HRthirtyone Posted September 30, 2006 Author Share Posted September 30, 2006 (edited) i have covered basically everything, except, the reason for the rebuild was i spun a main bearing. without touching the topend i put a new crank and bearings in, so i didnt touch the head, or change the offending con-rod, maybe it was buggered? Edited September 30, 2006 by HRthirtyone Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2542601 Share on other sites More sharing options...
James_03 Posted September 30, 2006 Share Posted September 30, 2006 The crank was measured at an engine shop, and the correct grade bearings were then installed going by the crank size. So did you use standard rb20 bearings again on the rebuild? What you mean by correct grade bearings I have not heard of such a thing. Sounds like you have used the wrong bearings to me. You shouldnt need to install custom bearings or machine them at all, the crank is hardened, at least thats what I understood. Anyway out of the 6 complete rebuilds I have done all of them used the same crank again with just new shells, then just tip oil on the crank and shells before installing. My rebuilt rb30 in the garage turns over by hand very easy. Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2542766 Share on other sites More sharing options...
HRthirtyone Posted October 1, 2006 Author Share Posted October 1, 2006 yea sorry, by that i meant when i bought the second hand crank i wanted to make sure it hadnt been ground down or anything, so yea the bearings used are all grade 0 which is the stock ones back in... motor is out now, going to see what the problem is Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2543162 Share on other sites More sharing options...
Adriano Posted October 1, 2006 Share Posted October 1, 2006 Undo the rods one at a time, seeing if the crank frees up. Make sure you mark the rod caps so they go back on the rod they came off, did you do that last time? If not they will need to be closed and honed. the little tongues on the big end bearings go on the same side of the rod, if they are the other way around they will make the engine tight, then possibly sieze. Hope it all works out Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2543448 Share on other sites More sharing options...
HRthirtyone Posted October 1, 2006 Author Share Posted October 1, 2006 Undo the rods one at a time, seeing if the crank frees up. Make sure you mark the rod caps so they go back on the rod they came off, did you do that last time? If not they will need to be closed and honed. the little tongues on the big end bearings go on the same side of the rod, if they are the other way around they will make the engine tight, then possibly sieze. Hope it all works out yup exactly right, big end caps were on the wrong way around. duhhhhhhh the cylinder no's are meant to line up on opposite side of oil hole in the conrod.. Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2543584 Share on other sites More sharing options...
Cubes Posted October 1, 2006 Share Posted October 1, 2006 oh... So it would have stuffed the bearings then? Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2543612 Share on other sites More sharing options...
James_03 Posted October 1, 2006 Share Posted October 1, 2006 I would replace all the conrod bearings now for sure. If it even began to turn over under the load of the starter then it would have marked the surface of the shells now. Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2543721 Share on other sites More sharing options...
HRthirtyone Posted October 1, 2006 Author Share Posted October 1, 2006 yup back to square 1! lucky theyre only $87 (trade price) it always helps not to do things in a complete rush (out rebuilt & back in in a day) all well, know for next time i guess. Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2543830 Share on other sites More sharing options...
Rolls Posted October 1, 2006 Share Posted October 1, 2006 (edited) You'll never make that mistake again Not as bad as my mate, he rebuilt a 12A motor from an RX7, expensive rebuild, cost about $2800 anyway they fired it up and some how he managed to drop a bolt down the carby. BANG, housings and rotors all had deep groves in them so needed a whole new motor. Lucky his dad's workshop forked out for the price. Edited October 1, 2006 by Rolls Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2543965 Share on other sites More sharing options...
Adriano Posted October 1, 2006 Share Posted October 1, 2006 Do i win a prize? hope the crnks ok, if it has any metal on it you could rub it off with some fine emery and wd40, just make sure you get it clean before you reassemble, and check the clearances with plastigauge, you want 1-2 thou maximum Link to comment https://www.sau.com.au/forums/topic/136771-rebuilt-engine-too-tight-for-starter-motor/page/2/#findComment-2544022 Share on other sites More sharing options...
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