Finding A Used Engine Block That Is Ideal For Rebuilding
Often when an engine rebuild is required, an engine block must be replaced. Used cylinder blocks often have defects of their own, and a thorough inspection before purchasing one can save the automotive enthusiast a lot of money and a serious amount of time.
It is very important to learn how the used cylinder block was stored. Blocks which have been stored in the elements may have taken in rain water which can crack the casting if it was subjected to freeze thaw cycles. Another problem with water is rust. Water which has entered the cylinders may cause extreme pitting, which can’t be bored out even when using the maximum oversized pistons. Pits in the ring lands are a significant problem with engine blocks that have been stored outside. Rings that must ride over pits will not properly seal and likely will lead to an engine that smokes because of blowby and a much shorter life.
As with any used engine component, it is likely that a used cylinder block has been machined before. Therefore, it is essential to determine the dimensions on the cylinder block prior to purchasing. There are a good number of automotive enthusiasts that have lost a major amount of money because they did not conduct a general inspection prior to purchase. A dial bore gauge, or dial calipers if a gauge is not handy, can quickly determine the present size of each cylinder bore. At such time the person considering the purchase of the block can determine parts availability of oversized pistons and rings.
When purchasing a pre-owned cylinder block, the engine builder must also pay close attention to the main caps. Main caps which have a cross-hatch pattern visible in them more then likely have been machined outside of the factory. Assuming the align bore is within tolerance, it is possible that an undersized timing chain set might need to be used to provide for adequate chain tension and valve timing.
Buying an engine block with matching main caps is very important. The cost of align boring and honing may easily surpass $200 and increase the total expense of rebuilding the engine.
Used cylinder blocks can easily hide flaws, defects and damage. Therefore, it is important to fully inspect a cylinder block before the purchase. If it is clean, then important dimensions can be carefully validated. With a detailed pre-sale inspection, the engine rebuilder may potentially save thousands and a major amount of time. [..]
Employed as an ASE Certified engine machinist, Bill Maxim has performed a variety of engine block machining operations for a variety of automotive, industrial and commercial applications. Bill has been an automotive machinist for over 10 years.
