Hello, I purchased a brand new harmonic balancer for a 73 350. Never used it. Now I have an 85 350 and need one. The part numbers are different on an online source, but are they interchangeable? Thanks Drew Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
you can fix the timing mark thing pretty easily. Also check the diameter, it may not match the timing marker. You can get aftermarket timing tabs to fit either one, right?
Check the inside diameter and keyway size. Check the keyway location to the timing mark on the outside diameter. Check the outside diameter and pulley bolt hole locations. Check the bolt hole sizes, they might be metric on the newer balance, so the diameter might be different. The timing tab on the front cover can be removed if need be so that TDC lines up with the mark on the balance. Some types bolt on, others are welded on.
As has been somewhat noted. 1. Yes, it will fit. 2. Yes it will dampen the harmonics. 3. Yes, a 350 to 350 damper will be balanced, close, not exactly. Exact requires proper balancing work with the engine apart. 4. Verify that the timing mark is where the "original" mark is. If it is not, there is a couple of ways to make a properly placed groove in your new damper. By using math or the more accurate but more time consuming way, by checking the actual crankshaft position. 5. The cranks are all the same diameter. 6. The seals are all the same diameter. You'll be fine. Mike
Thanks all Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
How likely is it that mine has failed? I get a pulsating vibration at 45 to 60 mph. It's like a woob.....woob.....woob.....woob..... spaced out maybe two or 2 1/2 pulses per second. At first, I thought it was driveline… When I first finish building the car… But if I pop the car in neutral, once the engine settles down to idle, it goes away. Furthermore, with the car in park or neutral, reving the engine to similar rpm's at a dead stop will produce the same pulses It is a junkyard motor that I don't know too much history about… Pulls good vacuum, for the most part steady vacuum, doesn't leak or burn much if any oil, and goes down the road just fine for the few hundred dollars it cost. I can't afford better Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
The damper is there to dampen torsional vibrations in the crankshaft. It is not a "balancer", even though that's what folks call it. Sounds like a driveline vibration, to me. But there could be some engine vibration going on, also. How bad is it? Mine all seem to shake a little bit at some speed, or another. I just keep driving them, unless it's pretty bad.
"Furthermore, with the car in park or neutral, reving the engine to similar rpm's at a dead stop will produce the same pulses" Not driveline.
It's annoying but doesn't seem destructive. In neutral it's more pronounced Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
I know he said that, but it still sounds like a driveline vibration, in addition to a small engine vibration. Without being there, neither one of us can rule out anything.
I've never heard of a driveline vibration in with the transmission in park. Are you sure it's a 350 and not a 400? Did the flexplate come with the motor? A 400 will have an extra weight on the flexplate. If you put a 350 flexplate on it, you will have a shake but it is usually noticeable at idle too. A 400 will have a notch in the outside of the damper.
It's a 350. Pulled it my self from a 1985 k30 Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
We can definitely rule out drive line for now cause it does it in park. If I fox that and it still pulses at speed then it's s driveline too. My pinion angles are good, other then possible metal to metal at the ****** mount (which still doesn't explain the pulse) I can't imagine it not being in the motor. The mount is isolated with rubber under and over, but the through bolts might touch the holes through the mount Is it likely that it could be a worn or damaged damper? Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
It's not very likely, but it's possible. The damper was balanced when it was made and if the ring slips on the hub, it can be out of balance. The torque converter is more likely to be out of balance.
What would cause that? Obviously that means a new one..., not necessarily expensive but a huge pain Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
Is the engine in good state of tune, vacuum lines etc..? A sketchy wire or plug etc, can cause a slight miss that may cause some bad vibes. You did say it was a junkyard motor.
Normally a "woob woob woob" vibration (good word, did you make it up?) is a harmonic vibration caused by a couple things being out of balance, and rotating at different speeds. For instance, if your engine fan and your harmonic damper both have a little imbalance, there are times when those imbalances will cancel each other, and times when they are additive. You could remove the accessory belts and see if it still vibrates.
The wires and plugs are new… The distributor is used, everything is in tune. I have been chasing an ever so slight Lee fluctuating Idol… That is, RPMs/vacuum will wander a little bit… Not fast like a leaking valve, but slow Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
I suppose I could try to illuminate each one of these things… I don't know how I would eliminate a miss or a torque converter, but if it gets better with the fan and water pump disconnected, that will tell me something Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
Inspect it closely, look for cracked rubber or the outer ring alignment. I have a 350 in a 36 chevy, i bought the motor already built, it was all new, with receipts. However, the engine was never as smooth running as it should be. During a recent inspection, i thought the balancer was coming unglued so i ordered a new one. Once i removed the old one, i saw it was made that way. I had the new SFI approved fluid damper so i installed it anyway. Glad i did, the thing runs much smoother with the new fluid damper than it did before. turned out to be a nice upgrade. I can tell the difference at almost any RPM.
If you need to check if the balancer has slipped, get a dead stop, find true TDC and compare to your balancer timing mark. Easy as pie.
What's a dead stop? And thanks. ***uming a tool for finding tdc- I could always fit the top of the travel and then turn the other way and find it again and take the average, yes? I did just find a small manifold leak and thought it went away. It's smoother but not like it should be. Also I figure I could Eliminate the torque converter by unbolting it from the flex plate and sliding it in. Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
Oh! Still probly tough to do accurately. And this means pulling all my plugs So is it possible every small block's dampener the same? There are many part numbers but is it all markings? Cause a 1973 350 And a 1985 one are different motors yes!? Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
Small block dampers changed over the years, and for different size engines. Most of the 350s used either the small one or the big one, there were two common ones. later ones often had the timing mark in a different place. only need to pull the #1 or #6 plug to find TDC
I had a similar vibration problem . Turned out to be either the torque converter or flywheel. I just replaced both at the same time. You might try unbolting the convertor and moving it around 120 degrees and see if that makes a difference ( much easier than replacing the flywheel or convertor.
@47ragtop makes an excellent suggestion regarding re-clocking the torque converter to the flex plate. Never thought of it, but it's a great idea.
The torque converter idea is good. I was going to unbolted anyway… I also remember torquing each one of those three bolts fully, then moving to the next. Perhaps something is bound up because of that… Should have torqued one at a time a little bit each. I will try this and report back, just as soon as I have the ability to get under my car. Squirrel, it's really hard to turn over my engine with the plugs in because of how difficult it is to get to the bolt on the harmonic balancer. Much easier if I take out all the plugs, unfortunately. Somebody once said to me "those early Chevy's were not in anyway shape or form intended to have a V-8 in them" they were correct… But boy is it a lot more enjoyable! It's true, because if you look at the same year Pontiac, or Buick, it was an easier swap. That is a vague, blanket statement… But it's true. Member: Rochester Street Rods - Est. 1970 http://www.rochesterstreetrods.org CrossMembers Car Club - Hebrews 12:2 http://www.crossmemberscc.com
The Jalopy Journal
