Some cause happiness wherever they go
... others whenever they go. -Oscar Wilde

Today's Birthdays
alserpa62, CHRISTIAN, JeffL, Solodrumer
Featured Chat Guy (or Gal)
Registered: 07/19/12
Posts: 74
VCCA Member Photos
Getting ready for the 4th of July Parade
Interesting Delivery
32' Oldsmobile Dovetail Receptacle
32 Special Bracket ID
Chevrolet Trim Plate
Pilot Bushing Removal Tool artile
VCCA Member Projects
Search for 1927 trucks
57th installment - '28 engine tear down
56th installment - '28 engine tear down
55th installment - '28 engine tear down
54th installment - '28 engine tear down
Topic Options
Rate This Topic
#389604 - 05/22/17 02:14 PM Oil Pressure Concerns
Papa_T Offline
Shade Tree Mechanic

Registered: 08/27/13
Posts: 37
Loc: Kent, England
Hello All,
I've been experiencing a drop in oil pressure - particularly after a run at highway speeds. The engine is a '54 235 with hydraulic lifters on its third 10/40 oil change since I fully rebuilt it 12 month ago. Under normal driving conditions where the engine is unstressed the oil pressure gauge easily reaches 30+psi and idles at 12psi. After a short 60-70mph run however, where things get a little hotter, the pressure drops to 20psi when I settle down to a 45-50mph cruise and reaches no more than 7-8psi at idle. It will then only reach 25-30psi when I nail it.
So, my simple question is under these conditions should my Powerglide spec 235 oil pressure be higher than this or is this normal?
Thanks in advance for any guidance I may receive.
_________________________
Learn today, teach tomorrow...

Top
The Filling Station 1949-54
#389605 - 05/22/17 02:32 PM Re: Oil Pressure Concerns [Re: Papa_T]
Junkyard Dog Offline




Registered: 11/23/01
Posts: 28070
Loc: Eagle Point, Oregon
My 1951 Chevrolet with a 216 has about the same oil pressure as you describe. However, with a 235 full oil pressure system your oil pressure should be more. When the engine was rebuilt 12 months ago, was a new oil pump installed or did they reinstall the used oil pump?

laugh wink beer2
_________________________
The Mangy Old Mutt

"If It's Not Junk.....It's Not Treasure!"

Top
#389607 - 05/22/17 03:03 PM Re: Oil Pressure Concerns [Re: Junkyard Dog]
Papa_T Offline
Shade Tree Mechanic

Registered: 08/27/13
Posts: 37
Loc: Kent, England
Thanks for the response Junkyard Dog. Thing is, unlike the 216 the '54 235 Powerglide spec engine has a full pressure oil feed system so shouldn't it be making more pressure?
_________________________
Learn today, teach tomorrow...

Top
#389608 - 05/22/17 03:14 PM Re: Oil Pressure Concerns [Re: Papa_T]
Chev Nut Offline




Registered: 01/08/02
Posts: 24286
Loc: West Allis,Wi.
With the full pressure oiling in a 1953 PG and all 1954's your oil pressure should be around 40 pounds at 50 MPH with hot 10W-30 oil. Idle would be about 15 pounds.
I would suspect a problem with the oil pump or the pump relief valve.


Edited by Chev Nut (05/22/17 03:15 PM)
_________________________
Chevgene

Top
#389611 - 05/22/17 03:24 PM Re: Oil Pressure Concerns [Re: Chev Nut]
Papa_T Offline
Shade Tree Mechanic

Registered: 08/27/13
Posts: 37
Loc: Kent, England
Gotcha. Pressure relief valve spring too weak perhaps?
_________________________
Learn today, teach tomorrow...

Top
#389615 - 05/22/17 03:58 PM Re: Oil Pressure Concerns [Re: Papa_T]
Chev Nut Offline




Registered: 01/08/02
Posts: 24286
Loc: West Allis,Wi.
Or valve sticking.
What is the history of the oil pump?
_________________________
Chevgene

Top
#389622 - 05/22/17 04:28 PM Re: Oil Pressure Concerns [Re: Chev Nut]
Papa_T Offline
Shade Tree Mechanic

Registered: 08/27/13
Posts: 37
Loc: Kent, England
Fully rebuilt with a new spring and the valve and bore were both in good shape. I'm going to take it out tomorrow however and see what's going on.
_________________________
Learn today, teach tomorrow...

Top
#389635 - 05/22/17 07:53 PM Re: Oil Pressure Concerns [Re: Papa_T]
Chev Nut Offline




Registered: 01/08/02
Posts: 24286
Loc: West Allis,Wi.
The cover gasket on the oil pump must be of the correct thickness. A new gasket should measure about .009". If too thick pressure will be low.
_________________________
Chevgene

Top
#389678 - 05/23/17 01:01 PM Re: Oil Pressure Concerns [Re: Chev Nut]
Papa_T Offline
Shade Tree Mechanic

Registered: 08/27/13
Posts: 37
Loc: Kent, England
Today's news - I checked the pump over and all seemed well. I didn't peel off the new felpro cover gasket to measure it, replacement stovebolt parts are not easy to come by in the UK. However, I did perform an experiment; suspecting a weak spring I milled up a 3/8in shim and slid it into the relief valve piston to pre-load the spring. This has made no difference whatsoever. Please correct me if I'm barking up the wrong tree here (not for the first time...) but my best guess is that the pump has been rebuilt previously with too weak a spring (a lot of mend and make-do goes on over here). This could be making the valve cave in at the slightest hint of pressure irrespective of any pre-load I might throw at it.
Given I have a 600+ mile journey to make in a few weeks I'm going to have a new one shipped over. Anybody know where I can get hold of one?
Thanks, T


Edited by Papa_T (05/23/17 01:26 PM)
_________________________
Learn today, teach tomorrow...

Top
#389691 - 05/23/17 02:50 PM Re: Oil Pressure Concerns [Re: Papa_T]
Chev Nut Offline




Registered: 01/08/02
Posts: 24286
Loc: West Allis,Wi.
I would recommend replacing the pump. New pumps are available from www.fillingstation.com...their #RW-715 for $99.50 in my 2014 catalog.
The pump fits only 1953 Power Glides and all 1954 engines.
_________________________
Chevgene

Top
#389692 - 05/23/17 02:55 PM Re: Oil Pressure Concerns [Re: Chev Nut]
Papa_T Offline
Shade Tree Mechanic

Registered: 08/27/13
Posts: 37
Loc: Kent, England
My futile search for a spring has led me to the same conclusion. Thanks your your help.
T
_________________________
Learn today, teach tomorrow...

Top
#389736 - 05/24/17 01:21 PM Re: Oil Pressure Concerns [Re: Papa_T]
blue38 Offline

pumpjockey

Registered: 12/31/10
Posts: 753
Loc: phoenix......az
National Chevy in Minneapolis Minn. Specialize in early 50s Chevrolet.. Great help in my rebuilding my 54 wagon
_________________________
Old cars have always owned me.

Top
#389743 - 05/24/17 04:04 PM Re: Oil Pressure Concerns [Re: Papa_T]
m006840 Online



Registered: 11/30/02
Posts: 4390
Loc: merrimack nh
The spring shows in my parts book to be 1-3/16" long. Might be good to measure yours to verify that is the problem.
_________________________
Steve D

Top
#389745 - 05/24/17 05:02 PM Re: Oil Pressure Concerns [Re: m006840]
Chev Nut Offline




Registered: 01/08/02
Posts: 24286
Loc: West Allis,Wi.
For the work involved I would replace the pump and cover all bases.
_________________________
Chevgene

Top
#392372 - 07/17/17 10:35 AM Re: Oil Pressure Concerns [Re: Chev Nut]
Rusty 37 Master Offline
Backyard Mechanic

Registered: 12/29/07
Posts: 332
Loc: Iowa
I concur that there is a problem in the pump.

Regardless of the spring in the relief valve you should have observed a pressure increase when you shimmed it if the pump was working correctly. The fact that there was no pressure increase indicates that the pump is bypassing oil internally and cannot build more pressure. In effect it is its own "relief" valve.

There are 3 areas where oil will bypass.
1) Between the gear teeth.
2) Between the OD of the gears and the bores in the pump housing.
3) Between the upper and lower faces of the gears and the housing and end plate. The end plate is the area where oil bypasses when the gasket is too thick. This often happens when someone grabs the nearest sheet of gasket material and makes that gasket as a make shift. Gene's advice about that gasket is right on target as always.
_________________________
Rusty

VCCA #44680

Top


Moderator:  brewster, brownie 
Your Status
Please login to post or reply.* * *
Send My Password
Who's Online
16 Chat Members (Steelin_Time, 63novaandy, chevytech3238, Sky1928, 36chev4DR, wesb, Dave39MD, 31chevyjg, m006840, HCB, jiaccino, johndee138, AntiqueMechanic, Bill Barker, nhinchas, terrill), 26 Lookie Loo's and 24 Spiders or Bots online.
Key: Admin, Global Mod, Mod
We speak Chevy!
Time Flys!
Since 12/16/2001
Previous Photos
Newest Chat Registration
RonB, pjsloan, LarryR, Mikecrownover, Cleary
14760 Registered Users
VCCA Info Links
NEWBIES START HERE
CHAT HELP
* * *
Send My Password
* * *
Kill My Chat Cookies
* * *
VCCA Home
G&D Calendar
Judging
Club Regions
Join Info
* * * *
Forum Stats
14760 Chat Users
77 Forums
48995 Topics
358472 Posts

Max Online: 304 @ 06/18/16 03:00 AM
See the USA
In your
Dinah says Hi!!

 

Notice: Any comments posted herein do not necessarily reflect the official position of the VCCA.