harmonic balancer again
Thread Starter
Instructor
Joined: Aug 2003
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From: west coast fl
harmonic balancer again
Well everything has been going great since I installed my harmonic balancer a while back. Its a press on small journal 327-1965. But as we were driving about 50 miles from home at around 70mph. it came off. Could of been worse it did no damage except to the fan blades, mostly alot of orange paint on them. So what I need to know is, has any body drilled, tapped and installed a bolt in one of these while the engine is in the car. I've made up my mind its going to have a bolt no matter what. Thanks for any help. Roland.
Supporting Vendor
Joined: Dec 2002
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From: Woodstock GA
Re: harmonic balancer again (ro.co3)
i'm not an engineer, and i'm not criticizing your decision, but i do know that the bolt would have to be able to withstand the rotational forces. it might fail due to the tension of being spun at high rpm. and the balancer would have to be machined and balanced to overcome the weight of the bolt, or else it's no longer able to do it's job of balancing the crank vibrations. it might be difficult to find a machine shop that would be willing to risk the liability of doing such a job.
in the long run, you might be introducing worse problems. i've replaced press-fit balancers before (with new press-fit units). i've never had a problem with one. just make sure you aren't using a bad used one. new ones are available.
just my two cents.
good luck.
:flag
in the long run, you might be introducing worse problems. i've replaced press-fit balancers before (with new press-fit units). i've never had a problem with one. just make sure you aren't using a bad used one. new ones are available.
just my two cents.
good luck.
:flag
Le Mans Master
Joined: Mar 1999
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From: Itasca IL
Re: harmonic balancer again (ro.co3)
Damn, that's scary. If the press fit (interference) was correct and the balancer was fully seated on the end of the crank, I cannot imagine it coming loose during operation.
The crank can be drilled/tapped for a bolt, but I don't know of any way in which it could be done accurately with the crank in the car. Even so, the bolt should provide added insurance not the primary retention for the damper.
The crank can be drilled/tapped for a bolt, but I don't know of any way in which it could be done accurately with the crank in the car. Even so, the bolt should provide added insurance not the primary retention for the damper.
Melting Slicks
Joined: Aug 1999
Posts: 2,848
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From: Atlanta, Ga, Fulton
Re: harmonic balancer again (Nicky71)
The crank can be drilled but not in the car. A lot of issues with accuracy as mentioned above. The addition of a bolt in the center should not effect balance of the crant/ balancer assembly IF the centerline of the bolt hole and therefore the bolt itself is aligned with the centerline of the crankshaft. Since the bolt hole centerline should (must!) be on the rotational centerline of the crank the weight of the bolt would not efect the rotational balance of the damper. Remember the keyway is in there also and that, along with the key, is the real locator of the balancer as far as rotational forces are concerned. The bolt will hold the balancer from walking forward but the keyway and key are the rotational locators of the balancer.
Team Owner
Joined: Oct 2000
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From: Washington Michigan
Re: harmonic balancer again (TheOman)
Also, the term "balancer" is a misnomer, except for later applications where it actually performs a balance function (383 strokers, 400's, 454's, etc.); on 265/283/327/350 applications, all it's intended to be is a "torsional damper", which absorbs/dampens crankshaft torsional vibrations - it's neutral-balanced, and has nothing to do with engine balance.
If it came off, it either wasn't fully seated or either the crank snout O.D. or damper I.D. is worn beyond spec so the press-fit was inadequate; the bolt is the best insurance. A film of Loctite "Bearing Mount" will keep it from walking off, but it'll be Hell getting it off next time. :thumbs:
If it came off, it either wasn't fully seated or either the crank snout O.D. or damper I.D. is worn beyond spec so the press-fit was inadequate; the bolt is the best insurance. A film of Loctite "Bearing Mount" will keep it from walking off, but it'll be Hell getting it off next time. :thumbs:
Racer
Joined: Apr 2000
Posts: 355
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From: sc
Re: harmonic balancer again (JohnZ)
As I rememeber the balancer, haven't fiddled with mine in a few years, there is the key, a large washer and a bolt. If the key was not installed and the bolt not torqued or at least tight, I can see it coming off.
I'd say you are one lucky Jose'. That thing coming off at 70 mph is around 3000 rpm depending in your gears and since they weigh about 10 lbs. your REAL lucky.
That being said, as if anyone cares, perhaps with the radiator and shroud removed and the steering control arm removed a shop might be able to drill and tap the crank. But, odds are you'll have to pull the motor.
On the bright side. The motor is not that hard to pull. I can get mine out in about 4 to 6 hours. But I have power nothing and no AC, so it's pretty easy. Once it's out, if all that needs to be done is drill and tap the crank, yyou can just make a mount for it, set it in the truck and off to the machinist.
I know, nothin is ever this easy.
Good luck. Change the front & rear main seal and install brass freeze plugs all the way around as long as you have it out. Assuming this has not already been done.
:banghead: :banghead:
I'd say you are one lucky Jose'. That thing coming off at 70 mph is around 3000 rpm depending in your gears and since they weigh about 10 lbs. your REAL lucky.
That being said, as if anyone cares, perhaps with the radiator and shroud removed and the steering control arm removed a shop might be able to drill and tap the crank. But, odds are you'll have to pull the motor.
On the bright side. The motor is not that hard to pull. I can get mine out in about 4 to 6 hours. But I have power nothing and no AC, so it's pretty easy. Once it's out, if all that needs to be done is drill and tap the crank, yyou can just make a mount for it, set it in the truck and off to the machinist.
I know, nothin is ever this easy.
Good luck. Change the front & rear main seal and install brass freeze plugs all the way around as long as you have it out. Assuming this has not already been done.
:banghead: :banghead:
Thread Starter
Instructor
Joined: Aug 2003
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From: west coast fl
Re: harmonic balancer again (mymaur)
thanks for all the feedback guys I really appreciate it. By the way is the bolt used a reverse thread or not .
Roland.
[Modified by ro.co3, 12:14 AM 12/1/2003]
Roland.
[Modified by ro.co3, 12:14 AM 12/1/2003]
Safety Car
Joined: Nov 2000
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From: Clinton Township MI
Cruise-In III Veteran
Re: harmonic balancer again (ro.co3)
ro.co3:
In a word, yes you can drill and tap a threaded hole in the tip of the crank with the motor in the car. We did this to my 300 horse, 327 about 6 years ago. The tip of the crank, if I'm not having a senior moment here :jester , has a pilot spot, an indentation for you to set your drill bit against.
I did not have my grille in the car when I did this and I did remove the shroud and radiator to accomplish this. Again, I'm not sure of the bolt size I ended up using but I believe the tap size was a 7/16" - 14. Threading the bolt to the crank, we put a flat washer then a lock washer along with a new keyway for the crank.
Oh, standard bolt threads, lefty loosey, righty tighty.
That's my experience. Worked for me!
Good Luck!
Jim
[Modified by 6T5RUSH, 7:10 PM 11/30/2003]
In a word, yes you can drill and tap a threaded hole in the tip of the crank with the motor in the car. We did this to my 300 horse, 327 about 6 years ago. The tip of the crank, if I'm not having a senior moment here :jester , has a pilot spot, an indentation for you to set your drill bit against.
I did not have my grille in the car when I did this and I did remove the shroud and radiator to accomplish this. Again, I'm not sure of the bolt size I ended up using but I believe the tap size was a 7/16" - 14. Threading the bolt to the crank, we put a flat washer then a lock washer along with a new keyway for the crank.
Oh, standard bolt threads, lefty loosey, righty tighty.
That's my experience. Worked for me!
Good Luck!
Jim
[Modified by 6T5RUSH, 7:10 PM 11/30/2003]
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Le Mans Master
Joined: Mar 1999
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From: Itasca IL
Re: harmonic balancer again (6T5RUSH)
Again, the primary issue is that something is clearly wrong for the balancer to come loose. I don't know off the top of my head, but I would assume that the balancer is meant to be at least and 0.005" diametral interference fit on the crank snout. I can't possibly see the balancer walking off the end of hte crank if it were fully seated and the press fit is correct. Surely JohnZ can enlighten us on the proper design interference here.
THis also makes me remember a time we were rebuilding a 327/300 for a customer back when I was turning wrenches and working my way through engineering school (about 5 years ago). We had ordered a balancer through Corvette Central, and the hub ID was actually oversize to the extent that the balancer was nearly loose on the crank. You may want to take a closer look to see what if the same thing could have happened here...
THis also makes me remember a time we were rebuilding a 327/300 for a customer back when I was turning wrenches and working my way through engineering school (about 5 years ago). We had ordered a balancer through Corvette Central, and the hub ID was actually oversize to the extent that the balancer was nearly loose on the crank. You may want to take a closer look to see what if the same thing could have happened here...
Melting Slicks
Joined: Aug 1999
Posts: 2,848
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From: Atlanta, Ga, Fulton
Re: harmonic balancer again (mymaur)
You must get the rotational centerline of the crank dead nuts with the centerline of the bolt. Any shop that claims thay can do this RIGHT without setting the crank up in a fixture is run by none other than BUBBA. My compliments to 6t5rush if you pulled this off. For me drilling the thing in the car would take a steady hand and eyes that I just don't have anymore. Sorta goes in the "are ya feeling lucky" category. For me this is a machine shop operation ...at least the reilling is. Running a tap down a correctly drilled hole should be easy but if the hole is off center..."Danger Will Robinson Danger"
Might be fun to try though. then we can have a thread....."The local Corvette "expert" drilled the snout of my 327 (casting #, dated nn-nn-nn.............................) now it vibrates like crazy at higher rpm. The mechanic says it must be .......... and adds that he knows the bolt is in the crank straight cause he used a new Black and Decker drill'.
his is not about clearance for the drill it is about accuracy that will be very hard to gt with just eyeballs and a with hand held tools.
[Modified by TheOman, 6:57 AM 12/1/2003]
Might be fun to try though. then we can have a thread....."The local Corvette "expert" drilled the snout of my 327 (casting #, dated nn-nn-nn.............................) now it vibrates like crazy at higher rpm. The mechanic says it must be .......... and adds that he knows the bolt is in the crank straight cause he used a new Black and Decker drill'.
his is not about clearance for the drill it is about accuracy that will be very hard to gt with just eyeballs and a with hand held tools.
[Modified by TheOman, 6:57 AM 12/1/2003]
Race Director
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From: Beverly Hills (Pine Ridge) Florida
Re: harmonic balancer again (TheOman)
Hey Oman, maybe he should use a "reverse cut" (normally called Left Hand drill) drill held still, and run the engine as on a lathe/screw machine! This would be the only way to be assured of cutting a true and centered hole.
By the way, left hand drills are available from MSC:
http://www.mscdirect.com
Only real problem is: Without the balancer on the crank, you will get oil out the front seal area as the engine is running (of course, this would keep the drill bit lubed - probably by quite a lot!). Probably be able to make a spacer to fill in most of the seal/crank gap while doing the drill job, but the best way is still to remove the crank and take it to a "qualified" machinist.
Good luck,
Plasticman
By the way, left hand drills are available from MSC:
http://www.mscdirect.com
Only real problem is: Without the balancer on the crank, you will get oil out the front seal area as the engine is running (of course, this would keep the drill bit lubed - probably by quite a lot!). Probably be able to make a spacer to fill in most of the seal/crank gap while doing the drill job, but the best way is still to remove the crank and take it to a "qualified" machinist.
Good luck,
Plasticman
Burning Brakes
Joined: Nov 2000
Posts: 813
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From: da up
Re: harmonic balancer again (ro.co3)
myself, I'd sure look at drilling it in the car
before engine removal and pull the crank.
could possibly install the balance and have a machine shop make
a bushing that would center off the ID of the balancer hub
to pilot the drill.
How was the fit
did balange go hard or easy?
rod
[Modified by yooperod, 2:36 PM 12/1/2003]
before engine removal and pull the crank.
could possibly install the balance and have a machine shop make
a bushing that would center off the ID of the balancer hub
to pilot the drill.
How was the fit
did balange go hard or easy?
rod
[Modified by yooperod, 2:36 PM 12/1/2003]
Melting Slicks
Joined: Aug 1999
Posts: 2,848
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From: Atlanta, Ga, Fulton
Re: harmonic balancer again (Plasticman)
Ya know that idea of the reverse bit .............Nah.
When ever I try things like this, things tat I just know in my gut I should not do, I end up screwed. If somebody here has done it "It aint bragging" as a baseball guy said way back when.
If it were not for bad luck I would have no luck when it comes to things like this though. As ugly as removing the crank is at least you can blame the machinist if the job goes south.
When ever I try things like this, things tat I just know in my gut I should not do, I end up screwed. If somebody here has done it "It aint bragging" as a baseball guy said way back when.
If it were not for bad luck I would have no luck when it comes to things like this though. As ugly as removing the crank is at least you can blame the machinist if the job goes south.
Thread Starter
Instructor
Joined: Aug 2003
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From: west coast fl
Re: harmonic balancer again (yooperod)
Thanks again for all the replys.I've read everything posted and at first I was a little nervous. But after looking at the crank snout Jim is right about the dimple in the end of it, also I found it has a hole about a 1/2" deep that must be a guide for a puller. Anyway I stuck a 5/16" bit into he hole and it fit perfect so I'am thinking this cant be that hard to drill with a pilot hole like that. I got a longer bit put my laser line on the bit sticking out of the hole and I could see the angle that I needed to keep while drilling. The side to side I used my father in law from above looking down to make sure it stayed steady, and beleave me this guy can see me doing something wrong all the way from his house. After drilling we tapped the hole 7/16x14 , used a grade 8 bolt with a liped washer and lock washer with locktite red on the threads. NOw is this the best way to do it ,no but if I'am going to pull this motor its going to be to replace worn parts or for something catasrophic not a balancer.
I took the car out today and ran it hard and everything is ok so far I marked the bolt to see if there was any movement ,none, but time will tell.
Roland
I took the car out today and ran it hard and everything is ok so far I marked the bolt to see if there was any movement ,none, but time will tell.
Roland
Race Director
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From: Central Arkansas
Re: harmonic balancer again (ro.co3)
I bet drilling that took some doing. Hope it works - I suspect it will. I love fixing things like this. Gives you a sense of accomplishment. :thumbs:
Safety Car
Joined: Nov 2000
Posts: 4,761
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From: Clinton Township MI
Cruise-In III Veteran
Re: harmonic balancer again (ro.co3)
ro.co3,
Welcome to the "bullheaded" club! :party: Glad it worked out. Just keep an eye on it over the next few months (as long as you're drivin' her).
Jim
Welcome to the "bullheaded" club! :party: Glad it worked out. Just keep an eye on it over the next few months (as long as you're drivin' her).
Jim
Melting Slicks
Joined: Aug 1999
Posts: 2,848
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From: Atlanta, Ga, Fulton
Re: harmonic balancer again (ro.co3)
Likely that hole is there for some machining operation that is performed on the crank at the foundry or at some finish machine operation as well as being useful as a guide for a puller. That is a large portion of the battle, having that hole already in the crank. In effect since it is there all you are doing is expanding the existing hole whch is concentric with the crank centerline.
I don't know if all "press on balancer" equipped cars have holes like you car did but if they do then I would likely give it a shot also. I still would avoid walking up to a blunt ended crank or one with a shallow hole and lettin fly with a drill. My kind of luck would almost garrantee a foul up during the drilling........broken bit, off center hole...you name it it can happen to me. Your father in law sounds like mine was. He could always dee a bteer way fro me to do something. Funny thing was he never would try anything...just comment on what I was doing.
Glad that it worrked for you.
[Modified by TheOman, 5:23 AM 12/2/2003]
I don't know if all "press on balancer" equipped cars have holes like you car did but if they do then I would likely give it a shot also. I still would avoid walking up to a blunt ended crank or one with a shallow hole and lettin fly with a drill. My kind of luck would almost garrantee a foul up during the drilling........broken bit, off center hole...you name it it can happen to me. Your father in law sounds like mine was. He could always dee a bteer way fro me to do something. Funny thing was he never would try anything...just comment on what I was doing.
Glad that it worrked for you.
[Modified by TheOman, 5:23 AM 12/2/2003]
Team Owner
Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan
Re: harmonic balancer again (TheOman)
Yup, the non-bolt crank snouts have a machined true-center hole; that's where it was chucked in the Landis crank grinding machine at Flint. :thumbs:
