305 sbc with low oil pressure??? Help - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 10-11-2002, 01:52 PM
New Member
 
Join Date: Oct 2002
Location: Pittsburgh, PA
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post 305 sbc with low oil pressure??? Help

Hey everyone, this is my first time posting anything on this site! It seems I am in a little bit of a problem. My '91 Oldsmobile Custom Cruiser has over 176000 miles on it and still rund fairly good. However, whenever the car has warmed up, and I am not moving (Stop light), my oil pressure will drop to zero and the needle on the gauge will be kinda wiggling and the light will be flickering. Kinda like i'm getting some pressure, but not enough. Once I put on the gas, the oil pressure goes back to "normal", but will drop again the next time it is stopped. What the heck is going on with my car?
Thanks, Carmen

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 10-11-2002, 02:18 PM
New Member
 
Join Date: Sep 2002
Location: pa
Posts: 19
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

you kinda might want to stop driving her any more than you have to.do you have a gauge and a light? check to see if you got a leak where your switch or gauges hook into the block sometimes it will leak around there and will cause that.if that aint it your oil pump/bottom end are shot. was the engine ever rebuilt? somebody might have not put the oil pump pickup in right or they didnt tork the oil pump down right.(60ft.lbs.) i hope its the a leak where i talked about.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 10-11-2002, 03:49 PM
helrazr3's Avatar
im on a highway to hell
 

Last journal entry: new wheels and seats
Last photo:
Join Date: Mar 2002
Location: billerica, mass
Age: 49
Posts: 689
Wiki Edits: 0

Thanks: 1
Thanked 1 Time in 1 Post
Cool

Welcome to the board.
Unfortunatly it sounds like your oil pump is about to give up the ghost! at 176000 mi. it's probably a tired motor did you change the oil? try going to a thicker oil, try a 20/50 see if that makes a difference. is there a lot of sludge in the oil return holes? theese are a few basic things to check. its really not to exspensive to change the pump you have to drop the oil pan.

i hope this helps you good luck.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 10-11-2002, 06:12 PM
E.T. divided by $ spent= Speed
 
Last photo:
Join Date: May 2002
Location: NYS america's unwiped butt
Age: 35
Posts: 1,858
Wiki Edits: 0

Thanks: 0
Thanked 5 Times in 5 Posts
Post

I had a pickup fall outr of the pump once.Replacing an oil pump in the car is a pain in the ***.Personally I would keep the oil changed often put a bottle of Lucus oil in and start looking for a low milage motor to replace it with.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 10-11-2002, 07:37 PM
New Member
 
Join Date: Oct 2002
Location: Pittsburgh, PA
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

Hey guys, thanks for the help. I will look into what you said! I know the car has a lot of miles, but I love it! I would love to find a low mileage replacement for the motor, but unfortunately, I am only 17 and don't have that kind of money. I'd love to get a motor and rip it apart and rebuild it, but that's just kind of a dream. I'll check what you guys said and let you know what happens.
Thanks, Carmen
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 10-11-2002, 07:40 PM
New Member
 
Join Date: Oct 2002
Location: Pittsburgh, PA
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

Oh, and another thing, It's been doing this for way more than a year and the car still runs pretty good. It went through many oil changes since this started and it was never fixed. I put an additive in the oil that kinda makes it thicker, but it still drops pressure when its at idle (warm).
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 10-11-2002, 08:04 PM
E.T. divided by $ spent= Speed
 
Last photo:
Join Date: May 2002
Location: NYS america's unwiped butt
Age: 35
Posts: 1,858
Wiki Edits: 0

Thanks: 0
Thanked 5 Times in 5 Posts
Post

Maybe try droppin the pan and change the oil pump.Its a pain but if you really like the car and don't have the bucks for a motor.ou can get a Small Block chevy for like $350,$200 for 305 if you look.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 10-11-2002, 08:20 PM
New Member
 
Join Date: Oct 2002
Location: Pittsburgh, PA
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

A $200 engine? It sounds like that wouldn't be much better than what I have. Although, I could do some stuff to it before I put it in! I like the sound of that. (My goal is 300+ hp. Pretty unrealistic, huh?
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 10-11-2002, 08:28 PM
E.T. divided by $ spent= Speed
 
Last photo:
Join Date: May 2002
Location: NYS america's unwiped butt
Age: 35
Posts: 1,858
Wiki Edits: 0

Thanks: 0
Thanked 5 Times in 5 Posts
Post

300HP just get a stock 350 pop in a decent cam,dual plane intake,600Holley,headers.
As far as a $200 motor I'm not talkin shiny new virgin motor with 5yr warrenty.I'm talkin a higher milage stock motor that has better oil pressure than yours and will get you to work reliably with out a smokescreen.If you look hard enough you can find good strong 350s for under $500.
Your car is that a Cutlass model???Is it rear wheel???I'm not familiar with that model.Just wonderin.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 10-11-2002, 08:32 PM
New Member
 
Join Date: Oct 2002
Location: Pittsburgh, PA
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

Yeah, 300hp would be great! It's actually a B-Body (Caprice/Impala). My car looks exactly like a 91-96 Caprice/Roadmaster wagon, that's why I love it. A lot of potential with looks and performance. Right now, i'm just trying to get it to run correctly, then i'll mod. It definately rear wheel. It's stock 170hp and is probably down to 150 or less by now.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 10-12-2002, 02:15 AM
aka Duke of URL
 
Last wiki edit: Finding vacuum leaks Last photo:
Join Date: Oct 2001
Location: Rockville, MD
Posts: 4,821
Wiki Edits: 1

Thanks: 0
Thanked 0 Times in 0 Posts
Arrow

An -excerpt- from a Tech Article at Mellings.

[quote]When the pressure drops, we get our first signal that something is wrong in the engine. With the increased clearances/decreased resistance, the flow from the oil pump is at its maximum. This is like opening all the faucets in your house. Pressure is down, but flow is at a maximum. If we used a flow meter instead of a pressure gauge, we would see a gradual increase in flow as the bearing clearances increase with wear. But flow meters are more expensive and more bulky than oil pressure switches, making this method impractical.

A few comments about the relief valve in an oil pump. The spring pressure behind the valve determines when it will open. If it is designed to open at 60-psi, it does not have an effect on anything below 60-psi, unless it sticks open. If it does stick open, the pressure is low at idle, but builds up to 60-psi at the point the valve opens.

If an engine has excessive clearances in anything but rod bearings, the oil pressure will be uniformly low throughout the rpm range. If the rod bearings have excessive clearances, the oil pressure will be low at idle and will get worse as the rpm increases. Rod bearings turn in a circle rather than on an axis, so they are subject to centrifugal force trying to pull the oil out of the bearing. The amount of loss will vary depending on the actual clearances in every bearing and lifter bore.

This gives you an idea of how much flow increases with a small increase in clearances, and how pressure can drop when we exceed the flow available from the pump.<hr></blockquote>

[ October 12, 2002: Message edited by: KULTULZ ]</p>
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 10-12-2002, 06:00 PM
Marcel
 

Last journal entry: Choo-choo town
Last photo:
Join Date: Feb 2002
Location: adairsville ga.
Age: 71
Posts: 413
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Post

KUTULZ is right on target. my exp. is with bad cam bearing. i don't know olds, but sbc oil pressure with be low at idle on an engine which i call over hauled and called rebulit, which they didn't change the cam bearing will have the same problem you're having. sounds like bad bearing. look for a chevy with a bad body which runs good at a low price and roll up your slieves and dig in. elcome to the world of auto repairs. LOL
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 10-12-2002, 10:03 PM
4 Jaw Chuck's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Mar 2002
Location: Manitoba, Canada
Age: 46
Posts: 4,905
Wiki Edits: 0

Thanks: 0
Thanked 73 Times in 61 Posts
Post

Kultulz's quote is right on the money, rebuild time! Your engine has had better days and a spun rod bearing is in your future if you push that motor too hard. She's worn out, drive it normally or you could run into serious problems.

They don't last forever.
__________________
Outlawed tunes from outlawed pipes
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 10-13-2002, 05:10 PM
New Member
 
Join Date: Oct 2002
Location: Pittsburgh, PA
Posts: 14
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

well guys, it looks like i'm in the hunt for a new motor, or is mine worth rebuilding. If i'm going to either swap engines, or rebuild mine, I want the result to be 300hp to the rear wheels. You guys are probably wondering why I am willing to put so much into this car and the truth is, I can't answer that. I can't explain why I like it soo much, I just do. I think it's how big it is!

I dream more than my wallet can handle
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 10-13-2002, 05:21 PM
Harlequin's Avatar
Member
 
Join Date: May 2002
Location: Pittsburgh, PA
Posts: 47
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Post

We all have that problem <img src="graemlins/drool.gif" border="0" alt="[drool]" />
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 11:45 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.