crank chewed out

[DilboBaggins]

G'day guys, we have a 1999 2.8lt turbo diesel patrol and the harmonic balancer key way broke and chewed up the crank. So id say we need a new one :/ im in perth (wa) and am trying to find the cheapest one, has anyone had this problem and got a new cheap crank? If use have please message me where or comment. Cheers :)

[DilboBaggins]

Or would it be worth getting it grinded down and welded? What is the reliability of this if anyone has done it? Cheers

[happygu]

I dunno and I hope I am wrong, but I think you may struggle to find anyone with a good second hand one, as it seems to be one of the weak points on the 2.8.

I think you would be best chatting to a toolmaker/fitter & turner, to see if they can weld it and grind out a new keyway and ask how much ...

[DilboBaggins]

Well I rang nissan, they quoted 2k, so I rang patrolapart and they said they have good second hand ones for $500 so I rang an engineering joint and they said they should be able to fix it for $250-$300. Im not keen on the idea of a second hand one because it could be the same problem. I need to know what the reliability of it will be if I hand it over to an engineer

[DilboBaggins]

Ive been reading some other threads and some say you can drill two hole behind and through the balancer and put high tensile metal in the holes but the holes have to be smaller then the washer on the main bolt so that you dont have to replace the crank or keyway. Has anyone done this successfully? Cheers

[happygu]

Dilbo,

There are a few repair methods, and this will depend on the amount of damage sustained.

When I used to work in the family business, we used to repair keyways on the main shaft on giant brake presses which hold the massive flywheels ( of which there would be massively more strain on the keyways than a harmonic balancer, but the repair depended on the amount of damage, and we probably had less damage than yours ), and we would use different methods depending on the repair.....

Let a machinist ( fitter/ toolmaker ) take a look if you can, and they can advise.

The cheapest method would be something like JB Weld, but I wouldn't want to rely on this long term if I was going into the middle of nowhere....

Welding and re-grinding is long term, but you can run the risk of the heat distorting the shaft.

Re-slotting the keyway, or widening the keyway on the shaft and pulley can sometimes be an answer too.


I have heard of someone welding the harmonic balancer onto the shaft directly, and although this will work, it wouldn't be my preferred option, as you then make it unserviceable for main seal repairs and the like.

A bit of food for thought for you....

[DilboBaggins]

I have photos of the damage but cant seem to find out how to post them from my phone. Ill have a chat to a engineering joint and see what they can do. Would they be able to fix it whilst still in the engine? Or would it have to come out? Cheers mate

[Avo]

you'd think it would have to out because of the heat would stuff the seals I think mate.and trying to get in there and do a good job.

[happygu]

If Patrolapart have good second hand ones, it may work out to be a good option, as i would think the crank has to come out anyway if you choose to repair - depending on the level of repair required........

If you have to take the crankshaft out, you can pull apart with the engine block in chassis, but you have to separate the engine and transmission to remove the crank and check bearings for wear or damage, and this can be difficult in car.

It is much easier to assess and replace components on an engine stand......

[DilboBaggins]

Thanks for that guys, ill ring the engineering place tomorrow and see if one of them can come have a look or ill just send some pictures. The troll will have to go to a mechanic as I dont have the necessary tools :( unless anyone in perth wants to lend me a engine crane :D thanks again guys, ill post more info tomorrow

[nissannewby]

If its only for the balancer and not timing related you could just get another keyway cut and then refit.

[DilboBaggins]

48537

Here is a picture of it, do use think its repairable? Cheers

[Punderhead]

<img src="http://www.nissanpatrol.com.au/forums/attachment.php?attachmentid=48537"/> Here is a picture of it, do use think its repairable? Cheers

It might be possible to have it sleeved and them recut the keyway, however that isn't the strongest.
A better option would be to weld the shaft, remaining round, and recut the key, however that can cause warpage

Iif the shaft is hardened. Which it should be. both these will be quite expensive. It may be cheaper to just buy another for cost, and that way you have the rig off the road for less time

Cheers

[DilboBaggins]

Thanks for the info mate, I am still in the process of saving up to get it done. I am trying to weigh up my options but nobody can give a set price except nissan for a new crank (2k) plus id have to get a new balancer, new belts ect. And pay for labour for someone to take the crank out for me :( wish I had the space and equipment

[happygu]

Looks repairable to me, as the keyway slot is only damaged badly on the trailing edge, but it is not totally destroyed.

This looks like a possible candidate for a weld and grind.....

The things I would consider are, do you need it repaired quickly, are you going off the beaten track regularly .... if the answers to both of these are yes, then the best answer might be to grab a good second hand crank and harmonic balancer from Patrolapart, and buy a new key to make sure it will be good for the long term.

It will take a machine shop a few days to get that fixed depending on their workload, and you are going to only save a couple of hundred dollars, and sounds like you will possibly always worry if the repair will hold.

[cos]

Is a small weld , so little or no warpage . Extra care on choosing right weld is important ( tig and alloy rod ... ) .


Main screw was no tight enough or harmonic balancer is way too loose fit on shaft . Maybe a Loctite 648 will solve the problem of loose fit ( for loose key/keyway also ) .

[happygu]

Is a small weld , so little or no warpage . Extra care on choosing right weld is important ( tig and alloy rod ... ) .


Main screw was no tight enough or harmonic balancer is way too loose fit on shaft . Maybe a Loctite 648 will solve the problem of loose fit ( for loose key/keyway also ) .


Good advice Cos,

Another alternative is JB Weld, but I haven't actually used this before to know how well it would come apart later on, if required. It is a cold weld product.....

[cos]

Is not near strong enogh , just a bandaid or a method to limit too much play between parts ( or maybe good for a emergency repair to can reach home at your own wheels , driving very calm witouth using much gas pedal ) . Any respectable good shop press will pull parts apart later ( except the case of usind realy strong sintetic resin liberaly aplied - parts will com apart but the end result will be more than two , because of the angular grinder contribution )
For a good result is necesar to put in practice a strong and clean mecanical solution ( steped custom key , face pins or any similar ) , even if this mean is a custom solve for the rest of the life in this engine .

Sorry for my twisted romanianenglish , should pay much atention at school in my early age .....

[DilboBaggins]

Thanks guys, and cos, the bolt was hard to budge with a 2 metre breaker bar! I still have no clue as to how it happened. I wouldnt even try to weld it myself as ive never welded before hahaha. I trust the guys at this engineering joint to do the job when I have the coin, they do seem like they are well organized, they have there own crank man! :)

[cos]

I.m in no doubt of the fact at the screw was tight , but is a clear evidence of a free play ( if is no play , the key will be untouched ) . How this hapend is a interesant subject , and should hapend no more after reparation .

So you want to weld yourself ( super ok , analize fist all problem involved and weld after that ) but how restore the keyway after welding ?

[DilboBaggins]

I think you misunderstood cos, I do not want to weld it, sure it would stay on there but there is more of a risk for more damage and it would be a nightmare trying to get it off if need be

[Stropp]

dilbo i think you misunderstood cos, from my take he is saying weld the slot and re cut the slot for the keyway.

[cos]

Stroop is right .

Even if a total and brutal weld is used , a further dismantle is posible ( never lose hope ) , using a right holesaw . But i imagine this is a sort of a last option when in no option at all and must weld with two car bateries and a welding rod made from a door opener wire coated in flour and dirt ( aaa ...never lose hope ...just say ....). Sorry for offtopic ...

[MrSka]

I'm looking at replacing my RD28T crank too, here is the cheapest quotes I have gotten so far from Nizzbits:

Crankshaft $1490
Harmonic balancer/pulley $350
Please note there is no stock of the pulley or crank in Australia. Lead time would be 3 weeks approx. from Japan.

Some other things you may need as below.
Front crank/pulley bolt $13
Front crank/pulley washer $13
Crank keyways $6 (pair)
Crankshaft timing sprocket $90
Sprocket plates $8 pair
Flywheel to crank bolts $30 (set of 6)
Spigot bush $15
Front crank seal $24


When you do yours, feel free to take lots of pics and post them here :D I'll do the same when I start doing mine as well :D

[cos]

What happend with you crankshaft ?

[MrSka]

It is "broken". I bought it like that, it was very, very, very cheap and thought it was a good opportunity to fix it up and learn all about the patrol base along the way :D

Mine starts up, but none of the pullies move, so it looks like the front of the shaft is actually broken of, but I havent pulled it apart to actually figure out exactly what is wrong with mine yet.

[DilboBaggins]

MrSka, that is the exact same problem with mine so ive taken it all off and they keyway is buggered. To save alot of money id like to pull the engine out myself but I have no clue as to what I am doing :/ so itll more then likely go to a mechanic

[MrSka]

I am really lucky, I have a truck mechanic who is going to help me replace it at his workshop on the weekends, I'll take HEAPS of pics, they might help you out!

[DilboBaggins]

Ive actually come to the relization the it would be better off in the long run if I drop a 4.2 in it. I can get a 2003 4.2 turbo diesel with upgraded turbo and intercooler with all bolt ons for $7500. And its only done 160***kms! So for a quick fix im going to find someone who's good at welding to weld the balancer back on to last me a couple months till I get another engine. Has anyone welded this before?

[MrSka]

Good luck, I think welding the crank on will just do the crank more damage internally?

[K1W1]

Just make sure when welding it that the weld area is well prepared to give it the best chance of good full penetration first time and most important the earth lead must be on the balancer/pulley or the flywheel and NOT the block.

This will prevent the current passing through the engine bearings which will shorten their life considerably.

[DilboBaggins]

Ive been talking to a mate of mine and he said it wouldnt be worth welding because of the type of metal the crank is and suggested to use liquid metal stuff and building the keyway up then fill in the gaps ect. Ive also read (to my understanding) that people have used a strong loctite to hold it in place? All I want is a quick fix to last a couple of months (with babying it of course) so I can still drive it while I save for another engine. I am really keen to get this done because the vn commodore's big end bearing has gone so im expecting that to go anytime soon. I know its not going to be reliable but id just like it moving for the mean time

[K1W1]

I looked at your photo earlier in the thread . If you get a larger key and file/grind/mill it till it fits snug in the crank and if your damper keyway is rooted get another one and use a Loctite product that has good gap filling properties you should be ok for a while. If going down this route try and dry fit all the parts before applying the Loctite as there seems to be some gremlins lurking under everyone's bonnet that just love to cause problems when you least need them.

[cos]

Welding is very posible , using a proper welding rod ( in this case must be a high nikel content , is more another options ) .

In any case , is a very last way to repair this problem .Better than weld , you can fit another key ( put the new key , fill the worn keyway with some soft steel by a very careful hamering , use Loctite or similar and drill a two pins in the balancer to fit the existing holes from the timing pinion ( or 3 , or 4 pins ... ) . This mean you must pull the timing pinion , align with balancer helped by a short shaft and drill in the balancer using timing pinion holes as a pilot holes . Holes in the timing pinion is only 5 mm diameter , but can be enlarged to 6 mm without problem . Pins can be from a drill end , a valve stem ...

So , in the end you get a full reusable parts , not a spooky ( also innocent ) engine .

[Dales300exc]

A mate kept breaking his balancer keyway in a high horsepower 4.8 turbo. After welding it broke again. He refitted, drill two holes (half through crank and half through balancer) and installed two dowels. Never had a problem again.

[DilboBaggins]

Would loctite or liquid meral holf it for awhile? I wouldnt be doing any 4x4ing or hard driving ect. Thanks for all the responses and ideas :)

[cos]

Nobody can be sure for this to answer .