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I don't think it's as simple as X head temp = bad or good. You really need to know the EGT as you could have amazing head cooling that keep them at say 250 and still burn the valves and seats with extremely high EGTs. When my dad was building and tuning 1000hp NA drag engines (on a water-brake engine dyno), he ALWAYS had thermocouples on the primaries and those were water cooled heads.
Interesting comments - you and Kevin (DK). On air-cooled aircraft engines, it's common to monitor both EGT and CHT, and to richen up the mixture if things get too hot. Harley might be using the oil temp as a 'proxy' indicator. (And odd that they only monitor the front CHT and use it to cut ignition to the rear cylinder.)
Agreed - bad things happen to the oil when it gets too hot, and bad things happen fast to the metal when it gets too hot.
Fans and oil coolers can help out on the oil temps, but good point on EGT. It would be interesting to see some Ghost-style "tune vs EGT" data.
So your saying that my bike was taking damage every summer ride before I put the fans/oil cooler on? Cause that was the average running temp even with a tune. I can't imagine what temp the stock bikes are running at?
I find it difficult to accept that real damage is occurring at 270 degrees. Or is it damage that will take 100k miles to become apparent?
Not being a wise ***, just really confused by that number.
Not wanting to hijack this thread about oil temps. I've been wondering about the Wimmers for years and am looking forward to Ghosts results.
Here is a copy and paste of what I sent in the PM on the subject-
Heat is a complicated thing, but yes, when the 270* ET, as displayed by the PV from the ECM, is crossed, damage begins occurring, faster than normal wear and tear.
The higher it goes above 270* the faster the damage occurs.
Harley has done a fantastic job of keeping the engines running, and not burning oil, even when the cylinders go out of round. So most folks don't even realize damage has occurred, in great part due to the drop in power occurring over a period of time.
We have seen dozens and dozens of Twin Cam engines that were running "fine", but the owners realized that they did not quite have the power that they used to have because excessive heat put the cylinders out of round and/or warped/burned the valve seats.
There is a simple way to find out, do a leak down test. If significant damage has occurred, then the leak down test will show it...because air will leak past the rings and/or valves from the heat damage.
After experiencing this ourselves, and seeing so many others experience it, we put together a report on how to cool down the Twin Cam. You can see it HERE.
btw, Head Temperature as displayed on the PV is NOT CHT. It is an algorithm derived number. ET as displayed on the PV is a direct readout of the sensor in the front cylinder head.
ET is used for most of the lookup tables including the fuel tables and multipliers, while Head Temp is used primarily for spark temp correction.
Last edited by DK Custom; Apr 15, 2017 at 06:28 PM.
Reason: Corrected for channel read-outs
Extended length oil filter. About twice the surface area of the standard washable...
It's a little insanely priced at $350, but if you want every little bit of oil cooling, there you go...
Plus you get an extra half pint of oil volume in the system! And probably that much less parasitic drag on the oil filter due to the large surface area of the filter.
Oh sure, go ahead and post that image Got a link? My wicked little brain is already trying to figure out how to get that beast to work with my oil filter relocation and the +3" extended shift rod
Oh sure, go ahead and post that image Got a link? My wicked little brain is already trying to figure out how to get that beast to work with my oil filter relocation and the +3" extended shift rod
The ONE thing I don't particularly like is the lack of a wrenching point on the bottom. Got to use their adapter to remove. I may stick with the DK customs version, which as I understand is the same K&P element in different housing. No special tool needed for removal. Unless its a standard filter wrench. Hmmm....
EDIT: Just called K&P - It's a standard wrench size, just not for a Harley. 68mm x 14 flats. Available at parts stores though. Thats always good in case it disappears.
The ONE thing I don't particularly like is the lack of a wrenching point on the bottom. Got to use their adapter to remove. I may stick with the DK customs version, which as I understand is the same K&P element in different housing. No special tool needed for removal.
That's what I noticed as well; I like the 17mm machined on hex on the billet housing of my PCS4C; the PCS4C is identical to the DK offering and they both use the K&P stainless steel mesh filter element. I did a bit of measuring and I'd have one hell of a time fitting that beastie
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.
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Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.
Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.
Got a link? My wicked little brain is already trying to figure out how to get that beast to work with my oil filter relocation and the +3" extended shift rod 
