware of.