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What is recommended normal operating rpm

johnsct

Member
I have a pair of TAMD41P-A's that I normally operate at 15 -1800 rpm to obtain the best fuel economy, Once an hour I do operate it at 3000 for 5 minutes. However I have heard that operating at low rpm causes the cylinder walls to glaze over as the internal temps do not rise high enough. However my understanding is cylinder wall glazing is caused by running at high rpm without any or enough load on the engine. Has anyone got any comments?
 
You are fine running it at 1500-1800, every once in a while getting it up to 3000 will burn the excess carbon off. It will not glaze anything, and will run nice and 160F cool :)

Wide open should get 3800-3900 rpm if you are propped right

Cruise should be in 3400-3600 rpm range
 
Exact words from Penta for the 41 - Light Duty
Eng. with this power setting are intended for applications where load and engine speed change, and full power is used max. 1 hour per 12 hour operational period.
Primarily for planning boats eg fire, rescue, patrol, charter boats.
On my boat there is a Penta Notice that says simply run at 200 rpm below maximum rpm. I double that advice and run 400 below my max which is 3400 - 3600 rpm depending on boat and sea state. I also try to vary the rpms.
As a side note .. if you use a tied in Racor CCV and drain back to the sump.. they say that only happens when internal vacuum drops, so idle back from time to time or oil vapour might pass thru their filter, coating the turbo and aftercooler.
 
Hello skiss,
Thanks for the info. I have been varying the rpm quite a bit more recently. I don't have the Racor CCV filter arrangement. Suspect that may be a good idea though.
 
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