Cortina GT MK1 motor in Lotus 7 - strange oil pressure

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Mon 11 Feb 2019 22:02
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - lotus7series123

Does anyone have experience with early Cortina 1500 GT? Everything is very new and clean but my oil pressure is very low ( 0 to 5 psi) for the first 30-60 seconds on restart after sitting a few days. New high pressure pump acts same as old standard one but now 60 psi & still running strong after pressure is up. Pump feeds remote HP-1 filter then routed to oil cooler and back through -8 tubing. 20W50 at 20 C temperature may move slowly at first getting to pressure sender at front of motor? Or can oil drain away from pump and lack of priming be the fault?

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Mon 11 Feb 2019 22:28
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - elekie&a/c doctor

Where are you taking the oil pressure reading from? Also ,are you using an electric gauge or a mechanical capillary type? Perhaps you should ask the question here;www.burtonpower.com/tuning-guides/tuning-guide-pag...l

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Mon 11 Feb 2019 22:40
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - bathtub tom

Could the oil filter be draining back into the sump?

I had a similar problem with a 'B' series engine when the oil filter housing was changed from a pendant filter to a standing filter. The aftermarket filter manufacturers were initially unaware of the change and were still listing filters without a non-return valve as being suitable.

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Tue 12 Feb 2019 08:38
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - RT

Lack of anti-drain valve in filter housing, as above - oil cooler flow is normally using the bypass, not the main flow - 20W50 oil is very viscous when cold

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Tue 12 Feb 2019 10:29
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - gordonbennet

If we assume a restart after a shorter period standing but still cold engine gives decent oil pressure within seconds, then its stands to reason that oil is draining back, it also begs the question whether this new pump is able to prime itself within a reasonably short period, 30/60 seconds sounds a long time even for an intial start up after rebuild.

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Tue 12 Feb 2019 14:20
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - jc2

On a lot of these "high pressure" pumps,there is no difference to standard pump-just a stronger spring or even a standard spring with a washer behind it in the pressure relief valve.If you can find a vane pump rather than a rotor pump,the flow is better at high rpm.

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Tue 12 Feb 2019 17:16
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - lotus7series123

many thanks for inputs. pump which functions great at high rpm once pressure gets up, is exactly like earlier one but changed spring. HP-1 filter is remote with about 20 cm of AN- 8 tube running to it and would need to fight gravity to drain. Maybe the connection where the oil pick up pipe meets the underside of the block came just slightly loose and air can get in thus allowing any oil in the pipe to slowly drain back down into sump? Any chance someone sells new or used oil pick up ? Early 1500 GT has a nut and an "olive" apparently but Ford changed that I think on later models. We are a bit short on Cortina stuff here in USA. Burton seems to

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Tue 12 Feb 2019 17:18
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - lotus7series123

sorry-meant to say Burton does not have old style oil pick up

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Thu 14 Feb 2019 23:56
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - Big John

I remember the pre crossflow engine (which the 1500 is) and in MK I Cortina the 1500 was a 5 main bearing crank ( the 1200 was 3 bearing).

I was more familiar with the pre crossflow fitted to the mk II Cortina. The new 1300 was now a 5 bearing crank but the 1500 remained the same. Later in 67 the famous crossflow was introduced including the 1300 & 1600 (as per formula Ford)

From what I remember (er it has been a while) the 1500 pre crossflow had an external oil pump with canister oil filter where the whole thing was attached to the engine block. An oilway then made its way down to an oil pickup pipe. If there is a leak anywhere between pump intake or oil pickup then oil could drain back to the sump after a period of time.

The original oil filter was vertically(ish) mounted that should hold oil overnight.

Are ther any physical modifications from the original design to consider? Worried about :- "HP-1 filter is remote with about 20 cm of AN- 8 tube running to it and would need to fight gravity to drain" - Simple syphon issue? this can defeat gravity!

Edited by Big John on 15/02/2019 at 00:02

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Fri 15 Feb 2019 17:07
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - jc2

All the small Ford engines from the earliest 105E(1959) to the last HCS(2003) had external oil pumps.The early ones had a changeable cartridge filter-the later a spin-on-all the pumps were inter-changeable-early and late pumps were rotor-there were a few vane type pumps-never heard of any concerns on either type.As already said,they had roughly vertical filters which would not drain.I am suprised that a 1500 GT would need external filter and cooler unless you're running "dry sump"but is obviously draining down whilst standing-which way up is the filter and where is the cooler in relation to the engine?

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Fri 15 Feb 2019 17:16
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - jc2

If you're in the States,the Pinto was fitted with a 1600 Kent at one time.

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Mon 18 Feb 2019 17:45
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - lotus7series123

Again- many thanks for info. The oil pressure indication is from the right side very near the front by a non-electric tube. I am pretty sure it is correct since it matches the reading on the mechanical gauge fitted to the accu-sump as noted after the engine has been run a while. My 1500 is set up similar to the old "Super 7" Cosworth types raced in the USA from 1960s onward. It has twin DCOE40s and 10.2 compression. The earlier pump was a standard type so 40 psi and the new one with stronger spring gives 60 but only after that initial lag I mentioned. I hesitate to pull the pan since things are pretty cramped in the old series 1 chassis as I have it. So I might try "priming" the pump by using a pre-oiling set up flowing backward to the pump outlet from the remote filter adapter which has 2 inlet ports and 2 outlet ports. This is different from the accu-sump which feeds the oil return in the pump. I have used the accu-sump to pre-oil the motor since it is in the line just prior to where the oil coming from the cooler goes back into the pump return port on the pump adapter. If it matters, I have opened the accu-sump to pre-oil the motor prior to starting and it does register pressure to the front of the motor but diminishes pretty fast as oil enters the motor and does not seem to help the pressure build delay.

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Tue 19 Feb 2019 14:43
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - skidpan

In my first Caterham I changed to a remote filter when I dry sumped the engine. The pressure take off was on the filter housing and I could never get a reliable reading with a previosuly reliable electrical gauge. Changed to a mechanical gauge and all was reading fine with no more issues. Since you have a mechanical gauge reading off the block you do not have this issue.

But I note that you have an Accusump and these are known to give issues with readings.

The only other issue I had was after an engine rebuild. Filled with the usual 10w40 and all was perfect and after 100 miles dropped it out as I normally do to flush out the engine. Could not get 10w40 at the stockist thus used 20w50 and there was little oil pressure at start up but it did increase over about a 2 minute period. I was told by the engine builder that the issue was probably the oil grade so I drained 1/2 the 20/50 out and refilled with 5w30 (making approx 10w40) and all was fine, perfect pressure and used 10w40 until I sold the car.

The 20w50 oil was simply too thick for a classic engine rebuilt with modern clearances to cope with when cold.

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Tue 19 Feb 2019 16:05
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - lotus7series123

That certainly sounds like the issue I have and more so since there is quite a length of tubing from the pump to the very large Fram HP-1 remote filter (gasket up) then to the oil cooler up front, back past the T connection with the accu-sump, then back into the pump/adapter and through the block to the gauge up front. By the way, I tried start up with the accu-sump valve off and also on and made no difference in the time to build full pressure. Although the accu-sump was used to pre-oil the motor and then shut off to start or left open- made no difference as the 2 quart accu-sump pressure dissipates pretty fast. But it is a nice feeling to see at least some pressure on the gauge prior to a cold start. I will definitely follow your advice if it ever warms up here in Philadelphia.

So again thanks to all for great advice.

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Tue 19 Feb 2019 19:13
Cortina GT MK1 motor in Lotus 7 - strange oil pressure - jc2

Did have a concern on one of my engines where on the first cold start with fresh oil(20W/50 in summer-10W/30 in winter)the pressure relief valve would stick open for several seconds and allow the oil to return to the sump.I usually left the sender switch on the front position and the pressure gauge connected from by the engine mount.

Edited by jc2 on 19/02/2019 at 19:17

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