Drag_S14

Background:

1994 EX Coupe, 5speed
Originally D16Z6, now JDM D15B

Ok, so about 4500miles ago, my 185k D16 decided to break the crank bolt. No big deal, the engine was tired anyway, so I bought a D15B from Hmotors, put a timing belt/water pump/clutch on it, and dropped it in. Everything went fine, car ran great. Around the time of the first oil change, 3000miles, crank bolt broke off in the crank. 2nd time this had happened, first time on the new engine. So, I get it drilled out, replace the bolt/keyway/crankpulley, and continue on my way. Now, roughly 1500miles later, the bolt breaks again. I have seen the bolts break on customer cars, maybe 2 times total, on 2 different cars. This has now happened to me 3 times in less than 5000miles. I have been working on these cars for a few years, I'm not a moron, but what the hell am I overlooking? SOMETHING is going on here, and I have no idea what. Also, all 3 times it has happened, it has been below 3000rpm, probably less than 15-20% throttle. First time, I wasn't even in the car, just letting it warm up in the parking lot! Second was in stop and go traffic, and the third tonight was in a neighborhood at about 20mph.


WTF is going on???

gato5254

honda hates u j/k, just some bad luck. sorry to hear it

fmrprojects

you sure you didnt overtorque. honda says to replace the bolt everytime its cracked loose. i always torque them down to 130ft lbs with some thread lock on it, never had a problem in the 3 yrs i been doing it

Drag_S14

Honestly, I have never torqued a crank bolt in the past, always just used my Matco impact, let it hit a couple times, and call it a day. Never had a problem doing it this way. After the 2nd failure, I think we torqued it to around 50-60ftlbs, max, and some of the threads were a little shaky, and didn't want to risk stripping out the crank. Also put some Loctite on it this time too.

Drag_S14

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gato5254 &raquo;</TD></TR><TR><TD CLASS="quote">honda hates u j/k, just some bad luck. sorry to hear it</TD></TR></TABLE>

I'm beginning to agree...

hall97civic

Problem one...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Drag_S14 &raquo;</TD></TR><TR><TD CLASS="quote">Honestly, I have never torqued a crank bolt in the past, always just used my Matco impact, let it hit a couple times, and call it a day. .</TD></TR></TABLE>

Problem two...
[QUOTE=Drag_S14]Never had a problem doing it this way. After the 2nd failure, I think we torqued it to around 50-60ftlbs, max, and some of the threads were a little shaky, and didn't want to risk stripping out the crank.QUOTE]

The functions of the impact is to hammer things loose. the hammering action severly stress the bolt. The second time it was because of the threads not being within tolerance so the vibration killed it. Not trying to be an *******, just try to do it by the book once and see what happens. Maybe get a higher grade bolt too.
good luck

D50boy

Dude, never tighten things with an impact.

Drag_S14

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hall97civic &raquo;</TD></TR><TR><TD CLASS="quote">Problem one...

Problem two...
[QUOTE=Drag_S14]Never had a problem doing it this way. After the 2nd failure, I think we torqued it to around 50-60ftlbs, max, and some of the threads were a little shaky, and didn't want to risk stripping out the crank.QUOTE]

The functions of the impact is to hammer things loose. the hammering action severly stress the bolt. The second time it was because of the threads not being within tolerance so the vibration killed it. Not trying to be an *******, just try to do it by the book once and see what happens. Maybe get a higher grade bolt too.
good luck</TD></TR></TABLE>

Get a higher grade bolt? Aparently you have never seen a Honda crank bolt.

I know how an impact works, but thanks for the lesson anyway. Like I said, I have *never* had a problem doing it this way in the past, and now it's happened 3 times on the same car. The first time it happened, the crank bolt hadn't been touched in at least 10k miles. I really don't think the impact is what is killing the bolt. And like I said, had you actually read my post instead of just seeing "impact" and freaking out, the last time we fixed it, we did not use an impact, and it still broke.

NJcoupe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Drag_S14 &raquo;</TD></TR><TR><TD CLASS="quote">Get a higher grade bolt? Aparently you have never seen a Honda crank bolt.</TD></TR></TABLE>

Um yes; a higher grade bolt.



http://shopping.lightningmotor...age=1

EG2Driver

so you've used an impact 3 times and it broke 3 times and you're still not convinced that its making it break? Do you like doing it over and over or are you stupid?


Go by the book using an ARP bolt, if that breaks, then Hondas really do hate you

Drag_S14

No, you moron. I did it the first 2 times, on 2 different engines. After the second one broke, I torqued it under the spec because of the damaged threads on the crank, and it broke again.

I thought I might actually get a decent response on here, but I guess not. I love internet mechanics.

Drag_S14

Since when will a B16 bolt fit a D16?

dohcdelsol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Drag_S14 &raquo;</TD></TR><TR><TD CLASS="quote">Since when will a B16 bolt fit a D16?

</TD></TR></TABLE>

since always....

we used a z6 crank bolt on a built gsr motor to get my friend back home after his backed out and went rolling down the street. at 3am in the morning, it was a life saver i had one laying around.

think maybe their is to much stress on the crank pully and thats whats causeing it to snap???

94Hatchd15b7

Do not tight'n any motor bolts or nuts down with an impact!!!!!!!

hybridmath

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DeadEnd9009 &raquo;</TD></TR><TR><TD CLASS="quote">so you've used an impact 3 times and it broke 3 times and you're still not convinced that its making it break? Do you like doing it over and over or are you stupid?


Go by the book using an ARP bolt, if that breaks, then Hondas really do hate you</TD></TR></TABLE>


i agree with you on using the arp bolt and see if it still breaks but i have been working on hondas since 1998 and have always used impact guns on this bolt and have never had one break i mean seriously unless this guy has serious pressure going to that gun then its definetly not the problem

NJcoupe

Since when did a headsize of a bolt matter for thread size?

Padawan

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Drag_S14 &raquo;</TD></TR><TR><TD CLASS="quote">I thought I might actually get a decent response on here, but I guess not. I love internet mechanics.</TD></TR></TABLE>

What response could you be looking for?

Most people here have suggested the same thing, which is to actually properly torque the crank pulley bolt in the future. They've also suggested that you replace the bolt after you've removed it, possibly with an upgraded version. There's not much else to be said.

monicle

Ok, so about 3 days ago, my dog decides to eat some rat poison. No big deal, that dog was tired anyway, so I bought a new dog from the dumb friends league, gave it a name/collar/tag and took it home. Everything went fine, dog is great. Around the time of its first birthday, a few weeks after I got it, gets into some rat poison. 2nd time this had happened, 1st time with the new dog. So, I get its stomach pumped, have the doc check it out, and take it back home. Now, a bout a week later, it gets into the rat poison again.I have seen other peoples dogs get into rat poison before , mabe 2 times total, with 2 different friends. This has now happened to me 3 times in less than a month. I have been taking care of dogs for a few years, I'm not a moron, but what the hell am I overlooking? Something is killing these dogs and I have no idea what. Also, all 3 times it has happened, it has been in the afternoon, probably around 2:30 or 3:00. First time, I wasnt even home, just out for a jog around the block! Second was while I was watching tv, and the third was just while walking around the neighborhood at about 5pm.

hall97civic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Drag_S14 &raquo;</TD></TR><TR><TD CLASS="quote">
And like I said, had you actually read my post instead of just seeing "impact" and freaking out, the last time we fixed it, we did not use an impact, and it still broke.</TD></TR></TABLE>

You are dumb, apparently you didn't READ MY WHOLE REPLY I said that the second time that b/c you said the treads weren't perfect that the vibration from the improper tolerence of the bad treads caused it to break.

92redhatch

i only had one crank pulley bolt break on me and it was because i left a rachet connected to the bolt and cranked the motor. it ripped the head right off the bolt. but i just took off the pulley and turned the remainding bolt with some needle nose pliers and it came right out with ease. then i replaced it with another honda bolt. i torqued it down as much as i could with a torque bar and ive done it this way 10 times after that happened to me. I have never had one break on me by just driving.

Sounds like your motor is off balance or something. because i think your problem is the crank pulley wiggles around on the bolt causing it to snap.

IDK just my opinion.

AutoLab

it is amazing to me how much time people will actually spend just to be a smart ***. its evident they spend the time doing so because they lack the competence to offer any type of real help to this guy.

way to go HondaTech, you can always count on it to show its ***.

drag_s14, maybe you should post up a picture of a half *** built d series with some suzuki pistons and an ebay turbo kit, maybe then youll get some input

wade

iTrader: (1)

I have NUMEROUSLY tightened over 30 crankpuley bolts with impacts over the years and NEVER had an issue. I see what you all feel and why you think the impact harms the bolt. I feel this guy has a out of round or bent pump pulley/shaft and puts loose/tight spots on the acc. belt which over time and high revs, COULD put unwanted side/stress on the crank pulley its self causing this to happen.

Bakeoff

^^^^^ I'm with Wade.
Gotta be something to do with one of the pulleys. Even an alternator pulley not being centered or something. That and how tight are you making the belts? It could be something as simple as having a rock hard belt.
There's no way in hell it's form the impact or having it too loose. Too loose, it will back out. Not break.

JDM_SOHC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by D50boy &raquo;</TD></TR><TR><TD CLASS="quote">Dude, never tighten things with an impact.</TD></TR></TABLE>

x2

redline75

i have had this same problem on mine bought an 88 lude had it happen three times put it back on all three times with a toque wrench to specs sold the car and bought a hatch with a z6 in it broke it with in a month replace retourqed broke again had to drive 22 miles since i was in the middle of nowhere had to get another engine since that one was toast called my local dealership and asked a tech about it he said that it has to do with surface of the crank the pulley bolts to isn't perfectly flat and the stress of that and the vibrations will shear it in two