Flathead Harmonic Balancer question

[markl]

All,
Well I have now obtained a harmonic balancer to be used on my 37 LaSalle flathead which has been bored out to Cadillac standard (3-1/2").  Thank you Jim Beard for going through the parts pile.  It had been my intention to disassemble it and then send it off to a rebuilder.  Much to my surprise, of the three rebuilders I've consulted, none has experience w/ the flathead harmonic balancer.  I think I may know why in that there doesn't appear to be any rubber parts in it, rather it appears that the unit allows movement w/ a series of spring steel "leaves". 

I haven't been bold enough (or perhaps foolish enough) to drill out the four rivets that appear to hold the thing together, so I'd like to know if anyone on the forum has actually taken one of these apart.  Or, has anyone heard of or used a rebuilder for one of these?  I may still send mine off to Dale Manufacturing in Salem Oregon if only to machine the OD of the collar to allow the installation of a "Speedie Sleeve".  I realize that they (or at least the LaSalle) used only a slinger, and not a seal, but I intend to change that to allow installation of an oil seal that rides on the outside of the shaft (actually the end of the balancer that extends into the front cover).

Mark Lowery, CLC#25216

[Doug Houston]

It appears that you have made up your mind to rebuild that harmonic balancer, even if it has probabhly never been done before, nor ever has needed to be done. I have never heard of such an operation.

I am more familiar with the later version of this engine, where there is some sort of a shaft seal for the balancer as it enters the timng case. If memory serves, the balancer was lightened in later engines; postwar models, I believe.

[Otto Skorzeny]

Why not limber it up with a penetrant soak for a while and then put it on a spindle like a lathe or something and see how well it works at high speed. Does it wobble or whatever? If it goes around smoothly it will probably work just fine. Maybe you have access to an engine on a stand that you could test fit it to. It might not need to be rebuilt.

[markl]

Doug,
No, I really don't want to re-build the harmonic balancer if there is nothing in it that wears out or degrades over time.  I am used to seeing the damping being provided by a flexible connection (rubber) between the two parts like in a small block Chevy.  I do need to address the sealing surface by either turning it or turning it & adding a Speedie sleeve as it is really rough due to corrosion.  As I recall the seal that is most readily adaptable requires that the collar be turned down to a slightly smaller diameter.  If I have this done by a shop that specializes in Harmonic Balancer work, I'll have them check the dynamic balance while they are at it since this is typically a service they perform during a rebuild.

Mark Lowery, CLC#25216

[Otto Skorzeny]

All that makes sense.

Can you post photos of it? Can you see the springs that do the damping? It sounds quite interesting.

[markl]

Otto,
Well your right, it may not need rebuilding and penetrating oil might be a good way to start investigating its condition, but the actual workings of the thing is somewhat of a "black box" issue as the riveted-on covers, front and rear, keep one from seeing exactly what the shape or condition of the "springs" is.  It would be of interest to chuck it up on a lath, but a metal turning lath turns rather slowly compared to the operational speed when fitted to an engine.  Not so sure I'd want to put it on a wood turning lath and bring it up to 1,000 or 2,000 RPM! 

Anyhow, still wonder if anyone out there has either taken one apart and/or if they've found a shop competent to work on one.  Perhaps I should post something on the modified site as anyone using on of these engines in a performance application would certainly want to think about the condition of a 70 year old unit such as this.

Mark Lowery, CLC#25216

[Otto Skorzeny]

As long as it isn't rusted, it seems like it might hold up better than the rubber ones. If you or a shop does take it apart for refurbishment, please take a lot of photos. I am quite intrigued by this. I have a visual in my mind of how it works but it could be all wrong. Pretty neat.

[Steve Passmore]

Mark, have you checked yet to see if it will fit the end of your crankshaft? I could not fit a 47 balancer on my 37 engine, too small or too large by 50 th, don't remember which.

[38FLATTIE]

markl,

The stock balancer works well, even in a Hi-Po situation. Remember, that these are relatively low rpm engines, even on the performance side. I'm having a custom one made, for my Bonneville flathead, but it's probably not needed. Even with all the custom work, and custom parts, it will still only see 4800-5000rpms, AND that's with all new, custom internals!

I have a stock balancer, off a '48 engine, that I would be condfident running as is. If you can't find the services you're looking for, you're welcome too it.

Buddy

[markl]

Steve,
Talk about putting the fear of the lord in someone!  I don't have the engine here, but I do have the original hub and using a caliper, I checked the internal bore on the 37 against my newly acquired balancer from Jim Beard, and they both appear the same.  The closest I can get it is about 1.36"   Were you saying 50 thousandths (0.050)? Using the rule of thumb that  0.060 is roughly 1/16", I'd say they are the same. 

The parts pile that this was from was meant to service a 39 LaSalle, but who knows the year of the donor engine.  Are you running a harmonic balancer or are you going to stick w/ the original hub and sheaves?  One interesting fact that was brought to my attention by Tom Beaver is that Cadillac used the Harmonic balancer on some engines and not on others during a given model year.  My recollection was that it appeared on the higher priced models (75 series etc.).

Mark Lowery, CLC#25216

[william_b_noble]

I have parts left from my 36 V-8 Cad - it's been decades since I looked carefully at the left over parts (I had two engines) but there may well be a balancer there - I was just getting rid of the pistons I'd been saving all these years on the basis of "who would want used pistons" - I suppose I should toss the timing chains I saved too

[Steve Passmore]

Sorry Mark, didn't mean to give you a fright! You should be OK, as I said I tried fit my 37 pulley on a crank from a post war engine and it wouldn't go, too small, as a lot of changes were made 41 on you will be OK with the 39 stuff,----- I think!

[Brad Ipsen CLC #737]

There are several different cosmetic styles of the harmonic balancer used but from examples I have seen they are all the same in principal with the leaf springs.  LaSalles did not use the harmonic balancer as well as the flexible flywheel.  The piece on the front of the crankshaft was just a solid pulley.  I don't remember exactly what I have done but I have removed the light sheet metal to inspect the springs by grinding the heads of the rivets.  I don't think there is a reason to do that though.  Machine the pulley seal surface to 1.813" diameter and bore the timing cover out to 2.279" and install seal CR 18025.  Balance the harmonic balancer when you balance the whole crankshaft, flywheel, clutch assembly.  When you bore the timing cover I have always had it line bored on the block.  Not sure if this is necessary but I have assumed so since the factory seal is on the face of the bore.  The center of this hole in the cover did not need to be aligned to the crankshaft center line.   

[markl]

Brad,
Glad to hear that what you were seeing once the harmonic balancer was opened up didn't indicate any need to service (change) internal components.  Even though the one I have obtained was fairly rusty, the slots that give access to the springs seemed fairly caked w/ dirt and grease, so I've taken Otto's suggestion and shot some penetrating oil in there and cleaned it up the best I could.  I was concerned that there might be some rubber component in where I couldn't see, and that it could be damaged by the penetrant.  With that resolved, I think I'll just turn the seating surface down as you've described (1.813") and fit the appropriate seal.

I think your procedure to align-bore the front cover while bolted to the block (and in position via alignment pins) is certainly the most prudent way to enlarge this hole, but my engine has the pistons and rods installed along w/ the crankshaft, and if possible, I'd like to avoid tearing all this apart.  So, all this begs the question: Has anyone bored the front cover off the engine, simply taking care to stay concentric w/ the original hole?  And in final analysis, did this seem to place the seal in the proper alignment to the nose of the crank?  My engine was not line bored during the rebuilding process, which would be another strong argument for doing this the right way as Brad described.  However, taking it all down to the point where a boring bar could be set up off of the main bearing saddles and caps at this point would be a lot of work!

I'd like to hear anyone else's experience as I think a fair number of owners have switched to a conventional lipped seal as Brad has described.

Mark Lowery, CLC#25216

[38FLATTIE]

markl,

The timing cover holes are often not perfectly centered with the crankshaft. I measured mine, marked it, then had the machine shop bore it. The hole doesn't have to be very far off to wear seals out in a hurry. An hour with a micrometer, and a trip to the local machine shop, and you'll be done!

[markl]

Buddy,
I agree w/ your warning about seal wear caused by lack of concentricity.  Now I'd like to know how you determined the offset of the hole in the timing cover vs. the crank center!  Perhaps using drill bits in various sizes as go-nogo gauges?  Or are you saying use an internal micrometer small enough to fit in the annular space between the nose of the crank and the hole in the timing cover? 

Mark Lowery, CLC#25216

[38FLATTIE]

Yes markl, I used a micrometer. I drew a crcle on a piece of paper, then measured in several places. I noted the measurements on the paper, then took it all to the machine shop. It was perfect the first time!

If a mistake is made, timing covers are easy to come by, or they can start over, and just use a little bigger OD seal. It's really a very easy process!