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Post by djm16 on Sept 16, 2018 14:05:19 GMT
Disclaimers:
1) I am not recommending this to anyone else
2) this is not a 3.5l V8, but a 2.6 IOE6 with flat tappets (in a P4 90)
3) the engine is relatively recently rebuilt, and has closely fitting inlet AND exhaust valve guides.
I thought I would try out what I have read elsewhere that *some* nominally diesel engine oils might well be used in *some* petrol applications.
In particular a high ZDDP content is normal for diesel engine oils, and flat tappet engines really do need the extra zinc.
Instead of my usual 20W-60 Penrite "Full zinc" semi-synthetic that I have been using for the last 10 years, I have just done an oil change and put in Penrite HPR15 15W-50 diesel oil.
Why you might well ask? One of the several reasons was that when the engine is very cold (as in 0-10 C) the starter really struggles to turn it over.
The result of using nominally thinner oil? It starts quite a lost more readily.
However, unexpectedly, at operating temperatures (80 C) and 400rpm, the oil pressure is higher than it was with 20W-60 (around 30 psi). At other revs, it is the same (65 psi).
Moreover, the engine sounds and feels just that bit free-er. I cannot say it goes any faster, is more powerful, or is more economical. After another couple of hundred miles I might venture an opinion.
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Post by Warwick on Sept 16, 2018 22:24:18 GMT
Diesel oils generally have a higher detergent level, so using them in a petrol engine will usually keep it cleaner. However, changing to a high detergent oil when the engine is old can lead to the rapid loosening/dislodging of years of accumulated black gunk throughout the engine and this can block narrow oilways. This of course is not a problem when the engine is nice and clean internally, as it is a after a rebuild.
I ran my 1987 3.5L Range Rover on Castrol diesel engine oil for years, simply because I was consuming quite a lot in a worn-out Peugeot 406 diesel and in a mid-'60s Lister stationary engine. It avoided having to buy 20L drums of two different oils. However, the Rangie had been running on LPG for years, so was very clean internally, therefore switching to a high detergent oil presented no risk.
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Post by enigmas on Sept 17, 2018 9:29:14 GMT
That's interesting regarding the higher oil pressure at idle with a 'hot' engine. Diesels are designed to run hot by design...so maybe there's something extra in the additive package?
Look forward to your ongoing reports with the experiment.
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Post by johnwp5bcoupe on Sept 17, 2018 15:23:03 GMT
Interesting I use the Shelsley Light 20w-60w what is the difference in the ZDDP using the Diesel?
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Post by Sam Bee on Sept 17, 2018 19:10:51 GMT
I use by Morris Golden Film 20W-50W Classic Motor Oil. It is aimed at normally aspirated older cars. It is low detergent and the ZDDP content is important and from memory in the region of 700 (Penrite is a little higher).
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Post by djm16 on Oct 13, 2018 11:27:24 GMT
The Penrite website states that all HPR grades contain between 1000 and 1600 ppm ZDDP.
IMHO 700 is not enough.
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Post by Eric R on Oct 13, 2018 13:17:50 GMT
what happened to the Club negotiating supply of Penrite oils to members?
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Post by David on Oct 13, 2018 13:47:27 GMT
Rather than ask here Eric, probably best to email chairman@roverp5club.org.uk with your question.
Not all committee members are on here as much as I am :-)
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Post by johnwp5bcoupe on Oct 13, 2018 14:29:20 GMT
what happened to the Club negotiating supply of Penrite oils to members? I think it was a case of bulk buying Eric in 20L lots then you would have store(for how long?), re-box and post and that's assuming there are guys out there who would want to pay for a good oil? |
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Post by lagain on Oct 14, 2018 19:21:24 GMT
I have used all sorts over the years, but after having had the engine rebuilt about 25 years ago I went on to semi synthetics. Looking in through the engine filler the other day it still sparkles !
In the 70s and early 80s I would use Duckhams Q, or similar and then I bought a new mower and the recommended oil was Duckhams Q and I thought 'hang on, the car deserves better' especially when the mower wore out.
At the moment she has Millers 20/50 Classic Sport Semi Synthetic, it says that it has high ZDDP, but I cannot find out how much.
When I was in the Stag club they recommended Valvoline VR1 racing oil with a ZDDP of 1400 and had negiotated a special deal for members at, if I remember Europarts.
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Post by Brendan69 on Jan 7, 2019 14:25:56 GMT
ZDDP  ? does this refer to the oils detergent qualities??? |
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Post by barryr on Jan 7, 2019 17:23:06 GMT
No Brendan it's the anti- wear properties- zinc and phosphorus based usually.
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Post by johnwp5bcoupe on Jan 7, 2019 17:44:01 GMT
No Brendan it's the anti- wear properties- zinc and phosphorus based usually. Which is what our flat tappet engines need Barry  |
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Post by Brendan69 on Jan 7, 2019 18:30:32 GMT
No Brendan it's the anti- wear properties- zinc and phosphorus based usually. Cheers for clarifying Barryr. I usually use " oipe oils " anyway for my lubricants so no doubt they will have a few options to give. Just wanted to get a general feeling from fellow owners on what they use. Regards, |
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Post by enigmas on Jan 7, 2019 23:21:08 GMT
Brendan the ZDDP is there to protect the camshaft lobes and flat tappets from premature wear. Flat tappet engines (such as the Rover V8) will chop out a new camshaft and lifters in no time if these high pressure elements aren't in the additive package at the correct percentage.
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Post by Warwick on Jan 8, 2019 1:34:34 GMT
ZDDP
Zinc dialkyldithiophosphate.
It was gradually removed from motor oils when unleaded petrol was introduced because it 'poisons' the catalyst in the exhaust's catalytic converter. And modern engines have different cam-follower designs that don't have the same high pressure wear-points of flat tappet engines.
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? does this refer to the oils detergent qualities???
