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stugilmour

PUK Oil Thermostat Installation

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Has anyone installed a PUK oil thermostat in a V8? The unit I bought is the second one down on this page. It is different than the sandwich plate type used on the four cylinder.

http://www.freudhoefer.de/lotus/esprit/products/oil_thermostat/index.htm

The supplied hoses look overly long to comfortably fit and attach to the hoses running to the front of the car. Pulling the long hoses forward might work but looks very awkward. Thinking of getting shorter hoses made up, but still looks like a strange fit. 

Wondering if anyone else has installed one of these? Are we missing something?

 

Stu


Stu Calgary Alberta ' 69 Plus 2 '0 0 Esprit V8

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The amount of heat that the 918 puts into the oil, I really would not see the purpose of this item.


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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You may be right Mike.

At any rate we got it installed. Does assist with warm up time particularly with heavy weight oil, which is what I was hoping for. 

I live at about 4300 feet next to the Canadian Rockys. Overnight temperatures are very cool, even in August. Wanted to run heavy multi grade oil for track use, but was concerned with lack of lubrication during warm up, particularly on a cool morning.

What would you consider typical oil temp and pressure for the V8?  I installed an oil temperature, pressure, and boost gauges for this season.  Don't have a feel for what would be typical readings  I see max boost of about 15 psi, oil pressure of about 20 psi when warm at idle, and oil temps of 70 degrees but going up to 90 or 100 degrees when jumping on the power  

Stu


Stu Calgary Alberta ' 69 Plus 2 '0 0 Esprit V8

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I now understand your reasoning behind the oil thermostat. The joys of colder climates.

- max. boost is 0.75 bar (~ 11psi) - if you are seeing a genuine 1 bar boost, you may have some over-boost issues. Which ECU calibration do you have?

- oil pressure (hot)     idle - 1.4 bar (~ 20psi)   3500 rpm - 2.4 bar (~35psi)   6500 rpm - 3.1 bar (~51psi)

your oil temperatures are nice and low (probably directly related to the low air temps). The 918 does put a lot of heat into the oil, so you would expect to see a fairly dramatic rise when pressing on or during a track session.


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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Thanks for that Mike. Those readings (except for boost) are what I am seeing.  A bit concerned with the potential over boost; believe the previous owner mentioned something was changed in the regard but not sure of details.  This was before change to Hi-Torque flash; assume the car had the stock MY 2000 NA flash when I bought the car.

I have the North American spec Hi-Torque reflash performed by Lotus USA about two years ago.

I also have a spare ECU (in for service right now). Have not settled on the flash it will get, but believe the tech is using a North American version of the Red Race flash. The ECU was equipped with a chip holder and after market chip when I bought it. It is presently not behaving correctly, and unfortunately never worked reliably in my car before being sent for service and repair. 

Original motivation for looking at the cooling systems was repeated overheat warnings during track sessions. This was indicated by flashing a coolant light with moderate coolant system temps on the dash gauge, which has been checked against an icing thermometer and the ECU readings.  I also got a similar high oil temp warning on a trip up Pikes Peak at our Lotus Meet last August; the warning only occurred at the very peak at a staggering 14,000 ft elevation!  Track Day was cut short at Pikes Peak International at a more moderate ~6,000 ft elevation and I think 5-40 oil; same issue with oil temp.

I then added the gauges, PUK oil thermostat, 10-60 oil. We also fixed a very small but persistent external head gasket leak (right front, was dripping on the alternator and evaporating off; believed to have caused two alternator bearing failures). Turbo's were removed and serviced during the head gasket replacements. 

Oil cooling appears to be working fine, no leaks  

Coolant system still not working correctly.  Pretty much at my wits end.  

Repeated air bleeding and testing, and I appear to be pressurizing somehow and blowing coolant out. New radiator pack, fans, overflow bottle, thermostat, pressure caps and gaskets, hose clips, etc.  

As soon as weather improves here I am dong yet another system pressure test, this time with shift gator removed to see if any leakage in the tunnel tubes; friend of mine on the other forum just found this issue on his car so going to check mine.  

Also going to do another check for combustion gas in coolant; previous tests came back OK with no combustion gas, but we will see this time.  

I have no indication of oil / coolant crossover, but have not sent oil for analysis.  

With the car cold I can rev the engine with a plastic bag over the rad cap, and the bag will collapse when revved and slightly pressure up when the engine is brought back to idle.  I put this down to the slight change in coolant level as the engine is revved. 

My biggest fear is I have an issue with the liners, or another head gasket issue.  I am not sure if liner failure would present as rapid cooling system pressurization?

Any suggestions welcome.  Sorry for length.  It has been a journey.  Love the car but need to resolve this issue.

Stu

 


Stu Calgary Alberta ' 69 Plus 2 '0 0 Esprit V8

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On the ECU calibration.  There is no difference in the max. boost setting with the 'Race ECU'. It is the same as the Hi-Torque with 0.75 bar.

The only differences in terms of boost are the limits applied in the lower gears in the lower gears.

I hope that you do not have a head gasket related problem, but pressuring of the coolant system would be one likely symptom :-(

Liner failure would not result in pressurisation of the coolant system, but apparent lose of coolant (in this case into the sump).

 

V8_ECU_Boost_Race.jpg

V8_ECU_Boost_S350.jpg

V8_ECU_Boost_Standard.jpg

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1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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