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| ForcedInductionPontiac |
 Posted: Sat Oct 20, 2007 12:03 am |
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Joined: 18 Oct 2007
Posts: 50
Location: Chicago
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Some people may or may not know a interesting fact about most modern engine oils that can be damaging to your older engines. So, here it goes.
Our older engines are unique in there lubrication requirements since they have so many direct metal to metal friction points, mainly the flat tappet lifters. Zinc is an oil additive that was in nearly all oils when our engines were built. Zinc is used mainly to protect these metal on metal parts from excessive wear. Most if not all modern engines use roller lifters (if even still using pushrods), electronic fuel pumps, and many other designs almost eliminating the use for zinc in oils. While some oils do still have this additive, most do not have much or any. There is also a few companies that sell break in additives with high zinc content to help as well. Zinc does have it's downfalls though. It leads to deposit formation on valves, and possible spark plug fouling from seeping past the piston rings/valve seals into the combustion chamber. It also can be damaging to the catalytic converter over time. More isn't better, but you do want it.
I prefer at least .15% zinc content. I like to run synthetic oil so I use Amzoil or Redline (0% zinc in both I believe) and I add a bottle of comp cams break in fluid with every oil change. I change my oil every 2500 miles and use WIX filters. Never use full synthetic oils when breaking in a new/rebuilt engine. I use 15w40 rotella T for that.
Any questions? |
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| Sir English Firebird |
| Posted: Sat Oct 20, 2007 1:26 pm |
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Joined: 18 Oct 2007
Posts: 275
Location: UK
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Thats interesting i have a rebuilt 350 sbc in my Bird, new pistons etc etc.
I ran it for the first 500 miles on Castrol RS a fully synthetic high spec oil ( it was avaliable at work, brand new VW's you see ) and as i was going to change the oil anyway i figured i wouldnt actually buy any!
i changed it and then ran it for a rew miles more approx 1000 -1500 ish and then wipped the heads off to do somr more mods...
this is a pic of the pistons.
I wiped them off and they shone just like they did when they were new, the pic doesnt really do them justice.
I was a bit worried about the properties of the oil in an older style of engine so ive gone back to one more suitable ( still from work  )
it is interesting though and suprising how much difference it can make.
Has anyone heard of "crank scrapers"?  |
_________________
The Imagery of heat and strength are used as ways of associating the car's punchy performance with the masculine fantasy of full-blooded heterosexual conquest |
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| ForcedInductionPontiac |
| Posted: Sat Oct 20, 2007 5:58 pm |
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Joined: 18 Oct 2007
Posts: 50
Location: Chicago
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While you shouldn't have run full synthetic oil in the engine for break in it may be just fine. Me looking at the piston tops does nothing. You need to look at the crosshatch in the bores and the skirt wear on the pistons. I see much better wear patterns and break in when using regular oil vs synthetic. You want that little extra friction that regular oil has compared to synthetics to assist break in, mainly for the rings. It also depends on the style of honing used in the cylinders for proper ring seating. Crosshatch angle, finish depth and if a Plateau finish was used or not makes big differences.
I use crank Scrapers all the time. They are a just another way to control oil. Depending on the engines use and rpm range depends if I use a scraper or not.
You need to dump that 350 Chevy for a 400 Pontiac. |
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| Sir English Firebird |
| Posted: Sat Oct 20, 2007 6:02 pm |
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Joined: 18 Oct 2007
Posts: 275
Location: UK
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400 pontiac? do you think so?
Id rather have a big block chevvy.
As for crosshatching etc you obviously know your onions mate, these are definitely knowledgeable opinions.  |
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The Imagery of heat and strength are used as ways of associating the car's punchy performance with the masculine fantasy of full-blooded heterosexual conquest |
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