wgonzo64

I have a problem I hope someone can help . I was pulling off the gear to the crank of my 330 with a gear puller. the puller started to slip off and as this happened it also got cocked and peend over the first few treads, I bought a new tap sized 3/4x16 to clean the thread. I am having trouble getting it started, the bolt will just start but cannot get the tap to start,
anyone have any soulutions, I know how to work a tap when the item is on a bench or in a vice please help

oldcutlass

Which type of tap are you using? You need to use a taper tap and some cutting oil to start.

woodie582

should be a "starter tap" tapered on the end.

Sugar Bear

X2 on the starter tap, the starter tap will be tapered. Will the OP need a tap of any special material since the 330 crank is steel? How hard is this crank?

oldcutlass

Just some cutting oil and a bottom or plug tap to rechase all the threads after he gets it fixed at the end.

wgonzo64

the tap I have does have a bit of a tapper at the very tip. and this will seem naïve but what is an op and a bottom or plug tap and where can I get it ???

don71

OP=means original poster-which is you.

You should be able to do this if you have the right tap. I know its troublesome. Keep trying.

wgonzo64

I will post a pic of the tap I have it that will help

Sugar Bear

A starter tap has more taper at the beginning than the bottom tap, this helps to start the tap and will reach most of the threads. Picture a drill bit without a pointed end and think of how difficult it would be to start, the point on the drill bit is similar to what the taper does on the starter tap. The bottom tap has less taper, is more difficult to start and will reach the threads toward the end that the additional taper will not contact.

Be patient and take the time to start the tap as straight as possible, a second person watching the angle may help. The goal is to catch the original threads and clean them up as opposed to starting new threads. If you can catch and clean the original threads the rest of the threads may be ok.

This bolt is a critical application, it has to be correct for the crankshaft bolt to stay tight and prevent the balancer from coming loose, wobbling and possibly flying off causing damage or injury, take your time and make it straight. There may be some identifiers on the tap you have to tell if it is a starter or bottom tap, if not a picture may help identify it. It may also cost less to take it to a machinist and have it done than buying the tap.

wgonzo64

thanks for all of the advice . cannot take it to a machinist since the crank is in the engine is in the car . the only other thing is it was a bear to find the tap I bought, guess ill have to search the net which was hard enough but thanks again

wgonzo64

thanks again the tap I have is a plug tap I am now searching for the taper and bottom tap set thanks for all ur help

oldcutlass

You don't need to find a bottom tap, the plug tap will work just fine for that. You just need the taper tap.

wgonzo64

oh well that's good thanks

Octania

page 3538 of the grainger catalog helps a little

http://www.grainger.com/Grainger/wwg/catalogPDF.shtml

and the overall rundown at wikipedia:
http://en.wikipedia.org/wiki/Tap_and_die

In retrospect, it seems you should put a scrap crank bolt or anything in there to protect the threads before putting a puller on it.

Also, hitting the old sprocket with a chisel in the area of the keyway will generally break it, after which removal is easy.

Remember to study up BEFORE starting the job... ask around [here] for tips....

droldsmorland

Or get yourself a thread restorer kit. Snap Off and Crapsmen and most others (steer clear of harbor junk here) offer thread restorer kits and individuals tools/bits if you don't want the whole kit. These are an invaluable addition to the tool box. Google it. A tap can snap these tools are a bit more HD not as brittle and are designed to simply restore verses cut new threads. A tap depending what version, tapper, thread pitch etc... usually removes too much material making the female to male thread interface a loose fit which isnt desirable in this application.
Also purchase yourself a set of thread files another invaluable tool. Theres usually a spot in the above mentioned kits blow molded box to store them as well.

wgonzo64

thanks just talk with a local auto machine shop and confirms that a thread restorer is the best way to go, after spending an hour trying to find the right sized one (most go to 9/16 and I need 3/4 craftsman and snap on matco does not carry finaly found it on mak tools thanks to everyone for all ur help and guidance

Sampson

After you get everything cleaned back up I would use some Loctite on that bad boy when I put it back together.

Mark57

One other thing that may help is a counter sink bit. If the opening is out of round due to thread damage it will make it extremely hard to start any thread repair tool into the opening. If you run a counter sink in just a little it can help true up the opening to make starting your tap much easier. Make sure you start it square and use lots of fluid.