High silicon in 99' Crown Vic 4.6L modular.

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When I bought my car in 05' it was always getting 10-11 ppm silicone and the last 2 changes were at 15 & 16 ppm. I checked the zip tube and airbox and cannot find any issues with it. Do I need to rip the intake manifold off and do those gaskets? I have always used the cheapo frams which have always performed well and do not block the MAF. I know the preoiled ones can screw with the MAF element. The air filter looks like it has always seated and the air box does not appear warped. Any suggestions on why the high silicon?
 
I may have missed it, but I don't see any UOA posted under your user name.

If the silicon isn't accompanied by AL and Chrome, then it can still be dirt, it's just not entering via the airhorn getting around the air filter. It can come in via the PCV plumbing. If it's getting big enough chunks, it can cause bearing wear. There you will see a spike.
 
Your right, I did not post it. I have it in a PDF. My scanner does not work with vista. Only win98 which I junked the computer years ago.

Anyway, the last sample of mobil 1 did horrible, engine was loud and it got black in like 700 miles, iron, silicone was high and aluminum was up by 1ppm. I dumped it and ran auto RX using the old forumla havoline and then went with PP 5w30. As soon as I dumped the mobil 1 the engine was nice and quiet again. All values are normal or lower now excpet silicone. I installed a new PCV every year and yes, I did check it and the plumbing real well. I also go overboard on the air filter, it gets changed way early before it every gets packed with [censored].
 
Hard to index without seeing the whole picture. If Al wasn't elevated (1ppm+/-)and other stuff (except for a slight kick in Fe), then I'd say it was some part of an additive component.

Just copy (as in tape and paste) someone else's UOA for the elements and junk ..and then swap in your values.
 
""was up by 1ppm.""

relax test to test lab to lab I would not worry about 10ppm of anything and 1ppm is just "noise"
bruce
 
Well, i am not sure if I found the problem, but a wire harness rubbed the rubber elbow on the fuel pressure regulator, there was a nice wear spot that looked like it may have been all the way thru. I rtv'd it and also rtv'd the air filter to the air box. Will make it super hard to get it apart but what the heck?

Here is a screenshot of the uoa, you will need to full size it to read.

 
Originally Posted By: bruce381
Bye the way are not "hyperutetic" spelling pistons high a SI used in the alloy?
bruce


They sure are! Good catch
wink.gif
Hypereutectic pistons are a high-silicon aluminum alloy that resists expansion/contraction FAR better than traditional forged or cast pistons, which allows for tighter piston-to-wall clearances, which subsequently reduces blow-by and helps with emissions.

Odd that it didn't like Mobil 1, my father's '03 Town Car Cartier lives on their 0w20 and the oil always stays pretty clean between changes, which are done at ~15,000Km.
 
Hypereutectic pistons are cast pistons. The high silicon content is used to impart high fluidity to the molten metal of the aluminum alloy during the casting process and the primary silicon that forms from the hypereutectic alloy during solidification imparts good wear resistance on the surface. It does not resist thermal cycling more than any other aluminum alloy. I've never heard of silicon content increased in aluminum alloys to offset expansion characteristics.

As far as silicon originating from hypereutectic pistons, I would expect a companion increase of aluminum present in the UOA if that were the case.
 
5ppm silicon increase could just be from winter driving on sanded roads or some gravel road driving.

15ppm silicon is nothing in a big American Iron V8 even with short 3k oic,s.
15 ppm is the lab's UA for this engine.
you have minimal to no wear metals

i'd run that Mobil 1 to at least 8k and will easily do 10k in that easy on oil Ford 4.6L
wasting money and oil at 3k
switch air and oil filter brands for peace of mind
spend the money saved on a bottle of oil nerve calming booze and an Amsoil Hi Tech air filter.
 
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""As far as silicon originating from hypereutectic pistons, I would expect a companion increase of aluminum present in the UOA if that were the case""

Makes sense to me
bruce
 
My 04 CV didn't like Mobil 5w20 either. And the iron about doubled when running Mobil.It was alot noisier too. I looked at the UOA and didn't see much to be concerned about. You may have introduced more silicon(e) into the system when you rtv'd the airbox. I had to do some engine work on my 04 and the silicone rtv sealant leeched into the oil raising the silicon reading for about 12k. If you use a factory Ford PCV, you really don't need to change them more than every 50k
 
How would wear accelerate on the pistons? I always warm the engine 1-2 minutes and then drive easy even during the summer. I only go to WOT when it is completely up to temp and only to pass a car not just for the fun.

I gave up on mobil1. Was WAY TOO expensive around my town and did nothing to benefit me. I got a bunch of PP at AAP for only 2.84 per qt. Still have boxes and boxes of it left. My engine was spotless inside when I bought it because the state did 3 ~ 4k changes religiously. I want to keep it that way. I may go to 5k when the UOA goes back to normal.
 
Originally Posted By: simple_gifts
Quote:

UOA still too small to read after clicking on it.

Did you click on the + sign along the bottom, then click on the screen again.


Thanks .... when I read that last night, I thought "original screen" would return it to the super-small size in this thread.... after all - "super-small" is the original screen.

Thanks again for the help.
 
Originally Posted By: Kestas
Hypereutectic pistons are cast pistons. The high silicon content is used to impart high fluidity to the molten metal of the aluminum alloy during the casting process and the primary silicon that forms from the hypereutectic alloy during solidification imparts good wear resistance on the surface. It does not resist thermal cycling more than any other aluminum alloy. I've never heard of silicon content increased in aluminum alloys to offset expansion characteristics.

As far as silicon originating from hypereutectic pistons, I would expect a companion increase of aluminum present in the UOA if that were the case.


I was told by a number of Ford engine builders that the reason Ford switched from the TRW forged pistons in the 302 for 1993 in the Mustang was due to the fact that the hypereutectic pistons did not expand and contract as much as the forged pistons, and subsequently allowed for tighter piston-to-wall clearances, which helped with emissions.

They were already using cast pistons in various other iterations of the 302, all non-HO versions, so I cannot see any reason for the switch to hypereutectic unless there was in fact some sort of advantage in terms of emissions performance.

And yes, they are cast, my "cast/forged" remark was in regards to traditional simple non-hypereutectic cast aluminum pistons, found in earlier engines which did not receive the same TYPE of cast piston, so I differentiated by use of the hypereutectic moniker and omitted the word cast for simplicity's sake, as it is generally implied.

Agreed on the aluminum comment, that would make sense.
 
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