csc
Contributor
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Reg: 12-05-10
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06-16-12 05:15 PM - Post#2237973
So this morning the harmonic balancer just fell off. The motor is a 327. After some inspecton I discovered the bolt was broke off. I assume it was broke when installed and just wasnt fixed. What are my options to fix?
Thanx
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72novaproject
Senior Member
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06-17-12 05:34 AM - Post#2238145
In response to csc
I am no historian on this stuff but I think some 327’s were not drilled and tapped for a center bolt. The balancer was a press fit and no bolt was used. Use a mirror and a flashlight and verify you see the fractured end of the bolt before you get too excited.
If it is broken you should be able to use an ex-out to remove it.
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66cayne
Frequent Contributor
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06-17-12 06:09 AM - Post#2238160
In response to 72novaproject
Yes, what he said.. When you look at the end of the crank you will see it has a machined opening on the end of the snout. You will want to drill and tap it for a balancer retention bolt. Also, if your balancer came off the woodruff key is probably ruined too. Install a new one before putting the balancer back on.
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csc
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06-17-12 08:02 AM - Post#2238202
In response to 66cayne
I cant tell?
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66cayne
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06-17-12 09:48 AM - Post#2238229
In response to csc
It does not look like a sheared bolt. What you see is typical of the opening that was used at the factory to 'chuck' the crank in a lathe for machining purposes. I drilled and tapped my 327 crank while it was in the car. I used a 1/2" drill and a centering fixture to keep the drill bit straight. Then tapped it for a bolt. It was not hard to do. What condition is the woodruff key in? I can't see from the pic. You will need to remove the timing cover to install a new key.
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csc
Contributor
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Reg: 12-05-10
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06-17-12 12:38 PM - Post#2238293
In response to 66cayne
The key was not there when I parked to see what the problem was.
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D.Mac
Senior Member
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Loc: Ontario Canada
Reg: 03-22-03
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06-17-12 01:27 PM - Post#2238307
In response to csc
What year is the motor?
Does the block have provision for a road draft tube?
Dave MacDonald
Ontario, Canada
'66 Impala LT1/C950-,EFI,700R4,(sold 07/2011)
'12 Sonic LTZ, Turbo, M6
'07 Pontiac Solstice GXP
'06 Caddy CTS-V |
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csc
Contributor
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06-17-12 01:42 PM - Post#2238310
In response to D.Mac
I bought the motor from a guy who did not know what it came from. Whats that?
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66cayne
Frequent Contributor
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Reg: 08-06-08
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06-17-12 08:32 PM - Post#2238509
In response to csc
The road draft tube is a crankcase ventilation tube located at the rear of the block. It was used on early small block Chevy's. After the introduction of PVC values many builders discarded the tubes and installed PVC values to ventilate the crankcase. Early smallblock Chevys with road draft tubes also did not use a harmonic balancer retention bolt. The balancers were just press fit on these early engines. This included 327s and 283 smallblocks ('57-'66). The early 327s are often referred to as having 'small journal cranks'. As smallblocks became more powerful Chevy engineers learned a balancer retention bolt was a good idea to keep the balancer from being spit off.
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csc
Contributor
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06-19-12 04:14 PM - Post#2239230
In response to 66cayne
Ok so Ive never tapped anything. What do I need to get the job done and are there any tips for a sucsesful job? Thanx for all the help guys.
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66cayne
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06-20-12 07:16 AM - Post#2239414
In response to csc
You will need to buy a drill and tap for a 7/16" SAE fine thread bolt (Mr. Gasket. Moroso and others sell the proper balancer bolt kit). Use a GOOD drill bit that is designed for drilling forged steel. The drill size will be slightly smaller in diameter than the 7/16" tap. I used a balancer removal tool as a fixture to help keep the drill centered. The length of the balancer bolt will help you determine how far to drill the crank. After you drill the hole you will run the tap. Just take it slow and squirt some oil or WD40 on the tap as you go. The tap will cut the new threads fairly easily. Sounds like you will need a new key for the crank snout, so you will need to remove the timing cover. Be sure your balancer is in good shape before re-using it. Check out the H.A.M.B. website and do a thread search on harmonic balancers. There is lots for info.. Good luck
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 MikeB
Senior Member
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Loc: Plano, TX
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06-20-12 02:50 PM - Post#2239545
In response to 66cayne
Drill bit size is 25/64" for 7/16-20 tap. And like 66cayne says, use a really good drill bit. You might want to see if you have an industrial supply store near you, like MSC or Grainger. I'm not sure Lowe's, Home Depot, etc. have any drill bits that are suitable for forged steel. And a Chinese tap probably won't do the job.
Real Hot Rods have a Clutch!
1955 210 2dr: 327, Brodix IK180 heads, Jones cam, Muncie M20, Wilwood front brakes
1969 C-10 pickup: 350, TH350
My car pictures
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Edited by MikeB on 06-20-12 02:51 PM. Reason for edit: No reason given.
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johnod
Forum Newbie
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Loc: Southern Ontario
Reg: 05-27-12
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06-21-12 06:05 PM - Post#2239943
In response to MikeB
You realise you don't absolutely need a bolt right?
It ran all these years with out one.
Just thought I'd point that out.
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busterrm
Contributor
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06-21-12 08:29 PM - Post#2240002
In response to johnod
You realise you don't absolutely need a bolt right?
It ran all these years with out one.
Just thought I'd point that out.
That really depends on the balancer you have. I have a aftermarket balancer on my nova that was a real paint even with a balancer installer. I think the issue is does this 327 produce a lot of HP/TQ. My Nova produces about 400 hp, so i put an retention bolt in it. If its a hot motor drill and tap it for the retention bolt and be done with it. Better safe than sorry. JMO
==== BOB ====
If I can't smoke the tires I want more!
1976 Chevy Nova
2007 Chevy 1500 1/2 ton
2005 Yamaha Vstar 1100 midnight custom |
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busterrm
Contributor
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06-21-12 08:31 PM - Post#2240005
In response to MikeB
Drill bit size is 25/64" for 7/16-20 tap. And like 66cayne says, use a really good drill bit. You might want to see if you have an industrial supply store near you, like MSC or Grainger. I'm not sure Lowe's, Home Depot, etc. have any drill bits that are suitable for forged steel. And a Chinese tap probably won't do the job.
Ditto, make sure your drill and tap are of the best quality. You wont regret it Friend!
==== BOB ====
If I can't smoke the tires I want more!
1976 Chevy Nova
2007 Chevy 1500 1/2 ton
2005 Yamaha Vstar 1100 midnight custom |
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csc
Contributor
Posts: 161
Reg: 12-05-10
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06-22-12 05:06 PM - Post#2240271
In response to busterrm
Well the fact that grainger wanted 150$ for a "quality" bit and tap, made me make some risky decisions. I decided to go with dewalt all purpose bits and some taps I bought at yard sale, craftsman brand. Around 30$ total. So two bits and a lot of pbblaster later and I have a nice square bolt screwed in. I havnt put the ballancer in yet but all looks good. Thanks for all the help.
Edited by csc on 06-22-12 05:10 PM. Reason for edit: No reason given.
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csc
Contributor
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06-22-12 05:12 PM - Post#2240273
In response to johnod
You realise you don't absolutely need a bolt right?
It ran all these years with out one.
Just thought I'd point that out.
How would it be pressed back on?
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66cayne
Frequent Contributor
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06-22-12 08:01 PM - Post#2240343
In response to csc
Good deal, you are getting back to being on the road.
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MikeB
Senior Member
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06-23-12 08:07 AM - Post#2240456
In response to csc
How would it be pressed back on?
It would be tapped on using a mallet and a 2x4, assuming crank snout, key, and damper bore looked OK. It could be secured with a bearing adhesive.
CSC -- glad you got it fixed. 
$150 for a drill and tap?  I would have guessed $25 tops.
Real Hot Rods have a Clutch!
1955 210 2dr: 327, Brodix IK180 heads, Jones cam, Muncie M20, Wilwood front brakes
1969 C-10 pickup: 350, TH350
My car pictures
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sidworks
Senior Member
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06-23-12 09:16 AM - Post#2240475
In response to MikeB
$10.00-12.00 ea list in the grainger cataloque. someone was more than likely quoting you for a set of taps
ron
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csc
Contributor
Posts: 161
Reg: 12-05-10
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06-23-12 01:10 PM - Post#2240509
In response to sidworks
I can't do it again. Gotta redo the oil pan again. Are you fing kiddind me. I didnt know. 3 times in one month. Swear I'm gonna take a sledge hammer to this truck.
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kitabel
Contributor
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Reg: 11-28-09
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06-24-12 08:05 AM - Post#2240726
In response to MikeB
You're hammering against the crank's thrust bearing.
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busterrm
Contributor
Posts: 999
Loc: Wichita Falls, Tx
Reg: 08-31-10
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06-24-12 12:08 PM - Post#2240792
In response to MikeB
How would it be pressed back on?
It would be tapped on using a mallet and a 2x4, assuming crank snout, key, and damper bore looked OK. It could be secured with a bearing adhesive.
CSC -- glad you got it fixed.
$150 for a drill and tap? I would have guessed $25 tops.
You can get a balancer install tool at the parts store, Orielly or Advance have one you can rent and return it for your money back.
==== BOB ====
If I can't smoke the tires I want more!
1976 Chevy Nova
2007 Chevy 1500 1/2 ton
2005 Yamaha Vstar 1100 midnight custom |
Edited by busterrm on 06-24-12 12:09 PM. Reason for edit: No reason given.
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68fastbak
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06-24-12 12:31 PM - Post#2240797
In response to busterrm
On my 327 I used a 2x4 across the radiator support and a scissor style car jack and pressed it on like that.... I knew it was fully pressed in when the 2x4 shattered. Once it's on it ain't going no where
"It is well that the people of the nation do not understand our banking and monetary system, for if they did, I believe there would be a revolution before tomorrow morning." -- Henry Ford
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busterrm
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06-24-12 02:56 PM - Post#2240842
In response to sidworks
$10.00-12.00 ea list in the grainger cataloque. someone was more than likely quoting you for a set of taps
ron
I agree, a full set is about 140 - 150 bux.
==== BOB ====
If I can't smoke the tires I want more!
1976 Chevy Nova
2007 Chevy 1500 1/2 ton
2005 Yamaha Vstar 1100 midnight custom |
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csc
Contributor
Posts: 161
Reg: 12-05-10
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06-24-12 03:05 PM - Post#2240843
In response to busterrm
It slid rite on and bolted down. No hammering needed. Got the top half put on today. Have to do oil pan tomorrow.
A little over spray on the frame, to be touched up soon.
Edited by csc on 06-24-12 03:15 PM. Reason for edit: No reason given.
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csc
Contributor
Posts: 161
Reg: 12-05-10
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06-24-12 03:18 PM - Post#2240851
In response to busterrm
$10.00-12.00 ea list in the grainger cataloque. someone was more than likely quoting you for a set of taps
ron
I agree, a full set is about 140 - 150 bux.
The quote was for full carbide bit 73$ and 3 piece tap 7/16/20 was around 50$. Over the phone quote, place wasnt open till monday.
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sidworks
Senior Member
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06-24-12 04:10 PM - Post#2240882
In response to csc
I can see that but you wouldn't have needed a carbide bit. just a good h/s steel. then they wanted to sell you a nice tap handle and something else.
It is that offshore stuff that doesn't make a complete turn before it is toast
ron
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66cayne
Frequent Contributor
Posts: 1810
Reg: 08-06-08
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06-24-12 06:22 PM - Post#2240928
In response to csc
It slid right on!!?? Did you remove the timing cover and replace the key?
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csc
Contributor
Posts: 161
Reg: 12-05-10
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06-24-12 06:41 PM - Post#2240932
In response to 66cayne
removed the timing cover. put new key that fit on. Old key was missing in action? The timing gear had key in it. Had a guy tell me it was a 2 key setup. Should it have not slid right on? I am growing long in the tooth with this motor.
Thanx for all the help guys.
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