FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: 69Shakar on September 28, 2018, 11:40:27 PM
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On a 445 build what is the usual or average deck clearance before machining block? I’m trying to figure out if I can use flat top pistons.. the calculators say the combo is 11-1 which mandates premium fuel.. that doesn’t bother me. I’m trying to figure out what would be needed to get to 10.5-1 this going with the trick flow heads which are 70cc. I’m planning on roller cam haven’t decided wether solid or hydraulic ... weighing costs involved same with the rockers don’t really want Chinese junk..I guess you could say how fast can I afford to go but yet make a educated decision on the parts to use..
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The TFS heads come up a little short of 70cc.....not quite 70, usually around 69.7-69.8.
To answer your question, typical block deck height is ~10.170".
The order of importance is to first square deck the block so that the decks are straight, flat, and parallel to the crankshaft centerline. It may take .005" to do that or it may take .020". I would get your block machined correctly first, then see what you have to work with.
To get to a 10.5:1 compression with a 4.080" bore and a 4.250" stroke, with a TFS head, typical head gasket, and the pistons at zero deck, you need a 15cc-16cc dish.
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There are reasons that I did my heads "the way I did"...
Getting compression options with readily (at least theoretically readily...) available pistons was one of those reasons...
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I was told a long time ago that all thing being equal including compression, flat top pistons create more power due to better quench profile?
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Lots of variables there....quench distance, chamber shape, etc.