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Crankshaft Keyhole Damaged - will devcon do the job?

Submitted: Tuesday, Dec 28, 2004 at 17:12

andrewhamilton

G'day folks

Had a bad experience coming back from holidays when the crankshaft pulley on my 1981 Landcruiser (2F motor) parted company with the motor... ouch (in every way)

The pulley is cracked and irrepairable and it has also damaged the crankshaft keyhole. One side is ok but the other is rounded.

A friend reckons I can put anoher key in with some devcon, whack the pulley on, tighten it all up and it will be ok.

I'd be interested in some second opinions.

Basically what I want to know is will devcon hold the key if the keyhole is damaged, because the only other option is major surgery... I don't want to waste time on a repair that won't work, but nor do I want to have to pull the motor out and change the crankshaft over.

Any help would be appreciated

Thanks

Andrew
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AnswerID: 90558   Submitted: Tuesday, Dec 28, 2004 at 17:32

Member - Geoff M (NSW) replied:

Hello Andrew,
This happened in my old FJ40, you've taken me back in time here.
Luckily I caught mine before it came right off.
What I did was rotated the crank until the keyway was uppermost. I filed the rounding out of the keyway and back to square. With the engine in place, all I did was removed the radiator and support panel, also bullbar if fitted. Climbed straight through the front of the truck.
I then filed the keyway in the pulley back to parallel.
Next step was to make a custom woodruff key (woodruff is crescent shaped on one side and square on the other, the shape of the installed key.)
Put the whole thing back together with some Loctite, exact variant was recommended by the local bearing shop.
Devcon should do a similar job to Loctite.
All worked great, think I kept the old truck for nearly 5 years after this.
One thing I did notice, there is a tab washer designed to keep the bolt that holds the pulley on from loosening. On mine the washer was broken.
If you work it out, this washer MUST be in place and intact or the bolt will work loose under engine rotation.
The bolt also doubles as a crank start dog, thats the reason it is made like it is. (Under crank start the bolt is tightened, the greater force)

Hope this helps,
Geoff.

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Geoff,
Landcruiser HDJ78,
Grey hair is hereditary, you get it from children. Baldness is caused by watching the Wallabies.
Reply 1 of 11
FollowupID: 349173   Submitted: Tuesday, Dec 28, 2004 at 17:58

Member - Geoff M (NSW) posted:

Andrew,
Another thought, if you just put a new standard key and pulley onto the flogged crank, no matter how much Loctite/Devcon you us it will flog out again. And no matter how tight the bolt.
You really need to file the keyway in the crank back to square and make a new custom key that is a slight interference fit. (Interference means lightly tapped in with a small hammer)
Other fix is as you guessed, new crank, key and harmonic balancer (pulley).

Geoff.

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Geoff,
Landcruiser HDJ78,
Grey hair is hereditary, you get it from children. Baldness is caused by watching the Wallabies.
FollowUp 1 of 1
AnswerID: 90560   Submitted: Tuesday, Dec 28, 2004 at 17:47

Member - Nick (TAS) replied:

Gday Andrew,one of my mates had a similar thing happen on his T/D Cruiser 92.The bolt that holds the harmonic balancer to the crank came loose and slogged the key way out.He got a new key and locked everything together with a filler/loctite but it only lasted 3 months when everything came loose again but bolt was still tight.In the end he bought a new genuine crank,harmonic balancer and all worn bits to fix it once and for all.All up cost was $3000

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Our Camps - Mainland Australia
Reply 2 of 11
AnswerID: 90569   Submitted: Tuesday, Dec 28, 2004 at 18:58

andrewhamilton replied:

Thanks guys for the real quick response.

I must admit I am very skeptical of the devcon as a solution, but my friend (a farmer / bush mechanic) reckons he has done this before and made it work.

I was just chatting with him and he reckons I need to fill the gap, file it back to square and then locking it all up will hold it in place.

This is the $200.00 solution... and I've got to admit, this one is much more tempting to at least try in a $4000.00 car.

To haul the motor out and replace the crank is freaking me out a bit.

Any other input would be valued. I'll let you all know what happens, what we try and what works.

I did also consider rnigng an engineering company to see if they could recut a keyway'pulley and key similar to what Geoff suggested.

I'm not sure it'd real easy for them though...

Your replies are very much appreciated!!
Reply 3 of 11
AnswerID: 90572   Submitted: Tuesday, Dec 28, 2004 at 19:51

fatboy replied:

Hi Andrew, Mate the devcon idea will not be a long term fix. and making a new cutom key is not either as woodruff keys are hardened, you need to have the crank removed and the keyway welded and recut . The 2 f is a petrol right so this keyway deetermines timing for the harmonic balancer so it must be recut in the same spot . If the crank is cast iron the engineering shop will T.I.G weld up one side with 99% nickel filler or a stainless steel and recut it , if the crank is steel it will be a little easier . I am a fitter and turner by trade and have done similar repairs on earthmoving machinery etc before and have had no dramas . Don't panic about the heat from the welding as the tradesman will know how to do it so the crank will remain cold . This fix requires a little time and effort but will be cheaper than a new crank.
Reply 4 of 11
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AnswerID: 90573   Submitted: Tuesday, Dec 28, 2004 at 20:00

Truckster (Vic) replied:

Would you risk it as a long term fix? You would hang yourself if you saved $1000-2000 now, adn then in 12 mths time it shi+itself in the middle of the Simpson...

Fix it right, fix it once.
Reply 5 of 11
AnswerID: 90585   Submitted: Tuesday, Dec 28, 2004 at 21:14

Member Eric replied:

Another reasnable fix , is to bronz it in place and to file the exess off

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Reply 6 of 11
FollowupID: 349246   Submitted: Wednesday, Dec 29, 2004 at 13:55

Michael ( Moss Vale NSW) posted:

Bronze would be strong enough but you would need to get it a dull red to get ti to flow. Its probably too much heat around that front area for my comfort. But having said that, i havent seen the front of a Toyota to make a fair judgement. Michael
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AnswerID: 90593   Submitted: Tuesday, Dec 28, 2004 at 21:45

Member - Brian H (WA) replied:

Devcon make a product called 'liquid titanium'. We sell about 1 a month to varous mechanics to fix the problem you have. Like most things I spose, done right it's OK.
Reply 7 of 11
FollowupID: 349357   Submitted: Thursday, Dec 30, 2004 at 21:24

Glenn D posted:

Hows it going Brian,

Have used a lot of Devcon products. I may be misinformed, but think you use liuid plastic for plastic, liquid metal for steel, Liquid titanium for titanium ?????
Cheers Glenn.
FollowUp 1 of 2
FollowupID: 349378   Submitted: Thursday, Dec 30, 2004 at 22:39

Member - Brian H (WA) posted:

Fair call, but how much titanium ya got lying around?
All the best for the new year.
Brian
FollowUp 2 of 2
AnswerID: 90601   Submitted: Tuesday, Dec 28, 2004 at 22:49

mik*2 replied:

Andrew,

Had the same problem on a Subaru a few years back, its just bad luck. I am a mechanical fitter by trade and can tell you from experience that Devcon will NOT work in your case.
It won't last, bite the bullet, get another crank (from wreckers)and new big end and mains bearings and fit them. Especially if you want to keep the car. Its not a big job, not as big as you think...

If you want to sell it, and decide on the devcon way, make sure you let the people on this forum know so they can avoid your vehicle.

cheers
mike
Reply 8 of 11
AnswerID: 90604   Submitted: Tuesday, Dec 28, 2004 at 23:50

andrewhamilton replied:

Thanks again all who have responded.

It seems the jury is out on whether Devcon will work or not. The answer is clear that it is not a long term fix.

Then again the car is worth only $4000.00

Those who have used it seem to think it will work...

Most mech fitters would seem to consider it a waste of time. I fully understand that. It will not give the original strength.

However given the other expenses incurred on our recent holiday and the age of the car I am thinking I'll give it a shot and see how it goes. Its $200.00 spent for the total repair v $2000.00. It seems like its worth the gamble.

Maybe it'll last 5 minutes maybe 5 years. I originally bought the old beast for just dropping the boat in and out and hitting the local sand dunes. If it does that for the rest of the time I own it I'll be happy.

Thanks again!
Reply 9 of 11
FollowupID: 349214   Submitted: Wednesday, Dec 29, 2004 at 08:27

Member Eric posted:

weld the bloody thing in there . The crank is a write off anyway . Clean it all up . sit the woodruff key in and give it a weld both sides. If you weld in the worn area then file it down , you wont have a issue . Just make sure you replace the oil seal behind it , because the heat will kill it

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FollowUp 1 of 2
FollowupID: 349235   Submitted: Wednesday, Dec 29, 2004 at 11:01

Michael ( Moss Vale NSW) posted:

Yes Eric, Reading the responses and thinking same as yours, remove the crank front seal and wet rag stuffed in where the seal should be and get someone to tig if possible and file. A good stick welding rod would be a CIG product... Weldall rods. They will weld a wide range of materials, especially when you dont really know what the crank is made of. Filing the Weldall is a little more difficult as it is tougher that mild steel rods. I wouldnt be using mild steel rods though. Michael
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Vehicle: Patrol ST 4.2TDI 2003
FollowUp 2 of 2
AnswerID: 90682   Submitted: Wednesday, Dec 29, 2004 at 19:28

andrewhamilton replied:

There are a few pics up here if you are interested...

We are in process at pres...

link text
Reply 10 of 11
FollowupID: 349264   Submitted: Wednesday, Dec 29, 2004 at 19:39

Bob Y. - Qld posted:


Andrew,
As you are going the Devcon way, may i suggest you obtain a 10mL bottle of LOCTITE "609" Retaining compound, and apply this to inside of Harmonic Balancer, and end of crank, before fitting together. Then use this on thread of retaining bolt, as well.

Will need to heat if you ever need to remove the bolt, but it may just help the devcon to last. Loctite products are available from Bearing Service.

Good luck,
Hooroo...
FollowUp 1 of 2
FollowupID: 349267   Submitted: Wednesday, Dec 29, 2004 at 20:00

Michael ( Moss Vale NSW) posted:

Hey Andrew, how do you keep the grease of the keyboard?? In fact you seem to have too much spare time on your hands, i'd go for a complete rebuild just to fill some time in LOL!!!! Good luck with the repair... Michael
Day at the beach
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Never do today what you can put off until tomorrow!!
Fortunately, tomorrow never comes.!!!
Vehicle: Patrol ST 4.2TDI 2003
FollowUp 2 of 2
AnswerID: 90819   Submitted: Thursday, Dec 30, 2004 at 22:47

Member - Brian H (WA) replied:

After looking at the pics I would be tempted to pack a key in the slot with some devcon to set it in the right spot then try and hit it with a welder.
Keep us posted on how it goes.
Reply 11 of 11
FollowupID: 349379   Submitted: Thursday, Dec 30, 2004 at 23:04

andrewhamilton posted:

All finished today...

The devcon set ok, I filed it back filled it a little more, left it to set again and the came back to put it all back together. Some stud lock on the crank shaft nut should hold it in place.

I guess only time will tell. Turns out the bloke across the street used the same fix on the same problem in his v8 Commodore and all went well.

I tossed up welding but was concerned that the heat might compromise the steel on the crank. My mate also reckoned devcon was tough enough to hold it.

I also spoke to the Devcon state manager who obviously had dealt with these questions before. He suggested their liquid titanium ($100.00 a tin) but I have gone with the basic version - again on the advice of my friend.

I doubt any mechanic anywhere would recommend what we have done, but then they need to garuantee their work. This is definitely a gamble.

I'll try and remember to post again in a few months with an update!
FollowUp 1 of 2
FollowupID: 349411   Submitted: Friday, Dec 31, 2004 at 09:59

Member - Brian H (WA) posted:

Glad you got it finalised. Hope all goes well. We'll all be here if it doesn't, some might even make the funeral ..... after the'missus' gets through with you.
All the best. Have a great new year.
FollowUp 2 of 2