RB30 Facts, Figures and Helpful Hints

These are the photos of the crank gear & the two thin plates that goes at front and back of it, from late 2015 when I did my timing belt kit. Basically the plates+crank gear should snugly fit onto to the crankshaft end in front of the seal when the harmonic balancer is inserted and tightened with the pulley bolt.

https://photos.app.goo.gl/CKOqHLOjIIpkA6P62

https://photos.app.goo.gl/Ni83tMzrAniqAwdl1

https://photos.app.goo.gl/bCOaF1Bb0DnOR08S2


So, you can see there is a slight protrusion out of the crank shaft for back plate+crank gear to touch, so they don't grind on the crankshaft oil seal. I'm guessing the reasons for your drama might be a loose harmonic balancer bolt or the crankshaft key wear or something along those lines???!!!

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Originally Posted by mudnut

Some rather sad news for my RB30. The small plate, or washer behind the timing sprocket on the crank has stripped out and is eating into the crank. The only fix is a new crank, but probably cheaper to get a whole engine. This is just a mongrel thing that the mechanic who changed out the timing belt has caused about 30,000ks ago. It is such a shame as the motor is running as sweet as.

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@mudnut, can't send any PMs to you. It's houseful. :)

The washer/plate closest to the engine oil seal has let go and stripped out. A mechanic has said it is caused by the other mechanic not torquing up the harmonic balancer quite enough.

I have just put the whole thing together until I can get. I can afford a fix.

Pics will have to wait until I can talk to the dyno guy, as he builds engines as well.

One fix I have thought of is to drill and weld the plate to the sprocket and get it machined to be centred.

My inbox has now been cleared.

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Originally Posted by mudnut

The washer/plate closest to the engine oil seal has let go and stripped out. A mechanic has said it is caused by the other mechanic not torquing up the harmonic balancer quite enough.

I have just put the whole thing together until I can get. I can afford a fix.

Pics will have to wait until I can talk to the dyno guy, as he builds engines as well.

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Hey Craig,
Below specifically applies to Diesel engine's and particularly the RD28.
The harmonic balancer bolt may be kinda TTY(torque to yield) and when it's been re-used over and over(tightened and loosened too many times as in my case), retightening it after a while may be important. I honestly don't know if this is the case with RB30, but I took no chances and make sure to chekc and retighten the bolt after few days and again after a month or so and then quarterly or so.
Other solution is to replace with a new bolt(which we don't know how good it is unless it's genuine Nissan one).
I reuse the headbolts which are TTY, so I make sure to retighten the headbolts(definitely this time after dramas from last time).

Are you saying the protrusion on the crank has been ground to the point the crank gear is grinding on the seal/seal housing?
If that's the case, driving is not good obviously. Plate is there to protect the crank gear from happening that as well as a balancing shim between the cam gear and crank gear I reckon.

When I tightened the harmonic balancer bolt late last month, I gave it quite a tightening with a breaker bar while the crank is locked by putting the gearbox into first gear(not sure if it's the right way but that's the only way I could do 'cos no room to squeeze in the type of rattle gun I have).


So, how did you find out about the problem? Oil leak? Noise?!

The plate is there to guide the belt as well as shimming the the balancer and sprocket. Like I posted, this engine is running so well, you can almost balance a coin on the tappet cover at idle, so I am really pissed off.

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Originally Posted by mudnut

The plate is there to guide the belt as well as shimming the the balancer and sprocket. Like I posted, this engine is running so well, you can almost balance a coin on the tappet cover at idle, so I am really pissed off.

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Yes, yes, I would be really pissed off if I'm you as well. As a dedicated DIY'er who doesn't go to mechanics unless I'm super super desperate, I may be able to suggest something useful. That's why I ask how you discovered the problem. In other words the symptoms.


And yes, the plate is there to guide the belt, so it won't jump out of place or grind on sides.
I reckon that's the most important role.

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Originally Posted by mudnut

One fix I have thought of is to drill and weld the plate to the sprocket and get it machined to be centred.

My inbox has now been cleared.

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Your inbox is still full & not accepting any messages.

Not sure about drilling & welding though. From what I understood so far, the crank is scored where the plate sits.

The belt has been on there since just after I bought the car, so it is due to be replaced (5 years or 100,000 ks). It has only done 30,000 but I have pushed this little engine to the limits in that time.

The shaft is not just scored, it has a fairly deep groove chewed into it.

Since this is a weak spot on the dirty 30, I also thought of spot welding the two new plates to the sprocket before I fit it all up.

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Originally Posted by mudnut

The belt has been on there since just after I bought the car, so it is due to be replaced (5 years or 100,000 ks). It has only done 30,000 but I have pushed this little engine to the limits in that time.

The shaft is not just scored, it has a fairly deep groove chewed into it.

Since this is a weak spot on the dirty 30, I also thought of spot welding the two new plates to the sprocket before I fit it all up.

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If the two key notches on the crank aren't damaged, then i think you can sleeve it using a matching sleeve from Bearing Wholesalers or similar people. I'm not sure whether your particular model's crankshaft front end is different than mine, but I'm not sure how the problem manifesting itself either.

I'm thinking there are methods to fill those grooves as well, using methods like spray welding or TIG filler, and sand/buff it back to shape. I'm not sure it's worth though, as you can get hold of an RB30 crank or motor for peanuts these days.

$900 which includes freight to my place. Or I can source a reco-ready block and see if the Dyno guy will rebuild it for me.

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Originally Posted by mudnut

$900 which includes freight to my place. Or I can source a reco-ready block and see if the Dyno guy will rebuild it for me.

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I'm sure you know what you're doing, but from my end I really don't understand it.
If the real issue is the risk of the timing belt slipping out of place and grinding on the crankcase front housing, then your idea of TIG welding a plate(I mean my idea ;)) to the sprocket should solve the issue. From what I hear, the groove that is carved into the crank has no effect on the crank oil seal. Employ a bit of parallel thinking outside the box and see what you can come up with.
I certainly won't be paying $900 for an engine, 'cos then on top of that you have some hefty labour bills to cover as well.
In my book I would have a totally different approach. But if it's your daily commuter, then you have a bit of an issue.

I will have to make choices when I pull it all apart again. I think the plates are high tensile (will have to check that), so if they are, then welding may affect their strength.

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Originally Posted by mudnut

I will have to make choices when I pull it all apart again. I think the plates are high tensile (will have to check that), so if they are, then welding may affect their strength.

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I think you need to worry about the crank gear than those plates. They basically get tightened around the crank gear & then turn with it. Welding something to the crank gear may or may not affect it's strength. But, crank gear's main function is to transfer the rotation force from crank to the camshaft.
If I'm in your situation that's what I would do, or I may make a custom plate to fit with the groove carved on the crankshaft by the plate. I would also attempt to either fill the groove with high strength & brittle steel epoxy or speedy sleeve it & then modify the plate to suit the speedy sleeve diameter.
There are few ways I can think of how I would approach the issue. All depend on what other damage you have there, other than the groove carved on the crank. For example, if the plate has been grinding on the protruded face of the crank where the plate rests on & where the crank oil seal goes in, then you have a slightly bigger problem I reckon, 'cos that would set the vertical alignment of the cam gear, timing belt and crank gear. I am not 100% certain how critical is that alignment, but I would say if any wear on that protrusion leaves the crank gear rotation untrue, then that would affect the harmonic balancer as well as the timing belt's true rotation.
The key(s) on the crank may or may not force the rotation to be true, but I'm not sure. But, my general guess is if the plate has been rotating on it's own and grinding on the crankshaft and carve a groove then any grinding it's done on the protruded vertical face of the crank should ideally be uniform, rather than an angle or uneven. In that case, simply making a right thickness plate for the lost amount of metal from grinding should correct any misalignment.

Quote:

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Originally Posted by mudnut

I will have to make choices when I pull it all apart again. I think the plates are high tensile (will have to check that), so if they are, then welding may affect their strength.

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You may be able to address that issue by heating the whole welded crank gear & plate to a certain temperature and then allow it to cool down slowly.

To tell the truth, I have known about the problem since I had to do the head gasket and then the water pump. This is way back in September 2014.

Like I said, I couldn't afford to deal with it, so have just kept my fingers crossed and drove the bloody thing.

I have taken the top timing belt cover off twice, and checked to see if any more damage has occurred.

I only saw that the belt was a little chafed so again, just put it back together and kept driving.

Thinking that I would now have to deal with it because the belt is 5 years old, I bought an engine for $220 from Smart Parts in Ballarat and took it to the dyno guy, yesterday.

He reckoned I have scored a good engine, but his response regarding the current problem was,"Look, if it was gunna destroy itself, it would've done so already. If you take the top cover off, I will check it all for you."

I pulled the thing off this morning and he came and had a look, while I cranked the engine over with the starter.

He said that there is zero movement in the plate, and that the belt is still in very, condition.

His advice is just to drive it for another couple of years, and to check it occasionally.

I have somehow been lucky enough to have clamped the plate onto the shaft in such a way that it will be ok.

I will re-check the balancer bolt torque and leave it at that, until the belt needs changing.

In the mean time, I have a spare engine to play with.

Quote:

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Originally Posted by mudnut

To tell the truth, I have known about the problem since I had to do the head gasket and then the water pump. This is way back in September 2014.

Like I said, I couldn't afford to deal with it, so have just kept my fingers crossed and drove the bloody thing.

I have taken the top timing belt cover off twice, and checked to see if any more damage has occurred.

I only saw that the belt was a little chafed so again, just put it back together and kept driving.

Thinking that I would now have to deal with it because the belt is 5 years old, I bought an engine for $220 from Smart Parts in Ballarat and took it to the dyno guy, yesterday.

He reckoned I have scored a good engine, but his response regarding the current problem was,"Look, if it was gunna destroy itself, it would've done so already. If you take the top cover off, I will check it all for you."

I pulled the thing off this morning and he came and had a look, while I cranked the engine over with the starter.

He said that there is zero movement in the plate, and that the belt is still in very, condition.

His advice is just to drive it for another couple of years, and to check it occasionally.

I have somehow been lucky enough to have clamped the plate onto the shaft in such a way that it will be ok.

I will re-check the balancer bolt torque and leave it at that, until the belt needs changing.

In the mean time, I have a spare engine to play with.

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Have you actually considered to spot weld the plate into the crankshaft groove, since the plate is already deep into it?!!

I know the crank is already stuffed but that would lock the seal on. I did think of getting a plate machined with an off centre hole, so that when it was pushed into the groove, the outer circumference was concentric to the shaft.

Be wary of welding a hardened shaft unless you know exactly what you are doing , your mechanics advice is sound but does leave that aspect of uncertainty, you don't want to be outbush somewhere in the future and have it all go to crap on you .
The less invasive methods of Doms and your own would be better from my point of view .

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Originally Posted by GQtdauto

Be wary of welding a hardened shaft unless you know exactly what you are doing , your mechanics advice is sound but does leave that aspect of uncertainty, you don't want to be outbush somewhere in the future and have it all go to crap on you .
The less invasive methods of Doms and your own would be better from my point of view .

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Yep, I totally agree.
Going on long trips with a timing belt that can possibly slip off the crank gear and grind all the way to end on the wall
will be a disaster.
I wouldn't try conventional welding methods on hardened steel of course.

Quote:

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Originally Posted by mudnut

I know the crank is already stuffed but that would lock the bearing on. I did think of getting a plate machined with an off centre hole, so that when it was pushed into the groove, the outer circumference was concentric to the shaft.

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I don't think I follow that.
What bearing are you referring to?

I meant the seal, brain in neutral when posting that.

Post amended.

Anyway used the endless chain to pull the engine from the back of the Old Trol. I whipped the plugs out and found some greenish deposits on #6 that smelt like coolant. Worst case scenario, is it has been hydrolocked, but the best is only a head gasket. I will shop around for a s/h engine stand.

Quote:

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Originally Posted by mudnut

I meant the seal, brain in neutral when posting that.

Post amended.

Anyway used the endless chain to pull the engine from the back of the Old Trol. I whipped the plugs out and found some greenish deposits on #6 that smelt like coolant. Worst case scenario, is it has been hydrolocked, but the best is only a head gasket. I will shop around for a s/h engine stand.

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Engine stands are pretty cheap. Check on ebay. If you have few scrap steel & a stick welder, you can make a one in no time.

Make sure to do a leak down test on the used engine you have.
If you've got it cheap, it will be a hit and miss, but most have pretty good bottom ends.

Removal of timing sprocket

I took the advice from another thread, to drill and tap some holes in the timing sprocket and use a puller to remove it.

Materials and tool list.

2x 6mm x 1mm thread pitch x 100mm hardened bolts with large washers.

1x small steel ruler, or vernier calliper.

1x 2mm drill bit.

1x 5mm drill bit.

1x 6mm x 1mm starting tap.

1x 6mm x 1mm bottom tap.

1x El Cheapo puller and spanner to fit.

1x hot air gun, hair drier or inductor heat gun.

1x centre punch and hammer.

1x scribe.

I soaked the sprocket with Inox for a few days and cleaned the crank, with a fine grained wet 'n' dry paper.

Position the sprocket with the key at the top.

Carefully measure and scribe two marks, on the outer edge of the machined step of the sprocket, each 90 degrees from the centre of the key.

Taking care to position the point of the centre punch. Make a light mark and check it is in the correct place. Use a few heavy blows to deepen the mark, so that the drill bit won't move off centre.

The sprockets are made of very soft metal so you must constantly check that the drills and taps are centred and parallel to the crankshaft.

Drill two pilot holes with the 2mm bit, approximately 17 mm deep.

Use the 5mm bit to drill out the pilot holes.

Use the starting tap to get cut the threads.

Use the bottom tap to cut to cut to the bottom of the holes.

When setting up the puller, screw the bolts into the holes until they hit bottom, then undo them half a turn. This is to ensure that if a bolt breaks under the strain it will be much easier to pull out the remaining piece.

Screw in the crankshaft bolt ( almost to full depth) to give the puller a good surface to act on.

Apply heat to the sprocket and begin to tighten the puller. The sprocket should slide off fairly easy, but in many cases it may be very tight. And you may need to use more heat. Be patient and don't break the puller bolts.

If you are unsuccessful, you may have to drill another hole above the key, or a series of holes along the key (in vehicle) and use a chisel to split the sprocket to remove it.

I did this job with the engine on a stand and there is not much room to work in the engine bay. There are drills with right angle heads or right angle attachments available.

I would recommend drilling and tapping these puller holes into the sprocket before fitting it to the engine.

There is a shallow groove worn into this crankshaft as well, but it is nowhere as deep as the one in the Old Trol.

You can see signs of movement on the rear washer, but the centre hole is not worn out, like the one fitted in the vehicle.

I have thought of drilling and tapping the sprocket puller holes all the way through and into the washer. I would grind the end flat of a pair of grub screws and fit them with just enough length protruding to seat the washer at centre, This would negate the washer being fitted off centre or spinning around and further chewing the shaft out.

I would also fit another short grub screw to lock each one, also using the correct Loctite to ensure nothing came loose.

Need to remove clutch fan and drive belts, swap clutch hub and fan over. Will try to remember to take some pics, hopefully help anyone else that may need to do it.

You still around Dom? Been a while since I've seen your name here!

Forgot all about getting pictures. Job was easy enough, was given the wrong p/s belt so that was annoying.

dom14 where are youuuuu?

In other news, car has it's power back with new fan clutch, it's no longer thinking it's a jumbo.

Flipside is looks like my rotor button is cooked again. Rev limiter kicking in around 4700. 3rd button in two years, cars lucky to do 5k kms a year.

Has anyone actually tossed the springs, I've seen it mentioned on a few forums here and there but be nice to speak to someone that's done it.

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Originally Posted by Throbbinhood

Forgot all about getting pictures. Job was easy enough, was given the wrong p/s belt so that was annoying.

dom14 where are youuuuu?

In other news, car has it's power back with new fan clutch, it's no longer thinking it's a jumbo.

Flipside is looks like my rotor button is cooked again. Rev limiter kicking in around 4700. 3rd button in two years, cars lucky to do 5k kms a year.

Has anyone actually tossed the springs, I've seen it mentioned on a few forums here and there but be nice to speak to someone that's done it.

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Interesting. What brand button have you been using? I've had no problems as yet, and have had the engine rev way over redline a few few times but it is all stock gear.

What ignition system are you using? Is the button getting hot for some reason?

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Originally Posted by mudnut

Interesting. What brand button have you been using? I've had no problems as yet, and have had the engine rev way over redline a few few times but it is all stock gear.

What ignition system are you using? Is the button getting hot for some reason?

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One has been from Bursons, the other Repco. No idea on the actual brand.

Yeah they're good for a while giving me 6300 or whatever. But they just seam to wear quick and I can't get it past 4800 now. Happens again and again.

I replace the button and it's all good again, so I know it's not a secondary issue or anything like that.

Whatever the stock ignition is lol, no idea. Nope not getting hot, didn't have long enough to get hot last time haha. #poorcar

Quote:

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Originally Posted by Throbbinhood

One has been from Bursons, the other Repco. No idea on the actual brand.

Yeah they're good for a while giving me 6300 or whatever. But they just seam to wear quick and I can't get it past 4800 now. Happens again and again.

I replace the button and it's all good again, so I know it's not a secondary issue or anything like that.

Whatever the stock ignition is lol, no idea. Nope not getting hot, didn't have long enough to get hot last time haha. #poorcar

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Yet to replace the button, but rev limiter is down to 4k now. Don't know why they keep doing this, the car sits for long periods so maybe they just get lazy from not moving, I dunno.

@mudnut on your snorkel post earlier (page 13 from memory). Have you done anything to seal the top of the airbox to the carby? I know there's a rubber seal there, but IMO it's a weakpoint and whilst I haven't had issues yet, it's next on my to do list (make up an airbox so I can have a silicone bend clamped to top of the carby).

Just a large washer and a piece of inner tube.

The real worry is the pre-heat flap inlet and vacuum diaphragm casing.

I ran a bead of silicon on the top and used a reducer and plug on the inlet but found it was too restrictive in cold weather with the plug removed.

I will probably get a full sized aluminium plug machined up and seal it with a fine bead of silicon so it can be removed in winter.

Think I'm going to do away with the airbox completely and move to a patroldocta style one or similar. Have heard most people block off the vac lines from carby to airbox with no ill effects, anyone know what they do/run/change?

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Originally Posted by Throbbinhood

Think I'm going to do away with the airbox completely and move to a patroldocta style one or similar. Have heard most people block off the vac lines from carby to airbox with no ill effects, anyone know what they do/run/change?

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Dom has posted the vacuum circuit earlier in this thread.

@dom14 you still around here mate?

Ok, all you Dirty thirty owners. Time to check and re-torque the crankshaft pulley bolt!! 152 nm or 112-113 ftlb.

Take off the stone guard. Unclip the radiator shroud extension piece and it is easily accessible.

For those who want to build a high-powered beast out of the RB block. https://www.youtube.com/watch?v=KF1iTh-2u3E

https://www.youtube.com/watch?v=TS3fFLg2QfU

Anyone have an aftermarket Airbox in their rb30? What do you do with the vac lines that feed into the stock one? Plug them? What do they all do?

bumpity bumpity bumpsalot

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Originally Posted by Throbbinhood

bumpity bumpity bumpsalot

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Post #56 doesn't help?