Ugh, more oil pressure woes, pressure is dropping at WOT now..
05-23-2006, 06:16 PM
#1
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Ugh, more oil pressure woes, pressure is dropping at WOT now..
I *thought* it held solid yesterday, but maybe I was wrong. I was watching the stock oil pressure gauge today and sure enough I have an oil pressure drop off at WOT. Oil pressure is as follows:
At idle, steady 40psi
Under mild acceleration it climbs to 60-70 (according to dash gauge)
At WOT it holds pressure then the gauge quickly drops to around 20psi... as soon as I let off the pressure comes right back up!
Here's my oiling system setup:
I've followed this through and through with reading problems others have had. I noticed the pump has a purple spring in it.
I did not adjust the windage tray in the Milodon at all, not sure if I was supposed to.. or if it even can be?
WHAT NOW...
I'm running 10W40 dino Valvoline, 7 quarts, including filter.
At idle, steady 40psi
Under mild acceleration it climbs to 60-70 (according to dash gauge)
At WOT it holds pressure then the gauge quickly drops to around 20psi... as soon as I let off the pressure comes right back up!
Here's my oiling system setup:
Fresh 355, built on the "loose" (bearings) side by engine builder, setup for spray use in the future.
Melling HV pump, Milodon 30909 stroker pan, Milodon pickup for the correct pan which has a brace that bolts onto the oil pump, the bolt was put in with loctite and properly tightened. Height was adjusteed using clay on the screen, with tape protecting the screen while we did this, due to the angle the closest point the pickup screen is 1/2", as it angles up furthest (towards the front) is 9/16" from the bottom of the pan. I've put in a Milodon baffle to keep oil from creeping up the back of the pan up the crank. Purolator L20049 filter.
Melling HV pump, Milodon 30909 stroker pan, Milodon pickup for the correct pan which has a brace that bolts onto the oil pump, the bolt was put in with loctite and properly tightened. Height was adjusteed using clay on the screen, with tape protecting the screen while we did this, due to the angle the closest point the pickup screen is 1/2", as it angles up furthest (towards the front) is 9/16" from the bottom of the pan. I've put in a Milodon baffle to keep oil from creeping up the back of the pan up the crank. Purolator L20049 filter.
I did not adjust the windage tray in the Milodon at all, not sure if I was supposed to.. or if it even can be?
WHAT NOW...
I'm running 10W40 dino Valvoline, 7 quarts, including filter.
05-23-2006, 06:34 PM
#3
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Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
Originally Posted by marshall93z
How many times have you heard NOT to run the high volume pump! 
Fresh 355, built on the "loose" (bearings) side by engine builder, setup for spray use in the future.
I purchased the motor new from a board member given the above information, per Bret as well this engine is recommended to have an HV pump, he knows the builder.
05-23-2006, 06:42 PM
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Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
Cool! I didn't notice that, OR the fact that you're running 7 quarts of oil! 
Josh, alot of people do it and it sucks their pan dry.
Josh, alot of people do it and it sucks their pan dry.
05-23-2006, 06:51 PM
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Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
Originally Posted by marshall93z
Josh, alot of people do it and it sucks their pan dry.
05-23-2006, 06:59 PM
#8
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Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
Originally Posted by Robs97Z28
did you make sure that you were about a 1/8" to 3/16" from the bottom of the pan?
Height was adjusteed using clay on the screen, with tape protecting the screen while we did this, due to the angle the closest point the pickup screen is 1/2", as it angles up furthest (towards the front) is 9/16" from the bottom of the pan.
I've now read to use 8 quarts of 15W50 in a few posts, and also read less oil in the system. It's a 7 quart pan..so that could be it i guess.
Maybe i just need to see if the builder will talk to me directly.
Last edited by Javier97Z28; 05-23-2006 at 07:06 PM.
05-23-2006, 09:10 PM
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Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
With that much oil I don't think this is the problem, but did you fill the oil pan to the recommended level, install it, then make a new mark on your dipstick for full?
If anything, it's probably the opposite, where the mark is lower (like on my Canton pan), but figured it's worth mentioning anyway.
If anything, it's probably the opposite, where the mark is lower (like on my Canton pan), but figured it's worth mentioning anyway.
05-23-2006, 09:15 PM
#10
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Location: Six Mile, SC, USA
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Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
verify this pressure with a manual gauge.
What filter are you using?
I had higher RPM oil pressure issues with my 355 rebuild and was using a certain brand filter and changed to a different one and it was fine.
Dont know why but it fixed the problem.
What filter are you using?
I had higher RPM oil pressure issues with my 355 rebuild and was using a certain brand filter and changed to a different one and it was fine.
Dont know why but it fixed the problem.
05-23-2006, 09:18 PM
#11
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Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
Same thing is happening with me. Everything I've read says the windage tray. I looked at my pictures as I was doing the install and I do have the windage tray in place. Would like to know what to do. My heads and intake are at Lloyd's right now.
05-23-2006, 09:45 PM
#12
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Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
Shon, what filter are you using now that cured the problem and before when you had one?
I'm running a Purolator 20049 w/ mine right now (not the pur-one, just the plain jane)
Jeff, the pan is a "7 quart pan" so I'm not sure if i should "just" have 7 quarts in there? or 8 to have 7 in the pan and 8 total in the system and filter.
Currently my dipstick w/ this pan is on the upper range of the "operating range" area with 7 quarts...
I'm running a Purolator 20049 w/ mine right now (not the pur-one, just the plain jane)
Jeff, the pan is a "7 quart pan" so I'm not sure if i should "just" have 7 quarts in there? or 8 to have 7 in the pan and 8 total in the system and filter.
Currently my dipstick w/ this pan is on the upper range of the "operating range" area with 7 quarts...
05-23-2006, 09:49 PM
#13
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Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
Originally Posted by Javier97Z28
Shon, what filter are you using now that cured the problem and before when you had one?
I was using a Texaco filter, buddy worked/owns the express lube so I took my car there to get out and about. The Texaco filters are made my Purolator (sp). and went back to an ACDelco filter.
Oddly enough, I have the Texaco brand on my 97 and didnt notice any OP drop in it. The 94 was 355 with a melling 55A pump. Labeled as the Z28 pump in jegs.
05-23-2006, 10:02 PM
#15
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Location: Brandon, Fla.
Posts: 387
Re: Ugh, more oil pressure woes, pressure is dropping at WOT now..
I'm not sure what the problem could be, but I don't think it's the Melling HV pump. On my 383, the Melling HV pump idles around 40 psi, and climbs steadily to just shy of 80 psi at WOT without dropping off ever. I have a Canton pan with the Canton pickup for the Melling pump and it's about 3/8" off the bottom of the pan. I use 6 qts in the system; fill the oil filter and put the balance in the pan.
