OK Kirbert, looks like this topic has stirred you up.
I am happy to think my estimate is in the ball park, maybe not the last word on the subject but near enough. One day we might have an even better estimate.
Like Ron mentioned, the rings are far more pertinent than bearings.
Let’s close it.
Makes sense. I presume large bores have more drag than small bores, too.
What is “barrel faced”?
K , you gotta be kiddin me? something you dont know about engines!
let me see if i can find my info for that?
ron
Interesting. You’d think it’d leak like crazy, just blowing past under pressure.
Thanks Robin, they dont because the pressure point is higher at the contact point, seals better with less drag/friction!
the Moly coat smooths out on Breakin and from there almost NO more friction!
ron
Is this anything like the Nikasil coating that caused the early XK8 engines to be recalled?
NO nothing like Nikasil, but today many aluminum engines do very well with it,!
after much development Nikasil works good!
coating on aluminum blocks was 1st mass developed by the General Motors Vega 4cyl, 1972/3!
Jaguar engineers just did things on the cheap, so ordered!
it has to have the proper rings also!
ron
So Ron, are you saying the Vega engine has survived the test of time WRT Nikasil bores? Or did they succumb to the sulphur in the petrol which is what did in both Jaguar and BMW engines?
Robin NO Vega did not survive most went down scouring cylinders!
but good old GM paid for iron sleeves installed , those engines are still around !
let me add, the best aluminumblock coatings i have worked with is HONDA 2L engines !
i had a 1995 Honda come in shop over 100K miles on it ,owner said overhaul the engine !
the cylinder walls were perfect ,still had perfect crosshatch pattern,all cylinders! course 25 yrs after GM tried it!
i think that Mercedes has some engines with treated cylinders!, by now probably many aluminum engine bores are treated ?
we dont give GM much credit for all the things they contributed to auto industry.
one comes to mind,LOL, is the 1st mass produced turbocharged car was the 1962 Oldsmobile Turbofire aluminum engined car!
i had new one for a couple days back 1962!
ron
Ronbros
I believe the Coyote engines from Ford now has treated cylinder liners .
This process has been improved to the point where they are no longer a liability.
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Pretty much everybody has treated aluminum bores now. Iron sleeves are a sign of an obsolete engine design.
As I understand it, the improvement in question is that the sulfur was removed from the fuel. It had supposedly been removed before, but too many petroleum companies were lying and claiming it had been removed when it really hadn’t. A couple of lawsuits probably cleared that up.
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all is well, until you want to modify it ,boring it over size , for more CCs.
i dont know of any small shops with the capability to treat RAW aluminium blocks??
so sleeving would be best! there are some really good steel sleeves available nowadys!
way back some engines had Chrome plated bores, but you diffenatly had to use the correct rings!
worked on some ,BIG PIA!
ron
Sulfur (even in the p.p.m. levels) in the fuel poisons the cats and leads to chemical reaction with the nickel component of the film coating the cylinders. As Kirby states, correctly, it wasn’t BMW, or Jaguar’s fault that this happened. Low mileage XK8 engines that survived the fiasco 20 years ago run perfectly fine with the fuel sold today at the pump…
Ron mentioned Mercedes – they did not use Nikasil coatings. Instead the big MB engines from that era – M119 (V8) and M120 (V12) – are made of alusil (or silumin, depending who you talk to). No liners, no coatings. Just an alloy that is hardened by the incorporation of very large amounts of silicon.
Many of those engines are coffee tables now. Rich running and cylinder washdown quickly cause excessive wear and there are very few machine shops that are equipped to handle the job:
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thanks steve , that clears up some things!
i’m kinda old fashioned , for rebuilds and modifing ,i’ll stick to iron cylinder bores !
i think the reason engine manufactuers went treating aluminum bores was a money saving idea!
(bean counters)?
and when worn out , they recycle the cars! and sell new cars!
ron
nothing good happens in the world where money is involved ? LOL.
except for the those collecting it!
ron
Actually, you might wanna rethink that. The nifty feature of the aluminum cylinder treatment is that it is oleophilic, meaning oil sticks to it and water does not. It’s also harder than steel, per the Wikipedia article:
" Nikasil is short for Nickel Silicon Carbide. Silicon carbide is a very hard ceramic (much harder than steel) that can be dissolved in nickel. The nickel solution can then be electroplated onto the aluminium cylinder bore. The piston rings will then rub off the exposed nickel, leaving a very hard layer of silicon carbide to prevent the cast iron/steel piston rings directly contacting the aluminium cylinder. With this setup, the engine tolerances can be much tighter for better performance. The cylinder must be re-plated after it is re-bored, but Nikasil is extremely durable, so the cylinder does not need to be reworked as often as an iron or chrome cylinder."
Just measured the old liner out of my 5.3.
98 OD & 89.5 ID.
So if Jaguar had been able to use Nikasil and provide a 98mm bore for the pistons,
all other things being equal would have given 20% more CC = 6.36L.
You can’t do a nikasil retrofit on the 5.3 block even if there was an outfit that can do that kind of work.
Due to the long collar on the outside of the liner, the aluminium part of the bore starts well below the head gasket area. If there were engines with a flush steel liner, no collar or flange, so the aluminium came all the way up to the gasket, thern you could dump the liner.
All highly conjectural of course.
Actually, I believe TWR did, fabbing Nikasil aluminum liners to install in the V12. They abandoned that idea pretty quickly, though. Perhaps racing fuel had too much sulfur in those days.