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Discussion Starter #1
Hello all

I have a question about ring cap and Silvo-lite pistons. Is the cap on the compression ring larger as the KB hyper pistons or is the cap the same as a standard cap.

They are going into a SBC 400 .040 Over

Stock ring cap
Bore 4.165x.004= 0.016

KB Hyper ring cap
Bore 4.165x.0065= 0.027

Silvo-lite
Bore 4.165x ? = ?



thanks in advance
 

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King of my Man-cave.
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Stock, cast Silvolite pistons use standard ring end gap factors.

"Claimer" Silvolite pistons, now sold by Keith Black, use the KB ring end gap factors.

There are a lot of the older Silvolite "Claimer" pistons out there. These hypereutectic pistons are similar the KB pistons (made by the same company) and use the KB ring end gap factors.

tom
 

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Discussion Starter #6 (Edited)
thanks tom

but i'm putting in bowtie heads (w/steam holes drilled) 2.02/1.60 valves, 1.6:1 RR, isky .488lift (518 total) [email protected], 750 holley w/victor Jr, ARP bolts heads & connecting rods, TH350 w/2500 stall. stock crank and rods

Is that cap size still good to run
 

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I wouldn`t run these pistons, and why is due to the compression height. The stock compression height from GM is 1.560, these pistons have 1.540, .020 off which will kill the compression ratio. I had flat top pistons like these in a 350 that had .020 off the compression height, with 64cc chambers and close to a stock cam it only had 140 psi and it was a dog power wise. If you run these pistons ring gap shouldn`t be a factor since the top ring will be way down from the top of the bore. I did some looking and came up with these:
http://cgi.ebay.com/ebaymotors/SBC-...019QQitemZ290043569510QQrdZ1QQsspagenameZWDVW
 

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Aha! NOW we have the rest of the story! ;)

As DoubleV and I have said, these are stock type replacement pistons. Your build needs a better piston, such as the ones he recommends.

I personally wouldn't buy them from e-bay, I have had 3 sets that guys have brought in that had some bad pistons in them. Chances are you may get a good set, but I'm tired of writing letters so guys will get their money back....... :mad:

tom
 

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Discussion Starter #9
Cylinder Bore Size = 4.165
Piston Stroke Length = 3.75
Head Gasket Bore Diameter = 4.166
Compressed Head Gasket Thickness = .031
Combustion Chamber Volume In CCs = 58cc
Piston Dome Volume In CCs Negative For Dished Pistons = -22cc
Piston Deck Clearance Negative If ABOVE Deck : = .015


with these number i come to 10.2:1 compression which is where i want to be for a street car.

do you still think i should go with a different piston.
 

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I had a nice talk with a KB tech one day regarding those type of replacement pistons. AFTER i bought them.

Silvolite reduces the compression height on all those replacement style pistons .020-.030" to compensate for decking. I am building a motor using a set of silvolites. I did my calculations using the info on the website and came up with 10.4 : 1 for the setup I have.
(1970 4V cleveland, with quench heads. stock is supposed to be 11+:1. I got the later dish pistons hoping to bring it down to mid 10:1)
When I actually CC'd everything after I got the pistons it turned out to be more like 9.5 : 1. :(

I really doubt that the piston you show will sit above deck.

(as usual I can't get the KB website to work on my computer. I don't know why that site always locks up. )

Go with one of the KB pistons. They are sized for performance motors.

Hope this helps, mikey
 

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Discussion Starter #12 (Edited)
anything help mikey thanks

My bad I ment -.015 deck height block was decked .003



Heads are Bowtie 14011034 64cc angle milles to .120,( intake to match) buddy of mind ran them in his circle track car when they had all their restriction to 10:1 compression
 

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If you are using a 5.565" rod (stock 400) you are very limited in pistons to get the CR you want. If you use a 5.7" rod, the KB168 (Keith Black) will give you aroung 10.4:1

58cc heads will limit your piston choices no matter what rod length you choose.

tom
 
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