Stupid and confused about oils :doh:

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I've actually got the search facility to work this time :eek:
Joining this discussion as I'm about to change my '87 efi's oil & am thinking about the ZDDP content. According to Comma this additive in their 'classic 20w/50' is 0.08% so am I right in thinking that equals 800ppm? Miller's equivalent on the other hand is specifically listed as 1000ppm (& Penrite as 1600ppm) but with the price escalating rapidly. The question is, given that I'm sticking to mineral oil, how much ZDDP is considered adequate for a 51k engine at 1500 road miles per year with an annual oil & filter change? or would I be better off going for the expensive product but with extended service periods.
As always, any informed advice is appreciated.
 
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norseman said:
I've actually got the search facility to work this time :eek:
Joining this discussion as I'm about to change my '87 efi's oil & am thinking about the ZDDP content. According to Comma this additive in their 'classic 20w/50' is 0.08% so am I right in thinking that equals 800ppm? Miller's equivalent on the other hand is specifically listed as 1000ppm (& Penrite as 1600ppm) but with the price escalating rapidly. The question is, given that I'm sticking to mineral oil, how much ZDDP is considered adequate for a 51k engine at 1500 road miles per year with an annual oil & filter change? or would I be better off going for the expensive product but with extended service periods.
As always, any informed advice is appreciated.
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This discussion is five years old. Zinc additive was used in older engines to prevent camshaft wear. A 20W 50 with high Zinc would maybe best. Change oil and filter often.
 
wammers said:
This discussion is five years old. Zinc additive was used in older engines to prevent camshaft wear. A 20W 50 with high Zinc would maybe best. Change oil and filter often.
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Thanks for that. I appreciate the age of the OP but thought I'd join the discussion rather that start a new thread. Perhaps I also got carried away by actually finding a post(s) on a subject I was seeking :eek:
 
norseman said:
Thanks for that. I appreciate the age of the OP but thought I'd join the discussion rather that start a new thread. Perhaps I also got carried away by actually finding a post(s) on a subject I was seeking :eek:
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Halfrauds classic 20W 50 has very little Zinc in it i hear so don't use that.
 
TVRConvert said:
I use Valvoline VR1 20/50 in the TVR, have done or the last 9 years.
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Valvoline was not originally on my radar but having done some research re. ZDDP levels & flat-tappet engines I've gone for their 20w/50 grade. The zinc additive level is higher than found in Millers (which in turn is a lot higher than Comma/Halfords) but the price is comparable.

Many thanks for your input.
 
When I first came across 5w-30 years ago, I thought you might as well bung in 3-in-1.

Apparently **** thin oil also helps fuel consumption as well as the comments from Wammers.

When I lived in the Med, I always used to put the heaviest weight oil in recommended as at those temps on idle it would help keep up a reasonable pressure.
 
Fergie46 said:
When I first came across 5w-30 years ago, I thought you might as well bung in 3-in-1.

Apparently **** thin oil also helps fuel consumption as well as the comments from Wammers.

When I lived in the Med, I always used to put the heaviest weight oil in recommended as at those temps on idle it would help keep up a reasonable pressure.
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Thick oil was required in the old days simple because of crappy machining tolerances - thin oil would get flicked out of the big end journals causing oil pressure to drop off. It would also help reduce oil consumption. The thicker oil would increase drag worsening fuel consumption.
 
StuckAgainSteve said:
Thick oil was required in the old days simple because of crappy machining tolerances - thin oil would get flicked out of the big end journals causing oil pressure to drop off. It would also help reduce oil consumption. The thicker oil would increase drag worsening fuel consumption.
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Come on Steve come up with a better one than that. Machining tolerance had nothing to do with it. Oil is supposed to be thrown out of the bigend journals, how do you think the cylinders, pistons and gudgeon pins are lubricated.
 
StuckAgainSteve said:
Thick oil was required in the old days simple because of crappy machining tolerances - thin oil would get flicked out of the big end journals causing oil pressure to drop off. It would also help reduce oil consumption. The thicker oil would increase drag worsening fuel consumption.
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amazing as how in the 21'st century that 10w40 oil is recommended on diesels that will do a million miles before rebuild
 
wammers said:
Come on Steve come up with a better one than that. Machining tolerance had nothing to do with it. Oil is supposed to be thrown out of the bigend journals, how do you think the cylinders, pistons and gudgeon pins are lubricated.
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I know my response was perhaps lazy - but it was still correct - the rate at which oil was flung out the big end journals was far beyond what's actually required for splash lubrication and as I said with thin oil the oil pump wouldn't be able to keep up - old engines were built very loose compared to todays' which have far far tighter internal tolerances.
 
StuckAgainSteve said:
I know my response was perhaps lazy - but it was still correct - the rate at which oil was flung out the big end journals was far beyond what's actually required for splash lubrication and as I said with thin oil the oil pump wouldn't be able to keep up - old engines were built very loose compared to todays' which have far far tighter internal tolerances.
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Tolerances have not change greatly other than were new materials have been used with better matched coefficients of expansion. Oil still leaks out of mains and bigend bearing, that is what it is supposed to do. Think you may find it is more down to thinner oil which is circulated faster using higher capacity pumps. I take it you have never rebuilt an engine using a bearing scraper.
 
wammers said:
Tolerances have not change greatly other than were new materials have been used with better matched coefficients of expansion. Oil still leaks out of mains and bigend bearing, that is what it is supposed to do. Think you may find it is more down to thinner oil which is circulated faster using higher capacity pumps. I take it you have never rebuilt an engine using a bearing scraper.
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Yes I have used bearing scrapers with the old white metal bearings. Perhaps the expansion coefficents are better matched which would be a better explanation. Your comment about higher capacity pumps makes my point about oil loss through journals with thinner oil. A higher capacity oil pump will by definition soak up more power - if you only had 38bhp to start with then greater oil pump losses would be significant! There are obviously a dozen reasons for the changes over the years. The requirement to use smaller batteries and cheaper starters probably had an influence too.
 
StuckAgainSteve said:
Yes I have used bearing scrapers with the old white metal bearings. Perhaps the expansion coefficents are better matched which would be a better explanation. Your comment about higher capacity pumps makes my point about oil loss through journals with thinner oil. A higher capacity oil pump will by definition soak up more power - if you only had 38bhp to start with then greater oil pump losses would be significant! There are obviously a dozen reasons for the changes over the years. The requirement to use smaller batteries and cheaper starters probably had an influence too.
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Oil has two purposes, to form a barrier between bearing surfaces and to carry away heat. The more oil you can get going through the bearing the more heat is dispersed. Also, as most engine wear takes place at startup before oil pressure is achieved, a thinner oil, as it is easier to pump round, gets to the bearings quicker reducing this wear. At least that is the theory behind it.
 
wammers said:
Oil has two purposes, to form a barrier between bearing surfaces and to carry away heat. The more oil you can get going through the bearing the more heat is dispersed. Also, as most engine wear takes place at startup before oil pressure is achieved, a thinner oil, as it is easier to pump round, gets to the bearings quicker reducing this wear. At least that is the theory behind it.
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Agreed - but new cars in the "old day" used to burn oil - a litre of oil in 1 thousand miles was not uncommon - put 0W20 in the same engine and it will guzzle twice as much. Tolerances, oil control ring design, valve stem seal, cranks seals, breathers - everything has got better. I've only done 2,000 miles in my current car but it has not used a drop of 0W20 - and I've given it quite a caning.
 
StuckAgainSteve said:
Agreed - but new cars in the "old day" used to burn oil - a litre of oil in 1 thousand miles was not uncommon - put 0W20 in the same engine and it will guzzle twice as much. Tolerances, oil control ring design, valve stem seal, cranks seals, breathers - everything has got better. I've only done 2,000 miles in my current car but it has not used a drop of 0W20 - and I've given it quite a caning.
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As i said before materials with better coefficients of expansion allow for tighter machining tolerance. That's not oil it's ****. If things didn't get better we would still be running total loss oil systems. :D:D:D
 
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