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To cool or not to cool ?


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Debating the potential benefits of fitting an oil cooler to my 5

Oil pressure drops low when hot on tick over . No flickering oil light but the gauge reads only 10psi ish. 
needle moves up smartly as soon as revs increase and runs 30-50 psi on normal hot running , say 2-3k rpm. 

I realise a cooler will initially reduce the pressure but will I benefit overall for having cooler oil ? 
It had a new oil pump a few years ago. 
thanks , Dave 

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Dave

Best spend you hard earned money on fixing the reason for the low oil pressure rather then hiding it with somthing like an oil cooler. It maybe something as simple as the relief valve, but unfortunately it's most likely bearings and if you get them early you may get away with with just the shells.

George 

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Faced with a similar issue on my TR6 some years back, I fitted an oil cooler, made no difference. I changed the oil pump to one from Chris Wittor and all the bearing shells. This only improved hot idle oil pressure by 5psi. Based on recommendations on this forum I then switched to using Penrite 20W-60 oil, got another 10psi increase in hot, idle oil pressure. Good result, now happy. Thought about removing the oil cooler but was convinced by fellow members to leave it there for long distance, high speed motorway use on the continent.

Mick

Edited by Mick Forey
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15 minutes ago, Mick Forey said:

 I then switched to using Penrite 20W-60 oil, got another 10psi increase in hot, idle oil pressure. Good result, now happy. Thought about removing the oil cooler but was convinced by fellow members to leave it there for long distance, high speed motorway use on the continent.

Mick

+1 For Penrite 20W-60

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Oil cooler plus thermostat and you've got the best of both worlds, there when you need it, but not over cooling when you don't, had both on my old 2.5Pi saloon for years would always give 20psi on tickover and 75 at full chat, got one on my 4A .. same thing, secret to it all is regular oil changes .. Penrite good.

Cheers Rob  

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6 hours ago, Ian Vincent said:

It s a pretty simple job to drop the sump and check the clearance on the shells with plastigauge.. At least then you know if it's something major.

Rgds Ian

+1

I have shepherded many a 6 cyl Triumph 

Drop the sump and ‘do’ the big ends as a minimum 

While in there check/replace the crank thrusts and centre mains.( the front is an arse to replace due to the aluminium sealer block.)

Overhaul the pump.

renew oprv  spring, if you trust repro items.

 

I  always ran an oil cooler with spin on oil filter conversion on saloon/estate triumphs with great outcomes.(I swapped the same kit from car to car)

Edited by BlueTR3A-5EKT
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Thanks for the replies folks , 

After I bought the car (Oct 2020) I found posts on here from the previous owner. 
it seems the engine had suffered a broken main cap at some point and this was rectified by simply fitting a replacement along with a new set of main bearings. No line bore or crank grind (against advice ).  I’m ‘guessing’ that this main has worn and is responsible for the low oil pressure . The new cap was obviously a pretty good match though as the car has clocked up a good few thousand miles since then . 
I’m thinking that all but one of the mains should still be pretty good and if one is worn a replacement will v quickly be the same !  
To rectify the problem ( assuming this is the problem) is an engine out and full rebuild etc which I’d rather not get into if the oil pressure can be improved as is , at least until the winter months. 
is my reasoning sound ?  
D. 

Probably should look at the big end bearings though ! 

Edited by Trumpy
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American Jaguar XJ6 owners complained a lot about low hot oil pressure...after years of complaints Jaguar fixed this by replacing the sender unit with a special oil pressure switch... cars then sat at ~60psi all the time the engine was running.... problem fixed!   My point is that as long as you have 30+ psi under load, i wouldn't worry about idle fluctuations.  Spend your engine rebuild money on tyres & suspension parts & enjoy the car.

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I was in the same situation a while ago. Fitted an oil cooler as I knew I was going to add a supercharger in the future and thought the extra oil cooling would be helpful. I fitted the cooler without a thermostat and the idle oil pressure was more than adequate even after a day driving the autoroute. However I was probably overcooling the oil somewhat and perhaps not a good thing to do long term.

Once the supercharger was fitted and engine rebuilt I added the thermostat and all is good. you can "see" the thermostat open by a slight flicker of the oil pressure gauge. Normal summer running the thermostat opens and stays open showing the oil temp is >80oC. Winter temps and the stat switches in and out depending upon the driving conditions.

Cheers

Tim

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On 4/8/2022 at 12:11 PM, Trumpy said:

Thanks , all useful information. 
Wow , supercharged 6 . That must be quite a handful! 

Yes its fun :D

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