KKtrips Posted September 14, 2011 Share Posted September 14, 2011 I would use red still. But up to you Oscar. My reasoning is red does 0.051 - 0.152. I doubt the problem will be too tight a tolerance as the engine is already worn, as you are allowed UP to 0.100 I would be measuring to make sure the clearance is no bigger than that.. PS Phil - red measures 0.051 - 0.152 and last time I checked my maths 0.100 is in between them numbers.. KTHXBAI Quote Link to comment Share on other sites More sharing options...
fuel Posted September 14, 2011 Share Posted September 14, 2011 but 0.1mm is the absolute limit, the Mitsubishi manual specifies that it SHOULD be between 0.02 and 0.05, which if MY maths serves me correctly is below what the red one can measure. This is assuming he is going to be using NEW bearings - I would highly doubt you would see anywhere close to 0.1mm when using new bearings. From memory when I put my motor together with new bearings and existing crank I was seeing clearances from 0.03 to 0.04mm Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 14, 2011 Share Posted September 14, 2011 I understand what you are saying - But with a worn crank and new bearings I highly doubt you are looking for tight clearances - you are looking for too loose a clearance which in my opinion is what the red would pick up better than the green. If the red squishes wider than 0.51 (the tightest red can measure) then it is a fairly safe bet to say the tolerances are sweet on a worn crank. If it was tighter than 0.51 and you wanted to be 100% safe then you should really check for tight clearances and this would then need green to measure it. I think we both are going for the same result but one of is pessimistic and one is optomistic - I just can't figure who is which.. LOL Quote Link to comment Share on other sites More sharing options...
Beaver Posted September 14, 2011 Share Posted September 14, 2011 If the red squishes wider than 0.051 (the tightest red can measure) then it is a fairly safe bet to say the tolerances are sweet on a worn crank. If it was tighter than 0.051 and you wanted to be 100% safe then you should really check for tight clearances and this would then need green to measure it. corrected. I think. you had 0.51. Quote Link to comment Share on other sites More sharing options...
fuel Posted September 14, 2011 Share Posted September 14, 2011 haha fair enough. Just I found in my experience with that very same type of motor, fitting new bearings on a 'worn' crank resulted in tolerances far lesser than 0.05mm, with one being quite close to 0.025mm. I would say this is determined by the quality of the bearings used and the care of fitting them. Sometimes if something is trapped between the rod and the bearing, or the bearing just doesn't quite seat right then you can have really tight clearances and risk running a bearing again. It just pays to be double sure when checking bearing clearances rather than saying 'she'll be right'. Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 14, 2011 Share Posted September 14, 2011 Oh yeah Beave - oops my bad typo.. Sometimes if something is trapped between the rod and the bearing, or the bearing just doesn't quite seat right then you can have really tight clearances and risk running a bearing again. It just pays to be double sure when checking bearing clearances rather than saying 'she'll be right'. You are right there Phil - I'm definitey being the optomist in this case... puhuhuhu Quote Link to comment Share on other sites More sharing options...
fuel Posted September 14, 2011 Share Posted September 14, 2011 this is only coming from me as I put together a motor without checking bearing clearances whatsoever. needless to say it didn't take too long for the bearings to fail. Quote Link to comment Share on other sites More sharing options...
shavenYak Posted September 14, 2011 Author Share Posted September 14, 2011 ok, so pulled off the rest of the caps etc and pulled the crank out. Here's what I found: all were ok except the middle one, took the crank in anyway and got it measured up. Will need a machine. $180+gst they reckon. Found a crank in Tauranga for $100 which is "mint" apparently and has been polished, but not machined. Might be a good option? http://www.trademe.co.nz/motors/car-par ... 851656.htm Quote Link to comment Share on other sites More sharing options...
fuel Posted September 14, 2011 Share Posted September 14, 2011 if it measures up to standard spec then you wont need to get it machined. polishing a standard sized crank is all the machining you will need to do. I wouldn't machine a crank because you are removing the factory hardening. Do you know what the crank looks like in the original engine (am guessing it's even worse?) Quote Link to comment Share on other sites More sharing options...
fuel Posted September 14, 2011 Share Posted September 14, 2011 am kicking myself a little bit as I not long ago scrapped two turbo bottom ends, both would have had good cranks. I would have scrapped that block you picked up from me too if I didn't run out of time. Quote Link to comment Share on other sites More sharing options...
shavenYak Posted September 14, 2011 Author Share Posted September 14, 2011 if it measures up to standard spec then you wont need to get it machined. polishing a standard sized crank is all the machining you will need to do. I wouldn't machine a crank because you are removing the factory hardening.Do you know what the crank looks like in the original engine (am guessing it's even worse?) Nah the guys at the rebuilders reckoned it was out of spec Quote Link to comment Share on other sites More sharing options...
fuel Posted September 14, 2011 Share Posted September 14, 2011 was meaning that crank on trademe, or were you meaning that the engine builders checked your original engine's crank too? Quote Link to comment Share on other sites More sharing options...
Raizer Posted September 14, 2011 Share Posted September 14, 2011 I know where a running 4g63 is in an L200 (possibly 2), would most likely be fairly cheap if you want me to find out more? /probably a waste of time since its here in Gisborne and you/I would more than likely have to pull it out. Quote Link to comment Share on other sites More sharing options...
shavenYak Posted September 14, 2011 Author Share Posted September 14, 2011 was meaning that crank on trademe, or were you meaning that the engine builders checked your original engine's crank too? Oh right gotcha - I just meant it was good that it was still standard size. Nah the original engine's still skulking away under the hood in Hastings. Be interesting to see just what's happened to it. Cause there was knocking, but also a hideous screetching from it when running. Raizer - good to know, I'll keep that as a backup for now. Will probably get this crank in tauranga. Quote Link to comment Share on other sites More sharing options...
shavenYak Posted September 14, 2011 Author Share Posted September 14, 2011 hey fuel, just out of interest, what's involved in fitting one of these 16v sohc heads? http://www.trademe.co.nz/Browse/Listing ... =406840245 Quote Link to comment Share on other sites More sharing options...
fuel Posted September 14, 2011 Share Posted September 14, 2011 cause it's later model and FWD it runs the wider cam belt and has the distributor hanging over the gearbox, would be unideal for RWD. You can get around the wider belt issue by running DOHC crank and oil pump housing but you may as well just go DOHC especially as you would have to go fuel injection (the SOHC 16V doesn't come carb'd). Quote Link to comment Share on other sites More sharing options...
rb drifter Posted September 14, 2011 Share Posted September 14, 2011 is it possible to run a dohc 4g63 head onto a sohc rwd block? would be a good combination to run in my van if it works.... Quote Link to comment Share on other sites More sharing options...
fuel Posted September 14, 2011 Share Posted September 14, 2011 you would want to change pistons, crank, oil pump housing and associated stuff on the front of the motor. May as well just run a complete DOHC engine. Quote Link to comment Share on other sites More sharing options...
Spencer Posted September 14, 2011 Share Posted September 14, 2011 Ok seen you found another crank in spam. I don’t know about you guys but putting a different crank in a old engine with STD size bearings makes me cringe. Not every crank is sized exactly the same from the factory, you could easily end up with very fucked up clearances. If any of the crank journals are out of round at all your plastigauge won’t tell you, I’ve seen plenty of engines that after a zillion heat cycles aren't round on the mains any more. If it was me I would get the journals measured properly by a shop with a dial bore gauge and check for roundness. If its ok Give the crank the minimum grind possible and buy bearings to suit, this will give you known clearences to your specs. I have no qualm with grinding a crank and removing the factroy hardening, it is common practice and a minimal grind will be fine, you can get it nitrided if it was a extreme perfomance build What are the big ends like? if they are as shit as the mains look they may need to be resized I seriously only used plastigauge to double check machine work and to make sure my method of torqueing up the bolts is giving repeatable clearances. Its easy (especially with a cheap torque wrench) to tighten up the mains several times and get large variations in clearance each time . Anyway I would only chuck a foreign crank, with no machine work into a engine I didn't give a shit about at all, or wasn't going to keep. Chances are high you will nip up a bearing again or have way out of spec clearances are high. Quote Link to comment Share on other sites More sharing options...
shavenYak Posted September 15, 2011 Author Share Posted September 15, 2011 Hmm what to dooooooooo? Yeah just paid for the new crank, so don't really want to pay for a crank grind for it if it measures up ok, or do you think it would be better to abort abort abort and get my money back and spend it on machining the old crank instead? Still new to this, so appreciate the input - trying to do a good job but not spend too much in the process. Quote Link to comment Share on other sites More sharing options...
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