M8 Engine Temp
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Road Captain
Joined: Aug 2005
Posts: 518
Likes: 27
From: PA
M8 Engine Temp
Came for a 14 FLHTK with SE Air cleaner, V&H Power Duals and Monster Ovals with a good FM Map and and a few good auto tune sessions.
Bike ran on average 195F on a cool day (Around 65 deg) and 210-215F on a 85-90 degree day.
My M8 FLHTK stock runs about 275F (on a 65 Deg Day) and about 260F with a Improved Stock Map from Dynojet on a 65 degree day. I was a little shocked it ran that hot. I can't wait to see what Headers and Pipes do to change it.
Smitty
Bike ran on average 195F on a cool day (Around 65 deg) and 210-215F on a 85-90 degree day.
My M8 FLHTK stock runs about 275F (on a 65 Deg Day) and about 260F with a Improved Stock Map from Dynojet on a 65 degree day. I was a little shocked it ran that hot. I can't wait to see what Headers and Pipes do to change it.
Smitty
Road Master
Joined: Apr 2011
Posts: 1,145
Likes: 98
From: Colorado Springs
Yep, so far my M8 runs at least as hot as my 103" did. But my 103" had a power commander with FuelMoto map. It was running much richer than my M8 with an HD stage one download. I believe the map is the difference. I don't have the ***** to use an aftermarket tuner/map until my bike's off warranty so I guess I'll live with the heat.
I do believe the factory is correct saying that a stock M8 is a bit cooler than a stock 103".
I do believe the factory is correct saying that a stock M8 is a bit cooler than a stock 103".
HD EFI Guru
Joined: Jan 2008
Posts: 4,453
Likes: 4,707
Yep, so far my M8 runs at least as hot as my 103" did. But my 103" had a power commander with FuelMoto map. It was running much richer than my M8 with an HD stage one download. I believe the map is the difference. I don't have the ***** to use an aftermarket tuner/map until my bike's off warranty so I guess I'll live with the heat.
I do believe the factory is correct saying that a stock M8 is a bit cooler than a stock 103".
I do believe the factory is correct saying that a stock M8 is a bit cooler than a stock 103".
Road Master
Joined: Jul 2013
Posts: 1,159
Likes: 322
From: Joplin, mo
Everyone needs to understand that this is a complete different set of readings. On the Twin Cam engine the temperature sensor was located on the outer most part of the front cylinder head just behind the horn. The M8 temperature sensor is in the rear head near the base of the head and in close to the cylinder barrel behind the air cleaner mounting plate. You are going to see completely different readings. I'm not say one is better or worse just expect all the readings to be different as the sensors are different and in different locations.
HD EFI Guru
Joined: Jan 2008
Posts: 4,453
Likes: 4,707
I am in the process of adding oil temperature into the pan area of one of our 107 test bikes and I think that is really going to let us know what is going on. I do not believe at this point the 107 M8 engine temperature runs any cooler than the Twin Cam. Going by the engine temperature readings it runs hotter but as I stated above we really do not know for sure.
We need to really know what the accurate temperatures are from the 107 and the HD 114 kit as we have a new big bore (117 & 120)kit almost read to test and temperatures with it has to be compare against the HD offerings.
We need to really know what the accurate temperatures are from the 107 and the HD 114 kit as we have a new big bore (117 & 120)kit almost read to test and temperatures with it has to be compare against the HD offerings.
Road Master
Joined: Apr 2011
Posts: 1,145
Likes: 98
From: Colorado Springs
Who do you work for? Who has a 117" and 120" almost ready to test?
Tourer
Joined: Aug 2012
Posts: 330
Likes: 16
From: Colorado
Please do post up when you get your readings. From the seat of MY pants, I would say that the '17 M8 Water Cooled runs hotter than a '16 Twin Cam Water Cooled.
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Seasoned HDF Member
Joined: Aug 2011
Posts: 11,814
Likes: 5,120
From: SW Ohio
I can't speak for the engine temps but I'd have to say oil temps are going to be much higher in oil cooled M8 engines. A TC doesn't circulate oil around the exhaust valves and ports heating it up. From what I can see, there's no provision for cooling that oil other than an oil cooler, which many TC engines came with stock.
If I were gonna pop for an M8 in 3-5 years it would have to be the water cooled model; oil isn't a coolant and trying to make it one degrades it's lubrication performance.
If I were gonna pop for an M8 in 3-5 years it would have to be the water cooled model; oil isn't a coolant and trying to make it one degrades it's lubrication performance.
Last edited by Campy Roadie; Oct 13, 2016 at 09:38 PM.
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Road Warrior
Joined: Jul 2009
Posts: 1,408
Likes: 1,808
From: pa
BMW has been using oil to cool its heads for years they don't seem to have a problem, Not to start a sh#t storm but I would find it hard to believe that they would be clueless as to an engine design and its ability to keep within operating temperatures. Most oils can cool up to 250C and synthetics higher. Its not the main cooling component the fins are its secondary cooling around the valves. Not saying the oil isn't hotter but well within limits of today's lubricants
Seasoned HDF Member
Joined: Aug 2011
Posts: 11,814
Likes: 5,120
From: SW Ohio
BMW has been using oil to cool its heads for years they don't seem to have a problem, Not to start a sh#t storm but I would find it hard to believe that they would be clueless as to an engine design and its ability to keep within operating temperatures. Most oils can cool up to 250C and synthetics higher. Its not the main cooling component the fins are its secondary cooling around the valves. Not saying the oil isn't hotter but well within limits of today's lubricants
250C is 482F. Oil breaks down LONG before that, even synthetics.
Last edited by Campy Roadie; Oct 13, 2016 at 02:33 PM.
