Perkins 4108: Removing stubborn crankshaft pully nut

[SteveNDar]

I had the same issue. I bolted a bar to the pulley so it would not turn, used a 6 sided socket, tried a big breaker bar but it didn't budge, then eventually slipped the pole from the wind generator over the socket handle and out through the companionway and with that leverage, it came right out. By the way, the seal was 5 dollars at a local bearing supply so I got a spare.

[stnick]

I have a perkins 4108 and I have removed that nut. It was not easy the first time. I purcheased a big socket and a large breaker bar . several days of PB blaster. I hit the nut with my 3 pound sledge each day and more pb blaster By the third day I used the sledge on the braker bar and it started to slip .More pb blaster. ! That nut was going to teach me a lesson.!It was my engine and i was going to teach it a lession or sheer it off.! I won !

[Arthur Garfield]

Seems many have had similar experience.Lol

My 2cents-
Take a step back for awhile.Formulate plan of attack.
Get PB or Kroll and liberally spray even behind pulley.Let sit a day or 2.Spray again.Let sit over night.
Buy a "6 point SHORT IMPACT socket"These are "grade 8" steel,
to correct size !(1/2 inch drive ) and a GOOD 1/2 inch breaker bar.
If bolt "deformed" from adjustable wrench you'll need to drive the impact socket over and FULLY onto bolt head.You'll accomplish this with weighty mallet/hammer with piece of hardwood between so as not to deform socket.Tap on at first when you KNOW socket "Truely" aligned.
Now as for chain holding engine from turning.I don't know your "setup" but I would look to prevent motor rotation from tranny side if possible.Often an engine will have place by starter to slip in a flat head screwdriver for this purpose.If not,perhaps starter removal to access flywheel teeth required.
Use persuader pipe to extend breaker bar leverage/torque.
Heat,for me,is always a "way last resort".
You can find an "IMPACT UNIVERSAL" to angle out of tight space for breaker bar.Though this may require an "experienced feel"/dexterity.Don't do the starter motor crank thing if you don't have the experience.
A "chain pipe wrench" like this can be used (Chain Pipe Wrench | eBay) with heavily doubled fabric under and around a pulley often is workable in situs like this.Though you must pay attention to chain pipe wrench's torque SPEC.
If relying on a belt to hold motor rotation will only work with just so much torque.


All the Best

[Jesse]

It is a very special bolt. Although the head is quite large the threaded part is only about 5/8" maybe 3/4" with fine thread and about the same length as diameter. The reason for the odd dimensions is that the outer portion of the bolt head acts as a flange to hold the pulley on the crankshaft nose. Some of the pulleys are aluminum so be careful as replacements can be difficult to find. Using heat seems to cause the pulley to expand with the bolt and doesn't help, particularly with the aluminum pulley. I used a six point socket with a breaker bar and a cheater with a friend tapping on the socket end before mine gave in. I don't recall it being left hand thread but not sure. If there is room an impact wrench is the best way by far.

[Hyrdflyr]

Buy a good half inch socket and extension. Go to Harbor Freight and buy an electric impact wrench for$49 plus tax. Throw away your adjustable crescent wrench. Real mechanics almost never use adjustable wrenches for engine or drive train work. They butcher the fastener more often than not.

[jimbunyard]

Maybe an addressing of the OP's situation might be in order.

For the 4108 there are three torque ratings for the 'crank pulley setscrew'

150 FT LB for the 1.56" long screw with 1.875" washer
180 FT LB for the 1.68" long screw with 1.75" washer
230 FT LB for the Phospated (black?) setscrew

It therefore seems likely that the problem he is having seems more a result of his inexperience than by any real issue with the bolt being other than normally torqued.

Hence, none of these 'heroic' measures (heat, favorite miracle sprays, excessive patience) are probably necessary, all that's needed is the sound application of standard mechanical practices, within the resources available to the OP.

That being said these would probably be the best tools for him to use, given the lack of access to the bolt.





But, since he doesn't have either of these two, and he does have a box end wrench and probably a hammer, then after securing the engine from turning, and ensuring that the box end of the wrench he does have is fully and firmly attached to the bolt head, his most expedient method would be to strike the wrench with the hammer whilst applying CCW pressure to the wrench.

If this fails then, by all means, break out the heroics...

As for efficiency, the straight box end wrench is by far the most efficient, because it directs the turning force in the same plane as the bolt head, evenly distributed around the bolt head.

The same goes for a socket driven by an impact gun, though the socket must be held very firmly against the bolt or a large decrease in efficiency will result.

A socket and breaker bar is probably only slightly better than a crescent wrench in this application; the limited access, the already half-rounded off bolt head, the inability to provide a balanced rotating force because of the offset induced by the depth of the socket and breaker/ratchet head all conspire against its efficiency, though this might be improved on if some way could be found to wedge the socket/breaker bar assembly onto the bolt.

As has been noted by several, this is a good place to use a cheater pipe; with a 3' cheater, 230 FT LB drops to an easy 77 lbs...

[lordgeoff]

Originally Posted by shanegeard

As seen in the photo, I'm getting nowhere with removing this crankshaft pully nut. The nut is starting to butcher from the adjustable crescent so I'm stopping to ask for help. Any tips welcome.

Attachment 152513

Chuck your crescent wrench in the drink and buy an exceptional socket set and a set of wrenches.

[deblen]

Don't leave home without one of these 1/2" drive impact drivers & a set of 6point sockets to go with it.
They are available in AC mains & battery voltage & a variety of brands.
Len

https://www.harborfreight.com/12-in-...nch-68099.html

[auskiwi]

Impact/rattle gun has always worked for me.

[sailah]

Originally Posted by jimbunyard

Maybe an addressing of the OP's situation might be in order.

For the 4108 there are three torque ratings for the 'crank pulley setscrew'

150 FT LB for the 1.56" long screw with 1.875" washer
180 FT LB for the 1.68" long screw with 1.75" washer
230 FT LB for the Phospated (black?) setscrew

It therefore seems likely that the problem he is having seems more a result of his inexperience than by any real issue with the bolt being other than normally torqued.

Hence, none of these 'heroic' measures (heat, favorite miracle sprays, excessive patience) are probably necessary, all that's needed is the sound application of standard mechanical practices, within the resources available to the OP.

That being said these would probably be the best tools for him to use, given the lack of access to the bolt.





But, since he doesn't have either of these two, and he does have a box end wrench and probably a hammer, then after securing the engine from turning, and ensuring that the box end of the wrench he does have is fully and firmly attached to the bolt head, his most expedient method would be to strike the wrench with the hammer whilst applying CCW pressure to the wrench.

If this fails then, by all means, break out the heroics...

As for efficiency, the straight box end wrench is by far the most efficient, because it directs the turning force in the same plane as the bolt head, evenly distributed around the bolt head.

The same goes for a socket driven by an impact gun, though the socket must be held very firmly against the bolt or a large decrease in efficiency will result.

A socket and breaker bar is probably only slightly better than a crescent wrench in this application; the limited access, the already half-rounded off bolt head, the inability to provide a balanced rotating force because of the offset induced by the depth of the socket and breaker/ratchet head all conspire against its efficiency, though this might be improved on if some way could be found to wedge the socket/breaker bar assembly onto the bolt.

As has been noted by several, this is a good place to use a cheater pipe; with a 3' cheater, 230 FT LB drops to an easy 77 lbs...

I would respectively disagree with your math. The original torque needs to have the rust multiplier factored in. Heat is by far the most effective first line of offense in my years of experience getting out nasty bolts. Getting thermal differential working in your favor can reduce the torque by a substantial amount because it breaks the rust bond. Using good penetrant can further this by effectively creeping into areas that heat can't. But you use these two tools before picking up the striking implements it will significantly reduce the torque required to back that bolt out.

Most box end wrenches are manufactured to a much looser standard than a high quality socket. My USA Armstrong wrenches are a looser fit than my big snap on sockets. As someone noted those combination wrenches are usually at an angle and so the force vector isn't perfect. I do think your striking wrench is an excellent idea and with his limited access that could very well be the best solution.

If faced with the OPs situation, this is where I stop and consider the possible ramifications if that bolt head gets rounded off. If he can't even fit a impact,
He can't fit a drill and that project turns into a nightmare. Even if he could drill the bolt head off it looks like getting a gear puller to get the pulley off isn't looking good. Plus drilling a grade 8 bolt with a handheld is a massive chore even with cobalt bits and flood coolant on my Bridgeport I don't like the task.

Spend your money now and get the right tools for the job or spend it later having a pro excavate that bolt.

[sailah]

And I want to throw a shoutout for crescent wrenches amongst the hate. I have a major collection of them from back in the day.

Utica, Crestaloy, JM Williams, they are some of my favorite tools to use. They are finely crafted and used with respect and moderation belong in any serious tool box. I would never not have a 12" Williams coated in WD40 in my ships tools., used for many things where you need some heft and major opening. Like a seacock etc. but I know their limitations. Buy a really nice old one on eBay they are nothing like the junk made today.

[deblen]

Originally Posted by deblen

Don't leave home without one of these 1/2" drive impact drivers & a set of 6point sockets to go with it.
They are available in AC mains & battery voltage & a variety of brands.
Len

https://www.harborfreight.com/12-in-...nch-68099.html

Video of battery operated gun-not as powerful as AC mains gun,but not bad.

https://www.youtube.com/watch?v=bmFiFgAtUpM

[model 10]

You almost went to far. A regular socket has a chamfer that is almost as deep as the good hex on the cap screw. Grind off the chamfer on the socket before you ruin even more of the hex. In the end you are probably going to need a pipe wrench and a cheater bar. Don't rely on just one screw in the front to hold things, 2 would be better.

[merlinuxo]

It's a left handed thread.
I've pulled this pulley to reset the timing cover and sleeve the forward seal rider on the back of the pulley on a 4-108 and 4-107.
Best way to go about this is a (IIRC) 6 point, 2 1/8" socket on a breaker bar with a cheater. The cheater is a length of pipe slid over the handle of the breaker bar.

[sailah]

Originally Posted by deblen

Video of battery operated gun-not as powerful as AC mains gun,but not bad.

Not to be disagreeable but my 18v Makita is rated for 1,180 ft-lbs in reverse and 740 ft-lbs in forward. That dewalt is 1,200 ft lbs breakaway. I think Snap On and Milwaukee are right around there too.

The best Milwaukee 120v impact I found on Amazon is rated at 300 ft-lbs and costs more than the cordless.

For comparison, my nicest Ingersoll Rand Thunder air gun is rated at 650 ft lbs

Those LI Ion cordless impact wrenches are serious tools, heavy as all get out but beats dragging out the air hose or for reaching places you don't have air.

For my own comparison I slammed on the nut on my trailer hitch using my air gun and wound it on there for a good 10 seconds. The Makita buzzed it off like it was nothing. I did the same test winding it on with Makita and the air gun got it off but it was about 5 seconds of hammering. Not very scientific but I had to admit I was skeptical about the claims from these wrenches and was a believer after seeing what it did. Since used it many time on some heavy equipment, old Jeep parts it's the real deal.