Oil pressure

[jondhm]

Went out for a long fast run on the motorway in my GT6, and after 50 miles at 70mph the oil pressure was sagging a bit.

 

At 60mph (3,000 rpm) I was getting 60psi, and at 50mph (2,500rpm) 50psi, but at 750rpm I only get about 18psi.  Bear in mind that this was with the engine and oil at full operating temperature on a warm day, with the water temperature gauge running at slightly above normal.

 

My Haynes Manual gives a 'normal oil pressure', whatever that means, of 40 to 60 psi at 2,000rpm.

 

So what do people think?  Are the oil pressure readings OK?

 

Other information - Halfords 20/50 oil, Club spin-on oil filter conversion.  Engine has done approx. 110,000 miles, a lot of which has been long fast runs.

 

All opinions gratefully received.

[KevinR]

Assuming your oil pressure gauge is reasonably accurate, your oil pressure is fine.

 

The pressure can drop because of a worn out pump, or bearings that are starting to fail.

 

You can hear when the bearings are starting to fail when you start the engine - you get the heavy knocking noise whilst the oil pressure builds up.

[Pete Lewis]

the spec in haynes manual is as triumph specifiy  

the 40-60 at 2000rpm is the std across the triumph range for 4 and 6 cyl engines 

 

yours sounds fine,  oil does make a vast difference, I used a lo cost 20/50 from a factors and it lost pressure at   modest temperatures

using stuff like millers pistoneze or valvoline vr1 with good z's 

  might be twice the price but there is no drop off in pressure with  arduous use .

 

Pete

[thescrapman]

As mentioned those figures are fine.

 

I would tend to shy away from Halfords 20/50 now, especially if doing long fast journies. Try Millers Classic Sport 20/50 (about £30 a gallon) or Valvoline VR1 (About £25 a gallon if purchased from Euro Car Parts during a sale day. Can get as low as £20 a gallon on "Special" sale days)

 

The Millers maintained 60psi in my Spitfire whilst enduring an 11 hour journy in 40 degree heat. I didn't manage quite as well! 

[jondhm]

Thanks for all your comments. So that's a job removed from the list. Really helpful to have these views.

 

On the subject of oils, I would agree with using a better oil if doing lots of long fast runs. But I don't do many runs like this, and prefer to use a cheaper oil (Halfords Classic is £20 a gallon) which I can buy locally without incurring postal charges, and change it more frequently. Historically I have used Castrol, but Halfords oil looks and smells like Duckhams.

 

Halfords recommend on their website that the oil is changed every 2000 to 3000 miles. With many of our cars only doing a small mileage, this means every 2 to 3 years which is quite long enough for an oil.

[Pete Lewis]

dont forget club shop sell oil 

 

Pete

[Unkel Kunkel]

Cheap oil ...I remember an  elderly relative who , as an  engineer reponsible for a large fleet  of heavy lorries,prided himself on the lack of engine failures  and used to tell  all who would listen how he insisted  on more frequent oil changes  than were  specified and how he used   the best quality oil,... "Oil's cheaper than engines,thou knows, lad"......

[PJM Stag]

I would change the oil at least annually, normally before laying up for the winter so its not sitting in the sump with all the products of combustion.

[Henry Boler]

I've been flitting between Halfords oil in that old green tin and some cheap stuff from my local factors. I've never had a problem with it that I'm aware of...

 

I'm interested on the lots of fast runs bit though... I do a lot of miles in my car, my other half lives in Manchester and I live in The New Forest, that's about a 500 mile round trip every time I visit!

 

My oil pressure is fine, but does that mean the oil is doing a good enough job or should I look at changing it to something more expensive?

 

Henry

[Guest]

Henry.

 

I have used and do use Millers oil for years, not just on a range of classics but also a modern 4x4 - all my cars work hard for their garage space !!

 

Millers is a quality product and it's protection properties are second to none.  

 

As PL states it is also high in ZZZZZ's which is very beneficial for classic car engines. 

 

At the Stoneleigh show a chap was selling Millers 20/50 Classic mineral @ £22 which is a very good price.

 

If you look at Ebay item 171316809653 it is being sold at a shade under £25 including delivery !! I've just looked and there are 6x left at this price.

 

Halfords oil is a million miles (no - light years away from Millers oil). I think Halfords charge about £20, so for an extra £5 you will have an oil that Halfords and other motor factors can only dream of and most certainly cannot match.

 

No matter how wonderful or what magic engineering a person does to their engine - it will only ever be as successful as the oil used.

 

Hope that helps ??

 

Regards.

 

Richard.

[Clive]

I would be looking at the valvoline VR1. It isn't much difference in price...

If you can find it cheap enough the Millers CSS 20-60 is superb, and I expect the 20-50 just as good, and on a regularly used car (that is a very good thing!) the extra £5-10 can be money well spent, especially that it will last rather better if you are doing more than 5000miles a year (and I hope many people are)

[mishmosh]

Morris oils are excellent too. There was 25 litres for £60 at stonleigh !

[Henry Boler]

Richard - There are now only 4 left! Thanks for mentioning that! I thought I'd get some and give it a try as the old beast is due an oil change soon.

 

Henry

[Clive]

Just be aware that is a different animal to the CSS stuff. I reckon for a well used car the css is worth the extra.

 

Luckily, I got mine at stoneleigh a couple of years ago at £19 a tub. I bought all they had left. 1 box of 4.

I see it sells for about twice that now, but on my fast road 1500 engine on track at goodwood, it maintained nearly 60psi. VR1 had managed just under 50, and another 20/50 it had dropped to zero losing me a crankshaft...... That is the difference between oils!

If a car is just pottered about in for show use, anything will be fine probably, but don't come crying if it causes an issue. For a car that is driven as intended, get the best you can. 

[Henry Boler]

It's all interesting stuff! I'm just intrigued to see if it makes a noticeable difference to mine. I'll do anything to make the engine last, it's great and I don't want it blowing up!

 

Henry

[Guest]

Henry.

 

Have to say I grabbed another 5L which has helped bring it down to 4 !! 

 

As Vanadium23 pointed out, frequent oil change is a crucial key. On the classics (mineral oil) I change every 3K or yearly, which ever comes first. With the modern diesel (semi-synthetic), I change every 4K even though the manufacturer states no requirement until 12K. 

 

I probably imagine it, but I'm sure the cars run smoother after the oil change.  

 

Regards.

 

Richard.

[docwad]

my old gt6 ran low pressures due to some wear often 20-30 pi  cruising ,  an oil cooler with thermostat brought it upto  50 psi

[Colin Lindsay]

Cheap oil ...I remember an  elderly relative who , as an  engineer reponsible for a large fleet  of heavy lorries,prided himself on the lack of engine failures  and used to tell  all who would listen how he insisted  on more frequent oil changes  than were  specified and how he used   the best quality oil,... "Oil's cheaper than engines,thou knows, lad"......

I’m a great believer in changing the oil regularly whether the car is used a lot or not. Tescos sell Castrol GTX for £6 per 2 litres - a claimed price of half their usual RRP - so for around £12 plus the price of a filter I get a year’s clean oil around the engine. Check yours the next time you dip the oil and ask yourself if you really want that black gritty stuff floating around the insides of your engine...

As Richard says, you can tell the engine is running more quietly after a change and good oil has been used.

[AidanT]

Can I ask a Quick question on this  - What's the difference between Mineral / Synthetic and Semi Synthetic?  I assume the CSS above means Classic Semi-Synthetic?  and which is the best for a car not used on a daily basis?

 

Thx

[Clive]

Best? there are some superb oils about, but some are not exactly cheap or even reasonably priced. 

Synthetics are man made, therefore not as random as mineral oil. And tend to last rather better (especially the ester based oils, mobil one being a good example)

For a car that does a few thousand miles a year, and not driven hard, a decent oil will be fine. Dare I suggest most 20/50 oils that have a proper specification (sf or whatever) For a better oil valvoline VR1 and better still millers css 20/60, or penrite? After that you will be paying upwards of £50 a gallon, fine for racing etc, but not required by the vast majority.

[Mike Lester]

I'm using cheap comma or halfords oil at the moment.

 

... mostly because it comes out as fast as I put it in   . Engine is being rebuilt this winter.

[jondhm]

Interesting to see how this thread I started is still of interest.

A couple of points - with our old engines one of the key things is viscosity.  You need to stick to a 20/50, and many modern oils are a lot thinner  And better to use a straight mineral oil and change it reasonably often, unless of course you are doing a lot of very high speed runs in hot weather.

[Clive]

I agree on the 50 bit, but not the 20.

 

ie a 10/50 oil will be better in our cars than a 20/50. I guess in the 1960's they just about managed to get a 20/50, but these days 10/60 are available (probably even better in our cars)

 

And yes, there is a world of difference in what is needed between a car that never gets revved about 3000rpm (seem to be a few on those) and others that get shown absolutely no mercy and are thrashed on a regular basis.,