[C38] engine temp

Thu Sep 3 14:17:04 EDT 2009

I went ahead and ordered the P/N 299818 from H & H Marine Engine Service on
Monday and it is scheduled to arrive today.  Hope to get it installed next
week after weekend race committee duties in San Diego.  I will let you all
know how it works out.  Running at 190 - 200 degrees at 2200 rpm has been
telling me that the 2" exchanger was not doing the job.  I'll bet my
thermostat was running wide open all the time.

Bob 

"Bolero" at Southwestern YC in San Diego

  _____  

From: listserve-bounces at catalina38.org
[mailto:listserve-bounces at catalina38.org] On Behalf Of Steve Smolinske
Sent: Tuesday, September 01, 2009 8:53 PM
To: Catalina 38 Listserve
Subject: Re: [C38] engine temp

Scott 

The link Charles posted earlier
http://www.go2marine.com/product.do?no=97977F  was less than the link I
posted, they are about $320. the 3 x 17 I purchased fit right inplace,
although I did fabricate brackets to accomodate the larger radius as well as
four T bolt clamps.  I also needed to swap out the 1/2 hose barb on the raw
water pump to accomodate 7/8.   On my 2 x 16 exchanger the inlet for raw
water was 1/2.   The universal p/n for the 3 x17 is 299818 it has 7/8 fresh
water ports and 5/8 raw water.  The 299835 is 3 x 13 and has the same size
ports as the 299818.   

I also had to step down hose size from the manifold to my heater (1" to 5/8)
and from the heater to the exchanger I used a 5/8 to 3/4 hose barb in order
to step up to 7/8 going into the exchanger.  Last going from the exchanger
to the fresh water pump the same holds true with stepping up from 7/8 to 1" 

curious when you cruise at 2400 how fast are you going?  I generally keep it
at 1800 and do about 6.5

Steve

Peregrine #312 

Seattle

  _____  

From: listserve-bounces at catalina38.org on behalf of Ann Boochever
Sent: Tue 9/1/2009 7:29 PM
To: Catalina 38 Listserve
Subject: Re: [C38] engine temp

Even with 52 degree water in Alaska, our 2" heat exchanger has been just
passable at 2400 rpms. Is there an off-the-shelf replacement that is larger
and would fit in the same location, or do they have to be built to order?
Thanks
Scott and Ann
Tacita II
Juneau, AK

On 9/1/09 5:48 PM, "Les" <hlhowell at pacbell.net> wrote:

> Thanks, Tom,
> I figured you would be the one with the answer.  I am an engineer
> wannabe, so I study things pretty thoroughly, but I find I sometimes
> miss a detail, such as the one you point out here.  Too hot is not good
> for any engine.
>
> Regards,
> Les H
> On Tue, 2009-09-01 at 21:11 -0400, Tom T. wrote:
>> Hi Les,
>>
>> You claim you don't want to appear stupid and then you go on to show you
>> are fairly astute about diesel engines.
>>
>> As you pointed out, the thermostat should regulate the engine temperature
>> for optimum performance.  The problem we have is that the original heat
>> exchangers on many of our engines were just too small and if the water
>> returning from the heat exchanger is still hotter than the operating
>> temperature of the engine, the engine is gonna overheat, clear and
simple.
>>
>> You cannot have a heat exchanger too large but you can have one too
small.
>> If you had a heat exchanger ten times larger than you needed, it would
just
>> mean your thermostat would regulate the coolant flow slower so that the
>> operating temperature would still be at the thermostat temperature.  With
>> the reduced flow from a very large heat exchanger, the flow would be
slowed
>> to a trickle but the engine would still operate at the correct
temperature.
>>
>> Another plus of an oversize heat exchanger is that it gives a margin of
>> safety in case you pick up some debris causing a reduction of cooling
>> efficiency.  The little 2" heat exchanger that came with the 5424 had
>> absolutely no reserve cooling capacity at full throttle, especially in
>> tropical waters.  Add debris restriction and you have a meltdown, even at
>> moderate speeds.
>>
>> Tom Troncalli
>>
>>
>>
>>
>>> [Original Message]
>>> From: Les <hlhowell at pacbell.net>
>>> To: <tdtron at earthlink.net>; Catalina 38 Listserve
>> <listserve at catalina38.org>
>>> Date: 9/1/2009 8:43:19 PM
>>> Subject: Re: [C38] engine temp
>>>
>>> Hi, everyone,
>>>
>>> I don't want to appear stupid, but I am.
>>>
>>> Diesel engines are basically heat engines.  Most are designed to run at
>>> some temperature range.  If they don't get to that range, they become
>>> very "dirty", with carbon and so forth, including poor combustion and
>>> greater nasty air products.  Does anyone have any information about what
>>> the "design" temp was for the original engines (I have an XP-25B in JACE
>>> now and it came with a larger heat exchanger, but that is no indication,
>>> as the engines internals will determine how much cooling is right.)  If
>>> the thermostat is working right, the engine should maintain the right
>>> temperature I think, but I don't know for sure.  The mechanical
>>> thermostats are in essence a two element spring that holds them closed,
>>> with a waxy cap that will solidify when the engine is cold to keep it
>>> shut until the engine warms up enough to run right.  These thermostats
>>> are really simple, but a vital piece of equipment for a diesel.
>>>
>>> Regards,
>>> Les H
>>> On Mon, 2009-08-31 at 08:22 -0400, Tom T. wrote:
>>>> 
>>>> Ditto,
>>>> 
>>>> This sounds like my own experience.  That little original 2" heat
>>>> exchanger has to go to the Davy Jones locker for good!
>>>> 
>>>> Tom Troncalli
>>>> Renata #95
>>>>
>>>> 
>>>>         ----- Original Message -----
>>>>         From: Steve Smolinske
>>>>         To: Catalina 38 Listserve
>>>>         Sent: 8/31/2009 2:33:21 AM
>>>>         Subject: [C38] engine temp
>>>>        
>>>>        
>>>>         fyi
>>>>         
>>>>         as a follow up to earlier discussions on engine cooling, I
>>>>         replaced the 2" x 16" heat exchanger with a 3 x17 and dropped
>>>>         30 degrees off of my normal operating temp.  went from 190 to
>>>>         160 under way. With the larger exchanger I was also able to
>>>>         step up to 5/8 from 1/2 hose from the raw water pump to the
>>>>         exchanger.  Im amazed at how much smoother, quieter and less
>>>>         labored the engine sounds now.
>>>>         
>>>>         Steve
>>>> _______________________________________________
>>>> Listserve mailing list
>>>> Listserve at catalina38.org
>>>> http://catalina38.org/mailman/listinfo/listserve_catalina38.org
>>
>>
>>
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>
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