How do I know if an aluminium engine block will be priced by weight alone or assessed for alloy grade?
Short answer: Most yards price aluminium engine blocks as generic "cast aluminium" by weight alone, because separating out the exact alloy from a used engine at yard level isn't economical. Alloy-specific premiums are mostly something larger-scale remelters or specialty buyers pay for bulk, sorted cast lots — not something an individual seller dropping off one block should expect.
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List Free →Why blocks usually get a flat “cast” rate
An engine block is a casting, and castings are made from higher-silicon aluminium alloys designed for pouring rather than strength-to-weight efficiency. Figuring out the precise alloy of a specific block would require lab-grade testing that isn’t practical for a single item coming through a general scrap yard — so in practice, most yards simply weigh it and pay the standard cast aluminium rate.
What can change that
Attachments matter more than alloy precision at this scale. Steel liners, bolts, brackets, or other non-aluminium parts still bolted to the block will usually get deducted or require you to strip them first, since they add dead weight that isn’t aluminium at all. A clean block with attachments already removed will weigh less on the scale, but it should be priced fairly at the full cast aluminium rate rather than being discounted again for “possible contamination” once the obvious steel parts are gone.
When alloy grading does apply
If you’re dealing in volume — a stack of blocks and transmission housings from a wrecking yard, for example — it becomes more worthwhile to ask a buyer whether they pay a premium for sorted, single-source cast versus mixed cast. At that scale, some specialty buyers do test and pay differently, but it’s the exception rather than the norm for casual or one-off sales.
How ScrapTrade Makes This Easier
For higher-volume cast aluminium — a stack of blocks rather than one — listing on ScrapTrade lets multiple buyers compete on the same lot, which is usually the fastest way to find out whether anyone in your area actually pays a sorted-cast premium.
Ready to sell or source aluminium scrap without the guesswork? ScrapTrade connects verified buyers and sellers with escrow-protected payments and transparent weighing.
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