synthetic oil

[Anonymous]

L.D., the reason the oils last longer and the manufacturers have extended oil change intervals is a combination of the better technology of the oil and their additives and also the engine techology. Todays engines are all fuel injected and machined to tighter tolerances. They have better temperature control and engine management that reduces the contaminants in the oil. The old carbureted cars did not have the computers controlling fuel delivery etc. Tolerances were larger and blowby and condensation was more of an issue. So as you mention, a synthetic in an older engine is not going to hurt anything and may out perform a dino oil. But it is likely to get the same contamination from fuel and condensation and combustion products. These cars are not typically racking a large amount of mileage and have a lot of starting cycles for the mileage that is racked up. So the oil is going to have a shortened life not due to breakdown of lubrication properties but from contamination inherent in the application.
Doug

 

[hotrodbob]

I've seen a lot of sludged up engines. Some where they changed oil at the recomended factory miles/time. The one common thread they had was a parifin based oil (Penz & Q-State).

Honda issued a recall a few years back on the V6 in the SUV they got from Isuzu. Varnish build up on the lifters caused clicking noise. The fix was switch to synthetic oil.

Alloy engines seem to sludge up quicker then cast iron. Could it be the fact that they cool quicker?

I use Mobile 1 in most of our new cars, but did not like it in my Vette. At the time they did not have a good viscocity range. I use Castrol Syntec in anything with a Chevy small block (350 & smaller). I will also use it after break in on my Ranchero.

Learned about synthetic benifits when I was part of an SCCA H/Prod team. Never had an engine failure with Synthetic oil. Always changed bearings after a race with dino oil. No wear with synthetic and better oil presure at race temps. Picked up MPH over dyno oil.

 

[Anonymous]

I am a big believer in running synthetic. My brother is an automotive machinist and when I was rebuilding an engine for my Granada 9 years ago he showed me two 302's he had in the shop. One had been run using synthetic and the other convention oil. The synthetic engine was spotless with no appreciable wear-the other looked like burnt fried chicken.

I run 12 to 15000 miles on a new motor using conventional oil prior to changing over to synthetic and so far this has worked well for me.

I have a 64 dart, 62 falcon and 61 comet all running mobil 1.

 

[Anonymous]

I am a big believer in running synthetic. My brother is an automotive machinist and when I was rebuilding an engine for my Granada 9 years ago he showed me two 302's he had in the shop. One had been run using synthetic and the other convention oil. The synthetic engine was spotless with no appreciable wear-the other looked like burnt fried chicken.

I run 12 to 15000 miles on a new motor using conventional oil prior to changing over to synthetic and so far this has worked well for me.

I have a 64 dart, 62 falcon and 61 comet all running mobil 1.

Why were the 302's in his shop?

 

[Anonymous]

Mine was the the burnt chicken (especially below the intake). The engine was real loose-timing chain lifetd off without removing the gears.

The sterile 302 he showed me for comparison was in for some performance modifications I think.

 

[Guest]

My cars always get synthetic. I would not recommend extending your oil change intervals. The benifits of a synthetic would certainly include resistance to thermal breakdown, much better than in the case of a regular oil.

Some older motors will pick up minor oil leaks if you switch to synthetic. Porches seem particularly suceptable to this symptom if they are older. Usually occurs around valvecovers and mains. This is minor and nothing to really worry about (although it is annoying). Leaks can often be fixed by new gaskets, or in some cases an engine overhaul. Had a customer a while back with an '84porsche that picked up a slight oil leak when he switched to synthetic. The car now has over 96,000 miles on it and it runs strong. I don't buy into the latest "extended protectoin" from Mobile 1, certainly not 15,000 miles. I'm sure there is a science behind it, but I have extreme doubts about such claims.

Filters can also play a role in engine longevity. Years ago my Dad's shop switched from Fram filters (I don't really remember exactly why, I think they were good for us but our supplier changed), and went with NAPA Gold filters. These filters are pretty good, not like that ProLine crap you pick up for 2 bucks. Generallly Wix makes the NAPA Gold filters and they have been good. For Fords and most imports our shop has always used Motorcraft, or genuine (toyota, volvo, mercedes etc.) filters.

Edit: just saw what Doug posted- he brings up a good point that I wasn't going to get into, but cars today are much tigher in tolerance. That's whay you NEVER change from the recommended viscosity in newer cars, which is frequently 5w30. Running 10w40 in a ford 4.6 is going to kill it. I have plenty of stories to prove it too. Also a good reason NOT TO EXTEND OIL CHANGE INTERVAL!!!!!