Slant Six Forum :: Harmonic Balancer Missing ?

Welcome!

That thin pulley on the crankshaft is the damper. The outer ring of the damper is grooved to take the accessory drive belt. The timing marks are cut into this pulley as well. Most slants did not come equipped with a bolt to retain the damper, but relied on a press fit to keep it from slipping off and a Woodruff key to keep it from spinning in relation to the crank. If you so desire a small block damper bolt fits once all the crud is cleaned from the hole in the front of the crankshaft.

Once you've checked the valve lash and gone over the ignition to make sure that's not the source of rough running and lack of power, you'll want to turn your attention to the carburetor. My track record with Holley 1920 carburetors is dismal. If you truck has a Holley 1920 that's been through the "reman wringer" it's likely unusable. Lots of remanufactured parts available over the counter at parts stores are of very poor quality. I have had better luck with Carter BBS 1bbls.

Author:	Spider1 [ Tue May 20, 2008 10:38 pm ]
Post subject:	Harmonic Balancer Missing ?
Hey people, New guy here. Nice forum ! And I am happy to have found it! I just picked up a 1964 3/4 ton Dodge pickup with a slant 6 in it for next to nothing. The truck is in good shape but the engine is running very rough and lacks power. I decided to check the timing and while looking for the timing mark, discovered that there is no harmonic balancer on the crankshaft ! Just a single, narrow grooved and thin pulley roughly 6 inches in diameter. Am I correct in thinking this engine is supposed to have one ? The alternator is new and has a narrow groove pulley on it too. So the belt matches both pulleys. I can turn the crankshaft pulley (by hand turning the fan) it rotates but the engine does not turn over with it. The engine will start and run with the starter though. I'm amazed it will even run at all this way. I suspect the crankshaft pulley nut is also missing and the pulley is just freewheeling. I just discovered this today. I intend to remove the fan and alternator belt and see what is missing. I have been wrenching for years but this is my first slant 6 engine. I turn to you slant experts to inform me if this engine is supposed to have a harmonic balancer or not. Thanks in advance for your reply's.

Author:	Joshie225 [ Tue May 20, 2008 10:49 pm ]
Post subject:
Welcome! That thin pulley on the crankshaft is the damper. The outer ring of the damper is grooved to take the accessory drive belt. The timing marks are cut into this pulley as well. Most slants did not come equipped with a bolt to retain the damper, but relied on a press fit to keep it from slipping off and a Woodruff key to keep it from spinning in relation to the crank. If you so desire a small block damper bolt fits once all the crud is cleaned from the hole in the front of the crankshaft. Once you've checked the valve lash and gone over the ignition to make sure that's not the source of rough running and lack of power, you'll want to turn your attention to the carburetor. My track record with Holley 1920 carburetors is dismal. If you truck has a Holley 1920 that's been through the "reman wringer" it's likely unusable. Lots of remanufactured parts available over the counter at parts stores are of very poor quality. I have had better luck with Carter BBS 1bbls.

Author:	Fopar [ Tue May 20, 2008 10:53 pm ]
Post subject:
the harmonic balancer is the pulley you described, it sounds like the key is missing or broken some have a bolt most do not. But the crank is drilled and tapped for a bolt.

Author:	Spider1 [ Tue May 20, 2008 11:06 pm ]
Post subject:
Quote: Welcome! That thin pulley on the crankshaft is the damper. The outer ring of the damper is grooved to take the accessory drive belt. The timing marks are cut into this pulley as well. Most slants did not come equipped with a bolt to retain the damper, but relied on a press fit to keep it from slipping off and a Woodruff key to keep it from spinning in relation to the crank. If you so desire a small block damper bolt fits once all the crud is cleaned from the hole in the front of the crankshaft. Once you've checked the valve lash and gone over the ignition to make sure that's not the source of rough running and lack of power, you'll want to turn your attention to the carburetor. My track record with Holley 1920 carburetors is dismal. If you truck has a Holley 1920 that's been through the "reman wringer" it's likely unusable. Lots of remanufactured parts available over the counter at parts stores are of very poor quality. I have had better luck with Carter BBS 1bbls. Thanks for the welcome and quick response. Joshie 225 So, your saying that what I see,...one thin pulley with a narrow belt grove in it, is the complete "unit" (damper pulley combination) all in one piece ? Ok !!! So, that means (because it (pulley/damper) is "freewheeling" the woodruff key is gone, or not matched up to the pulley and the guy I got the truck from (and told me he had timed it recently) timed it to wherever the timing mark was on that day... LOL, no wonder it runs so rough. Do you know where I can get a key and also a crankshaft bolt. ? I do appreciate your help. p.s. thanks for the carb advice, it does have a "rebuilt carb" on it I have yet to check what brand it is.

Author:	Spider1 [ Tue May 20, 2008 11:15 pm ]
Post subject:
Quote: the harmonic balancer is the pulley you described, it sounds like the key is missing or broken some have a bolt most do not. But the crank is drilled and tapped for a bolt. Thanks Fopar, You guys are great! I may just get some power out of this thing yet...

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Author:	GTS225 [ Wed May 21, 2008 3:09 am ]
Post subject:
You say that you can turn the crankshaft pulley by hand, but the crank doesn't turn. Clarify, please; Is the outer ring of the pulley/dampner turning by hand, but the inner hub is not turning? Those are actually two pieces, held together by a thin band of rubber. It's been known that the rubber detiorates, allowing the outer ring to slip and really play hell with timing. I suggest you also bring the engine to TDC #1, by using the eyes-on-valves method. If the outer ring has slipped, you'll soon know it. Roger

Author:	Charrlie_S [ Wed May 21, 2008 3:55 am ]
Post subject:
It sounds to me like the rubber in the damper has sheared. These dampers are available, rebuilt from Damper Doctor and/or Damper Dude. You can do a search on this site for their contact info. Before tearing into the carb, get the damper/timing mark fixed, and adjust the valves. Then continue on from there. If the engine still has points, make sure they are in good condition or replace with a new set, along with a condenser, and gapped correctly. Better yet would be to convert to electronic ignition.

Author:	DusterIdiot [ Wed May 21, 2008 6:46 am ]
Post subject:	And...
Quote: The truck is in good shape but the engine is running very rough and lacks power. After correcting everything above you might check the valve lash per the manual... -D.Idiot

Author:	SlantSixDan [ Wed May 21, 2008 8:36 am ]
Post subject:
Welcome on the board. The crankshaft bolt is "missing" because it was never there in the first place (though if you want to install one, get a bolt that is Â¾"-16, 2Â¼" long. The appropriate flatwasher is about 2" diameter or a little under. There's no reason or need to install a V8 damper; a slant-6 damper in good condition will be fine. You can get a brand-new one here. Made in Australia, sold by a reliable US vendor, and it has two timing marks, for compatibility with timing indicators on either side (different year slants had the timing indicator located differently). Tune-up parts and procedural recommendations are in this thread valve adjustment procedure is here.

Author:	Spider1 [ Wed May 21, 2008 9:32 pm ]
Post subject:
Thanks for all the links and advice folks ! I pulled the balancer/pulley today. Yes, the rubber between the grooved pulley outer ring and the balancer is broken down to the point where just the outer ring was freewheeling. The crankshaft keyway and the woodruff key were fine. So I will be checking your provided links to see what I can get. Hopefully a good used one. Gonna check local salvage yards too. This engine is worth working on. It does not smoke and seems to have good compression . I pulled the plugs and they look good, just carbon soot-blackened from running too rich. No oil crude on them. The guy I bought this truck from has done a lot of work on it. New distributer, points, plugs, wires, alternator and rebuilt carb. He said he had problems when he timed it. And now I know why. I will also need a timing pointer. The one on it now is homemade out of plumbers tape. And yes, I am gonna have to find TDC by sticking a TDC finder tool (or whatever it is called) down the #1 spark-plug hole and rotating the engine. I hope the piston top can be reached this way. I have done this on Fords with a 'chop-stick' before. I may have to make my own pointer too. After I find TDC. Anyway, one thing at a time. Tomorrow I'm off to town to search for a new or good used balancer. Can't thank you all enough. I am sure I will have more questions as I go along. And will keep ya all posted with my progress.

Author:	Doc [ Thu May 22, 2008 10:10 am ]
Post subject:
I have some used balancers and timing marks if needed... I am only a "mailbox away". DD

Author:	Spider1 [ Thu May 22, 2008 10:20 pm ]
Post subject:
Quote: I have some used balancers and timing marks if needed... I am only a "mailbox away". DD Thanks Doc, Just sent you a PM.

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