Delayed Oil Pressure On Startup

Technical advice Q&A

Topic author
Quelch
Posts: 6
Joined: Sun Nov 22, 2015 10:28 pm
Location: Halifax NS Canada
Canada

#1 Delayed Oil Pressure On Startup

Post by Quelch » Fri Sep 30, 2022 7:20 pm

I have just finished the restoration on my 1967 series 1 OTS. The engine was completely rebuilt with a new oil pump. However I have noticed that after the car has been standing for a few hours there is a delay on startup of about 3 seconds before the oil light goes out. I think this is a little too long? If I stop the engine and immediately restart the light will go out straight away.
I just like to get a little feedback on whether this is normal.

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

abowie
Posts: 4155
Joined: Wed Sep 07, 2011 9:15 pm
Location: Australia
Australia

#2 Re: Delayed Oil Pressure On Startup

Post by abowie » Fri Sep 30, 2022 11:20 pm

I don't have a light but I have 4 cars with XK engines. In all of them it takes 5 to 10 seconds before oil pressure comes up on the gauge.
Andrew.
881824, 1E21538. 889457. 1961 4.3l Mk2. 1975 XJS. 1979 MGB (supercharged).
Adelaide, Australia

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

DWW
Posts: 1204
Joined: Sat Mar 12, 2022 1:14 am
Great Britain

#3 Re: Delayed Oil Pressure On Startup

Post by DWW » Sat Oct 01, 2022 11:19 am

The gauges work on the basis of thermocouple and it takes time for the metal to heat up.
Danny

1962 S1 3.8 FHC (1012/1798)
2015 Range Rover Sport SVR
"Experience is something you don't get until just after you need it."

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

caveman
Posts: 711
Joined: Sun Nov 18, 2007 10:55 am
Great Britain

#4 Re: Delayed Oil Pressure On Startup

Post by caveman » Sat Oct 01, 2022 9:27 pm

I have a separate light to my gauge and when starting with 3/4 choke the light extinguishes pretty quickly and approx. 1-1.5 seconds after it fires.
Steve
1965 S1 4.2 FHC (early)
:wavegreatbritain:

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

Series1 Stu
Posts: 1809
Joined: Thu Feb 02, 2017 12:26 pm
Location: Shropshire
Great Britain

#5 Re: Delayed Oil Pressure On Startup

Post by Series1 Stu » Sat Oct 01, 2022 10:24 pm

DWW wrote: ↑
Sat Oct 01, 2022 11:19 am
The gauges work on the basis of thermocouple and it takes time for the metal to heat up.
I think you mean bimetal based, where the bimetal in the gauge deflects in proportion to the current supplied by the sender.

Thermocouples are an electrical junction of 2 dissimilar metals generally used to measure temperature.

It's a commonly made mistake so no big deal.

Regards
Stuart

If you can't make it work, make it complicated!

'62 FHC - Nearing completion
'69 Daimler 420 Sovereign
'93 Jaguar X300 XJR basket case
'93 Audi 80 quatrro Sport

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

DWW
Posts: 1204
Joined: Sat Mar 12, 2022 1:14 am
Great Britain

#6 Re: Delayed Oil Pressure On Startup

Post by DWW » Sun Oct 02, 2022 6:09 am

:yeahthat:
Danny

1962 S1 3.8 FHC (1012/1798)
2015 Range Rover Sport SVR
"Experience is something you don't get until just after you need it."

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

mgcjag
Moderator
Posts: 9239
Joined: Fri Jul 09, 2010 6:15 pm
Location: Ludlow Shropshire
Great Britain

#7 Re: Delayed Oil Pressure On Startup

Post by mgcjag » Sun Oct 02, 2022 9:37 am

Newly rebuilt engine.....what pressure is your pressure switch rated at....genuine part or after market....you need a mechanical oil pressure guage to see whats really going on....without one its just speculation..what your seeing isnt really abnormal as far as im aware.......Steve
Steve
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

caveman
Posts: 711
Joined: Sun Nov 18, 2007 10:55 am
Great Britain

#8 Re: Delayed Oil Pressure On Startup

Post by caveman » Mon Oct 03, 2022 4:12 pm

:yeahthat:
Steve
1965 S1 4.2 FHC (early)
:wavegreatbritain:

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

chrisfell
Posts: 1597
Joined: Tue Oct 06, 2009 9:52 am
Location: Salisbury
St Lucia

#9 Re: Delayed Oil Pressure On Startup

Post by chrisfell » Mon Oct 03, 2022 5:50 pm

Am I the only one asking “oil light? On a 67 4.2?” Mine doesn’t have an oil light.
Chris '67 S1 2+2

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

bitsobrits
Posts: 596
Joined: Tue Dec 27, 2011 2:09 am
Location: Omaha, NE area
United States of America

#10 Re: Delayed Oil Pressure On Startup

Post by bitsobrits » Tue Oct 04, 2022 2:50 am

Perhaps he's thinking the alternator light is for oil pressure?
Steve
'65 S1 4.2 FHC (early)

Link:
BBcode:
HTML:
Hide post links
Show post links

User avatar

mgcjag
Moderator
Posts: 9239
Joined: Fri Jul 09, 2010 6:15 pm
Location: Ludlow Shropshire
Great Britain

#11 Re: Delayed Oil Pressure On Startup

Post by mgcjag » Tue Oct 04, 2022 8:32 am

The poster is in Canada...a 67 registered car there could be a 66 build in UK....poster says he has an oil pressure lamp....he could even have an after market fitting...Steve
Steve
69 S2 2+2 (sold) ..Realm C type replica, 1960 xk150fhc

Link:
BBcode:
HTML:
Hide post links
Show post links

Post Reply Previous topicNext topic