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Message started by mpescatori on 03/18/13 at 08:14:01

Title: Oil pressure and alternator ratings
Post by mpescatori on 03/18/13 at 08:14:01

Two small quesitons, because I sifted through the Tech section but couldn't find the two bits of data I need.

1. OIL PRESSURE MAX - MIN
I was reading the thread on fitting an oil pressure gauge http://suzukisavage.com/cgi-bin/YaBB.pl?num=1271818321
and I realized I do not know the ideal high pressure (i.e. cruising at 3000 rpm on a cold engine)
and the lowest acceptable low pressure (i.e. idling at the lights on a hot engine).

I read 1-3 psi, which is ridiculously low by my standards - literally, oil being randomly splashed on the cam lobes etc.

20 psi would be more like it, with 15-17 psi being the lowest acceptable (= 1 bar)

So, I do not know what the "working, cold engine" oil pressure could be... 50psi ? 80 psi ?

I need to know in order to source the ideal gauge, it's pointless to have a 0-60 gauge if working pressures are in the 60-80psi range.

2. ALTERNATOR RATING
I am aware our alternator is on the itsy-bitsy side, unfortunately every thread I found states "how to upgrade" but none say what is the OEM rating to start with.

100 W ? 10 Amps ? Either measuning unit is acceptable, as long as I know what I have available.

I need to know because I'm happy to switch over to LEDs for run/brake light and front side markers...
BUT
if I am to use fog lights (legal and recommended in Europe) I need to know what I'm starting with and working on.

Thank you all 8-)

Title: Re: Oil pressure and alternator ratings
Post by Oldfeller on 03/18/13 at 08:30:40

Oil pressure is highest when cold starting a 20w50 oil. That shoots up to 60-80 psi immediately and drops as the oil warms up. Of course if you were measuring at the head during this same period, it would be 0 psi because the molasses hadn't moved that far yet and it won't get there for a while.

Lowest oil pressure is fully warmed up oil measured at idle, which generally runs at 2-4 psi which is nothing for pressure and is why we want folks to run a 1,000 rpm idle speed to get it up into the 5-7 psi range.

Can't answer your question about alternator output, but somebody else can.

Title: Re: Oil pressure and alternator ratings
Post by verslagen1 on 03/18/13 at 08:39:03

I know you can run two stock headlights, but not three.

yup, 5ish when cold, up to 50/60 at full speed.

Title: Re: Oil pressure and alternator ratings
Post by Dave on 03/18/13 at 08:51:31

Not sure the alternator output has ever been pinned down.

Here is a link where it was discussed previously:
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1292092970

Title: Re: Oil pressure and alternator ratings
Post by justin_o_guy2 on 03/18/13 at 08:59:23

Ive seen diesel engines idle, COLD, at 3 to 5 PSI.. goose them up & watch the oil pressure bounce on up toward 30 maybe 40. How those things didnt make the noises metal things make when they stick to each other & grind to a halt, I do not know. It would seem to me that 3 PSI isnt enough to keep an oil film between rod cap & crank in an engine that compressing diesel hard enough to detonate,

Title: Re: Oil pressure and alternator ratings
Post by thumperclone on 03/18/13 at 09:16:35

oil pressure specs
above 7.1 psi
below 10.7 psi
@ 3000 rpm,140 F

only generator spec in sevice man
14.0 - 15.5 dc @ 5000 rpm read @ battery terms

no load spec yellow wires(any 2) at generator
more than 100v ac @ 5000 rpm

Title: Re: Oil pressure and alternator ratings
Post by Charon on 03/18/13 at 18:41:43

Oil pressure as supplied by the oil pump does not maintain the oil film in the bearings. In fact, oil is usually supplied to the UNLOADED side of the bearing, not the side under load. Hydrodynamic forces pull the oil into the bearing as the moving shaft "drags" oil into the bearing clearance. All the oil pump has to do is make sure there is enough oil available.

Prior to the advent of the Timken roller bearings used in rail car axles, they used the top half of a bearing. The weight of the car rested on the top of the pillow block, the bottom of which was a half-circle resting on the axle. There was no bottom half of the bearing, as the weight always rested on top. The axle box was filled with enough lubricant to touch the bottom of the axle. As soon as the car moved, lubricant was carried by the axle into the clearance, and it then supported the weight of the car. No pumps at all. Very reliable, as long as there was enough oil.

Title: Re: Oil pressure and alternator ratings
Post by justin_o_guy2 on 03/18/13 at 21:25:45

One,, I did not KNOW thayut!
Two.. Its gonna take a while for it to sink IN!

I mean, I can understand putting the oil into the bearings in the "gap" when theres no pressure between the parts, but to think that it would deliver enough to hold up the kind of load, but, then theres the RR car thing.,,,This is an amazing bit of info & one Im very happy to have. Thank you, very much.

Title: Re: Oil pressure and alternator ratings
Post by mpescatori on 03/19/13 at 00:47:14

OK, thanks.

I understand my oil gauge will have to read 0 - 80psi.
I plan to use a mechanical gauge, which I prefer (old school) to the "electric sender" type.

I also plan to fit an oil temp gauge, but that's another story.

As for oil pressure, my diesel truck (which is powered by an industrial-design TD engine, 3000cc 4-pot, 110 hp at 2800rpm) reads 7 bar starting cold, and 1.5 bar idling hot.
That's 100 psi (!!!) and 20psi, respectively.
Yet, NEVER EVER had issues with oil seeping through the gaskets (until last week :-X but, again, that's another story, the truck's now 7 years old...)

As for the alternator, I see... nobody really knows.
"14.0 - 15.5 dc @ 5000 rpm read @ battery terminals" gives me a voltage reading, but until I have the AMPS coming out of that alternator, all I know is the battery's being charged.

However, assuming "all is on":
- 60W high beam
- 20W stop light
- 5W rear running light
- 20W two indicators (hey, I can only blink on one side at a time! ;) )
- 5W two dash indicators (for high beam and blinkers)
____________
110 W required, PLUS whatever is required from the coil... 10W? = 120W.
Give another 15% margin for safety (nobody would ever dream of running any appiance at 100% peak output, ever) = 20W
and I have an estimated 140W = 10 Amps DC.

I'll work from that.

- 35 W HID headlamp
- 5 W LED stop light
- 1 W LED rear running light
- 10 W two indicators
- 1 W LED dash indicators (new speedo with LED indicators ;) )
______________
52-55 W overall... :) half of my initial 110 requirement.

Allows for another 50-55 W available for foglights etc.

Title: Re: Oil pressure and alternator ratings
Post by wambr on 03/19/13 at 01:59:34

Maurizio, if you decided to install instead of the regular lamps, ledlights, then you need to think of the better cooling regulator rectifier because it will have more heat...
and even our (Russian) guys measured the parameters of the generator and work: the max. power of generator=350 watts.

Title: Re: Oil pressure and alternator ratings
Post by ToesNose on 03/19/13 at 04:07:29

@Wambr- Is your English getting better or are you drinking less vodka?! :D

@Mpescatori- Too bad your not state side, I have both a mini 1 1/2" analog oil pressure and temp gauge :-?

Title: Re: Oil pressure and alternator ratings
Post by wambr on 03/19/13 at 11:10:10

7C474D5B66475B4D280 wrote:

@Wambr- Is your English getting better or are you drinking less vodka?! :D

yeah! more vodka-better english! :D
but I can't drink more...iak! :D
p.s. I'm falling under the table..