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metallicats33

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High oil psi on BBC
« on: June 27, 2012, 07:50:07 PM »
Not too sure if I have a problem here. The electrical gauge always pegged at 80(max reading) i figured it was defective. I hooked up a mechanical gauge today and watched them both. 70psi at idle when cold on the mechanical and 80psi on the electric one. I let the engine warm up a bit, probably about 5 min of idle and watched the mechanical gauge. It was reading 65 at idle but the needle was shaking quite a bit. Reved the engine up and the psi reached 90psi by the time I was at 5000 RPM. I was doing all of this on the trailer and did not want to run it too long because the dominator pump is water lubricated. I probably ran the engine a total of 7 minutes I know it will probabley drop down with more time to warm up but does 90psi sound right at 5000 RPM?

Stock 454
10w30 oil
7 minutes of run time
Water temp @130*
Oil filter not swolen or leaking
« Last Edit: June 27, 2012, 08:13:27 PM by metallicats33 »
  • Boat #1: 1978 Challenger
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GT Jets

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Re: High oil psi on BBC
« Reply #1 on: June 27, 2012, 08:42:57 PM »
Could just be a tight engine..

There is really not anything wrong with having that much pressure with cold oil.

There are times when you will need to be careful to make sure you get the oil up to temperature before you romp on it....

The problem with that much pressure on a 454 is the load it puts on the pump.  This is going to sound odd, but hang in there for a second... :sly:

The Chevy engines 283-400 small block and the 396-502 big blocks have a distributor driven oil pump, the distributor is driven by the camshaft. That being said, the camshaft is being pulled rearward with a large load on it, this causes the cam gear to wear on the thrust of the front cam hole on the block. this is just a splash oiled surface and survives from sling from the timing gear and spray from the front cam bearing. What we do on our engines is to drill a very small hole in the oil galley going to the cam bearing in the thrust for the cam and run a hardened thrust washer. This prevents excessive cam walk among other issues that could wear things out too fast.

You oil pump, depending on what it is, has a pressure relief built into it that typically relives at 90 PSI, the problem this can cause is a foaming situation, so keep an  eye on the oil temps, foamy oil WILL NOT cool off properly, it just keeps getting hotter and hotter until it is so light and watery that it will begin to push oil out every vent available....


In all honesty, I don't think I would have a problem running it as is, but I would rather see the pressures in the mid 60's...Where are you taking the pressure readings at?

GT
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
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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

metallicats33

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Re: High oil psi on BBC
« Reply #2 on: June 27, 2012, 09:08:15 PM »
Thanks for the reply GT. I asked my father if the oil pump was stock or not but he's not sure. He said it was replaced when the engine was rebuilt, he assumes it was replaced with a stock one... The mechanical gauge was hooked up right next to the electrical one, I've included a photo of the plug i removed to install the gauge. I also changed the oil filter and cut the old one open. I didn't see anything that I haven't seen in older engines before. When I removed the gauge the oil that came out felt hot to the toutch but not burning hot so i know it could go down a bit more if I ran it some. Pressure did get down to 65 at idle,  but right up to 90 when reving. It's just a bit alarming because my 460 and 455 never saw more than 60-70 cold and never hit 90 when idling up in the morning... but those were in cars
« Last Edit: June 27, 2012, 09:12:04 PM by metallicats33 »
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Nixonnow

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Re: High oil psi on BBC
« Reply #3 on: June 27, 2012, 09:22:02 PM »
What size thread is that plug? And where did you get the gauge? My oil pressure pegs the gauge on the dash. Also I'm running valvoline 20/50 so maybe I should switch to a lighter oil. I don't know. I just figured its better than having no oil pressure. What say you GT?
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GT Jets

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Re: High oil psi on BBC
« Reply #4 on: June 27, 2012, 10:13:34 PM »
What size thread is that plug? And where did you get the gauge? My oil pressure pegs the gauge on the dash. Also I'm running valvoline 20/50 so maybe I should switch to a lighter oil. I don't know. I just figured its better than having no oil pressure. What say you GT?


Without touch taste smell and feel it's hard to say..... I don't really see anything wrong with the 20w-50 as long as the temperatures and clearances will support it.

I guess that is a convoluted way of saying not enough info. ;D

GT
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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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

Nixonnow

  • Karma: +4/-0
Re: High oil psi on BBC
« Reply #5 on: June 27, 2012, 10:23:37 PM »

Without touch taste smell and feel it's hard to say..... I don't really see anything wrong with the 20w-50 as long as the temperatures and clearances will support it.

I guess that is a convoluted way of saying not enough info. ;D

GT

Lol my bad. I should know better. My gauge in the dash maxes out at 80# and when I first start the boat it shoots right up to 80 and pegs the gauge. Only goes down to about 65-70# at idle after 5000 rpm runs. It's a 454. Holds 7 quarts of valvoline vr1 20/50. Remote mount single filter. Unfortunately I don't know the clearances or anything about the internals. Bought the motor used out of another guys jetboat that cracked the hull do he was parting it out. Previous owner said he ran 20/50 in it so I thought it would be best to use the same stuff. I guess I should stick to the old saying "if it ain't broke don't fix it" lol.
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GT Jets

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Re: High oil psi on BBC
« Reply #6 on: June 27, 2012, 10:32:56 PM »
Lol my bad. I should know better. My gauge in the dash maxes out at 80# and when I first start the boat it shoots right up to 80 and pegs the gauge. Only goes down to about 65-70# at idle after 5000 rpm runs. It's a 454. Holds 7 quarts of valvoline vr1 20/50. Remote mount single filter. Unfortunately I don't know the clearances or anything about the internals. Bought the motor used out of another guys jetboat that cracked the hull do he was parting it out. Previous owner said he ran 20/50 in it so I thought it would be best to use the same stuff. I guess I should stick to the old saying "if it ain't broke don't fix it" lol.


Personally if the oil gets stupid hot, I would leave it alone, but if it stays under about 240*F I would drop it to 10w-30 VR1, but I have found it to be difficult to find...I am an Amsoil guy, sooooo... ::)

Totally agree on the "if it aint broke"...   Except my mantra is "If it an't broke, break it"... :sly:

GT
  • Boat #1: 1992 Carrera 20.5 Elite (I/O bitches)
  • Boat #2: 19' Bubble deck Jet BBC Berkeley
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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

metallicats33

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Re: High oil psi on BBC
« Reply #7 on: June 27, 2012, 10:44:22 PM »
What size thread is that plug? And where did you get the gauge? My oil pressure pegs the gauge on the dash. Also I'm running valvoline 20/50 so maybe I should switch to a lighter oil. I don't know. I just figured its better than having no oil pressure. What say you GT?

Borrowed the guage from a guy at work, brand is U.S. general. I believe thats a Horbor Freight brand. Came with three NPT adapters, I used the 3/8 adapter. I guess to get a better reading I need to leave it hooked up while cruising the lake and a nice hot engine.
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Nixonnow

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Re: High oil psi on BBC
« Reply #8 on: June 28, 2012, 06:30:41 PM »
Borrowed the guage from a guy at work, brand is U.S. general. I believe thats a Horbor Freight brand. Came with three NPT adapters, I used the 3/8 adapter. I guess to get a better reading I need to leave it hooked up while cruising the lake and a nice hot engine.

Thanks man.
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metallicats33

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Re: High oil psi on BBC
« Reply #9 on: July 10, 2012, 10:11:16 PM »
Got a nice good run in today with a mechanical gauge hooked up. After the engine was nice and hot oil was 35psi at idle and 60psi cruising. The electrical gauge was all over the place but mostly pegged at 80psi. I'm going to try a new sending unit and see if that fixes it.
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