Guys - I'm rebuilding a '65 vintage 283 and trying to get the harmonic balancer on without a big hammer. I was able to tap a 3/8 by 24 thread in the crank end but I'm afraid it wasn't strong enough and I'm having to re-tap to the next larger 7/16 by 20, as the factory did on later engines. I'm having trouble getting the tap started even after drilling the hole out with my 3/8ths bit. I hesitate to use anything larger, because it'd be a 7/16ths and that won't work if I want to thread a bolt in, that size. Is there a secret to getting a tap started? I prefer to press this balancer on rather than whack away at it. and crank steel is anything but mild!
It may not be the cheapest approach but paying to have someone machine a sleeve that slides over the crank snout with a piloting hole is about the only way to ensure maintaing a "true" center short of disassembling the engine and having the work done on a lathe. With removable pilot bushings it could be used as both a drilling fixture and a tapping fixture.
There is a tool for that purpose. I am thinking 12bolt.com has such a tool available. If not there, the tools is available elsewhere. Worth looking for to get the job done accurately. Just had it done at my local high performance automotive machine shop on my 250 Chevy six build. Ray
Don't tap it, Just heat the balancer in the oven. Then use a piece of tubing large enough to go over the crank snout ,and bash away! You can hear to tone change when it is hit home. If you use some Aerosol "freeze spray" on the crank, you could probably push it on by hand
Never had any issue driving a dampener on with a cut section of 3" thick, 4" diameter round stock, and a good sized hammer. Keep the block of steel centered, and hit it in the center, and methodically. And yes, the tone change tells you it's set. I don't even have the "install tool" for cranks that are tapped; they get their dampener driven on also. The only thing is, the dampener then has to be repainted. I am Butch/56sedandelivery.
To cut a 7/16 20 thread, drill hole depth 1st with a letter U Tap drill, your tap should start easier For any other size, check a drill and tap chart to cut correct hole size
Really? I won't risk messing up crank thrust, seals or bearing seats by whacking on the balancer? It's got a rubber cushion and I hesitate to stick it in my oven. Guess I'm over cautious. Thanks all!
The Tap Drill for 7/16-20 thread is 25/64 Purchase the correct size drill ( Good Quality ) and tap along with some "Cool Tool" or "Rapid Tap" tapping fluid. You may have to go to an industrial supply to find these rather than the hardware store. Use plenty of fluid both drilling and taping. Keep the drill square with the snout and the Tap and handle square while tapping. Turn in 1/8 to 1/4 turn and back out to clear the chips. You may need a "Bottoming Tap" depending on the bolt length. hole depth required.
I have a 327 in the works right now and the crank is not tapped. When I dropped the block at the machine shop I asked them to tap the crank too ($80 fee). I asked for this not for ease of install but to prevent it walking off (even if it's rare).
I wasn't referring to a furnace. 200 degrees max Engines get up to 200 deg constantly. The 4 rubber contact patches on racecar tyres get over that. What you're trying to do is install a warm balancer onto a cold crank snout [before the temps equalize] You're hitting on a 6 pound damper with a 3 pound hammer onto a 45lb crank How much force is transmitted to the crank trust bearing? [you can always wedge a block of wood between the rear crank flange and the engine stand]
Hammering a dampener on is terrible advice, it’s a fantastic way to totally fuck up a thrust bearing and endplay. Sent from my iPhone using H.A.M.B.
Hammering a balancer on is not the best way to do it, but I’ve seen it done plenty of times without a problem.
There’s plenty of shit that happens supposedly without problems, doesn’t make it right Sent from my iPhone using H.A.M.B.
There is a guy on the Stovebolt Forum that goes by the handle Hot Rod Lincoln that has a guide set up for crank drilling/tapping that I think he rents out for a very reasonable sum.
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