I would like to replace my 401 balancer because of it's age (1963). I heard that a 455 is the same. Is this true? Should I just have mine rebuilt.
The harmonic balancer CANNOT be replaced with something aftermarket unless the engine assembly is apart & gets balanced. I do sell the balancers for the "nail" that are SFI approved. I ALWAYS replace the balancer with the SFI approved one when rebuilding ANY "nail" I do. If yours hasn't slipped, the rubber coming out or getting ANY vibrations just leave it alone for now. I DON'T like any of the rebuilt units because they don't use the same type of rubber, remove the balancing pins that may be there & the rubber ONLY seems to last 5-8 yrs. EVERY "nail" from the factory left the engine shop with a final balance using the balancer by using pins in the outer holes or drilling holes/marks in various spots. What I'm trying to say is that NO TWO "NAIL" BALANCERS ARE THE SAME. You can get close with used, but no sense doing that if yours is still OK. Tom T.
When TA Performance reproduced the 455 balancer we took into consideration of it's ability to be used as a replacement part on the 401 and so on. Our new TA2026 balancer WILL work on your 401. The 455 balancer needs to be shortened, I believe .230" so the pulleys line up. There are two timing marks on our new balancer, the thicker/larger one is for the 455. The thinner one is for the nailhead. After you paint the balancer I recommend you color the thin line before you install it. I have personally myself balanced nailhead crankshafts with an untouched factory nailhead balancer with no pins. Once the crank was at zero, removed the nailhead balancer and installed the new TA 2026NH balancer with no pins and spun the crank. The difference was inside of 10 grams. You will not feel a 10gr difference if you just installed it. But if the engine is apart and being rebuilt by all means have it balanced with the new part. Folks rebuild engines all the time and install larger pistons and do not balance with out a problem. I will assure you that the engine will be further out than 10grams from the factory and or after the rebuild. I believe we charge $35 to shorten the balancer to fit the nailhead. Have been selling these for years just don't believe my son ever added it to the catalog. We also sell an SFI part but its a bit more expensive. I personally feel much better using a new balancer with fresh rubber than using a old 455 balancer in this case with rubber that is hard & cracked plus has been absorbing harmonic tones of the other engine for its entire life. I don't even recommend using a good looking factory balancer on a rebuild if I can get a new part. We have seen many more the once on lets say a 455 Buick even 350 Chevy's. Rebuild the engine, new cam and so on, get the engine running and have the outer ring on the balancer move or totally come off. Install a brand new balancer and never have the problem again on that engine.
Okay one says no and one says yes. Has anyone else used a 455 balancer? I have a very slight vibration at 2000 rpm. I have changed out the flex plate when I converted to a TH400 from the dynaflow and that didn't change the vibration at all. I thought it might make it worse or better but no change. Thanks Pat
It's clearly stated that the 455 one is roughly .230" longer and that the timing mark is in a different location. I also read how a new TA 455 unit compares to a Nail unit w/o pins as a comparison. Everyone suggests that you are taking your chances with balance on any replacement dampner, however the new TA one is very close. I interpret your response as that you are disregarding that info and asking if anyone else has done the swap? Was there always a vibration? When you changed flexplates did you duplicate someone else's error?
When you are looking for engine vibrations you MUST go through a series of steps. 1st & easiest is to remove all the belts to check any acc. vibrations. 2nd. is remove the torque converter bolts & push back the converter to see if it's an out of balance converter. 3rd. look to make sure the pilot holes in the crank & flexplate line up. 4th. remove #1 plug & bring to TDC & see where the timing makes lines up. Last you could actually remove the balancer to see if the vibration stops or is the same. If none of the above singles out a vibration it could be the entire engine balance needs to be gone over if the engine has EVER been rebuilt. Recently went through this on a customers engine that was rebuilt. Everything checked OK within 2 grams. For some reason there was a non factory drill hole, which amounted to 1 1/2 ozs. that was the culprit. Could have welded with heavy metal, but opted for another crank. In the long run was less $$$. Tom T.
I bow down to the engine guru's but I would like to add that sometimes engine vibration can come from the exhaust touching somewhere and also collapsed engine/transmission mounts Most likely not the problem, but something for consideration Mick
All responses are excellent! The forum doesn't really know if the car had zero vibration issues to begin with, or if the original poster's topic was a stab in the dark after some type of "event" that caused the problem.
I have a Romac aluminum balancer designed for the 455 on my Nailhead. Had to be shortened as previously stated and the timing marks were off, but it works well. I had whole rotating assy. balanced together though.
