Phil C Posted July 9, 2019 Report Share Posted July 9, 2019 Hi All, Just refitted the crankshaft, rods and pistons. Block has been re-bored, crank has been re-ground so obviously with new bearings, pistons and rings. How easy should it be to rotate the crank once all torqued down? I haven't rebuilt an engine for 25 years so lacking a bit of feel/experience. I just want a little confidence before proceeding further!! Currently it is very difficult to turn simply gripping the front pulley but needs a lever between the fan bolts. Is that normal? Thanks Phil Link to comment Share on other sites More sharing options...
JohnD Posted July 9, 2019 Report Share Posted July 9, 2019 Did you oil, or better use a graphite lubricant in the bearings? More important than how easy it is to turn - very subjective! - is that it turns smoothly, no hang-ups. most of the resistance will be from the piston rings so make sure they are oiled too - no graphite there! John Link to comment Share on other sites More sharing options...
Phil C Posted July 9, 2019 Author Report Share Posted July 9, 2019 Liberally oiled everything. I checked the rotation at each stage. The crank was beautifully smooth on its own but as you say there is a lot of resistance from six pistons being attached. The rotation effort appears uniform with no obvious high spots. Link to comment Share on other sites More sharing options...
Sparky_Spit Posted July 9, 2019 Report Share Posted July 9, 2019 On a freshly rebuilt 4 pot it took quite some effort to turn the engine over by hand as it was pretty stiff, and I had to use a socket and bar on the crank pulley nut to turn it over for setting the cam timing, rockers, etc, etc. I used Graphogen on all bearings and cam lobes, pre-pumped the engine oil around until I got some pressure using a drill down the dizzy hole, but only used a very light smear of engine oil on the pistons. When starting it for the first time it was fine and the starter didn't struggle. With two more pistons than me I expect yours will be even stiffer to turn by hand. With mine it was definitely the pistons causing the drag, because when it went over TDC/BDC every time it went suddenly easy for a few degrees. Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 9, 2019 Report Share Posted July 9, 2019 If you think about the loads applied by the rings it takes a lot to overcome the friction Stiff to turn yes , some change as forces legthen with tdc , bdc and efforts to compress valve springs all add to what can be a huge effort to rotate a new build . Pete Link to comment Share on other sites More sharing options...
poppyman Posted July 10, 2019 Report Share Posted July 10, 2019 You have taken care to do it right, everything sounds good to me.... If they dont turn at all you have a problem! Tony. Link to comment Share on other sites More sharing options...
JohnD Posted July 10, 2019 Report Share Posted July 10, 2019 15 hours ago, Phil C said: Liberally oiled everything. I checked the rotation at each stage. The crank was beautifully smooth on its own but as you say there is a lot of resistance from six pistons being attached. The rotation effort appears uniform with no obvious high spots. Good to go, then! John Link to comment Share on other sites More sharing options...
Phil C Posted July 10, 2019 Author Report Share Posted July 10, 2019 Thanks all. I think I was just worrying too much! Onwards and upwards eh? 🤓 Link to comment Share on other sites More sharing options...
johny Posted July 10, 2019 Report Share Posted July 10, 2019 Perfectly understandable after all the effort..... Link to comment Share on other sites More sharing options...
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