machine shop

[Bo0sTeD 4G63]

well i finally took my motor ro the machine shop and the guy told me he had to redo the whole head no problem, then he told me my block was good and was drilling my cylinder 2 go .20 over and then he told me that my crankshaft is bad and he would have to machine were the bearings were because it got scratched up so then crank might be bad so my question is should i reapir the crank if its still good? buy a new stock crank? or buy a stroker crankshaft?

 

[97GSTAUTO]

Get a 2nd opinion just to make sure this guy isnt jerking you around. Next thing you know he will tell you that youhave a bad flux capacitor.

 

[delta448]

Did this engine seize or have a bearing failure? If not then your crank should not need anything except for maybe a light polish on the journals. If the machinist says #2 needs an 0.020" overbore, he's probably looking to make some money off of you. Unless a ring or ringland broke on #2, or you had serious detonation issues, you probably only need honing. Cylinder 2 for some reason seems to be the one that gets the hottest in stock 4G63s, and he's probably just showing you a little glaze and discoloration. Get a second opinion, and if they are in agreement, then you should get all 4 cylinders bored the same oversize amount. Pistons are sold in sets of 4. Don't buy a new crank unless he can show you in first person where the cracks in the one you have are by using a dye penetrant or with magnafluxing. Most people will tell you that a 4G63 crank should not be undercut at all, but I have heard of at least 2 sponsoring shops of this site say they do exactly that when it is necessary. I'll leave that up to you to decide, but IMO the crank is pretty durable.

 

[Bo0sTeD 4G63]

well the only thing i saw was the crank was scratched were the pistons go i guess the bearings scratched them or something but he said he had to sand down the scratches to get it smooth again and id probably need oversized bearings for the rods, but i am going .20 over with new je pistons on this block

 

[delta448]

going .20 over

You mean 0.020. The block can't be bored 0.2, the cylinders are too close together, 0.2" is +5mm. When someone says "bored twenty over" they mean twenty thousandths of an inch. Every 0.020" is a half of a millimeter.

If you can see scratches on the crank is different than if you can feel them by dragging your fingernail across them. If you can't feel the "scratches" then you probably only need to polish. Sounds like this engine had a fair amount of miles on it before it was torn down, or else the oil wasn't changed regularly. Either way if you know this machinist has done good work for someone else and has at least a 3-4 years experience he probably knows what he's doing. But that still doesn't mean he won't try to make a bunch of money off of you by doing unecessary stuff.

Good luck with your build. When you start putting things back together be sure to post a thread up with some pictures for all of us build whores out there.

 

[Bo0sTeD 4G63]

yea i will be posting pictures on the weekened

 

[Defiant]

Mitsubishi says to not machine their crankshafts, but to replace them only. They are a non-serviceable item.

Many ignore this rule. Sometimes, cranks break.

 

[DRAGIN]

I've also heard that if you do opt to turn the crank you should only do so when you aren't planning to make bigger power. If you are just doing a basic rebuild you'd likely be ok. If not I'd spend the extra on a clean crank.

 

[delta448]

I'm not personally advocating the practice at all.
But I know it's a heavily debated topic and wanted to make sure I left it up to the OP to decide.