Drilling straight (into crankshaft gear)

[peejay75]

Greetings.

Alrighty, not looking forward to drilling and tapping this crankshaft gear to remove it, but that seems to be the preferred method (or splitting it) but if I'm gonna do it, I'd like to do it as close to right as my means will allow! What's the best way for a shadetree to make sure the holes are straight/perpendicular to the gear face? Perhaps using something like flange bushings to guide the drill bit(s)? Thanks in advance!

 

[speed bump]

Split it, otherwise it's trash, straightish will be close enough.

My personal preferred method would be a torch though.

 

[Slupie]

Amazon.com

 

[Jgaz]

Is the face of the gear ”proud” (sticking out past) the snout of the crankshaft?
Can you see a way to use something like this?

Big Gator Tools

Precision Tools for Professional Results

biggatortools.com

If I was doing this job I’d probably take a piece of maybe 3/8” flat stock, scribe a circle on it the diameter of where you want the holes and drill a couple of appropriately size holes at 12 and 6 o’clock.
After drilling the tap drill holes, enlarge the holes to accept the tap you need.
Then drill on your circle center mark a hole that will accept your crankshaft bolt.
Presto. Homemade drill guide.

I had bread loaf pan about 2/3 full of homemade drill/ tap guides when I retired

 

[peejay75]

Amazon.com

I've got one of those, but it's too big to fit on the gear face.

Is the face of the gear ”proud” (sticking out past) the snout of the crankshaft?

Nope, the gear is recessed onto the snout of the crankshaft, apologies for that poor pic that doesn't show the depth.

I like your circle-scribe method.

My personal preferred method would be a torch though.

I saw that that could potentially warp the crank?

The gear obviously can't be reused once drilled into, but for satisfaction, and ease of threading in bolts for the puller, getting the holes as "straight on" as possible would be nice, but not critical. I'll mull over you all's suggestions before committing1

Oh, any recommendations on drill bit type for the crank gear material, and best to prevent walking?

 

[Jgaz]

and best to prevent walking?

Transfer punch thru your drilled holes in the guide.
You might have to remove the drill guide and use a real center punch to make a centering divot

 

[peejay75]

(Just thinking out loud...this is overkill, but a 3D printed "jig" would probably be ideal, and I'm going to hafta repeat this process on a similar vehicle, so that might be work looking into down the, ahem, road.)

 

[dcg9381]

Why not weld something on this - the heat may help free it up and yank it with an impact-puller?

 

[Spareparts]

Will a bearing seperator fit behind the gear, if not drill a 3/16" hole between the root of the gear and crank
and directly across to the other side, increase the size of the bit until it almost through both sides, smack it
with a chisel it should split. You said shadetree.

 

[peejay75]

Will a bearing seperator fit behind the gear

Nope, not much clearance. The "paperback" repair manuals suggest using pry bars, but others have said that will destroy both the shim/guide (behind the gear) and the soft aluminum oil pump.

Will be busting out the drill and puller or drill and chisel!

 

[Jehannum]

Nope, not much clearance. The "paperback" repair manuals suggest using pry bars, but others have said that will destroy both the shim/guide (behind the gear) and the soft aluminum oil pump.

Will be busting out the drill and puller or drill and chisel!

It's all fun and games until you bust the oil pump casting behind the timing cog with your prybar.

Heat and penetrating oil, and then if that doesn't work in a sufficient amount of time, dremel a spot for your chisel to crack it between two of the teeth.

 

[BTL-A4]

I vote for cutting it off as @Jehannum suggests. Cut it with a hacksaw, then tap the kerf with a chisel and the gear will likely break off. You can twist it with a screwdriver as well. Just don't cut into the shaft.

 

[Jehannum]

I vote for cutting it off as @Jehannum suggests. Cut it with a hacksaw, then tap the kerf with a chisel and the gear will likely break off. You can twist it with a screwdriver as well. Just don't cut into the shaft.

I've done it before (on a 300ZX from 1996), and a dremel with a cutoff wheel is as close as I would get to the crank nose with an abrasive tool. I can't imagine the angle would work out to get a hacksaw in there.

All I did was notch out a bit between the two top teeth so my chisel wouldn't run the risk of slipping off and nailing the crank.

 

[peejay75]

Alrighty, just bear with me, please, this could be bordering on "excessive"...(too much "free" time!)

Had this jig printed to help me drill the holes straight...the holes are the diameter of the center punch, to help guide it straight...now, do I even need the center punch, if the jig is "supposed" to do the work of keeping the bit (1/8 to start) straight? Who's to say that the punch mark is gonna be straight, and then when I put the bit in, it may not actually be starting on the punch dimple? Ditch the punch? Use 'em both?

Thanks!

 

[Brianf60]

Use the Center punch. It will keep the drill bit from skating. Then it is time to just send it.

 

[peejay75]

Use the Center punch. It will keep the drill bit from skating. Then it is time to just send it.

Well, "one" question...if the jig holes are 1/8", and the drill bit is 1/8", should the bit not skate?

 

[jessesandy]

Just eye ball it.
Have a buddy look from the side.
You look down from the top.
When both of you see the drill bit is at a right angle to the face of the gear, start drilling.

Shadetree.

 

[claymont]

Greetings.

Alrighty, not looking forward to drilling and tapping this crankshaft gear to remove it, but that seems to be the preferred method (or splitting it) but if I'm gonna do it, I'd like to do it as close to right as my means will allow! What's the best way for a shadetree to make sure the holes are straight/perpendicular to the gear face? Perhaps using something like flange bushings to guide the drill bit(s)? Thanks in advance!

I'd drill a hole above the keyway and just into it some. Drill size about key width. Then I'd remove the rest of the metal above the keyway with a die grinder with a bit sized to fit between the gear teeth. Drive a wedge in there and pull it off.

 

[Brianf60]

you will get better results with the Center punch. You can use the guide for the drill bit as well if you like. There are multiple ways to accomplish this task. Just pick one and don’t spend too much time overthinking it. You got this!

 

[peejay75]

Thanks, all! Will do something tomorrow (weather permitting) and report back!

 

[jessesandy]

Well, "one" question...if the jig holes are 1/8", and the drill bit is 1/8", should the bit not skate?

True.
However, we always used jigs for locating and spotting. (Just drill a dimple.)
Then remove the fixture and drill the hole.
Otherwise, the fixture would trap chips/cuttings while drilling the hole.
Tends to chew up the fixture.

 

[MBfreak]

Use a hi-amp stick welder and weld with 1/8 rod a seam all around fast . Let somebody turn the crank.
Gear will fall off.

Ola

 

[peejay75]

Update...

Well, several test prints and a 3D printer later, finally got the jig to satisfactory results. I learned about "heat set inserts" during this process, but couldn't find a suitable size for this jig, so I went with brass bushings. Not sure if they'll spin on me, or get chewed up, haven't tried drilling yet, because now i HAFTA buy that right-angle drill I've been "needing". Been getting by with a right-angle adapter lo these many years, but that was BEFORE the days of GJ, and now I know better!

 

[no704]

Well, I thought I over thought things. Can’t u just use a puller on it?

 

[peejay75]

Well, I thought I over thought things. Can’t u just use a puller on it?

"Over"??? No such thing, only "additional"!

From my understanding, the best approach is to drill holes so you can then use a steering wheel/harmonic balancer puller. There's not enough room behind the gear for a jaw-type puller.

 

[cannuck]

"Over"??? No such thing, only "additional"!

From my understanding, the best approach is to drill holes so you can then use a steering wheel/harmonic balancer puller. There's not enough room behind the gear for a jaw-type puller.

I have a shelf full of pullers made for specific jobs such as this. There may not be room for a leg-type puller jaw, but there WILL be room for something a lot smaller. Start of with gear OD less amount of actual room at the rear and select a piece of pipe or tubing with enough wall thickness to machine an increased diameter to fit the gear. The little lip at the back is a 360 degree "hook" to pull the gear. Leave enough length at the outer end to put the crank bolt back in and cut another increased diameter at the outer end to fit a round "nut" with fine thread hole. Put the puller into your saw and slit in half along axis. The two halves make a split sleeve that will pick up the gear at one end and the pulling nut at the other. Use gear clamp or vice grip chain wrench if uber tight around the outer "stickout" and lube a pulling bolt thread with EP grease and run it into the nut. You gear will be off with no damage in a few turns.

 

[larry4406]

I’m still having difficulty understanding the objective.

Make / model of engine and what is being done?

Pretty poor of an OEM to pocket a gear in a case with no chance of extraction.

 

[ez-duzit]

Update...

Well, several test prints and a 3D printer later...

It really sounds like you're more focused on weeks of playing with a 3D printer, than with actually removing this gear. A drill press and some steel plate is all you need to create a more than adequate drill jig. But splitting it might not be so bad either.

 

[no704]

At a previous employer I happened upon a puller situation. Guy was trying to pull a steering wheel and had managed to strip the factory pulling holes. He had gotten a couple ratchet straps hooked to the steering wheel thru the rear hatch and attached to a forklift boom. The van was sliding on the smooth concrete. So he had about 5 more guys loaded in the van for extra weight.
I shut this activity down immediately! Drilled and tapped a couple new holes in the hub and had the wheel off in 5 min.

 

[peejay75]

It really sounds like you're more focused on weeks of playing with a 3D printer, than with actually removing this gear. A drill press and some steel plate is all you need to create a more than adequate drill jig. But splitting it might not be so bad either.

busted!

 

[peejay75]

I have a shelf full of pullers made for specific jobs such as this. There may not be room for a leg-type puller jaw, but there WILL be room for something a lot smaller. Start of with gear OD less amount of actual room at the rear and select a piece of pipe or tubing with enough wall thickness to machine an increased diameter to fit the gear. The little lip at the back is a 360 degree "hook" to pull the gear. Leave enough length at the outer end to put the crank bolt back in and cut another increased diameter at the outer end to fit a round "nut" with fine thread hole. Put the puller into your saw and slit in half along axis. The two halves make a split sleeve that will pick up the gear at one end and the pulling nut at the other. Use gear clamp or vice grip chain wrench if uber tight around the outer "stickout" and lube a pulling bolt thread with EP grease and run it into the nut. You gear will be off with no damage in a few turns.

This sounds interesting...how is the lip/360 degree "hook" created?

 

[peejay75]

I’m still having difficulty understanding the objective.

Make / model of engine and what is being done?

Pretty poor of an OEM to pocket a gear in a case with no chance of extraction.

HORRIBLE design, as are most things on this engine. It's a 1994 Nissan Pathfinder V6. Replacing the water pump and timing belt. And I will hafta repeat this process on a 2002 Nissan Frontier, same engine. Seems that most (all?) who do this repair go into it knowing they will hafta destroy the gear and buy a new one.

And @no704 , lol @ "I shut down this activity immediately!"

(Sorry, I'm still trying to figure out the multi-quote, to combine in one response!)

 

[cannuck]

This sounds interesting...how is the lip/360 degree "hook" created?

you select or bore the ID to what will fit behind the gear, then chuck up the complete tube/pipe and open a "pocket" that fits the gear OD and length. the minor ID forms the ring that does the pulling. Will take some pics in shop tomorrow.

 

[Jehannum]

HORRIBLE design, as are most things on this engine. It's a 1994 Nissan Pathfinder V6. Replacing the water pump and timing belt. And I will hafta repeat this process on a 2002 Nissan Frontier, same engine. Seems that most (all?) who do this repair go into it knowing they will hafta destroy the gear and buy a new one.

And @no704 , lol @ "I shut down this activity immediately!"

(Sorry, I'm still trying to figure out the multi-quote, to combine in one response!)

ah, the VG33E.

All of my experience on Nissan timing belts is with the VG30DETT in my 300ZX and the VG30E in my friend's 300ZX, which are largely the same in that department, so my notch + chisel advice goes pretty much straight to the heart of it.

 

[peejay75]

Slid off like butter! Thanks for all the tips, stay tuned for the next episode of Zen And The Art Of Overthinking!