M54A1 Posted September 20, 2009 Share Posted September 20, 2009 Well I just pulled the head on the endt-673 in my 64 B613 to fix a small oil leak. I found no hone marks left in the cylinders, and a small ring groove at the top of the cylinder. The motor ran fine and started easy but had very low oil pressure when hot like 20psi WOT and 5psi at idle. When cold it would have about 45psi at 1800rpm. I thought my oil pressure was low because the oil pressure line was plumbed to the oil inlet of the turbo, but the worn hone marks and low pressure make me think I should rebuild the motor while I have the fenders and cab off. Any advice or recommendations. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/10726-thermodyne-rebuild/ Share on other sites More sharing options...
Mike Posted September 20, 2009 Share Posted September 20, 2009 Hi Jase, It's time to get out the micrometers for those 6 cylinders and see what they read. This will tell you if you have larger than standard size pistons etc. Barry can help when it's time for engine parts. Remember to take some pictures during the teardown process and post them here. And also the re-assembly.You can go back into this forum and find some posts showing some pretty rough looking scuffed up liners and pistons, also cracks in the liners letting oil and antifreeze inside the engine crankcase. Regardsmike Quote Link to comment https://www.bigmacktrucks.com/topic/10726-thermodyne-rebuild/#findComment-40627 Share on other sites More sharing options...
Rob Posted September 20, 2009 Share Posted September 20, 2009 http://cgi.ebay.com/MACK-ENDT-673-Maxidyne-Converted-In-Frame-Overhaul-kit_W0QQitemZ370118006718QQcmdZViewItemQQptZBI_Heavy_Equipment_Parts?hash=item562cc097be&_trksid=p3286.m20.l1116 Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/10726-thermodyne-rebuild/#findComment-40635 Share on other sites More sharing options...
M54A1 Posted September 20, 2009 Author Share Posted September 20, 2009 I pulled the pan today and checked the main and rod bearing, they are worn down to the copper, so I guess I'll pull it on down and start fresh. I've seen the kits on ebay, but they are for a maxidyne converted engine, which means I'll have to use maxidyne rods and have the head cut for o-rings. So I'll try Barry and see if I can get a normal thermodyne rebuild kit. Thanks for the suggestions Quote Link to comment https://www.bigmacktrucks.com/topic/10726-thermodyne-rebuild/#findComment-40645 Share on other sites More sharing options...
Rob Posted September 21, 2009 Share Posted September 21, 2009 I wish you luck as I've had little finding the original type bearings. There are also three styles of cam bearings used in those engines through the years and a couple different types of ring sets. Most are obsolete as are the original style gaskets. Unless dead set on remaining original you would be more cost effective to replace the engine with something more modern.Good luck in your quest.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/10726-thermodyne-rebuild/#findComment-40651 Share on other sites More sharing options...
M54A1 Posted September 21, 2009 Author Share Posted September 21, 2009 So are the thermodyne and maxidyne main and rod bearings different? I thought only the wrist pin size was different. I still haven't found an original style rebuild kit either, although I did find a good running maxidyne still in a truck for $2000. Ya'll may have saved me a lot of time and energy. Again, thanks for the help. Quote Link to comment https://www.bigmacktrucks.com/topic/10726-thermodyne-rebuild/#findComment-40657 Share on other sites More sharing options...
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