Dp351zcar Posted February 2, 2002 Share Posted February 2, 2002 I am putting together a 74 302 and I had the pistons put on the rods a couple weeks ago. The rods go on the crank one way, and when I put the short block together I had seven pistons with arrows pointing to the front and the one in my hand would point to the rear. My question is can the pin be pressed out and in again without any damage being done to the assembly? Can I assemble the engine with one arrow backwards? I don't know if pistons have a offset pin or why a arrow would be there as they have the four valve reliefs so the could be used in eather side. They are just cheap cast pistons but if it's going to be put together I want to do it right. DP Quote Link to comment Share on other sites More sharing options...
Dp351zcar Posted February 2, 2002 Author Share Posted February 2, 2002 I know the rods can go anywhere. When I said that the rod goes on one way what I meant was that the bearing is offset in the bigend of the rod. There is a little bit of the bigend that is not covered by the bearing and I have found that if that side does not go towards the radius of the crank rod journal the two rods won't fit on the journal. Or that is the way it was for my H- beam rods on my 351, I haven't tried it on the 302. What I was wondering is if the pin can be pressed out and installed with out damaging it. The reason I am asking this is the shop that did this closed and with my job it is hard to get out to any other shops. Quote Link to comment Share on other sites More sharing options...
Guest scca Posted February 3, 2002 Share Posted February 3, 2002 arrows should be forward, the valve reliefs may not line up reversed... the shop that installed the pistons on the rods messed one up or the rod itself doesnt matter in this case. the arrow is the important part generally not the location of the number on the rod. or at least AIR.. Quote Link to comment Share on other sites More sharing options...
Dp351zcar Posted February 3, 2002 Author Share Posted February 3, 2002 bump Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 3, 2002 Share Posted February 3, 2002 http://www.jason.fletcher.net/tech/sherman/sherman.htm There is a very informative article on the location of the piston notches. You can run the pistons with the notches towards the rear,valves should be OK. AS LONG AS THEY ARE THE STANDARD 4 VALVE RELIEF PISTONS Read the article,BEFORE TRYING THIS,it is a scan from a well regarded magazine and engine builder. They made a hair over 400 hp on an engine dyno,a bored 302,ported stock heads,off the shelf cam,and a 4bbl carb. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 13, 2002 Share Posted May 13, 2002 Don't install part of the pistons reversed and part facing the correct way! The arrow isn't just there to insure the valve notches are correct. Almost all pistons have a offset pin to minimize thrust against the cylinder wall. Any that are install reversed will "rattle" upon cold engine start. As far as removing the pin to correct to problem, as long as you don't overheat the rod end, you should be ok. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted May 13, 2002 Share Posted May 13, 2002 Just press the pin out, reverse the piston, and press it back in. Offset, even with the symetrical relief pistons will still call for all of the pistons to be installed alike. When you do press the pin out, make sure the pin still slides into the piston freely before pressing it back in. Sometimes when this is done, the pin holes in the piston need to be lightly honed (very lightly) to free up the pin again. Quote Link to comment Share on other sites More sharing options...
Dp351zcar Posted May 13, 2002 Author Share Posted May 13, 2002 I tracked the person who did the work and he took care of it. After I told him the right things to reassure him I was rignt. He just pressed out the pin and heated up the rod pressed it back in. It is in my 302 now it will be a while before I get to test it as I am just welding in the subframes in now. The body is stripped of everything now, maybe someday I will get to hear it run. Thanks guys Don Quote Link to comment Share on other sites More sharing options...
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