I just ordered a 1 1/4 inch diameter chucking reamer, with the idea of converting stovebolt balancers to a snug slip fit instead of a press fit, and using a 7/16-20 bolt to hold it in place. Since drill bits don't make perfectly round holes, the reamer should open up the balancer bore just enough to eliminate the need to drive or press the balancer on, and also make it possible to tinker with camshaft timing by using an offset woodruff key on the crankshaft timing gear. I'm also considering doing a similar conversion on the cam gear, to allow fine-tuning the cam timing the same way during dyno runs. A one degree change in the crankshaft gear position alters cam timing two degrees, while the cam position only changes half that much when an offset key is used. Advanced cam timing builds more low end torque- - - -retarding the cam improves top end horsepower. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Just a question, and I may have asked it a long time ago. I wish I would have kept a phone number for the place, as I remember seeing a special tool that they offered that would push those balancers on the stovebolts. Yes the oil pan needed to be off because it pushed on the counter weight as well sort of like a big clamp. I've never liked hammering on a balancer, even the old 265 is like that, seems like in those days they wanted it pressed on. Has anyone else seen that clamp thing I'm talking about?
For drilling and tapping the crank did you make a drill fixture for that?
Last edited by Truckrolet; 10/29/20259:59 PM.
Kicking self for selling off my Taskforce trucks. Still looking for an LCF or conventional big bolt in decent shape.
As of 10-26-2022, A 55.2 Taskforce long bed now the work begins
I made and rented or sold a drill/tap fixture for a while which also included a ball bearing balancer pressing fixture with an Acme thread, but even with a 2-page instruction sheet, most people had problems using it. I finally gave up on that. I guess common sense isn't all that common! A lot of other engines use slip fit balancers, with a tightly torqued bolt to retain them, so why not a Chevy stovebolt? Ditto for cam gears! I guess the Chevy engineers were trying to save the cost of a couple of bolts and washer over the span of a few million engines! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
A crank nose drilling and tapping fixture is available from 12bolt.com for about $50. Once you have that, a standard balancer puller/installer (like THIS) can be used, although on a balancer with the hand crank lugs (216's), you'd have to gin up an adapter to get enough reach to push it on. Also, the 216 doesn't have the flat area where a washer could be used to retain it. A little machine work on the balancer fixes that.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Just for reference to this topic, I thought I would share my modification of the balancer I got from Jerry. Before, after I machined it and then installation pic.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
When I was making my alignment tool for the timing cover out the hub portion of one of my spare balancers, I used a brake cylinder hone to gain the slip fit needed to make use of the hub as a tool. So using a hone is certainly one way to gain the clearance and it did not take long to hone it out.
As for making a 235 or 261 balancer a slip fit retained by a bolt, I am not so sure. I have no empirical evidence but I would worry that just a bolt retention would heighten the possibility of even a slight loosening of the bolt, would then allow the balancer to work back and forth and create all kinds of havoc long term.
On the other hand, when I rebuild a 235 or 261, its SOP to have the crank snout drilled and tapped for a balancer bolt. I also have a fixture for drilling and tapping a crank snout with the motor together. I got mine from Mr. Hot Rod 6, but Tom Lowe at 12bolt.com also has a version.
For context, I recently won the street tire drag racing class at the Trifive Nationals in Bowling Green Kentucky this past August. In the ten years that that show has occurred, I was the only inline 6 powered vehicle to run in competition and the only inline 6 powered vehicle to ever win a class at that show and race, in the entire ten years. I buzzed my 261 to 5800 rpm, once or twice to 6000 rpm, and at the end of each day drove back to the hotel, lol. Standard press on balancer, drilled snout and small block chevy bolt and washer. I did my usual post racing check when I got home to Pennsylvania, including checking the balancer bolt, and not a bit of movement or looseness after about 15 runs over that week, and driving all over creation in Bowling Green.
To my way of thinking, you need both the press fit and the bolt to really make sure the balancer stays put. That and by drilling and tapping the snout for a bolt, you can use a standard balancer installer to install the balancer, instead of a hammer and block of wood, and have really good confidence that you have pressed the balancer right up against the crank gear as required, instead of administering a few extra blows of the hammer to make sure you are.
With a 1/2-20 Grade 8 bolt, 100 ft/lbs of torque, and red LocTite, even a snug slip fit balancer should stay put. A minute or less with a rosebud torch tip will break the LocTite bond on the bolt if it ever needs to be removed again. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I've seem enough Pontiac balancers with broken key ways to know a press fit works better than a loose fit. They use a 5/8"-18 bolt torqued to 180 ft lbs plus a very snug fit, not a beat in on hammer fit, more of a use the bolt to pull it on fit. Since the inline is pretty well balanced by design anyway, a bit looser fit may work as long as it stays in a reasonable rpm range. Green retainer Loc-tite on the shaft, and red on the bolt would be a good practice.
Since an inline six is inherently balanced, there isn't the torsional twist and harmonics to deal with that a V8 experiences. Try spinning a V8 crankshaft in a balance machine without bob weights sometime- - - -it tries to jump out of the machine. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
