47-59 Crank pulley bolt question

[TX3100Guy]

Long story short, I managed to snap the head (and some of the length) of the crank pulley bolt. I have been able to drill the remaining section and use an EZ-Out to extract the bugger.

Now the question is, should I replace it with a Grade 5 or 8 bolt? My first thought is Grade 8 to ensure it wouldn't happen again, but then I thought "if it does break again (unlikely) would a Grade 8 bolt be harder to drill out and extract."

Don't ask how it broke, its a dumb story.

[mongocanfly]

Grade 8 will def be harder to drill than a g5.....I would use a g5

[burnin oil]

If I used that bolt to turn the motor over by hand then I would use the grade 8. Be mindful to replace of ot ever feels like it stretched. If not I would use the grade 5 recomendation.

[TX3100Guy]

Originally Posted by burnin oil

If I used that bolt to turn the motor over by hand then I would use the grade 8. Be mindful to replace of ot ever feels like it stretched. If not I would use the grade 5 recommendation.

After calming down post drilling/extraction, I determined that the original bolt was a Grade 8 by its markings. Since I had already purchased a Grade 8 to replace it, I just went with it.

[Rickysnickers]

I don't remember what engine you are running, but if it's an SBC or similar, I'd invest in an ARP bolt.

[TX3100Guy]

Originally Posted by Rickysnickers

I don't remember what engine you are running, but if it's an SBC or similar, I'd invest in an ARP bolt.

Admitedly, I've not heard of ARP bolts. Are they significantly stronger than a garden variety Grade 8 bolt? I see they have both Stainless and Chrome Moly, any difference between these two choices too?


EDIT: Running an inline six cylinder 261 cu in 1959 engine.

[mongocanfly]

You "broke" a grade 8 bolt ...wow.!!
ARP bolts are top of the line bolts made for engines

[TX3100Guy]

Originally Posted by mongocanfly

You "broke" a grade 8 bolt ...wow.!!
ARP bolts are top of the line bolts made for engines

That's me..... an Arnold Schwarzenegger look alike.....LMAO. That and a two foot pipe on the ratchet.......dumb dumb idea, but all is well now.

[Russell Ashley]

I'm surprised that the threads in whatever you are putting that into didn't strip. Were you using it to pull the balancer back on to the crank? Never mind, I went back an looked and it looks like it broke from being bent over, not from twisting.

[TX3100Guy]

Originally Posted by Russell Ashley

I'm surprised that the threads in whatever you are putting that into didn't strip. Were you using it to pull the balancer back on to the crank? Never mind, I went back an looked and it looks like it broke from being bent over, not from twisting.

Upon removing the remains of the bolt with the EZ Out, I had a new bolt with the correct thread pitch ready to check out the threads. I also had a tap handy in case I needed to re-thread it. Fortunately, the new bolt threaded right in with no resistance at all.

[dsraven]

OK, fess up time.
what were you ttryingg to accomplish when you busted off the gr8 bolt? if pulling the balancer on with it you might think of using a stud that screws in, then the balancer is slipped into place, then a thick washer just a bit smaller than the id of the balancer, the nut on the end of the stud is used to pull the balancer in tight. when done remove the stud and install the proper bolt and washer and torque to spec.
hey, we all do dumb stuff. as long as you learned from it.

[TX3100Guy]

Originally Posted by dsraven

OK, fess up time.

hey, we all do dumb stuff. as long as you learned from it.

Bless me father for I have sinned..... I was attempting to hand crank the engine and busted the bolt.

Now for a fuller explanation. I had just put oil in the engine for the first time, used an old distributor shaft (minus the timing gear) attached to my drill. I wanted to ensure that after sitting for so long that the oil pump was operational and that oil flowed to all the weep holes in the valve train. (1959 - 261 cu in inline 6 engine). When I first started the drill, the pump seemed to be spinning easily and then as it began to draw in oil (a few seconds while the drill was spinning up) there was a small load on the drill as the pump began flowing the oil. The good news was that seconds later all the weep holes flowed oil easily.

At that point, I wanted to ensure I had the engine at TDC by watching the valves as well as watching for the bubble in the site window above the starter. I put my 1/2 socket wrench on the crank pulley bolt head and began to try to turn the engine. Mind you, a week earlier it cranked manually very easily, this time it was a struggle. Given that I had just felt the drill take on a load when the pump began pushing oil, I had it in my head that the engine was sluggish in turning over due to both the oil and some potential problem.
When I was having difficulty in turning the crank with the 1/2 socket wrench, I added a two foot long pipe to the wrench and moments later the top of the bolt was on the floor and I was vocalizing each and every bad word I knew.

What I haven't told you yet was that for the past four months I've been working on the truck, I've had it in neutral. A week earlier my adult son and I were discussing some potential upgrades to the interior when the time comes and he was messing with the floor shifter and put it in gear. As a result, I was attempting crank an engine that was in gear. My only defense is that I didn't realize it was in gear until the bolt head was on the floor. After the swearing was completed, I had to ask "why is the engine so difficult to turn over?" I only wish I had asked that question two minutes earlier.

[dsraven]

well, thats about as honest as it gets. funny thing, when I was reading it, i thought " it's in gear". I know, I shouldn't but, haha. no harm (except a little ego maybe. and of course that frickin, frackin, frockin bolt....) so keep plugging away and keep us posted.
I don't have enough time to list all the dumb things I have done in the shop. once, years ago working up north in ft mcmurray, 18 hour days for 3 months, I changed oil on a pick up, dumped in 6 litres of oil, cranked it up and got no oil pressure on the gauge. shut it off and got out but slipped on the pool of oil on the floor. forgot the oil filter, duh. that was the quickest oil clean up and floor wash I ever did. before somebody seen it. haha.
one highway truck shop I worked in was a 24/7 shop. I was working the midnight shift with another mechanic and a wash rack guy. my partner was having one of those days. we went for coffee break and about 5 minutes into that he sprang up an ran out to the shop. turns out he didn't turn off the oil dispenser before comingh in for coffee break. those engines would take about 40 litres of 15/40 oil at the time. well, it took that plus enough to fill the entire engine until it started to come out the top. yup, that was a big clean up and then work to drain the engine properly.
your busted bolt kinda sucks but, in perspective, it's just something you can laugh about that didn't cost a bunch of money to fix.