42D22 Posted January 31 Report Share Posted January 31 (edited) Is there a minimum and maximum clearance between top of piston and top of block at TDC? Nothing in any of my service manuals. Machine shop called asking for spec. Thank-you Edited January 31 by 42D22 Quote Link to comment Share on other sites More sharing options...
Sniper Posted January 31 Report Share Posted January 31 Well theoretically the bore is straight and true and there shouldn't be any variation to speak of from top to bottom or anywhere in between. As far as I know there's no specified clearance given the parameters you mentioned. However there is a specified clearance and it's applicable anywhere in the bore. I don't know what it is off the top of my head though Quote Link to comment Share on other sites More sharing options...
42D22 Posted January 31 Author Report Share Posted January 31 Machine shop says he has 0.035 depth between top surface of piston and surface of block at TDC Quote Link to comment Share on other sites More sharing options...
FarmerJon Posted January 31 Report Share Posted January 31 Check out this engine build guide, from Tony Smith. He recommends having .040 from the piston crown to flat of cylinder head. Due to the availability of gaskets, this usually ends up with the pistons OUT of the block around .020 Quench is often neglected by rebuilders, but it plays an important role in an efficient combustion process. Tight quench both keeps your compression up AND reduces preignition. https://p15-d24.com/topic/59234-engine-build-recommendations-mopar-flathead-6pdf/ Quote Link to comment Share on other sites More sharing options...
Dave72dt Posted January 31 Report Share Posted January 31 Tony also says most aftermarket cast piston are .020 shorter to the crown than stock so that would place stock at about .015 below deck so you should be able to take at least that .020 off the block and then take a good look at the head before going any further. It may have already been planed and a cleanup pass to ensure a flat head surface may be all you need on it. It will run at least as well as it did when it was new at that point. The more work you have done, the higher the bill. Quote Link to comment Share on other sites More sharing options...
Sniper Posted January 31 Report Share Posted January 31 The problem with shooting for good quench is that you're connecting rods and your Pistons all have to be equalized. Yes it can be done and yes it's going to cost money. Quote Link to comment Share on other sites More sharing options...
FarmerJon Posted February 1 Report Share Posted February 1 Low buck, middle of the road option is to deck for good quench of the highest piston/rod/cylinder. Yes some will not be perfect, but nothing will hit, and all will be better than leaving them way down in the hole. Quote Link to comment Share on other sites More sharing options...
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