1989martin1 Posted October 28, 2014 Posted October 28, 2014 Hey all Does anyone know the standard crankshaft diameters I've bought a new engine and I'm not sure if it's been reground already so I'm looking for the standard size so I can get it machined and buy the correct oversized bearings from td Quote
5e colin Posted October 28, 2014 Posted October 28, 2014 measure your journals/lobes and get back to me ( if you have the tools to measure them ??? ) also the inner diameter from the caps on rods and mains is needed to calculate your bearing size Quote
1989martin1 Posted October 28, 2014 Author Posted October 28, 2014 Cheers Colin I actually just want to know the diameters so I can work out if it's been done before if it has I'll just get it ground to .5 and get the oversized acl bearings I need an original reference so I know what I'm working with Quote
5e colin Posted October 28, 2014 Posted October 28, 2014 i cant give you them because there al diferent sizes mate !!!! have a read tru this thread al is explained there http://www.ukstarletowners.com/topic/86453-big-end-and-main-bearing-sizes/ Quote
1989martin1 Posted October 28, 2014 Author Posted October 28, 2014 Ahh I get it now mate so as a standard shaft it could be between 3 sizes can you explain this to me Say my shaft is 1 43.00-43.07 am I right in assuming if I buy .25 oversized bearings the machinist will grind the shaft to 42.75 within the .07 tolerance ? Quote
5e colin Posted October 28, 2014 Posted October 28, 2014 nope more like 43.007 its in the last thousands where the diferent sizes are in but why do you want a regrind if she is running ????? and nope you need the measurements of each lobe then inner caps then a bit of calculating to see if your still whitin size of the bearings if there not then the crank will nead a regrind and polish and have to measure again an.d. order a bigger size bearing so what i am saying is after calculations if its within the spec then its not regrinded if its out of spec its bean grinded before and crank will be ready for the bin if anything happens Quote
1989martin1 Posted October 28, 2014 Author Posted October 28, 2014 Wow I didn't realise the tolerances were so tight, The engine isn't running its knocking 500 miles after the previous owner rebuilt it, I haven't had time to check the actual shaft yet but I presume he's fucked up somewhere, so tomorrow I'll whip it out and take it into the machine shop at work and get it measured, what sizes am I looking for as in tolerance wise? Just want to know so I can either scrap it or get it ground Quote
5e colin Posted October 28, 2014 Posted October 28, 2014 around 39.000 best to bring block and cranck to get it al measured for main lobes an journals same for big ends as i said cant give you a precise nr because between 39.000 and 39.010 is miles of and several bearings slot in there si its 39.??? Quote
1989martin1 Posted October 28, 2014 Author Posted October 28, 2014 Excellent thank you very much Colin I'll get the guys to check it all over and give me the sizes and the bearing sizes I need if the crank is no good I'll just get a new one Quote
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