I'm rebuilding a d16z6 and one of the rods was knocking. The bearing is still there, but pretty beat up and the scratches on the crank journal are around .004-.005. Can that be polished out or would that require grinding(junking the crank)? Don't tell me about nitride coating,etc. Only post if you know something concrete about this. Also, I know a machine shop will be able to tell me, but im trying to determine if I should start looking for a crank this weekend or wait til monday to polish it out. TIA

 

Polishing really doesn't take out a measureable amount of material--so if it indeed does have a deep scratch the crank would have to be ground. You could try the old "copper penny test"--take a copper penny and rub it perpendicular to the scratch, if some of the copper rubs off onto the journal--its too deep and must be ground out or replace the crank. Why did you say "don't tell me about the nitriding"? The nitriding seems to be very important--and a clue is that OEM Honda doesn't even offer undersize bearings that you would need if the crank was ground 0.010" or 0.020". When I had a scratched up rod journal from a spun bearing on an a6 crank, I just got another used crank and then got it micropolished--cheap and easy.

 

The guy at my local machine shop runs his fingernail perpendicular to the scratch, if it catches at a scratch, it has to get reground.

 

i would recomend getting a newer crank with no signs of scratching and whatnot, dont want to mess up your new build

 

this is the second shortblock ive bought because i can't seem to find any d16 cranks for sale. That's why I'm trying to get away with this one plus the whole idea of needing to have the tunnel align bored. The reason I say I don't want to hear about nitride coating is because I realize you aren't supposed to grind these and I just want to know how far you can go and if it's possible. I just want to keep good solid info in here

 

Junk it. Rod knock trashes the entire surface of the journal.

 

You cannot polish any scratches out of a Honda crank.If you do you have gone to far.You are going to need to keep looking.

 

im not sure I believe any of this "not being able to polish/grind honda cranks". I haven't seen any "credible" a.k.a. direct from honda info on this. Also, I was looking into the OEM bearings I would be able to use if the marks were taken out and they do allow .005. It would seem to me that you could take as much off as is available in bearings. hey, who knows....THIS is why I'm looking for black and white information from Honda or another credible source...not just hearsay or anything else. Don't take it the wrong way, I appreciatte all the help and I'm looking for a different crank currently; I just would like to find conclusive evidence(can you tell it's sunday?lol)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PA MATT &raquo;</TD></TR><TR><TD CLASS="quote">im not sure I believe any of this "not being able to polish/grind honda cranks". I haven't seen any "credible" a.k.a. direct from honda info on this. Also, I was looking into the OEM bearings I would be able to use if the marks were taken out and they do allow .005. It would seem to me that you could take as much off as is available in bearings. hey, who knows....THIS is why I'm looking for black and white information from Honda or another credible source...not just hearsay or anything else. Don't take it the wrong way, I appreciatte all the help and I'm looking for a different crank currently; I just would like to find conclusive evidence(can you tell it's sunday?lol)</TD></TR></TABLE>

honda doesn't specify procedure for repairing or replacing a crank with chewed up journals because they write their manuals for dealers and a dealer will replace the crank.

I would contact Castillo's crank shop in CA (not sure their website or #, look it up) they do crank grinding and I am sure they can help you. I have seen cranks done by local machine shops and they haven't worked out. . .

 

thats some good info. Will a machine shop have information on this? I was planning to take a crank to a machine shop and seeing what they said, but I don't want to walk in and just hear them say, sure we'll grind that down for you if it won't work out. Is there a service manual they will use to ensure that it's a good practice?

 

crank grinding is common practice in the v8 world. For our honda motors, its not as easy. I am not well educated or experienced in this subject, hence my reference to Castillos. Look them up on google, they can help.

 

I have built several Honda engines w/ ground crankshafts. My daily driver is a 98 Prelude that I rebuilt the motor for about 50k miles ago. The crankshaft in it is .010/.010 and I beat on it everyday with no problems at all. Clevite sells oversized bearings.

 

i wouldnt use that crank at all. I'd look for another one.

We do alot of engine builds and we also tear down alot of block cores. For every 10 blocks that we tear down, we'll see 2-3 bad cranks. Either they had spun bearings, or journal surface has scratches, rust, or pits on them.

We never try to grind them down to 'fix' them since scratches and similar damages arent worth fixing and compromise the whole engine build. Its best to start with a Perfect crank.

 

finding a perfect crank is the tough part I have a motor in my car with low cr in one cylinder which is the main reason im building a new motor. I've considered taking that motor out, but then i'd be without a car and theres no sure way to tell how that crank is either