Oil type for quick cold lubrication / piston slap

Route--66--

Route--66--

Well-known member
Related to another topic I posted about piston slap.. I was looking at how the bores are lubricated .. which is apparently by the crank 'splashing' the oil up from the sump to inside the bores.
On these engines is the wrist pin / little end, lubricated by the same method?.. or by some kind of oilway up the middle of the con rod?

I read this morning that if you use a thinner oil (I currently use 20/50) it would lubricate the wrist and cylinders better when cold and reduce my cold piston slap (the slap is certainly not massive, but is noticeable).

Is this true .. as, if the oil is being splashed up there anyway surely it wouldn't make a difference if the oil was thick or thin as far as the cylinder walls are concerned, (although might make a difference to the wrist pin)???

Cheers :)
 
Run the thinnest oil you can,....as long as you still have acceptable oil pressure.


Example:
Someone (past owner/Mechanic??? ) put a HIGH pressure spring in my 400 truck engine's oil pump
It currently has 5W30 in it. It also has about 80 PSI @ cold idle and 40 PSI @ Hot idle.
When i got it was even higher with whatever weight oil it had.
I am thinking about 5W20 for it. But at the current rate of 1000 miles per year, IT doen't get oil dirty all that quick.
 
I don't know your temperature range there, but I can only get by using 20w-50w in the heat of summer. Once temps get below about 40* F, the engine is laboring to turn over. 10w-30w is much easier on the engine/oil pump. As long as you can maintain 10psi per 1000rpm at hot idle, run the thinner oil as already posted.
 
Thanks for that guys - I will read that article fully tomorrow.
Interesting on thinnest poss oil -
coldest to hottest weather here in Fahrenheit is probably about 38 at lowest (colder than that and I wouldn't take it out anyway..) and hottest summers day would generally be around 80 degrees (could be higher but very rare)
Average temp range to take it out would be about 50 to 68 degrees kinda region ..
Although I've only read a very little amount of that article posted by turbo, I did see it said that it didn't matter about the ambient temperature (although as u say maybe if you have too thick oil on a too cold day it may have trouble turning perhaps..
Will read tomorrow and get back - thanks for answers today (y)
 
Synthetic oil will remain more "stuck" to the metal than dino oil.
I'm using Redline in 5/30 and 10/30.
 
if you have a 7 main motor I would run 10w30 or something even lighter like a 5w20....you have plenty of bearing surface to support the crank.

my 170 I always ran 20w50 in since it was only a 3 main motor and had much less bearing surface area.

The 350 in my s10 (same year motor as the truck...1997) calls for 5W20 and it is not any different than any other SBC other than it has a roller cam. a Decent sythenic oil and filter goes a long ways.

I run royal purple in my Hemi Charger (2007) and go about 7500-10,000 on an oil change (7 quart system with a oil/water cooler) with a WIX filter.

if you are only driving this in fair weather I would just load it up with some synthetic 5w20 and a decent filter and change it once a year or so. the 200 isn't much of a perfomance motor and has plenty of bearing surface as stated.
 
I'm a big fan of the 0w40s. I used that in two turbo volvo's that saw well past 200k miles each on the original turbos. Just like that article says, which is how I was taught to thing about these oils. the first number is how the oil acts when cold, and the 2nd when the oil is warm. 0w40 is the best of both worlds IMO. I wanted quick flowing when cold (live in New England) and have more thickness when hot (especially for protecting the turbo bearing)
 
Really interesting - has changed my knowledge about oils..
I have also read a fair amount about the use of synthetic detergent oils in older engines - i.e. using a detergent oil will flush out old clumps of gummed-up oil blocking small oilways and starving the engine of oil ...

Has anyone changed to a thinner synthetic detergent oil ..? what are your experiences..?
are there non-detergent synthetics ...?

Cheers!
 
Route--66--":1cc7tzio said:
Really interesting - has changed my knowledge about oils..
I have also read a fair amount about the use of synthetic detergent oils in older engines - i.e. using a detergent oil will flush out old clumps of gummed-up oil blocking small oilways and starving the engine of oil ...

Has anyone changed to a thinner synthetic detergent oil ..? what are your experiences..?
are there non-detergent synthetics ...?

Cheers!
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My experance is do it a little at a time. 5qt change only go with 1 qt of synthetic. Next change 2 and so on. If it starts to develop leaks around gaskets you might want to go back or replace gaskets.
 
From my understanding, switching to synthetic isn't what it used to be, with leaking gaskets. That was still a legacy from leaded gas. People have forgotten that leaded gas gunked up the engine. Tear apart a modern engine at 200k miles now, that has had nothing but regular gas in it with regular oil changes, and the engine looks practically new except for losing the cross hatch on the cylinder bores. So, the old adage about leaking gaskets was (at least in my opinion) based on the fact synthetic oils would clean out lead deposits on gaskets, and thus old rotten gaskets would start leaking.

I bought an old turbo volvo with 100k miles on it. First oil change, all synthetic 0w40, no leaks for the next 60k miles until I got rid of it.

But, no reason not to go slow either and see.
 
Back in the day's these engines were made, Quaker State parrafin based oil was popular. That would definatly gum up an engine. Switching to a detergent based oil would break all that crap loose and plug oil passages and drain holes. Seen many an engine that overhead oilers were added and drain holes cleaned out. (showing my age now) Stuff worked great, as long as you didn't swap oil types.
 
CobraSix":10dq24pb said:
From my understanding, switching to synthetic isn't what it used to be, with leaking gaskets. That was still a legacy from leaded gas. People have forgotten that leaded gas gunked up the engine. Tear apart a modern engine at 200k miles now, that has had nothing but regular gas in it with regular oil changes, and the engine looks practically new except for losing the cross hatch on the cylinder bores. So, the old adage about leaking gaskets was (at least in my opinion) based on the fact synthetic oils would clean out lead deposits on gaskets, and thus old rotten gaskets would start leaking/
Click to expand...

Most of the issues with leaks caused by vintage synthetics oils was that dinosaur oil would swell seals, and the synthetic might shrink or harden a seal. A swollen seal that later shrunk could result in a leak. That was cured fairly early on with modified additive packages in the oil and improved elastomers in the seals. Hasn't been a problem for a couple decades now, but rumors persist.

If you are paying for good motor oil, be sure you're getting it. There is a huge variation in this country between "synthetic" oils, and not all are created equally. As it applies low-tech motors like ours, I can't readily believe the *performance* difference matters, but it seems folly to pay $10/qt for a hydrocracked group III oil when $10/qt buys you a real synthetic group 4 oil. It's a bang for the buck issue, nothing more. On the same note, be cautious about exactly what oil you're using - modern lubricants designed for modern engines may not have the right additive packages to keep older motors healthy.

FWIW, I've been running the Falcon on 10w-40 Mobil 1 High Mileage, which is branded as synthetic in the US, but is probably a hydrocracked G3 or G3/G4 blend. However, it has extremely high levels of anti-wear additives, which is good for old engines - zinc, etc. It also keeps my Saab turbo, XR4Ti (turbo) and Audi turbo happy, so it's nice to have one oil for a lot of cars. I am switching over to Motul 6100, however, as it produced similarly and has a similar additive package, plus has specific ratings for the Audi and is rated for my diesel Suburban too. It's also a little cheaper - especially when purchased sans sales tax from Amazon.com. :D
 
This line of education reminds me of the recent update (in my life) of ingredients on our food packages.
Can we read the capital letters embossed under the titles - usually in fine print - & can we trust them, in selecting motor oil for different (esp. an older I6) types of engines?
Thanks oh great gurus!
 
The biggest advantage to synthetic oils, IMHO, is the increased oil change interval.
You can run them out 5 - 10 thousand miles before changing.
 
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