shua1269 Posted September 2, 2014 Share Posted September 2, 2014 I am in the process of piecing together my Small Block 400. Here is what I have: SBC 400(509 Block) .030 over bore. Callies Crank Stock replacement pistons and rods. And I just picked up some Dart Iron Eagle heads. 10510020F. 215 Iron Eagle head. It has a 215cc intake runner and a 49c combustion chamber. It has a 2.05” intake valve and a 1.60” exhaust valve. WHAT I NEED HELP WITH: The Guys at Dart told me that with these heads I would require a -21.5cc Dish piston because The reason being is with the 49cc chamber, the casting is rolled when we machine it. this mimics angle milling which changes the valve angle. But I can't find any of these pistons for my particular application. Where is the best place to find these? Thank you in advance for your information. Link to comment Share on other sites More sharing options...
Bromley's Corvettes Posted September 2, 2014 Share Posted September 2, 2014 Have you tried diamond or you could call Chris at Five Star #623-939-0345 Why are you wanting to run heads with such small c.c? Be better to swap heads so you can use flat tops. Also if your on a tight budget it be hard because you could have forged pistons made for your engine but not cheap. Link to comment Share on other sites More sharing options...
shua1269 Posted September 2, 2014 Author Share Posted September 2, 2014 Have you tried diamond or you could call Chris at Five Star #623-939-0345 Why are you wanting to run heads with such small c.c? Be better to swap heads so you can use flat tops. Also if your on a tight budget it be hard because you could have forged pistons made for your engine but not cheap. I picked the heads up for a steal, as I am on a budget, the guy didn't know the cc's and I didn't know how to check it when I bought them. Found this out now after talking to Dart. I'm trying to find pistons for a decent price, otherwise I'm stuck til I can get these sold and find another set of heads that will work better. I'll call Chris to see if he's got some. Thank you. Link to comment Share on other sites More sharing options...
Two Fangs Posted September 2, 2014 Share Posted September 2, 2014 What are your engine requirements? Do the pistons have to be forged? Summit has these hypereutectic versions that will work, as long as you use a more common 350 rod (5.700"). http://www.summitracing.com/parts/uem-kb168-030/overview/ Link to comment Share on other sites More sharing options...
shua1269 Posted September 2, 2014 Author Share Posted September 2, 2014 What are your engine requirements? Do the pistons have to be forged? Summit has these hypereutectic versions that will work, as long as you use a more common 350 rod (5.700"). http://www.summitracing.com/parts/uem-kb168-030/overview/ Well I was hoping to use it as a street/strip motor. The pistons do not need to be forged. After doing a lot of research and calling a couple machine shops, I was told that my likely minimum Compression Ratio will be 12.4:1 which will not be good for the street. Thank you for the link, It looks like those might work. I'll have to check the deck clearance so I can get a better idea of what my compression ratio would be with them. Link to comment Share on other sites More sharing options...
Two Fangs Posted September 2, 2014 Share Posted September 2, 2014 If you convert it to E85, you can run the hell out of it on the street with 12.5:1 compression, LOL. Chances are, however, in order to be truly happy, you may have to sell or swap those heads and get something with a bigger combustion chamber. Link to comment Share on other sites More sharing options...
shua1269 Posted September 2, 2014 Author Share Posted September 2, 2014 If you convert it to E85, you can run the hell out of it on the street with 12.5:1 compression, LOL. HAHA yea a little more work that I'd hoped for. How bad would it be driving on the street with 12.5:1? Like to and from car shows and meets? Link to comment Share on other sites More sharing options...
shua1269 Posted September 2, 2014 Author Share Posted September 2, 2014 Using Summit's compression calculator. I ran through a couple scenarios and this seems to be close to what I could have. Thoughts? Bore: (diameter) 4.155 in. Stroke: 3.75 in. Cylinder Head Volume: 49cc Effective Dome Volume: +22 cc. Use (-) for Dome and (+) for Dish. Deck Clearance: 0 in. (Still not sure what it actually is but just in case) Compressed Gasket Thickness: .07 in. Number of Cylinders: 8 Compression Ratio : 10.63 : 1 Total Displacement (in.3) : 406.77 Total Displacement cc's : 6668.36 Link to comment Share on other sites More sharing options...
LastC3 Posted September 2, 2014 Share Posted September 2, 2014 Difficult tuning for street enjoyment with this compression and 91 octane fuel ... probably leaving power on the table .... Have to agree with above ... especially with a budget number ..... get a good set of heads that is more in line with what you want to build .. Will save you dollars in the long run trying to make what you have work and be able to take full advantage of the power capabilities ,,,, Link to comment Share on other sites More sharing options...
Two Fangs Posted September 3, 2014 Share Posted September 3, 2014 Deck clearance is the how far down in the cylinder bore the piston is at TDC. Traditionally, engines have the pistons recessed very slightly at TDC. Zero decking is a phrase used to state the piston is even with the deck of the block when at TDC. Negative deck clearance is when the piston top is slightly higher than the block deck at TDC, requiring the head gasket thickness to prevent the piston from contacting the cylinder head. To figure this, block deck height, rod length, crank stroke and the compression height of the piston must be known. To measure it requires a dial indicator, or a straightedge and feeler gauges. Link to comment Share on other sites More sharing options...
Two Fangs Posted September 3, 2014 Share Posted September 3, 2014 If you convert it to E85, you can run the hell out of it on the street with 12.5:1 compression, LOL. HAHA yea a little more work that I'd hoped for. How bad would it be driving on the street with 12.5:1? Like to and from car shows and meets? If it is strictly car shows, meets, and a jaunt to the dragstrip, I would run it on race gas or e85 with that kind of compression. It is really the only way to keep those hypereutectic pistons safe from detonation, while still being able to at least make enough power with timing to get the car out of its own way.. Link to comment Share on other sites More sharing options...
joe@cpr.com Posted September 3, 2014 Share Posted September 3, 2014 calculate dynamic and static compression, depending on the cam you might be able to run pump gas if it's bleeding some compression off. 12:5:1 doesn't tell the entire story. Link to comment Share on other sites More sharing options...
Two Fangs Posted September 3, 2014 Share Posted September 3, 2014 calculate dynamic and static compression, depending on the cam you might be able to run pump gas if it's bleeding some compression off. 12:5:1 doesn't tell the entire story. SCR is calculated pretty closely above in the mid 10's with a gargantuan .070" head gasket that will kill any chance at all of a substantial quench area. However, with the engine in this configuration, delaying the IVC to the mid 60's after TDC yields a DCR combination that will run on pump, but it will certainly be doggy, especially with no appreciable squish or quench. Link to comment Share on other sites More sharing options...
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