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synthetic oil myth or magic?

5.7K views 11 replies 6 participants last post by  reidmct  
#1 · (Edited by Moderator)
i wanted to offer a few words on synthetic oil and use and misuse. it is probably one of the best,yet misunderstood items we have in our garage. im not interested in debate, only to offer good advice for the folks with enough good sense to think for themselves.

i dont care to discuss oil engineering or application just common sense use of oil. most modern bikes use a synthetic oil from new with no issues,and most older machines can benefit from synthetic oils superior qualities. but the stuff is not magic, and using it in a well worn motor with oil control problems will magnify these oil control issues. synthetics will usually burn easier and can increase oil consumption as compared to mineral oil counterpart. using synthetics in freshly rebuilt motors or new motors is never a good idea.

yes i realize bikes are manufactured with synthetic lubricants in production and OEM recommend synthetics for subsequent changes. still not a good idea until motor is run in. yes, modern motors require very little break in and composite cylinders and low friction coatings on piston rings and low tension/low friction piston rings and perfectly round cylinders and pistons and rings all combine to minimize break in required. but the other parts of the motor all combine to create small wear particles in the engine and combined with the small amount of wear from cylinder,are circulated through oiling system. changing motor oil after run in is critical for good long engine service life, if you were paying double the price for synthetic oil,why put it in your fresh motor only to drain it after a short run in?

there are no logical reasons to use its superior lubricating qualities for break in, its anti friction ability can actually hinder the break in process for some engines.
 
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#3 ·
I put synthetic in my ‘66 Galaxie Convertible and reduced oil consumption was the result. The couple of drips it had, it still has, but no worse. Since it gets fired up infrequently, with regular oil, it would blow out a huge cloud of smoke and pollute the garage atmosphere for an hour or so. With syn, even if it hasn’t been started in 2 months, no smoke on startup, so my experience with syn is that it burns less than dino oil, not more. I also use syn in my 2 Norton Commandos and the leakage is no worse than before.
 
#6 ·
old ford smoke



im an old time ford guy. owned and raced and drove lots of old fords then and now. you can usually find most of your FE series motors smoke as a result of restricted oil returns causing oil to remain inside valve cover and upper cylinder head area. i used to keep a length of wire cable in my tool box for snaking the sludge out of those tiny return holes. saw many a good mechanic replace valve stem seals in those old smokers, only to find a pissed off ford owner returning with a smoky exhaust. be sure to post up pictures of your old ford if you can. i owned every year ford from 1953 to 1966 at some point over the years. 55 ford altered drag car. 63 1/2 fastback A F/X drag car. 63 convertible 427 4 speed. 64 fastback 390 4 speed. ah yeah. good old ford smoke.... got pictures somewhere. gotta dig them out and post em soon
 
#8 ·
Where there’s smoke...there’s an old ford


The oil is pumped up to rocker arms during normal operation.
The drainback route from outer channel does not have enough pitch to allow oil to drain back down to lifter valley. Oil will remain in upper cylinder head area like a plugged sink. A giveaway was a constant leak from outboard side of valve cover. I saw valve covers removed and a quart or so of oil leak out upon removal. Your high detergent synthetic may have helped remove sludge in return channels and allow better oil drainback. This may explain reason for less smoking. The synthetics are like a liquid enema for those old motors
 
#12 ·
Ive always read that for wet clutch systems that synthetic caused more slipping.
I would suggest you not trust the sources where you read that. Friction modifiers in 'Energy Conserving' oils cause clutch slip. They can be found in both synthetic and conventional oils. Read the API roundel on the bottle (USA).