Orange Indy
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 posted on 5/6/07 at 07:47 PM |
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Low Oil Pressure
I have a serious worry about low oil pressure on the pinto in my MK Indy. When the engine gets properly hot (like at a track session a Donnington
last night) the oil pressure is dropping to around 1 bar. In warm weather it can even get to this sitting at 4000rpm on the road. However with
slower driving and cooler weather the pressure holds up well above 2 bar.
I am using Duckams 20/50, the engine is a well modified 2.1 kicking out around 175bhp, I do not have an oil temp gauge, so I can't tell what
kind of temp I am running, but the engine temp does not stray above 100.
It is all very worrying as the engine was only re-built about a year ago and I cant afford another disaster!
Anybody any ideas??
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nitram38
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| posted on 5/6/07 at 07:50 PM |
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Have you fitted a competition oil pump and an oil cooler?
If not, you are asking too much of the engine.
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flak monkey
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| posted on 5/6/07 at 07:55 PM |
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I think an oil cooler is a bit extreme in this application, and more bling than use in my opinion anyway, but I would suggest a high pressure and high
capacity oil pump for sure. Available from burtons and ebay. I have one fitted to my modified pinto.
David
Sera
http://www.motosera.com
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Orange Indy
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| posted on 5/6/07 at 08:15 PM |
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High pressure oil pump fitted when the engine was re-built, also I dont think I am suffering with surge, I have a modified sump with some baffles.
Colud I be getting some foaming of the oil?
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nitram38
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| posted on 5/6/07 at 08:28 PM |
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It sounds like oil temp is the problem.
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david walker
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| posted on 5/6/07 at 08:51 PM |
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An oil cooler will reduce oil pressure in itself but would (marginally) cool your oil which in itself would thicken it up and increase pressure.
High pressure / high capacity pumps aren't really necessary, they can be a "sticking plaster" to cover up other problems. Not many
wet sump competition Pintos use them.
I wouldn't want to see engine temp above 90. Is the rad up to the job? Is the ignition timing correct? Is the mixture correct?
Could be a combination of things. If the engine wasn't spotlessly clean when rebuilt the main bearings could have a problem (they are what in
effect establish oil pressure) or the pump could be worn.
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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Andy S
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| posted on 5/6/07 at 09:27 PM |
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Whats the cold pressure?
Has the pressure changed recently?
Mechanical or electrical gauge?
Are you certain of the accuracy of the gauge?
Cheers
Andrew
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Orange Indy
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| posted on 5/6/07 at 09:46 PM |
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The cold pressure is 4-5 bar. The situation is a bit worse than previous but the last time it had proper use was on a track day in the winter. Not
sure about the gauge but the cold pressure reading is I think about right? It is a Racetec electrical gauge.
Anyone any views on the 'right' oil to use in a reasonably tuned pinto?
Thanks
James
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britishtrident
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| posted on 5/6/07 at 10:03 PM |
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Drop the sump stick a new set of big end shells in, clean the oil pump suction strainer.
Fit an oil cooler (with thermostat).
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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DarrenW
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| posted on 6/6/07 at 10:27 AM |
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Ref oil - most people recommend a decent 20W-50. My local factors didnt have any (only a very cheap and crap bare oil) so i went for Valvoline turboV
15W 50 (£13 for 5l). i could have got Valvoline Racing 20W 50 (£25 for 5l) but dont believe my use or state of tune demands such an oil
Cold i get around 70 psi, hot it only drops to 60 ish. This is all just normal road running. Being spiritted i get a corresponding rise in
pressure.
Ref temps, coolant runs between 93 and 98 typically (controlled by fan), but will rise to around 105 ish on track. Oil temps follow a similar pattern
but of course temp reading is also dependant on location of the senders. i use my tepms mainly as a onparitor between std road use and track to gauge
if a problem is occuring.
iirc 1 bar is around 14.5psi
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NS Dev
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| posted on 6/6/07 at 03:38 PM |
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Britishtrident and Darren are right, as was said, put a new set of big end shells in, its an easy job and costs little.
14 psi (1 bar) is not uncommon with a hot engine that is a bit tired, but its not great either if its got expensive bits in it then changing the
shells makes sense.
An uprated pump is NOT necessary either, the std pinto one has MASSES of capacity and is quite up to the job as long as the strainer is clear and the
casing is not worn.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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david walker
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| posted on 6/6/07 at 05:39 PM |
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Main bearing wear has a far greater impact on oil pressure than big ends
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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DarrenW
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| posted on 7/6/07 at 08:29 AM |
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Orange Indy,
Not sure if you know Dave but id defo listen to him. He has masses of experience building race engines.
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DarrenW
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| posted on 7/6/07 at 01:46 PM |
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Just been out for a spirrited jaunt and took more notice. Gauge was showing high 60's / low 70's all the time. Datalogger recorded max of
85psi. I have seen over 90 recorded after a track day.
Water temp peaked at 99 deg, oil temp at 103 deg (as said before temps can be subject to sender location and gauge etc so take with pinch of salt).
ETB DD2
Oil pressure gauge is in std location. Water temp again in std location. Oil temp sender is in one of the oil gallery plugs. All senders came with
dash.
[Edited on 7/6/07 by DarrenW]
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Orange Indy
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| posted on 7/6/07 at 08:24 PM |
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Thanks very much guys that is really useful advice, sounds like a few jobs need doing, - new shells, change of oil type, maybe I should fit an oil
temp gauge and possibly an oil cooler as well!?
Best get down to the garage and get that sump off!
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rusty nuts
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| posted on 7/6/07 at 08:38 PM |
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Was a bit concerned about the oil pressure on my recently rebuilt crossflow after a good run , fitted an oil cooler with thermostat last night, now
after a good run the oil pressure is approx 10 PSI higher than it was before and the coolant temperature is about 10 degrees cooler at 80 degrees.
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