3126 and C7 Long Blocks Caterpillar

3126 and C7 Long Blocks

Long Block Selection: General Information

The purpose of this technical supplement is to help you decide if there is a AVSpare remanufactured long block available for a particular engine application. When making your decision, please keep the following points in mind.

Long blocks are not available for every engine application. The long blocks we do offer can, however, be used to service many applications even though the long block does not exactly match the original engine configuration. When the consist of the Reman product offering differs from the consist of a customer's engine, only the dealer and customer can decide whether or not it makes economic sense to change the parts that differ.

It's AVSpare's policy to incorporate the latest critical engineering changes into Cat Reman products. Therefore, long blocks may be offered with some parts from a later design era as service repairs for engines from an earlier design era. An example is the 3406C crankshaft, connecting rods, and pistons which are in certain 3406B long blocks. The result is that the parts in the long blocks match each other but do not match the parts consist of new production engines, nor do they match any single parts book. When long block parts consists differ from the official parts list, Reman provides an engine plate alerting the customer to Special Instruction or Service Magazine articles for information on non-standard parts.

Make sure any future engine/long block repairs that do not use parts called for by the original parts book, or official replacements called for by parts and service sources, are carefully documented. If you choose to make any configuration or consist changes, good documentation can prevent problems the next time parts are ordered.

3126 and C7 Long Block Selection

First, use normal parts information sources (parts books, microfiche, SIS, NPR, the Reman Products Guide, etc.) to look up the Reman short block intended to service the customer's engine arrangement. Next, find that short block in the following chart and read the long block part number from the top of the same column.

Next, follow the long block candidate column down into the consist section of the chart. Check the camshaft, then cylinder head part numbers shown against the part numbers called for by normal parts information sources to service the customer's engine. Don't forget to check the NPR to determine that you are using the most current part number. Now check the other part numbers listed in the same column of the consist chart. For a long block candidate to become a "selection", all the part numbers listed under the long block part number should match the correct service part numbers for the customer's engine. If, at any point in the above process the Reman consist fails to match the part numbers called for to service the customer's engine, Reman does not have an offering that matches the customer's engine. You may select a long block which isn't a perfect match if you believe changing the parts which don't match is worth the time and money to do the work.