Let’s talk motor oils

[Michael Oritt]

Healey Nut--

Saying that this discussion is unnecessary and that the oil recommendations in "The manual" are still operative ignores the FACT that while the needs of our camshafts, etc. are the same as they were when manufactured, the current version of the oil specified back then to lube them is not.

The name "Castrol GTX" may remain the same but as the oil has devolved to comply with API ratings its content of zinc, phosphorus and other things you call snake oil (which keep the cam lobes from going away, etc.) has decreased and will undoubtedly continue to do so in the future.

If we don't want to fix what ain't broken we must feed our cars what they needs so they hopefully won't break.

 

[RAC68]

Hi All,

Back when my car was new and my daily driver, I used Esso (who remembers Esso) 10W30 in my Healey and over the years, having
little interest in acquiring a more in-depth understanding of engine lubricants, had responded to the latest advertising promotions on the greatest level of lubricity of the day. These slick promotions commonly extoled the virtues of their oils and how they would eliminate any concern since they were definitely on top of all possible issues. Back then 10W30 gave way to 10W40 and eventually 20W50 became the viscosity choice with Valvoline and Castrol the favored brands. Eventually synthetic oils gained favor over conventional mineral oils and so progress continues. As a mildly aggressive driver who commonly shifts at around 5K RPM, I can't say whether this lubricant progression worked to the betterment of my engine's internals but the only oil-related components replaced during the 54 years of use were a few lifters and valve train bushings.

Today, I use Mobile 1 15W50 as my oil of choice and found this synthetic to allow for easier cold starts and freer revving then the VR1 20W50 I previously favored. Additionally, since my dependency on my Healey for general transportation has been eliminated for a number of decades now, the number of yearly oil changes has been curtailed to 1 and falls in line with the suggested longevity of the Mobile 1 15W50 as relayed to a Forum member by Mobile and stated in a previous discussion on the topic of oils.

Is ZDDP important and to what extent is it necessary? What about other oil additives and lubricant components (i.e. Calcium, magnesium, etc.)? I have come to rely on more knowledgeable interested Form members to determine the answers to these and other question on the topic and have been rewarded by the logic of their explanations as well as the validation of their comments by others during Forum discussions.

Today, my engine is running quite nicely with good oil pressure and responsiveness. How long it will be that way is always an open question .... even for the experts.

Just my thoughts,
Ray(64BJ8P1)

 

[Deleted member 21878]

i read in a few places on other car forums, etc, that it was a mistake to go to a synthetic oil if your car had run on mineral oils. not that it hurt the engine per say. but that, just like with the MT90 in the gearbox, it seemed to find a way to leak. after reading those posts, i have never changed any of my older cars to a synthetic oil. i run it all the time in my truck but not in my cars. i use the Brad Penn, 20w-50 in mine beacuse i have used it in my other cars. i am lucky if i put a thousand miles a year on these cars, so i was more trying to keep as much oil in the car as anything.

not true? or is that something maybe true 10 years ago but has changed?

 

[Jim 58 BN6]

i read in a few places on other car forums, etc, that it was a mistake to go to a synthetic oil if your car had run on mineral oils. not that it hurt the engine per say. but that, just like with the MT90 in the gearbox, it seemed to find a way to leak. after reading those posts, i have never changed any of my older cars to a synthetic oil. i run it all the time in my truck but not in my cars. i use the Brad Penn, 20w-50 in mine beacuse i have used it in my other cars. i am lucky if i put a thousand miles a year on these cars, so i was more trying to keep as much oil in the car as anything.

not true? or is that something maybe true 10 years ago but has changed?

That's been my experience with older cars, after changing over to synthetic engine oil. The leaks are not so much like a hemorrhage or even a drip, but more of a wicking, where wet areas appear around some seals and gaskets, and nothing difficult to keep clean. The drips on the floor stayed about the same. I don't think it's a mistake to go synthetic, but as always, YMMV!

With the newer cars, the "wicking" was much less obvious. I guess 50 years of seal design has made a difference.

 

[RAC68]

wHi All,

Although I have changed gaskets over the years, my Healey does not seem to leak andy more with Mobile 1 10W50 then it did when using 20W50 mineral oils and runs a lot freer with good pressure. Does it drip and leave spots on the floor after a run? YES. I have also switch to Mobile 1 20W50 in my '79 TR7 as well and see no dripping from that engine at all. I can understand not wanting the engine or transmission to drip but, as I see it, if its going to drip anyway, why not use the best oil available as long as it maintains the same level of escape.

As far as using a synthetic (i.e. MTL /MT90, etc.) in the transmission, seepage could be greatly or totally eliminated by make sure all bolts penetrating the outer housing are sealed and front/rear seals and gaskets are also sealed. MTL has a tendency to escape from the transmission through these openings as well as doubling the single "O" ring around the transverse transmission activation shaft controlled by the solenoid. All in all, I see little to cause me not to choose a synthetic over a mineral except where there is a chance that cause a major difficulty as in the rear when leakage could result in making the rear brakes inoperable.

I appreciate you feel it works for you but a multi-viscosity oil with a detergent is designed to keep debris in suspension until eliminated by a filter. Since the Healey transmission has no filtration system, this debris could remain in suspension far longer then would happen with non-detergent oils and this added debris circulation only extends the potential for damage.

Just my thoughts,
Ray(64BJ8P1)

 

[Michael Oritt]

It may be a false choice but if I must choose an oil based on its ability to protect my engine versus its tendency to leak a bit I'll go for the former every time.

 

[twas_brillig]

Have a look at:
Modern Oils for our Flat Tappet Engines https://www.britishcarforum.com/bcf/showthread.php?109277-Modern-Oils-for-Our-Flat-Tappet-Engines
for some hopefully useful information and references. Doug

 

[twas_brillig]

Just an FYI as to what I'm using - and kindly don't ask as to 'why' specifically, as I'll be durned if I can remember particularly. Might switch the engine oil to Valvoline VR-1, but probably not get 'round to doing it. Doug

Austin-Healey	Sprite	948/1275 cc engine	Castrol GTX 10W40 or 10W50;
		4 speed transmission	Red Line MT-90- GL4
		differential	Red Line 75W90 GL-5 Gear Oil
		Steering Rack	Royal Purple Maxgear with Synthetic 75W-140
		Datsun 5 speed	Red Line MT-90- GL4
Austin-Healey	3000 Mk II	2912 cc engine	Castrol GTX 10W40 or 10W50
		overdrive transmission	Red Line MT-90- GL4
		differential	Red Line 75W90 GL-5 Gear Oil
		Toyota 5 speed	Red Line MT-90- GL4

 

[Deleted member 21878]

hey, i was not advocating mineral over synthethic oil. i was more asking the question. since i had read those articles years ago, i just never switched to synthetic. not saying that is right. just saying i did not. i did switch to MT90 in my TR6 gearbox to help with some tight shifting and it now leaks where it did not before.

As far as the best oil for my car.... i certainly understand where you all are coming from. lots of work go into these cars and you want what you believe to be the best. i guess i am somewhere in between the guy who says stick anything in it and the guy who wants only the best. my car was 55+ years old and had 135k miles on it. who knows what oils were in it over the years and how it was thrashed when it had no value.

i figure if i keep up with the maintenance and treat it nice for my thousand miles a year or so... well it is going to last longer than i am.

So if it might leak more... well i may as well stay with what i have used for the last 20 years. Not like it hasn't work. that is, if it was going to leak more with synthetic???

i was laughing at myself for spending all the exrtra on SS bolts, washers and nuts. i believe they are better but i pulled out a bunch of old bolts that were fine after 50+ years. did i really need SS?

I did it and now.... i am thinking i will probably change oils at the next change.... is that wishy washy or what? i should be a senator.

appreciate all the info here. i like reading all the different views and i get to learn something.

 

[Deleted member 21878]

Ray
i do have a few questions.

you say your car runs freer on the 10w-50. do you mean it revs easier? is that something you can actually feel? was your engine recently rebuilt when you switched to the syn oil? or had you had mineral oil in it for a while when you changed?

i was going to wait until i had 500 miles on my engine to change the oil but after i had the pressure dropping and had to change the filter, i thought i might go ahead and change it at 250 miles and put on another filter as well.

And since my gearbox is a rebuilt one, i will probably do it at the same time.

so this is all great info for me.

 

[gonzo]

Drone Dog, ..." but after I had the pressure dropping and had to change the filter, i thought i might go ahead and change it at 250 miles and put on another filter as well."

Just curious, from pics it looked like you were running an original canister filter unit rather than a spin-on conversion, so what are you attributing the pressure drop to? Certainly not the your oil choice. Filter perhaps? I run Castrol 20W-50 with Lucas ZDDP chaser and short shift until engine warms up, then it's 4K to 4.5K RPM shifts. Alternating between original canister and spin-on conversion oil filtration systems, there appears to be slightly lower pressure of approximately 3 to 5psi from spin on. But then the gauge is more "responsive" with the spin-on.

 

[Bob_Spidell]

... Alternating between original canister and spin-on conversion oil filtration systems, there appears to be slightly lower pressure of approximately 3 to 5psi from spin on. But then the gauge is more "responsive" with the spin-on.

Compared to canister with cloth (felt) or paper element? I'd SWAG the paper element would be closer to a spin-on, but who knows.

 

[Patrick67BJ8]

Healey Nut--

Saying that this discussion is unnecessary and that the oil recommendations in "The manual" are still operative ignores the FACT that while the needs of our camshafts, etc. are the same as they were when manufactured, the current version of the oil specified back then to lube them is not.

The name "Castrol GTX" may remain the same but as the oil has devolved to comply with API ratings its content of zinc, phosphorus and other things you call snake oil (which keep the cam lobes from going away, etc.) has decreased and will undoubtedly continue to do so in the future.

If we don't want to fix what ain't broken we must feed our cars what they needs so they hopefully won't break.

i agree with you 100% Michael but one more point just as important and that is what may be old hat to us may be very important to a noob.

 

[steveg]

Ongoing discussion is relevant because of new developments. I welcomed the new info above re the Castrol oils with higher ZDDP levels and new grades of Mobil 1, as well as keeping an alert eye on old faves such as VR1 20w-50, lest the manufacturers change the formulation for the worse.

 

[Michael Oritt]

Patrick--

You said "what may be old hat to us may be very important to a noob."

I totally agree and am not trying to squelch the conversation. What I tried to point out is that as far as I am concerned the issue of whether an oil leaks a bit more is WAY WAY less important than if an oil has the properties our engines require, and those who simply say that it is best to use the oil specified in a manual written 65 years and god knows how many oil formulations ago are dispensing, to my mind, dangerous advice that may cost someone--newbie or old-timer--a lot of $$.

 

[RAC68]

Hi All,

Drone Dog, Except for the valve train, a few lifters, and timing chain, my engine has all its original internal components. I have over 100K Miles and like to shift around 5K when driving in the hills around where I live. When I say runs freer, my RPMs seem to build nicely and a little better then when using 20W50 VR1. It also spins much more easily when cold starting and has allowed me to extend the use of my present battery. Although easier spinning on cold starts may be the result of now using 15W rather then the prior 20W, there is a definite noticeable increase is spin that has made for easier starts and less battery.

As far as oil pressure, mine never drops below 20 lbs at idle (around 800-900 RPMs) and when cold, I believe is retained about 60 lbs by the release valve. After hard driving in the summer, the pressure usually drops to just above 40 lbs when driving around 2300 lbs. and would extend to about 50 lbs when aggressively shifting (around 5K RPM). Although we can only depend upon pressure, or flow resistance, to indicate the health of operating lubrication, I have often wondered how much it indicates (save 0 pressure) it actually is and if I ever decide to replace my use of original-type canister for a spin-on filter would make.

Since my engine has not been rebuild, I would only suggest following the recommendations of the engine builder or cam/crank resurfacer. However, once well broken in, I would recommend a Synthetic oil and Mobile 1 and personally favor (now) Mobile 1 15W50.

Ray(64BJ8P1)

 

[Deleted member 21878]

gonzo,
i do have a spin-on conversion. i believe my "perceived" (since it just felt like it was not what it was) OP drop was the filter. but i also cleaned the fitting to the gauge and pulled the pressure relief valve. Not sure how you ever know if the pressure relief valve is indeed closing all the way.... but that is for another discussion.

here we are talking about oils. i was going to change the oil, thinking, if the filter became clogged that quick, could be i did not clean as well as i thought and an extra change can not hurt.

Ray, thanks for the info.

for you all that have been on this forum a long time, i feel your pain about having to endure the same questions over and over. but like the post above said, it is nice info for us new guys who were not here and are not very good with the search feature.

 

[steveg]

IMO when there are new developments (such as the oils discussed above), it's worth revisiting these "hardy perennial" topics.

If more tires became available in appropriate sizes, it would be worth revisiting that one, too.

The search feature is pretty cryptic, but it's worth new postings on an old thread to keep the knowledge in one place.

 

[Deleted member 21878]

I have one more question on syn oils.

New engine build. Should One wait until after 500 miles to go syn?

 

[RAC68]

As I understand, synthetics are slicker then the oils recommended for used during the seating of critical parts in a newly rebuilt engines and I would not use synthetic oils until the recommended duration of this procedure was definitely completed. However, after that, I would use synthetic oils, from that point forward...assuming nothing better is introduced.

You mentioned an unexplained and worrying drop in oil pressure between initial and present operational runs. If I am not mistaken, installing the oil filter cartridge adapter upside-down will cause reduced oil pressure. Additionally, I have also experienced excessive leakage in the valve train that has caused will this condition as did the displacement of the hydraulic timing chain tensioner piston. Each of these conditions happened at different times during the engine's operational life and were found and corrected separately.

Just my thoughts,
Ray(64BJ8P1)