The Stovebolt Site Forums The Shop Area Engine Shop 2-groove 235 harmonic balancer

Guys and gals- - - -I'm putting the finishing touches on a new project. It's a 2-groove version of a stovebolt harmonic balancer suitable for 235's, 261's, and possibly some 216's, using brand new over-the-counter parts for a cost of approximately $100.00. Anybody interested?

It's going to require a very minimal amount of adapting, and it looks like the work can be done with just a drill press and hand tools. As soon as a few more bits and pieces arrive mail-order, I'll be ready to do a trial fit on one of the engines I've got stashed away in the shop.

More to come- - - - -
Jerry

Jerry count me in.

I will take one to have "At Ready" for my future plans. Thanks for your effort in finding solutions for this 2 grove pulley problem if we want to add any Powered accessories.
Jerry

Once I've got one built up and fit-tested, I'm planning to write a tech tip, including part numbers and procedures. I've been kicking the idea around for a while, and just got most of the parts in last week. The pulley will be for the later-model thin belt and it looks like the rear belt is going to run within 1/8" or so of the original position of the single-groove pulley.
Jerry

Update:

I got the basic balancer assembled tonight. I have not installed it on an engine yet, but preliminary measurements look promising. Here's what I'm doing:

The balancer I am using is a new 6" diameter "Engine Pro" item available from several merchandisers on the internet. Mine came from an Ebay vendor:

http://www.hunt101.com/data/500/stovebolt_balancer_022.JPG

http://www.hunt101.com/data/500/stovebolt_balancer_023.JPG

http://www.hunt101.com/data/500/stovebolt_balancer_002.JPG

The hub dimensions are identical to an old 216 balancer I had handy, inner and outer diameter and depth- - - -it should be a direct swap for a 216, 235, or 261 balancer. Its intended application is for a 283, 307, or early 327 V-8.

Now, here's the sneaky trick- - - -V8 balancers don't have pulley grooves- - -the pulley is supposed to bolt on ahead of the balancer ring. Let's find a 2-groove pulley for a big block V8- - -396/427/454, etc. Turn the pulley backwards, after grinding off two small projections intended to align a second pulley, like so:

http://www.hunt101.com/data/500/stovebolt_balancer_012.JPG

http://www.hunt101.com/data/500/stovebolt_balancer_013.JPG

The balancer hub projects above the balance ring by about 1/8", so the inverted pulley lets it dampen vibrations without any interference from the pulley.

http://www.hunt101.com/data/500/stovebolt_balancer_011.JPG

http://www.hunt101.com/data/500/stovebolt_balancer_014.JPG

I use 3/8-24 tapered-head Allen screws to exactly align the pulley with the puller holes in the balancer hub:

http://www.hunt101.com/data/500/stovebolt_balancer_016.JPG

The finished product compared to the 216 balancer- - - -the pulley grooves are almost exactly in alignment. A little shimming of the water pump pulley and/or generator or alternator mountings might be necessary for perfect belt alignment.

http://www.hunt101.com/data/500/stovebolt_balancer_0191.JPG

Total cost for the balancer, pulley, and bolts, all brand new, including shipping, was about $90.00!
Jerry

Wow, that is great please let us know how it works once you get it installed. Do you have a part number for the 2-groove pulley?

Thanks,
skipper

Great Idea! Will the thin belt work for the other stock pulleys? or will the original think belt work on the new pulley? There is probably a water pump pulley from some era Chevy that will be aligned perfectly. More money than a shim though.

Good thinking. I like the "new" damper and pulley. Beats looking at worn and cracked to see if it is better or worse than what I already have. Thanks!

If I try to post an ebay link the PC Patrol will zap it right away. Just search ebay for "big block pulley" and it should come up.

The thickness of the pulley grooves should match the late-model 216 water pump with the 1/2" belt, and all the 55-up 235 water pump and generator pulleys. Just about all alternators use the 1/2" belt size unless you buy an aftermarket 5/8" wide pulley. I believe it would be possible to machine a bit of material off the back end of the hub where it meets the timing gear to make the whole assembly line up with the existing pump and generator pulleys, but don't take off enough to make the hub damage the front oil seal. I've got a 261 engine stashed away in the shop that doesn't have a balancer on it, so I plan to use it as a test bed for checking belt alignment. I'll also do a step by step pictorial of the drill and tap procedure for the crankshaft snout and include it with the machining kits I loan out.

I like the idea of being able to use new, over-the counter parts instead of paying through the nose (or other bodily orfice) for one of the custom-built 2-groove dampers!
Jerry

I found this on the Spectre site. It's chrome and cheap, so you can add some bling to it.

Chrome pulley

One concern I have is about the size in relationship to the old pulley. The OE pulley is about 6.5" and the new one is 7.25" If you're using the 216 water pump pulley, it'll be turning too fast. The 261 or 235 pulley, you'll probably be o.k.

I also have a question too. What weight dampener are you using? I've found 11 lb. and 5 lb versions of the dampener.


BTW- Great work. I'm glad you took the time to share it with us.

Denny, I have run dozens of generic balancers on small block Chevy and Ford racing engines with no problems. If the rotating assembly is internally balanced, the damper functions well. On 120-degree firing impulse inline 6 cylinder engines, they don't even need bob weights for crankshaft balancing- - -the crankshaft counterweights are perfectly spaced for almost vibration-free rotation. On engines such as the Chevy 400 and the Ford 302 where the balancer and flywheel have offset weights to compensate for internal imbalance, no deal. Stovebolt sixes and the vast majority of V8's fit the "internally-balanced" category.
Jerry

Denny, you're true to form- - - -coming up with obscure theoretical objections to people with overwhelming anecdotal experience. That makes your opinion seem a little silly, but I, for one have come to expect that you'll chime in with those kinds of comments. Thanks for being predictable! I'll keep on doing what has worked for me for years, and ignore most, if not all of your comments.
Jerry

Dennys' point is not esoteric nor is it just to work up the masses. "harmonic" issues with a long crankshaft are real. Why would a company that is driven by profit use a part they don't need? Why go from 4 main bearings to 6 when you made your "new" motor? The rubber insert is designed to damp the flexing at the end of the crankshaft. Like a shock absorber. The real question is are they "tuned"? Or do they just eat up the bigger deflections? I don't know. Maybe some one else does. Now look what you made me do with all them big words and long sentences. Hell, I can't even spell any more. Hotrod Lincoln has a very good point where he talks about internal versus external balanced motors. However, that has to do with dynamic balance and that is a function of piston weight, rod length, engine layout, and rpm. Not to mention rocking couples and a bunch of other stuff I don't know spit about. Now my head hurts and I hope you guys can stay friends.

Jerry, what is the advantage of going this route vs. using a 250 or 292 dampener?

The belt alignment won't be as good on the later-model 6 cylinder dampers, IMHO. I believe the 250 damper needs some pretty extensive machining to make it line up, and the 292 is a massive cast iron thing that might have clearance problems with some motor mounts and/or radiators.

Denny and I have these kinds of discussions all the time- - - -I enjoy locking horns with him, and I believe he participates in our conversations with the same sort of good nature. No offense intended!
Jerry

Jerry,

I've witnessed some of you and Denny's conversations. This one was maybe one of the most civil. LOL

You guys are like a cat and dog chasing after a field mouse. Both of you want the same thing, buy if you were put in the same paper bag. Boy would there be trouble.

I'm looking forward to seeing what you further come up with on your endeavor. Particularly with pulley alignment and sizing the water pump pulley.

I'm a fan of looking outside the box for a solution. There's no sense in dropping a ton of money on something, especially when there's perhaps an easier or better alternative at hand.

Keep up the good work.

Chris

BTW, I was doing some research at BHJ Dynamics site. They have way more information about Dampers than I thought possible. Anyway, the difference in depth of a 235/261 damper and a smallblock is .33", I hope that helps.

Some time ago there was a lively discussion on the inliners board on this topic regarding the effectiveness of using a modified balancer designed for the 292 on the earlier engines. I'm gonna side with Denny on this one in that the potential for increased crankshaft stress is a possibility unless proven otherwise. Is this negligible? Possibly.

Hmmmm- - - - -looks like I'm going to have to drag the bits and pieces of the dyno out of storage and do some testing on an actual engine. I can put the equivalent of thousands of miles of full-throttle, full-load operation on one in a few hours. The hills never top out with a water brake dynamometer!
Jerry

Interesting discussion, I was wondering about this also. Gets pretty technical for sure. Even using a like type damper from a 250/292 might be different. The newer engines are running in 7 mains, the old in 4 mains.
Nothing wrong with questioning something, we all learn something in the process.

John

It appears the trick is going to be making the damper work at whatever RPM and sequence of impulses the firing order inputs to the crankshaft. I have run several race engines totally without a damper, mostly on boats, but we expected to scatter a few engines as a consequence of the abuse we gave them. I don't recall breaking any crankshafts, though. The 3 main bearing flathead V8's we ran on the dirt track broke cranks pretty regularly, but they were running a 3/8" longer stroke than stock at 50% higher RPM than the factory designed them to run. They were also getting hammered from open to closed throttle several times a lap and running 11:1 compression and alcohol. It looks like the only way to see if the idea will work will be to do some extensive dyno testing. Fortunately, I'm equipped to do that with a little setup work.
Jerry

There's tons of variables that go into Engine harmonics. Compression, camshaft lift, camshaft duration, connecting rod length, crankshaft deflection, etc...

If you want to get more in depth you can go right down the driveline; transmission(s), driveshaft, rearend, radial tires. All are contributing factors to the overall harmonics of a vehicle.

It seems to me, the engineers just picked a narrow range of variables to work with and then picked the best dampener to work in that range. Why else would you have the same dampener on a 283, 307, and 327?

I too have ran boats that have no dampener at all. For you farmers, go out and try to find the dampener on that Oliver. It isn't going to have one.

Even though the dampener Jerry picked, isn't technically the right one. At least he has one. I'm sure it's better than the 60 year old one that came off the engine, and probably alot better than a "remanufactured" Chinese one.

Jerry,
Did you ever test this setup either on the dyno or in a car. If this is as good as 60 yo balancer, I would be deeply indebted to you. Thanks for the great help in advance. I realize that this is an old thread but I hope that you will respond. BTW, my 1950 has the 235 with just a mild cam and would not be used at even close to full throttle.
Kent

A note of encouragement: Keep after this idea please. Even if it is not as good as the original at damping, and that is a very big if. It will be better than any loose, damaged, rusty and oil soaked unit you can find any where. Warning! Opinion coming: Original was used to damp vibration at some range of RPM. This one might be at a slightly different range but I would bet at least 1 cold beer that the range overlaps. V8 shakes harder than an I 6. Could be just the ticket to ket that like new feeling.

I am going to proceed with this. When I measure the damper versus the add-on pulley, the outside diameters are about 18 in. Versus 24 in. That means that the water pump and alternator and power steering pump would be spinning about 33% faster than with stock damper. Do you have any concerns about this? BTW, my father-in-law is a machinist and will be modifying the new damper to fit and align perfectly.

The damper I made up as a test project is currently being fitted to a very nicely restored 235 which hasn't gotten to the starting and running stage quite yet. It required shortening the balancer hub about 5/16" to get the belts to align properly, and a corresponding amount needed to be machined where the hub OD meets the main body for clearance at the timing cover seal. I've also come up with a 3/8-16 shouldered Allen bolt that will replace the tapered-head screws for attaching the pulley to the balancer and help align it properly. I'm planning to possibly build another one and do some further testing which would also provide me with an incentive to get my GoPower engine dyno back in operation!
Jerry

Edit: On the pulley diameters- - - -some of the later 235 dampers had a much larger-diameter belt groove, so I don't think the big block V8 pulley will be a problem. That's particularly true if an alternator is used. Overspeeding a generator can throw windings out of the armature. Altertnator rotors spin several times crankshaft speed with no problems at all.
Jerry

Old thread I know. Did this project ever come to a good end? A/C is in my future and my front end sheet metal is off so this is a hot topic for me....Al

I haven't made any further effort on the project, for several reasons that don't need to be discussed on the open forum. I would be happy to communicate by PM with anyone who is interested, however. I'm still convinced it's a viable option, and MUCH less expensive than having a 50-something year old damper rebuilt or modified. I checked on the availability of the parts on Ebay a few days ago, and the cost is still well under $75.00. That leaves quite a bit available for custom machining in case someone doesn't have access to a lathe before the cost gets prohibitive.
Jerry

Sorry guys, late to the conversation

I need to build up my post count before I can message you directly, Jerry. Maybe you can initiate a PM. I am interested in purchasing the jig set that you designed for drilling and tapping the crankshaft, and also in acquiring the parts to replace my harmonic balancer on a 1959 Chevrolet 3B with the 235 engine.

Thank you for all of your contribution.
Michael

Some of the hardened drill bushings I use on the drill/tap fixture are getting difficult to acquire so I'm having to make and harden my own. I think you can PM me after making one more post. The PC Patrol doesn't like when I discuss the kit anywhere but the buy/sell forum, so please try to communicate with me by PM or email (email is in my profile)
Jerry

I just came across your thread and I am in the middle of a 235 build that requires a Double pulley. Is this still on going? I just registered so I can’t PM yet. Maybe you can PM me. I would appreciate any help on the subject. I would like to avoid having to pay $350 for a 50 year old pulley or $500 for a new built one. I was already going to purchase the parts in the thread but would like advice on the direction to go in? Thanks!

3 more posts will get you access to the private message function and/or the members' profile area. My current email is on my profile page. I haven't built up a 2-groove balancer in a while, but several people I've coached through the process are very pleased with the results.
Jerry

I know this is an old post, but the pic's aren't available anymore. Plus, I'm not able to PM Hotrod Lincoln directly, does anyone have updated info on this issue? I had a 235 in my Bel Air that was running a 2 groove balancer, but the balancer was lost during the re-builder going out of business while having my engine. I've 261 that I'm now putting in my Bel, but need a 2 groove to get it back on the road again. Any help would be greatly appreciated.

Hey there new guy! Not a problem that this is an "old post." In the schemes of things these days, this is not very old. I'm sure folks will chime in with help soon.

(Welcome to the Bolt!)

Post a few more questions or replies ( I think after 5 you're able to PM people) or whatever and you will be able to PM Hotrod.

A 2 groove balancer for a Chevy 230/250 inline six can be modified easily to fit a stovebolt engine by shortening the length of the snout about 1/4" and machining the outside diameter of the snout back the same distance to keep from damaging the timing cover seal. The inside diameter of both balancers is the same (1 1/4") and the balancer can either be press fitted onto the crankshaft snout like the original, or the crank can be drilled and tapped for a 7/16-20 thread bolt if you choose.

www.ebay.com/itm/145926932748?

Jerry