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SOHC.co.uk Forums => CB350/400 => Topic started by: allankelly1 on September 17, 2021, 07:47:39 PM

Title: Strange question
Post by: allankelly1 on September 17, 2021, 07:47:39 PM: Just wondered out of curiosity how much oil in litres per min a CB400F oil pump displaces on tick over

Any oil pump experts out there?

Best wishes Al

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Title: Re: Strange question
Post by: McCabe-Thiele (Ted) on September 17, 2021, 11:35:45 PM: I have no idea but as long as the oil light goes out reasonably quickly I think it's enough to do the job.
Title: Re: Strange question
Post by: Athame57 on September 18, 2021, 12:53:11 PM: (https://d2eehagpk5cl65.cloudfront.net/img/c800x450-w800-q80/uploads/2015/09/14434686408523.jpg)
Assuming the oil pump completes it's cycle 1200 times a minute, perhaps you could find out the capacity of said pump and multiply? Otherwise you could ask those boffins at NASA? ;D
Title: Re: Strange question
Post by: Bryanj on September 18, 2021, 01:57:50 PM: It pumps more than enough but not too much is the only answer i can give
Title: Re: Strange question
Post by: allankelly1 on September 18, 2021, 07:12:39 PM: Hi thanks for all the answers

Best wishes Al

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Title: Re: Strange question
Post by: Seabeowner on September 19, 2021, 08:14:03 AM: Quote from: allankelly1 on September 17, 2021, 07:47:39 PM
Just wondered out of curiosity how much oil in litres per min a CB400F oil pump displaces on tick over

Any oil pump experts out there?

Best wishes Al

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Depends on how worn your bearings are.
Title: Re: Strange question
Post by: TrickyMicky on September 19, 2021, 08:46:53 AM: To my simplistic way of thinking, worn bearings should not alter the output of the pump. If the pump is in good order it will still pass the same amount of liquid at a given speed. Don't forget that you cannot compress a liquid, only a gas. If the pressure gets too high then there should be a by-pass valve somewhere, otherwise something will definitely break. Look what happens to the conrods and crankshafts in diesel engines when they suck in some water.
Title: Re: Strange question
Post by: taysidedragon on September 19, 2021, 12:39:27 PM: Quote from: TrickyMicky on September 19, 2021, 08:46:53 AM
To my simplistic way of thinking, worn bearings should not alter the output of the pump. If the pump is in good order it will still pass the same amount of liquid at a given speed. Don't forget that you cannot compress a liquid, only a gas. If the pressure gets too high then there should be a by-pass valve somewhere, otherwise something will definitely break. Look what happens to the conrods and crankshafts in diesel engines when they suck in some water.

Dead right. Wear in the pump itself will affect the output. Wear in the engine bearings affects the oil pressure.
Title: Re: Strange question
Post by: SteveD CB500K0 on September 19, 2021, 12:44:51 PM: Isn’t there a pressure relief valve in the oil filter bolt?

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Title: Re: Strange question
Post by: Bryanj on September 19, 2021, 12:52:20 PM: Thats only for if the filter blocks so oil bypasses the filter and lubes the engine albeit with contaminated oil Steve, there is an over pressure relief built into the pump itself and operates at about 65psi if memory serves
Title: Re: Strange question
Post by: K2-K6 on September 19, 2021, 01:29:26 PM: The one in the pump (virtually all engines have this) is to protect the oil pump drive while the oil is thicker when cold. Essentially it will hydraulic lock (dynamic and relevant to the system resistance that is normal oil flow) if revved under those conditions and risk shearing the drive arrangement.
Title: Strange question
Post by: allankelly1 on September 19, 2021, 07:02:46 PM: Thanks for all the answers everybody

The original reason was that I have just finished off my oil cooler installation

(https://uploads.tapatalk-cdn.com/20210919/f4d8110173e56b05dcebf11fc6caf5f7.jpg)
(https://uploads.tapatalk-cdn.com/20210919/c233a2928917533f5f5686112ee83184.jpg)

But on initial checks during cranking on the starter (before firing the engine as wanted to ensure the system was flowing oil) there seemed to be less flow thru the cooler than I was expecting?

But then I remembered the there is a bypass port in the take off plate

(https://uploads.tapatalk-cdn.com/20210919/5262252a3c16a9487fed75ea517663a6.jpg)

So most flow goes direct to the engine via this port with a percentage flowing via the cooler hence my initial worry about lack of flow of oil

Again many thanks for all the answers Al

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Title: Re: Strange question
Post by: 400 Cafe Racer on September 19, 2021, 07:45:15 PM: Quote from: Bryanj on September 19, 2021, 12:52:20 PM
Thats only for if the filter blocks so oil bypasses the filter and lubes the engine albeit with contaminated oil Steve, there is an over pressure relief built into the pump itself and operates at about 65psi if memory serves

Hi Bryan, ;)

I can confirm this 65psi as I recently fitted an oil pressure gauge which tops out at 65psi when the engine is started cold. A good indication the oil pressure relief valve is functioning correctly.

Dennis
Title: Re: Strange question
Post by: Bryanj on September 19, 2021, 09:31:06 PM: Unless you arr racingan oil cooler is overkill if not fitted with a thermostatic bypass
Title: Re: Strange question
Post by: allankelly1 on September 19, 2021, 09:33:21 PM: No just prepping as planning to fit a 460cc lump in the future and an oil cooler was highly recommended as part of the changes when going up to 460cc

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Title: Re: Strange question
Post by: ka-ja on September 20, 2021, 11:41:39 AM: My original enquiries (1985) and subsequent conversion of my 400/4 to Yoshimura racing trim, the oil cooler was only considered necessary when fitting Carrillo? conrods with bigger diameter gudgeon pins, allowing engine max revs up to 16,000rpm,standard conrods were considered OK to 12,000rpm by the tuners.
Title: Re: Strange question
Post by: allankelly1 on September 20, 2021, 03:59:49 PM: That strange

My tuner said taking the engine to 460 increases the normal oil temp so the requirement to add the oil cooler?

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Title: Re: Strange question
Post by: ka-ja on September 20, 2021, 04:08:21 PM: I am only giving the tuning advice I received from the people that actually raced them in clubman's 500cc racing back in the day.