416 ls3 oil pressure dropping as oil heats up
#1
416 ls3 oil pressure dropping as oil heats up
416 ls3. New pump when built. Oil pressure has dropped. at start up is 40 psi. But as oil warms up it drops down to 10 psi. . oil temp is 190 cause car is just ideling but pressure does raise with rpm when blip throttle. opsu, bearing, pimp or oring....would like to hear what you guys think. As this has just happened after few thousand miles.
Also i changed the oil i running 10w40 .... the pump is melling high volume with high pressure spring the red one I think.
Also i changed the oil i running 10w40 .... the pump is melling high volume with high pressure spring the red one I think.
Last edited by EXCESSIVE81; 08-19-2010 at 05:47 PM.
#2
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416 ls3. New pump when built. Oil pressure at start up is 40 psi. But as oil warms up it drops down to 10 psi. does raise with rpm when blip throttle. From my research I think It it is probably the pick up tube o-ring but would like to hear what you guys think. As this has just happened after few thousand miles.
Also I running 10w40 .... the pump had two springs.... which Iput the higher one red I think in It. Pump is ported aftermarket.
Also I running 10w40 .... the pump had two springs.... which Iput the higher one red I think in It. Pump is ported aftermarket.
My Ls2 403, with a Melling Does 45 psi at idle hot and 55-60 psi at 2000-2500 For comparison.
#4
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What are your bearing clearances set at, particularly the mains?
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#8
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And its not a stock oil pump, Its a Melling HV
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10 psi sounds awfully low. My 250 mile old iron 408 idles with about 55psi hot. On a cold start, it damn near pegs the factory gauge at 80psi. I'm running 10W-30and my oil pump is a Melling high volume with the high pressure spring in. Granted my block and bearings are set up differently than your aluminum, 10psi is def not enough. Last time I saw 10psi on my gauge was the end of my 346 LS1 to a rod bearing.
#11
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10 psi sounds awfully low. My 250 mile old iron 408 idles with about 55psi hot. On a cold start, it damn near pegs the factory gauge at 80psi. I'm running 10W-30and my oil pump is a Melling high volume with the high pressure spring in. Granted my block and bearings are set up differently than your aluminum, 10psi is def not enough. Last time I saw 10psi on my gauge was the end of my 346 LS1 to a rod bearing.
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I know about too high of oil pressure. Builder said it may lose a little after break in when everything gets seated. Not gonna worry about it till after break in and when I get a gauge on it thats more accurate. I'll take my 55psi at idle on my new engine all day over the op's 10psi on his new engine. Call it high if you want... I'm really not worried about losing power to oil pressure in the least bit. To me, its just reassurance that everything is working properly.
#13
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I know about too high of oil pressure. Builder said it may lose a little after break in when everything gets seated. Not gonna worry about it till after break in and when I get a gauge on it thats more accurate. I'll take my 55psi at idle on my new engine all day over the op's 10psi on his new engine. Call it high if you want... I'm really not worried about losing power to oil pressure in the least bit. To me, its just reassurance that everything is working properly.
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It really depends on bearing clearance and what weight of oil. If your main bearing clearance is .00028 to .00030 (iron block) and oil is 20w-50w and your pressure is 60 psi at idle and over 80 psi at WOT does not always tend to help bearing spin. This is my setup for about 4 years and many others and still running strong.
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I hear what you're saying. I'll put a different gauge on it after I get another 1000 miles or so and see what its reading. I have read that the high volume/high pressure spring combination will produce a little more pressure than say a ported LS6 pump, but I don't trust the factor gauge at all. It more so gives you an idea what your pressure is.
#16
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It really depends on bearing clearance and what weight of oil. If your main bearing clearance is .00028 to .00030 (iron block) and oil is 20w-50w and your pressure is 60 psi at idle and over 80 psi at WOT does not always tend to help bearing spin. This is my setup for about 4 years and many others and still running strong.
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I'd be interested to see what your exact clearances are!
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#18
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Just wondering, if you checked your oil sending unit, I cracked mine and gave me the same reading as your did. Are you having a noisy valve train when the oil gets hot ?(no oil reaching the rockers). Or like above your having clearance issues. Just thinking of any reason for the low oil pressure.
#19
no have not checked the sending unit. and there is zero changes when oil pressure drops. no noise no nothing. i noticed it when the hud not said check gauges and dic said low oil pressure (c6 corvette).... so i limped it back to my shop to diagnose since when at higher rpm i had pressure over 15 psi. if it the sending unit that sure would make my day. hate to have to completly tear the car apart...AGIAN lol. but in my experience when they go bad oill gauge is pegged all the time..... in fact my bonneville is doing that now after my blower install.
as far as the clearances go. i had pics but i cant find them from the build.... but they where right on callie specs. i know because i personaly checked them with calipers and bore gauge as well as plasti gauge during assembly.... i keep looking for pics to confirm. also this has just happened. i have been driving it almost two years with zero issue granted very low miles
as far as the clearances go. i had pics but i cant find them from the build.... but they where right on callie specs. i know because i personaly checked them with calipers and bore gauge as well as plasti gauge during assembly.... i keep looking for pics to confirm. also this has just happened. i have been driving it almost two years with zero issue granted very low miles
Last edited by EXCESSIVE81; 08-19-2010 at 05:50 PM.
#20
think it time to start looking into building mechanical pressure gauge like i have on fuel rail for double checking oil pressure. there is plenty of room on the oil bulkhead above the filter. i just cut off the oil cooler lines and tapped it for an fittings during my flip drive install so i know there room ....
Last edited by EXCESSIVE81; 08-19-2010 at 05:56 PM.