SOHC.co.uk Forums > CB350/400
Oil coolers
allankelly1:
Some more pics of how I routed my hoses to suit my Dekelvic exhaust down pipes to keep things nice and tidy
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Scottish Badger:
Thanks Al, much appreciated.
Laverdaroo:
Pure 'Bike Porn' as ever out of your garage Al, lovely problem solving and really tidy finish mate, love it.
Giz a glimps of the 'special' progress, aaaaahhhhhh, go on 8) ;) ;) ;) :D
allankelly1:
Hi Roo
Hope you are well
Ok here are some pics but progress is slow
(Sorry Brian for the post hijack)
Now finally got a set of LC cases but going to fit 350AC barrels and head to solve my engine cooling requirements
Got the correct KTM duke front wheel coming and a set of engine side cases and planning for a local frame builder to do some slight changes to the frame to accommodate the AC barrels as they are wider than the original LC as shown in a couple of pics
Enjoy and happy Xmas
Ps bit of yellow bike porn too as it you and bought a matching yellow speed block leather jacket the other day
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400 Cafe Racer:
--- Quote from: Scottish Badger on December 07, 2022, 10:35:27 AM ---
--- Quote from: K2-K6 on December 07, 2022, 10:18:28 AM ---Yes to that type of arrangement, but in agreement with you as to how effective it may be in cooling, I was referring to method of fixing as interesting point. The fit for F2 was this plus larger fins on head and barrels as complete package when they ran into trouble with lubrication on that model and kind of stop gap until the twin cam arrived in market.
Wondering the need for cooling as running oil too cold produces just as many problems as too hot. If you've no definite figures of your running example it may be worthwhile assessment to define this.
Running oil too cold, and especially at high rpm can bring unintended side effects. The pump is protected from hydraulic locking (virtually all engine have this) by a pressure bleed off valve that blows excess to sump effectively startng to starve key points in the lubrication system of supply, that's ordinarily the crank and big end bearing sites.
The flow is optimised for stated viscosity (varying with temp) at 90 degree C to give designed flow as originally tested and researched. You'd need to target this temp range in specifying cooling capacity.
--- End quote ---
I'm going to build a 460 engine for my bike, I have a spare 400 engine as a donor for the project and I now have most of the parts needed for the build, but I've read a lot of older posts claiming oil temp gets marginal with the larger bore size hence the need for additional cooling. I was looking to use an in-line oilstat to regulate the temp, being aware of the pitfalls of overcooling. (I'm an aircraft engineer by trade, spent decades working with both piston and gas turbine engines).
--- End quote ---
Hi,
Having fitted both an oil pressure guage and temp guage to my CB400F some months ago, I can confirm that in normal riding you will easily be running at 95c + with 40ish psi @ 3000 and if you give it the beans for a few miles you will be at 120c with 15psi @ 3000. I suspect the reason a low 4.5psi oil pressure switch used was to prevent worry of riders seeing the light blinking at idle on a hot engine.
IMHO If your seals and gaskets are newish, there is a definate case for synthetically improved oils which wern't available in the day to handle the higher temp better, and I will be running some tests next spring.
I think one of the major reasons for piston ring and groove failures is the deposits and gumming caused by burnt 10w 40 oil which cannot handle the excessive conditions at the top of the piston.
Regards
Dennis
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