Topic: Oversize Merc Pistons Available?


joel robb    -- 01-12-2012 @ 5:48 AM
  Attempting to use a 4" Merc crank in '48 Ford block already prepped for .083 pistons. Anyone know a part # for the Merc pistons that I need to use (+.0825 Merc pistons, have the .0825 Ford set that came out of it)? This engine came from a Canadian Ford Engine rebuild facility and the valve area in the block is ported/relieved.


supereal    -- 01-12-2012 @ 7:14 AM
  When you say "prepped", does that mean the block has been bored and honed? Fitting pistons to the bore is one of the critical parts of engine building! As is fitting piston rings. We obtain our oversized pistons from a company called Egge. They have a web site, egge.com.


37RAGTOPMAN    -- 01-12-2012 @ 3:07 PM
  what I do is buy the pistons first,[after deciding what oversize piston will clean up the cylinders,] and then have the person boring the engine, mic the pistons and bore accordling to the size of the pistons, you will be surprised the differences in sizes from one piston maker to another,
hope this helps 37RAGTOPMAN

This message was edited by 37RAGTOPMAN on 1-12-12 @ 5:13 PM


joel robb    -- 01-12-2012 @ 4:35 PM
  Thanks for the info and what I meant was this engine was already done, bored and honed for the .083 oversize pistons. I am trying to find same oversized Merc pistons to use the Merc crank. May just have to buy new if others can't be found


TomO    -- 01-13-2012 @ 8:06 AM
  I would buy new pistons for any rebuild job. The newer pistons have been so improved from what was available in the 50s, that it does not make sense to put that old technology into a block that just had expensive machine shop work done to it.

There have been reports on other web sites that the Egge pistons have been hitting the heads. It may be just one or 2 out of a set of pistons.

Tom


supereal    -- 01-13-2012 @ 11:24 AM
  We build lots of engines, and haven't had that problem, Tom. If the heads are not standard, or have been shaved, we "clay" the heads to be sure there is no piston or valve interference. Another supplier of pistons is Mahle. They are now coating the piston skirts with a permanent anti friction substance. We mostly use Egge because they are less expensive than others. It is tough to buy pistons for a block that is already bored and honed. When we take on a job, we obtain the pistons first, then bore and hone to fit them. Trying to find pistons to fit a non standard bore might be OK on old engines, but today's close tolerances make that unlikely.


joel robb    -- 01-13-2012 @ 2:32 PM
  Thanks to everyone for their input and help. leaning towards EGGE at this time - their online catalog lists a +.083 for the 4" Merc crank but everyone has provided some things to think about. Thanks!


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