Timing chains and sprockets

[Bob Heritage]

I asked on the old forum a question about timing gear sprockets and got one reply, now the forum is used more I will relist it as follows.

One of our local members rebuilt his Stag engine and drove about 400mls on the new engine. He was driving slowly when the engine seized. The sprocket teeth had completely stripped and the engine destroyed. The engine parts were all bought from what is probably the largest supplier of Stag parts. He had the sprockets tested and they were about 15% softer than theoriginal parts. I am about to replace my timing chains and probably sprockets as well, but unsure about the sprockets, will probably fit German chains. I am sure you guys will have plenty of opinions on this one.

Bob.

[Mark S]

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I would guess one of the heads was nipping the camshaft putting extra load on the chains. What torque was required to turn the engine after it had been rebuilt? Did it still turn easily when hot?

Unfortunately the quality of pattern parts is not what it could be, but it's a fact of life that theyare engineered to a price that we are willing to pay.

Mark.

[Paul B]

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OK now I'm worried. I have just rebuilt my engine and used new timing chain sprockets. Is this a common problem?

[seaside bill]

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Paul B wrote:

OK now I'm worried. I have just rebuilt my engine and used new timing chain sprockets. Is this a common problem?

I'm afraid so, but not just limited to timing gear sprockets or Stags. It seems to me that this problem is getting worse and buying from a reputable supplier, while obviously thesmarter option,is not a 100% guarantee of quality and durabilty.

[Sheepdip]

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Hi Bob. You know the problems I've had with my engine, but sprockets have been fine. I'm beginning to wonder tho whether an oil change should include removing the timing cover and checking all is well!

Does anyone know ifall the parts come from the same manufacturere (ie independent of supplier)?

[Bob Heritage]

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The parts used on the car mentioned were all from a major supplier. Although it is common practice that the suppliers inter-deal with each other and the same sprockets could be sold by more than one dealer. Correct me if I am wrong but I think that manufacturers and/or suppliers should carry a product suitability insurance. Perhaps we should use this forum to make other members aware of the sub standard parts on the market and list them under a seperate heading, then maybe we might get better quality parts.

Bob

[Paul B]

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There has been a problem with quality of Triumph reproduction parts now for many years. The water pump spindle is a prime example.

I doubt very much whether there is more than one actual manufacturer of thesereproduction parts with a number of retailers selling them.

I really don't understand why, particularly for engine parts which can do so much damage if they fail, these quality problems cannot be sorted. I would certainly be prepared to paymore to buy a part I could use with confidence.

How widespread is this problem with timing chain sprockets? Is this an isolated failure. I have just fitted an engine with new sprockets which were purchased about 3 months ago and am very concerned. Would I be better re-using the old ones,finding another source or getting the 'new' ones hardened if thats possible?

I am not sure what the liability is of the supplier, particularly when the engine has been assembled by an 'amateur' mechanic such as myself. The sale of goods act says parts should be fit for purpose, but how would you prove after the engine has failed, it was not due to poor assembly. Would any liability, assuming it could be proven, just cover replacement of the failed part, or include damage caused by its failure, and possibly replacement of the entire engine.

[Sheepdip]

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I've heard conflicting views on the water pump saga - some say it was ir was the original BL supplier units that failed, others aftermarket suppliers. My "new" pump from 3 years ago came with a hardness certificate which gave me confidence (the jackshaft didn't).

I guess we should be gratefull there are suppliers out there who are trying their damdest to ensure a supply of parts to keep our motors going, but if quality is questionable then we have a problem that can only get worse. As you suggest Paul, cost becomes secondary if they fail within a few months.

I think product liability would be hard to prove,need toprovea specific item failed due to poor quality and who supplied the part. I think would only have recourse if bought (say) a fully built and professionally installed engine.

Perhaps the tooling club could get involved here to quality test and control selling of these problematic items?

Sheepdip.

[NickA]

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Sheepdip wrote:

I've heard conflicting views on the water pump saga - some say it was ir was the original BL supplier units that failed, others aftermarket suppliers. My "new" pump from 3 years ago came with a hardness certificate which gave me confidence (the jackshaft didn't).

Sheepdip.

I understood it to be the Unipart waterpumps that had the problem. So watch out if you're buying NOS from eBay. I used a 2nd hand one that I re-conditioned last time I changed the waterpump.

[Bob Heritage]

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Tip Assuming that all the sprockets are fitted as a set and all at the same time.Also assuming that they wear at the same rate, you can keep an eye on any wear through the oil filler cap via the off side cam sprocket. I have also fitted a magnetic sump plug (via e-bay) I don't know yet how effective it is but they used to work a treat on the old Mini's. Hopefully there is no loose metal floating around.

Bob