Oil Pressure too high
- VanIsleSprint
- Guest contributor
- Posts: 167
- Joined: Tue Aug 18, 2009 6:28 am
- Location: Nanaimo Vancouver Island BC Canada
Oil Pressure too high
I am currently building a Sprint powered TR7 for a fellow club member here on Vancouver Island.
When I started the engine for the firs time today, the oil pressure went up to 100psi on the live
line gauge. I have oil coming out of the bottom of the bell housing. I wonder if the oil pressure
has blown out or unsealed the plug at the back of the engine that covers the jack shaft.
Doug
When I started the engine for the firs time today, the oil pressure went up to 100psi on the live
line gauge. I have oil coming out of the bottom of the bell housing. I wonder if the oil pressure
has blown out or unsealed the plug at the back of the engine that covers the jack shaft.
Doug
DOUG
1980 Dolomite Sprint lhd
1980 Dolomite Sprint lhd
Re: Oil Pressure too high
If this is a new oil pump made by "County" then you need to change the pressure relief valve spring. The ones supplied with the pump are far too strong - this has been an issue for quite a few years now and I can't understand why it hasn't been sorted. Many suppliers list the correct spring separately or use the spring from the old pump.
As to whether the excessive pressure has blown any seals I can't say.
As to whether the excessive pressure has blown any seals I can't say.
1975 Sprint Man O/D in Honeysuckle Yellow
1971 Stag Auto White
Too many cars, too little time!
1971 Stag Auto White
Too many cars, too little time!
- Mad Mart
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- Location: Winscombe, North Somerset, England
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Re: Oil Pressure too high
I agree with marshman. Replace the spring and see if it is still leaking oil.
Sprintless for the first time in 35+ years.
... Still Sprintless.
Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S


Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S

Re: Oil Pressure too high
When it leaks now it will not stop when the pressure is lower with a different spring.
Seals aren't oil pressure pressurized. It can be the rearplug dislocated but that would be strange because the oil can flow on the other side of the journal free into the sump.
Jeroen
Seals aren't oil pressure pressurized. It can be the rearplug dislocated but that would be strange because the oil can flow on the other side of the journal free into the sump.
Jeroen
Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com
- Mad Mart
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Re: Oil Pressure too high
True but it's worth a go before removing the engine again.

Sprintless for the first time in 35+ years.
... Still Sprintless.
Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S


Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S

Re: Oil Pressure too high
The other thing with oil pressure too high is excessive loading on the oil pump gears causing the jackshaft to wear the end plate. Can also cause problems with the timing chain tensioner.
Russ Cooper
Dursley
UK
Dursley
UK
- VanIsleSprint
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- Posts: 167
- Joined: Tue Aug 18, 2009 6:28 am
- Location: Nanaimo Vancouver Island BC Canada
Re: Oil Pressure too high
Jeroen, you are right. New oil pump with 55psi when cold, still leaking oil from bottom of bell housing.
guess it's engine and gearbox out again!
Doug
guess it's engine and gearbox out again!
Doug
DOUG
1980 Dolomite Sprint lhd
1980 Dolomite Sprint lhd
- VanIsleSprint
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- Location: Nanaimo Vancouver Island BC Canada
Re: Oil Pressure too high
The oil leak was caused by the machine shop. When they cross drilled the back journal,
drill came through to the back off the boss where the pilot bushing fits. I have, at their
suggestion, fitted a core plug with sealer to stop the oil from coming out. I was expecting
the threaded plug or the plug behind the jackshaft to be the cause.
Doug
drill came through to the back off the boss where the pilot bushing fits. I have, at their
suggestion, fitted a core plug with sealer to stop the oil from coming out. I was expecting
the threaded plug or the plug behind the jackshaft to be the cause.
Doug
DOUG
1980 Dolomite Sprint lhd
1980 Dolomite Sprint lhd
Re: Oil Pressure too high
I understand that they suggested such a repair but it's a bodge I think. A proper plug pressed in the hole would be better. Are you sure you wan't to use the crankshaft in you engine?VanIsleSprint wrote: ↑Fri May 06, 2022 5:44 am The oil leak was caused by the machine shop. When they cross drilled the back journal,
drill came through to the back off the boss where the pilot bushing fits. I have, at their
suggestion, fitted a core plug with sealer to stop the oil from coming out. I was expecting
the threaded plug or the plug behind the jackshaft to be the cause.
Doug
A machineshop making these mistakes and suggesting such repairs isn't very promising. Crankshafts can break by wrong drilling or wrong journal grinding..
Jeroen
Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com