HEELING the FEVER in the Atomic 4

[RobertLangdirect]

Let me set this up with my boat, GOOD TRADE, a Pearson 31, hull 14 with its original, raw water cooled A4.

When motoring under sail, I notice that when on a starboard tack, my temperature guage shows a "normal temperature," (maybe 180 degrees) but on a port tack, the guage reads nearly 200 (or more).

At first, I thought this was an raw water intake issue. The through hull is on the startboard side, so, when heeled over to the starboard, the intake is well underwater. When on a port tack, the intake is nearer the surface. Could turbulence be disturbing the flow in a manner that makes the intake less efficient?

But recently, I began to think, maybe it is not the position of the boat, ON THE WATER that makes a difference, but in reality, the position of THE WATER IN THE ENGINE. Could it be on a starboard tack the water covers the sensor, but on port, the sensor is out of the water, in a steam pool, or lleft to take heat without relief, directly from the block?

Does anyone have any experience on this? Also, might I ask, is there actually a heel limit for running the motor?

Thanks!

Robert

 

[Eddie7045]

You should be running no more than 145 degrees

operating in salt water and no more than 160 degrees operating in fresh water when you have a raw water system. You might want to check the impeller in the water pump. It might be worn to the point where it has difficulty lifting water above your waterline when heeled. Marine water pumps have veins that rub against the inner surface of the pump and so are prone to wearing out.

 

[kloudie1]

Usually, raw water cooled engines should have a 140F thermostat.. so ya may be having a problem on both tacks, but one worse.. I second Eddie's comment on the pump.. but hose connections and gaskets can leak vacuum (?), that is, admit air bubbles, and not leak water.. check all hose clamps/hoses and check the raw water strainer to be sure it is not admitting air under power. You may be correct as well, that the inlet is getting close to the surface and gathering air bubbles. If ya have a clear raw water strainer, go down and look in it on the bad tack and see if air is getting in there..

 

[tommays]

I would WAG your thermostat cover is a bit funky as it controls the water flow through the block and disappears with age

The exhaust manifold is very prone to clogging and can limit water flow OUT of the motor

My original waterpump was SHOT

 

[RichH]

I think Tommy has the best plausible explanation --- exhaust manifold blockage by 'slab rust'.

The Universal exhaust manifold is highly subject to 'slab rust' .. large 'platelettes' of rust due to rust separations of the 'stratifications' inherent in cast iron and are due to cooling anomalies of the molten cast iron in the molding/foundry process. These 'slabs' break loose from the cast iron and are moved by heeling and water flow and usually partly or fully block the outlet nipple of exhaust manifold. When the engine is stopped they then crop back to the bottom of the manifold, etc. The remedy is to remove the manifold, go inside the cooling side with stiff wire and 'break up' then invert the manifold and 'shake out' the rust particles.

Slab rust in cast iron is prevented/lessened by never 'drying out' an engine for long term storage; rather, the engine should be filled with a 50:50 mix of antifreeze - containing 'rust inhibitors'. Once an engine + exhaust manifold develops 'slab rust' you should ONLY use descaling compounds that are 'inhibitted' ... such as RydLyme, etc. and never plain or un-inhibited 'acids'.
Running the engine hard and long and 'hot' will redevelop protective 'black rust' (ferrous) and will convert internal red (ferric) rust back to ferrous rust. The 'hotter' the engine runs to near 180°F the greater the formation of black rust ... but you then begin to foul the engine/manifold with 'carbonates' that need to be periodically removed by 'descaling'.
The best 'life extension' method for an Atomic 4 is to install a retrofit Hx (www.moyermarine or www.indigoelectronics) .... better combustion pressures/temperatures, less to no 'slab rust' (when the exhaust manifold is included in the 'fresh water circuit") ... much less block 'rotting' due to internal corrosion. The only thing that 'mostly' kills an A4 is 'internal rust' and a FWC retrofit will mostly stop all that internal rust & corrosion.

To determine and increase your suspicion of 'slab rust' blockage ... measure the outlet flow of cooling water at the stern ... bucket and stopwatch with the engine running at ~2000 rpm. Should be delivering 3 gallons per minute. Then, when the engine later 'overheats' and without shutting down measure the outlet flow and if much less than 3GPM then 'highly' suspect that the manifold is partly blocked with 'slab rust'.

hope this helps.

 

[higgs]

I had the same problem with my Irwin 32 w/A4. I had completely torn down and rebuilt the engine, so crud in the manifold or water jacket was not an issue. It too happened on the tack when the intake was on the low side. I just learned to live with it. I figured that when heeled over, water flow over the intake actually made it harder for the pump to suck up water.

 

[Ron20324]

...I figured that when heeled over, water flow over the intake actually made it harder for the pump to suck up water.

I agree. I found that when i take out my speed impeller, less water comes in if i am under way instead of standing still.

 

[RobertLangdirect]

Eddie, Kloudie, and Tommays! Thanks for the inputs. I do have a thermostat in GOOD TRADE. I will go back and sheck on it. While the original three spring theremostat was NOT on the boat when I bought it, I found that there is a Volvo (I think) theremostat that works, albeit that you have to cut a spacer for the extra rise.

Regarding the manifold or the cooling water injector at the end of the motor, there was a blockage three years ago. Carbon from the exhaust and other crud, will plug the passages and make any water flow impossible. While you can use a wire to break out some of the crud, you cannot readily reach all Ibased on shape and geometry. However, I crilled and tapped an access whole and with that was able to carve the crud.

Higgs and Ron! Thank you for sharing your experience. I am going to do an at the dock test soon and heel the boat over, perhaps even put a on the deck force feed can of water so that there is no current and no lift effect. Then, if we see the temp difference, at least we can rule out intake issues.

To all readers: If you have seen the same, please add on. Thanks to all.

Robert