More rubbish parts to look out for

[GDPR]

Two crankshaft timing gear sprockets on the same engine (supposedly rebuilt by the same Stag specialist as that cylinder head that was rotted through to the cooling jacket). One suspect OEM, and the other very new.

Mileage far from large post rebuild, RH tensioner about to pop but LH ok-ish.

Note the colour of the metal, and look at the teeth - considering how mission critical these bits are and how much abuse they get in comparison with the cam and jackshaft sprockets, how much do you now trust those new sprockets you did not so long ago?

Worries the hell out of me that this sort of rubbish is being supplied in good faith

Russ

IMG_2731.jpg

[Motorsport Micky]

Holy crapper Batman, that's disgraceful.

Micky

[Andrew S]

I had the same Russ years ago plus both cam sprocket teeth looked more like hooks holding the chains

[mjheathcote]

I am completely fed up with crap quality parts, not just car parts.
We are finding the quality of parts being supplied for use in our industry (pipeline fittings) is going the same way. Undersize (to save material, but then out of standard), oval, inaccurate cut threads, poor quality material etc. They are simply not fit for service, but the suppliers just say 'it is what people want to pay', that is fine, but not when you can't use them, or do, and you have leaks and failure to rectify at a later date, at a cost that then has to be paid.

[flying farmer]

Is that darker coloured sprocket hardened by any chance?

Certainly most of the crank sprockets I have bought new for the last several years have been made of butter and this is on of the reasons I have taken to using the jwis chains in the hope that their extra quality and reduced stretch will give the crank sprockets an easier time.
Only problem is that it is going to take years to do enough mileage to find out whether this works or not

[Lingen]

I think someone must be making them properly. I have always bought them from the same supplier and they have easily lasted the life of the chains when I came to replace them. That is at around 40k miles, or four changes since I bought the car 26 years ago. I suspect that black one is dirty oil stained rather than hardened!
Mike.

[jagorstag]

Perhaps fitting a more modern V8 in there is the way to go in future, at least while there are still real OEM parts made for any such engine...

[GDPR]

I think someone must be making them properly. I have always bought them from the same supplier and they have easily lasted the life of the chains when I came to replace them. That is at around 40k miles, or four changes since I bought the car 26 years ago. I suspect that black one is dirty oil stained rather than hardened!
Mike.

Going to disagree with you there Mike - took a file to them, and the darker one is orders of magnitude harder, and likely an oem re-used when the work was done, whereas the bright one, was, as Neil described, soft like butter

[tonypy1]

When I had crank sprocket failure as shown below:

tc18.jpgtc17.jpg

I compared an original dark coloured sprocket against the failed ones and found that a file didn't make an impression on the original type but sank right in to the remnants of the engine stoppers above.

[mole42]

I suppose a magnetic sump plug would be a good idea? At least we'd have evidence that something was wearing rapidly.

[TR5convalescent]

Can anything be done to harden these? I have no knowledge of metallurgy but don't blacksmiths heat & quench horseshoes to make them durable?

Could a machine shop do something similar?

[tonypy1]

I did think about induction hardening as there's a company near me that does this, whether they would take on a small job I'm not sure and again not being an engineer I'm not sure whether this would be the best approach. For the time being I've just put some of the currently available gears on my spare engine to get me mobile and will take my time rebuilding the valve / piston hitting one. I did notice the same thing again with the spare engine, the original crank sprockets were darker coloured and hardened and showing very little signs of wear. One thing that I have been careful with on the rebuild engine however is making sure that the cams run freely in the bearings after trying them with the valve springs etc. removed as the head that corresponded to the most worn sprocket was a little tight.

[flying farmer]

I also wondered about hardening, might be possible to get them tufftrided, the colour of the original ones looks similar to a tufftrided crank.

Might make some enquiries when I get time.

[Motorsport Micky]

Maybe a difficult choice,

Can anything be done to harden these? I have no knowledge of metallurgy but don't blacksmiths heat & quench horseshoes to make them durable?

Blacksmiths heat and quench the horseshoes to set the shape after beating them around and prevent them spreading after fitting.

Also if you harden the sprocket you need to get a compatible level to the adjoining touching components so that the hardened component doesn't cause problems inadvertently carrying out machining on them. I'd get it tested for Rockwell hardness or ask a firm who's going to harden the new component to match the original sprockets hardness.

Micky

[mole42]

I suppose the prudent thing would be to do the file test on any new sprocket before fitting and reject any that fail. Of course, I didn't 3000 miles ago.....

Richard