RB30 Facts, Figures and Helpful Hints

[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.

[dom14]

$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.

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.

[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.

[dom14]

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.

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.

[dom14]

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.

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.

[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.

[dom14]

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.

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

[mudnut]

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.

[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 .

[dom14]

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 .

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.