We purchased a Triumph Stag in August coming from a super reliable MGB, we needed to change to a 4 seater for the boys. I have always been sceptical of the reliability of the Stag TV8 and this has now proved right. Luckily the car came with a good 3 months warranty, which was just as well as before too long the oil light started to come on at low engine speed as well as the brake warning light, we gather this to be on the same circuit. The engine was removed and rebuilt (under warranty), have put the car back on the road again the engine failed once more after 200 miles, mainly crank main bearing failure. Once again the engine is being rebuilt with a new crank and oil pump again under warranty, I hope this will be the end of the story, I would be interested to hear from anyone who can give me some confidence in the engine, would the oil pump cause such a catastrophic failure, before hearing tell tail noises form other parts of the engine. Happy motoring!!
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Sorry to hear your tale - not a good introduction to a great car!
Sounds like bad workmanship to me but I would say you need to get the oil pressure checked, also I would have thought they will need to get the crank hardened after havinga couple ofgrinds as I believe it is thin on Stag cranks. Otherwise blocked oil way or something to cause a failure that quick - I would be asking them a lot of questions.
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Hi David,
sorry to hear of the trouble with your car, as you say at least its under warranty.
I suspect it could be poor workmanship or "penny pinching" that hasn't paid off. What I would say, and I agree with Giles here, get the crank checked out properly. I have read somewhere on this forum, and elsewhere, that the Stag crank suffered from insufficient or incorrect hardening, Tuftrided???, and if its reground as Giles says this hardening could have been compromised. I am not aware of a particular weakness with the bottom end on a Stag - though it is not unknown for the odd batch of dodgy oil pumps to appear in the supply chain.
Good luck
Roger
Now Stagless but have numerous car projects
So many cars, so little time!Comment
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There will be a specific reason for these repeated failures which hopefully will be eliminated.
Most Stags on the road do not suffer from this problem and the engines are usually strong andreliable these days, but they do needtrusted specialist mechanics to maintain them properly.
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David Maddern wrote:Sounds like you got a dud followed by the garage trying to do a quick fix.Once sorted and regularly serviced they can bedriven hard with no issues.I would be interested to hear from anyone who can give me some confidence in the engine,
Steve
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Stagdad wrote:I agree, once sorted the engine can be very reliable, I've done 20K miles on mine since a rebuild with no problems (famous last words!) stick with it.David Maddern wrote:Sounds like you got a dud followed by the garage trying to do a quick fix.Once sorted and regularly serviced they can bedriven hard with no issues.I would be interested to hear from anyone who can give me some confidence in the engine,
Steve
ian
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Ian B wrote:brave words Ian!:shock:Stagdad wrote:I agree, once sorted the engine can be very reliable, I've done 20K miles on mine since a rebuild with no problems (famous last words!) stick with it you.David Maddern wrote:Sounds like you got a dud followed by the garage trying to do a quick fix.Once sorted and regularly serviced they can bedriven hard with no issues.I would be interested to hear from anyone who can give me some confidence in the engine,
Steve
ian
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I believe that any crank should be hardened after a regrind as the hardening is only a very few thous thick. This will have been removed in the process.
You are right that the oilpressure switch and brake warning light are interconnected.Your experience shows the value ofbuying from a reputable dealer. He is at least trying to put things right albeit perhaps not very expertly. Had you bought privately you wouldbe up s*** creek without a paddle. Good luck and I hope you get to enjoy your Stag
Paul
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Dave, consider yourselfsensible that you bought yours from a dealer and he is trying to sort it out.
I bought mine privately and payed what I now realise was way to much for it, but that's my fault for being an ignorant novice.
I have done a grand total of 700 Milessince Junebut thankfully not because of engine failures just drive train and auto box problems. Basically the old girl needs some TLC.
But when I have been out it's brilliant and the looks she gets is, well !! worth it.
If I was you I would get a reputable garage ( which are hard to find now) to check your oil pump, I took mine out as it was leaking at the seals, but when I stripped it down, I was well chuffed that I removed it as it was quite a mess and had probably been there for 32 Years. God knows how it was kicking out the correct 60 psi.
New one will cost you about 48 quid from Rimmers, just a thought my friend
Mike
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Unless I'm mistaken, the crank would not have been "hardened" from new. The race boys have been tufftride hardening cranks for years but this is a salt bath form of heat treatment and is actually only usually 0.0002"-0.0004" (that's 2-4 tenths of a thou!).
Forged steel cranks are plenty hard enough when run against white metal bearings providing everything is cleaned meticulously. I'd also be asking a whole lot of questions. It sounds like they either haven't got all the debris out after an earlier failure or have not got the crank pins round.
These engines are as solid as anything built in the seventies if done well and anything built badly will quickly go bang.
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My engine is currently being rebuilt. After 90,000 miles, the crank bearings were in good enough condition that they just needed a polish and would be fine going back in with original sized bearings. If that is anything to go by, there isn't much wrong with the crank design!
Rgds
Dave
http://www.stagwiki.com | http://parts.stagwiki.com (Under Development)Comment
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Stag cranks were tuftrided and a stag crank that has not been so treated will fail in about 200 to 300 miles.Comment
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