Mercruiser 3.0 harmonic balancer

[SpinnerBait_Nut]

Re: Mercruiser 3.0 harmonic balancer

Ok fellows, chill out and stick to the OP question please.

 

[Coors]

Re: Mercruiser 3.0 harmonic balancer

Are we talking about $1 difference in price to be on the safe side?
I have also stripped threads trying to get a balancer off.
Be safe.

 

[ron7000]

Re: Mercruiser 3.0 harmonic balancer

it's not about the cost of the bolts to use with the puller. It's about the reasoning or lack thereof surrounding the whole thread. it's also winter and just fun to torque you guys off.
a guy i work with (jeremy) who gets much humor of reading some of these posts sometimes, wants me to ask what planet some of you guys are on.... regarding stripped threads and why you should use grade 8 bolts. I guess the thought is grade 8 is harder/stronger and won't strip or break?

a grade 8 bolt, because it is much harder, that in this type of application would most likely be the cause of stripped threads in the balancer if the threads on either the bolt or in the balancer are bad when you first insert it. If the goal is not to strip the threads in the balancer, you would be better off using a cheapo "soft" bolt and strip the threads on that. In jeremy's words, better to have the bolt be the consumable for a dollar rather than strip the threads in a balancer that if you can't fix costs a few hundred bucks.

Aside from that if the thought is something less than a grade 8 bolt will be too weak and the pulling force put through it will break it or the threads won't hold, consider this.
http://www.almabolt.com/pages/catalog/bolts/proofloadtensile.htm
If you believe their chart, or if you can do the math based off psi tensile strength, proof loads and that's not even the snapping point for a grade-2 bolt 3/8" diameter is at least 4000 lbs. Considering you would be using 3 bolts on the balancer on the 3.0L... the balancer in question per the original post.... you're looking at 12000+ lbs of pulling force. If you need or think you need more force than that to get your pulley off, then go right ahead and buy a grade 8 but Jeremy respectfully requests you make an effort to post about all your other mechanical (mis)adventures because he enjoys reading them.

 

[JCF350]

Re: Mercruiser 3.0 harmonic balancer

http://www.almabolt.com/pages/catalog/bolts/proofloadtensile.htm
If you believe their chart, or if you can do the math based off psi tensile strength, proof loads and that's not even the snapping point for a grade-2 bolt 3/8" diameter is at least 4000 lbs. Considering you would be using 3 bolts on the balancer on the 3.0L... the balancer in question per the original post.... you're looking at 12000+ lbs of pulling force.

SAE lists the "SAFE" working load of a grade-2, 3/8-16 bolt as 400lbs at the thread root base diameter.

 

[Bondo]

Re: Mercruiser 3.0 harmonic balancer

Ayuh,......

JC,... You're talking to a Troll,... You're just throwing Gasoline on the Fire.....

It's Too Easy to shoot Holes thru his rather Lame arguement......

 

[JCF350]

Re: Mercruiser 3.0 harmonic balancer

Ayuh,......

It's Too Easy to shoot Holes thru his rather Lame arguement......

It's cold here in Panama City this morning and I need some warm up shots.

 

[Coors]

Re: Mercruiser 3.0 harmonic balancer

If he ever needs help in here, he probably needs to change his user name.

 

[ron7000]

Re: Mercruiser 3.0 harmonic balancer

SAE lists the "SAFE" working load of a grade-2, 3/8-16 bolt as 400lbs at the thread root base diameter.

are you posting just to get me to respond or do you really believe what you posted? can you provide the reference where you got that from?
I'm guessing you don't know what it means and justed posted it out of context. If at all true then maybe 400 lbs safe working load for a bolt already preloaded at or near yield, but that doesn't apply in this case so unless I say anything factual all you clowns will start referencing how a grade 2 3/8" bolt is only good for 400 lbs.

A grade 2 bolt proof load,
by definition proof load = safe working load, is 55000 psi.
A 3/8" bolt coarse thread stress area is 0.0775".
55000 * .0775 = 4262.5 lbs safe working load.
Try the math for yield strength (57k psi) and tensile strength (74k psi).
Fine thread 3/8" has stress area of 0.0878"
And grade 5 and 8 are in the 120000 and 150000 psi ranges.
You can look all these numbers up on the web and find them at credible sources, search on "bolt grade proof tensile yield".


Ask for help on iboats?
I don't think so, not after the showing of credibility from some of you in this thread.

Ayuh,......

JC,... You're talking to a Troll,... You're just throwing Gasoline on the Fire.....

It's Too Easy to shoot Holes thru his rather Lame arguement......

if it's that easy and you care about factual info and good judgement then start shooting.

 

[JustJason]

Re: Mercruiser 3.0 harmonic balancer

I dunno how many balancers or flywheel's you've pulled ron... But a grade 8 3/8th bolt snaps around 70-80 foot pounds.

I only use grade 8. Yes you can get "some" at depot. And i break them all the time.

And yes, sometimes it takes more than 210 foot pounds (70 X 3 bolts) to pull friggen outboard flywheels. I've had plenty of balancers be stubburn as well... they are not usually as stubborn as flywheels though.

I dunno what your math or method is there buddy.... but sometimes it seems like grade 8 isn't strong enough either.
Grab your torque wrench and start torqeing one down yourself... tell me when it breaks.