455 oil pressure question

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Nobody077

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« on: October 06, 2013, 11:06:13 PM »
Had a few questions for the 455 owners on there oil pressure readings.  New to the owner side of the boating world and have read a lot about oil issues with the olds 455. So I now own a Anthony 21 ft day cruiser with a believed stock 455 other than a elderbrock intake and a Jacuzzi YJ pump. Boat ran good , I put all new digital gauges and senders in boat before taking it out (gauges were striped by previous owner) so they should read good. Had 45 Psi cold idle, around 18 hot idle, Cruising around 3000 rpm I was running 28 Psi and on a few runs at 4000rpm it would rise to 35-38 and slowly start to drop, I backed down at around 25psi to 3000 rpm and it would slowly raise back to 28ish.  What are others seeing for oil pressure, I normally figured 10 psi per 1000rpm.  Is the oil drop I am seeing the normal olds issue of oil on the top-end? I have what looks like a 10qt pan, not sure how much oil is in the pan if the dip stick is correct but it was in the normal marks, PO had done oil change before I got it and it was clean so left it in for first run
.   I plan to pull the motor soon to inspect the oil pump and see if there are any restrictors, or baffles and measure the dip stick and just figure if im stock or not. 
I have read a few people recommend running less oil to avoid foaming, could the slow drop be a sign of foam? and what would the recommended fill be for a 10qt.
I also figure if the motor is out I will add the external oil return lines from valve covers to pan and open the stock passages up some, any other low cost mods to look into?
What oil weight would you recommend? Found a receipt for some 10-40wt in boat so that may be whats in it now. I did add some zinc to the oil before taking it out

Thanks
  • Boat #1: 1976 Anthony 21 Day Cruiser


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renegade

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« Reply #1 on: October 07, 2013, 10:20:12 PM »
 My olds runs 60 psi cruzzing and 40 psi idleing. 10 seasons on motor with high volume mellings oil pump. if your gauges are working write that seems to low of oil press. i would check mains and rod bearing clearence on the bottom of the crank. you asked..........
  • Boat #1: 1976 renegade
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GT Jets

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« Reply #2 on: October 07, 2013, 10:40:10 PM »
Had a few questions for the 455 owners on there oil pressure readings.  New to the owner side of the boating world and have read a lot about oil issues with the olds 455. So I now own a Anthony 21 ft day cruiser with a believed stock 455 other than a elderbrock intake and a Jacuzzi YJ pump. Boat ran good , I put all new digital gauges and senders in boat before taking it out (gauges were striped by previous owner) so they should read good. Had 45 Psi cold idle, around 18 hot idle, Cruising around 3000 rpm I was running 28 Psi and on a few runs at 4000rpm it would rise to 35-38 and slowly start to drop, I backed down at around 25psi to 3000 rpm and it would slowly raise back to 28ish.  What are others seeing for oil pressure, I normally figured 10 psi per 1000rpm.  Is the oil drop I am seeing the normal olds issue of oil on the top-end? I have what looks like a 10qt pan, not sure how much oil is in the pan if the dip stick is correct but it was in the normal marks, PO had done oil change before I got it and it was clean so left it in for first run
.   I plan to pull the motor soon to inspect the oil pump and see if there are any restrictors, or baffles and measure the dip stick and just figure if im stock or not. 
I have read a few people recommend running less oil to avoid foaming, could the slow drop be a sign of foam? and what would the recommended fill be for a 10qt.
I also figure if the motor is out I will add the external oil return lines from valve covers to pan and open the stock passages up some, any other low cost mods to look into?
What oil weight would you recommend? Found a receipt for some 10-40wt in boat so that may be whats in it now. I did add some zinc to the oil before taking it out

Thanks

Your oil pressures don't worry me too terribly much.

I probably have said this fifty times before on here, but you simply cannot run the oil level to the OEM dipstick with an aftermarket pan.

It sounds like a foaming issue, however, without knowing the oil temperature at the time of the issue you were seeing, it is just a WAG.

An infrared thermometer works well for this purpose.

In all honest I would dump the suspected 10w-40 in favor of a fixed weight or narrow multi vis oil. If you truly do have an oversize pan and an OEM stick, run it to the bottom of the stick.

I would look for some straight 40 racing oil or bump up to a 20w50..

10psi for every 1000rpm is a good starting point. Wouldn't mind seeing 15 though.

Just as a stupid fyi that few think about, a rapid rise in oil temp indicates some serious foaming. I like to see oil temps in the low 200 degrees. But I'm wierd that way.

GT





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« Last Edit: October 08, 2013, 12:49:15 PM by GT Jets »
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
If i get some free time tonight at work, ill play with it and post it for everyone to see.

Time to man up and yank it John!  :banghead:
Ray

Nobody077

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« Reply #3 on: October 08, 2013, 10:18:32 AM »
Thanks guys, gives me some things to check when I pull the motor. I did go take a peak and the pan is a Hardin 10 qt has part of old tag on side won't know if its baffled till I pull it. So not sure if dip stick is stock length or not, will just check when I refill after change and scribe new mark around 9 quarts if needed.  I may add oil temp gauge just to keep an eye on it.  The motor could just be tired, not sure of its history or run hours on build may be the original, guy I got it from said he pulled stock intake to put on the edelbrok that's on it now. Starting to look for a Craigslist motor to build for when the time comes is starting to sound like a nice winter project
  • Boat #1: 1976 Anthony 21 Day Cruiser

 


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