Piston questions......
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Elder User
Joined: Jan 2005
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From: Lindsborg, KS
Piston questions......
Which are better: domed, flat tops, or dished?
What material is better: Hypercutic (however ya spell that), forged, or cast aluminum?
Do you suggest replacing pistons when rebuilding an engine?
What material is better: Hypercutic (however ya spell that), forged, or cast aluminum?
Do you suggest replacing pistons when rebuilding an engine?
Posting Guru
Joined: Sep 2005
Posts: 2,238
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From: Kiefer, Northeastern Okla
The top configuration of the piston determines compression ratio (short explanation). The dome will have the highest, then flat, then dished (used to reduce comp. for turbo or supercharging.
Cast pistons are the cheapest, then hyper (which have a higher silicon content, that allows them to withstand higher cylinder temperatures), then forged, which are the most expensive, but are a must for nitrous and most turbo applications.
Pistons can be re-used in a rebuild, but should be checked closely for cracks (especially the skirts) and measured for wear and out-of roundness. One side of the piston will sometimes wear quicker. Pistons will have to be replaced if you have the cylinders bored oversize. Hope that helps.-Pete
Cast pistons are the cheapest, then hyper (which have a higher silicon content, that allows them to withstand higher cylinder temperatures), then forged, which are the most expensive, but are a must for nitrous and most turbo applications.
Pistons can be re-used in a rebuild, but should be checked closely for cracks (especially the skirts) and measured for wear and out-of roundness. One side of the piston will sometimes wear quicker. Pistons will have to be replaced if you have the cylinders bored oversize. Hope that helps.-Pete
Posting Legend
Joined: Sep 2001
Posts: 30,255
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Dish usually refers to compression related issues. Valve reliefs are usually cast or machined pockets for valve clearance. Some dishes can provide valve clearance but valve clearance is frequently needed towards the edge of the piston. Your individual engine forum would have more information on that subject.
