[Supras] Dowel pins

[berniek at technicaldevelop.com]

Jon:

    You are correct about the stud neckdown.  I was trying to avoid scratching the head. block surface or gasket by trying to put the thing together without the dowels.  I'll probably put them in the head, and will use the engine hoist to carefully lower the head onto the block.

    About the dowels:  I was also thinking about making up dowels about .020" smaller than stock.  The head grows in length about .040" more than the block in a 100C temperature span because of expansion coefficient differences.  It seems as if tight fitting dowels would cause stress concentration to occur possibly leading to localized head distortion around the dowels.  Any comments would be appreciated.  

    Thanks for the tip about diamond paste.  I was going to use silicon carbide since I have quite a bit of it, but your idea sounds better.  The way I was going to do the lapping was with a 10" diameter cast iron plate with compound retention squares cut in it, adapting it to a 1/4" socket drive, 1/4" universal joint, and a drill or motor running at perhaps 100 RPM.  I've got a precision straight edge and feeler gauges for cheking it.  

    Apparently you have done this before.  How much tedium would you expect in the job?  I do have a rebuilt head prepared.  

    Thanks.

        Bernie