Speed Six timing chain gear bearing failure - common issue?
Discussion
I've recently had my engine rebuilt at 38k miles after the timing chain snapped, which was caused by the failure of the half time gear bearing.
From speaking to my dealer and other SP6 experts, it appears that this is a reasonably common issue, and is known as a weak point in the engine. Apparently the bearing begins to break up, the gear starts to move around, and eventually the chain breaks thus causing a lot more damage to the engine. Additionally, although the bearing failure will cause a noise, it isn't likely to be noticed over the general noise of the engine, and certainly mine sounded perfect right until the moment it seized, even though the bearing had apparently been failing for a while.
I've now been advised that this is something that would be worth checking/replacing at certain intervals in the future, which seems good advice if it is as common as I've been told, and I assume the cost of checking/replacing before failure would be much less than a full rebuild.
My question is though - how common is it, and if it is a known weak point, then why aren't us owners made more aware of it? A couple of SP6 owners I know aren't aware of this, and I certainly wasn't.
From speaking to my dealer and other SP6 experts, it appears that this is a reasonably common issue, and is known as a weak point in the engine. Apparently the bearing begins to break up, the gear starts to move around, and eventually the chain breaks thus causing a lot more damage to the engine. Additionally, although the bearing failure will cause a noise, it isn't likely to be noticed over the general noise of the engine, and certainly mine sounded perfect right until the moment it seized, even though the bearing had apparently been failing for a while.
I've now been advised that this is something that would be worth checking/replacing at certain intervals in the future, which seems good advice if it is as common as I've been told, and I assume the cost of checking/replacing before failure would be much less than a full rebuild.
My question is though - how common is it, and if it is a known weak point, then why aren't us owners made more aware of it? A couple of SP6 owners I know aren't aware of this, and I certainly wasn't.
I recently had my Tuscan serviced, the garage commented on a noise coming from the engine which I have noticed, it sounds like an unlubricated chain noise. Its only happens for the first ten minutes after startup and only whilst the engine is cold, when it warms up the noise goes away - could this be the timing chain?
p.s the engine has done 32k however, it had a rebuild at 15k.
p.s the engine has done 32k however, it had a rebuild at 15k.
Tamster, my rebuild cost me about £5000 in total, although I did have quite a lot of additional work done at the same time (inc new clutch, wheels refurbished, new main bearings and crank check/regrind). The warranty co paid an extra £1500 on top of that for the work directly related to the failure of the bearing.
Not sure whether I've had the upgraded bearing fitted - I'll check next time I speak to the dealer.
Last service was back in the summer, probably about 2000 miles before it failed. If I'd been told it was a potential failure point, I'd have had it checked/replaced then but the first I heard of it was after it failed when people said "ah, they all do that"...
Last service was back in the summer, probably about 2000 miles before it failed. If I'd been told it was a potential failure point, I'd have had it checked/replaced then but the first I heard of it was after it failed when people said "ah, they all do that"...
ehasler said:
Not sure whether I've had the upgraded bearing fitted - I'll check next time I speak to the dealer.
Last service was back in the summer, probably about 2000 miles before it failed. If I'd been told it was a potential failure point, I'd have had it checked/replaced then but the first I heard of it was after it failed when people said "ah, they all do that"...
Ed - the engine has to come out to change the bearing. The best you could hope for at a service (assuming a fault could be heard) is to be advised of it. Last service was back in the summer, probably about 2000 miles before it failed. If I'd been told it was a potential failure point, I'd have had it checked/replaced then but the first I heard of it was after it failed when people said "ah, they all do that"...
bosscerbera said:
ehasler said:
Not sure whether I've had the upgraded bearing fitted - I'll check next time I speak to the dealer.
Last service was back in the summer, probably about 2000 miles before it failed. If I'd been told it was a potential failure point, I'd have had it checked/replaced then but the first I heard of it was after it failed when people said "ah, they all do that"...
Ed - the engine has to come out to change the bearing. The best you could hope for at a service (assuming a fault could be heard) is to be advised of it. Last service was back in the summer, probably about 2000 miles before it failed. If I'd been told it was a potential failure point, I'd have had it checked/replaced then but the first I heard of it was after it failed when people said "ah, they all do that"...
ehasler said:
Yeah, I gather that, but if I had known of it, I would almost certainly have asked for it to have been changed, as sod's law says it will fail at the worst possible time. In this case it was on a driving trip to Spain!
How much damage did your engine suffer when the bearing failed?bosscerbera said:
ehasler said:
Yeah, I gather that, but if I had known of it, I would almost certainly have asked for it to have been changed, as sod's law says it will fail at the worst possible time. In this case it was on a driving trip to Spain!
How much damage did your engine suffer when the bearing failed?Luckily it happened on the penultimate day of Eurohoon, rather than at the start, so wasn't as inconvenient as it could have been.
I've had it happen. Apparently it's very easy to damage and often occurs after the tappets are done if the cam chain is adjusted.
The timing chain tension is critical and unless your mechanic's an absolute expert and very precise in their work, it's all too easy to damage.
Just over tensioning the chain will cost thousands
Moral of the story is a cheap service for £350 can cost you £2K to fix even if bearings just started making a noise!
That's why I look very carefully at independents and ask myself if they can afford to pay £2K if they slightly over tension the chain. If they can't afford to fix it, you might as well pay the money for a professional service and go to TVR Power.
The timing chain tension is critical and unless your mechanic's an absolute expert and very precise in their work, it's all too easy to damage.
Just over tensioning the chain will cost thousands
Moral of the story is a cheap service for £350 can cost you £2K to fix even if bearings just started making a noise!
That's why I look very carefully at independents and ask myself if they can afford to pay £2K if they slightly over tension the chain. If they can't afford to fix it, you might as well pay the money for a professional service and go to TVR Power.
johnbear said:
I've had it happen. Apparently it's very easy to damage and often occurs after the tappets are done if the cam chain is adjusted.
The timing chain tension is critical and unless your mechanic's an absolute expert and very precise in their work, it's all too easy to damage.
Just over tensioning the chain will cost thousands
Hmm - that's interesting you say that. After the rebuild, my engine is a bit whiney (sounds like a sewing machine) and when I took it back to the garage (well regarded ex TVR main dealer) for them to check, I was told it was fine as the chain was just slightly tight and it's better to be too tight than too loose.The timing chain tension is critical and unless your mechanic's an absolute expert and very precise in their work, it's all too easy to damage.
Just over tensioning the chain will cost thousands
According to them, it should bed down in the next 1000 miles, and if not will be adjusted at the 1000 mile service. I'm not convinced personally, as it doesn't sound right, but I've asked them twice, and they've checked it and confirmed to me that it's perfectly OK.
Edited by ehasler on Thursday 3rd January 11:02
Just had my T350 MOT'd (it passed! 
) ... tester identified a noise coming from the engine, so straight to my local dealer and initial diagnosis suggests it's the half-time bearing. Will know more on Monday, hope i've caught it earlier - and that due to it being component failure the warranty company will cover the cost....!?
) ... tester identified a noise coming from the engine, so straight to my local dealer and initial diagnosis suggests it's the half-time bearing. Will know more on Monday, hope i've caught it earlier - and that due to it being component failure the warranty company will cover the cost....!?I took mine in to Power three weeks ago and they said the enginge was on the verge of blowing up. There was making quite a bit of noise comming from around the timing chain area. They took it out and checked the bearing, this was fine but the cams and followers were showing signs of over heating/dis-colouring. So rebuild time and its only done 15000.
By the way the timing chain bearings are now upgraded to a roller bearing. Alot stronger and better design, this is one of the reasons they give a two year unlimited mileage on all SP6 rebuilds now.
By the way the timing chain bearings are now upgraded to a roller bearing. Alot stronger and better design, this is one of the reasons they give a two year unlimited mileage on all SP6 rebuilds now.
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