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Stag Engine - worst production V8 ever made?


Peterjbay

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Let me start by saying that I have owned 2 Stags, with original Triumph v8 engines, and I currently own 2 TR6’s that I love  :), and am in the process of buying a TR7 V8. 8)

The Stag is a beautiful car – wonderful to drive, and would have been a world beater had it had as original factory fitted equipment a powerful and reliable robust V8 engine, such as the Buick / Rover v8 or the Ford 302 Windsor (Mustang version – over 220 bhp!).

Imagine if Triumph has emulated the Rootes experience with the Tiger, which used firstly a 260 cu in Ford Windsor engine, then later a 289 cu in Windsor engine.

I am of the opinion that the Stag V8 engine, and its close relative the 4 cylinder TR7 / SAAB slant 4 engine was the major cause of Triumph’s demise.

The Triumph V8 3.0 engine is simply one of the worst V8 engines that I have ever dealt with – possibly one of the worst ever made. :'(

My take on some of the major (design?) faults on the Stag engine:

1.     Cylinder head bolt and stud arrangement – at different angles  :o– ridiculous!
2.     Water pump is too high in the block.
3.     Water pump position in the block and jackshaft drive arrangement is ridiculous. An externally driven water pump would have been much better. Why have an extra shaft which can go wrong when you already have a crankshaft and two camshafts more than capable of driving the distributor, oil pump etc.
4.     Very long and single timing chains? Surely duplex chains would be much better?
5.     Mains and big end journal diameters too small for a performance V8 engine.
6.     Non free-running engine (valves hit each other and pistons if valve timing is out). If Toyota could get over 140 BHP from their 1600 cc Twin cam 4AGE engine AND make it free running and belt driven, what could Triumph not do something similar. BTW the Toyota Twin cam engine was a copy of the Ford BDA – just 20 times more reliable!

Yes, I know that nearly all the problems are now known and can be sorted, and IF you use an upgraded cooling system, and change the oil every few thousand miles, and drive the vehicle carefully, it can be reasonably reliable, BUT there is a reason why people do not even DARE to power tune a Stag engine (ported heads, increased CR, high lift / long dwell cams etc) – they are just too happy for the engine to stay in one piece in standard trim – around 145 BHP, which is pathetic for a 3.0 L V8.
The Standard Rover 3.5 l V8 Engine output of 155 BHP was equally pathetic, but at least that engine is bullet-proof.

I have read on the forums of people spending $4,000 Sterling on overhauling a Stag ‘thoroughbred” engine.

Are you frikkin MAD? For that price, you can land a 302 Ford crate engine putting out more than 250 RELIABLE BHP, with a decent warranty.

I may possibly own a Stag again in future – first order of business will be to fit a decent V8 engine – 4.6l Rover or Ford Windsor!

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That is why so many have reached 150,000 - 200,000 miles then. And why in excess of an estimated 85-90% of remaining Stags still have the TV8 fitted. And why Tony Hart has not only successfully raced Stags with original V8s, but has recently supercharged one, which is running successfully and producing over 200BHP. And also why several people have successfully fitted fuel injection of varying types.
Yep. Really crap engine that TV8.

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It may well be the worst production V8.  You certainly make a compelling case!!

It's not all a bed of roses for those 4.6l Rover V8s though.  I thought thery were notorious for having porous block castings?

At three years old, the Range Rover had covered 60,000 miles yet needed weekly coolant top ups.  There were no leaks.  It also belched blue smoke from one of the tailpipes when it was started up in the morning.  I was glad it was a company car!!

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382 wrote:
Let me start by saying that I have owned 2 Stags, with original Triumph v8 engines, and I currently own 2 TR6’s that I love  :), and am in the process of buying a TR7 V8. 8)

Let me start by ripping your post apart and giving comment on the various issues.....

382 wrote:
The Stag is a beautiful car – wonderful to drive, and would have been a world beater had it had as original factory fitted equipment a powerful and reliable robust V8 engine, such as the Buick / Rover v8 or the Ford 302 Windsor (Mustang version – over 220 bhp!).

Triumph wasn't dealing with Ford.  When Triumph (Leyland Cars) started developing the Stag they also were no dealing with Rover - that would come a few years later.  The US market research stated a V8 was a must.  Truimph duely started on the V8.  After all that effort and money spent to develope the V8 do you think that Triumph was willing to throw all that investment away in favour of another engine that had its own problems?  Remember that they were all strapped for cash back then.  Rover bought the rights to the Buick 3.5 because Buick didn't want it - they had trouble with it and ceased to use it in their own vehicles.  Rover eventually got it right, but by the time Rover could meet production demands of their own cars and those of their sister companies Land Rover and MG, the Stag was well and truely in production.  A bit too late really.  The common thought isn't so simple as it sounds.
At the time, Triumph made arguably the right decision with what they had in mind.  Sometimes the right decision is the least bad choice.  Chosing the lesser of two evils as they say.  Hindsight tells us that maybe it could have been done otherwise but I don't think Triumph was going to wait until Rover met production demand.
382 wrote:
Imagine if Triumph has emulated the Rootes experience with the Tiger, which used firstly a 260 cu in Ford Windsor engine, then later a 289 cu in Windsor engine.

And Rootes was subsequently bought rather soon after by Chrysler who said no to the Ford power.  Chryslers V8 didn't fit so the car was binned.  Not what I call a success story to compare with.
382 wrote:
I am of the opinion that the Stag V8 engine, and its close relative the 4 cylinder TR7 / SAAB slant 4 engine was the major cause of Triumph’s demise.

I hold a different opinion.  Mr Stokes had a lot of crap to deal with.  I don't think anyone could have done better.
There were a host of issues that dwarf the Stag V8 in how bad things were.
382 wrote:
My take on some of the major (design?) faults on the Stag engine:

1.     Cylinder head bolt and stud arrangement – at different angles  :o– ridiculous!
2.     Water pump is too high in the block.
3.     Water pump position in the block and jackshaft drive arrangement is ridiculous. An externally driven water pump would have been much better. Why have an extra shaft which can go wrong when you already have a crankshaft and two camshafts more than capable of driving the distributor, oil pump etc.
4.     Very long and single timing chains? Surely duplex chains would be much better?
5.     Mains and big end journal diameters too small for a performance V8 engine.
6.     Non free-running engine (valves hit each other and pistons if valve timing is out). If Toyota could get over 140 BHP from their 1600 cc Twin cam 4AGE engine AND make it free running and belt driven, what could Triumph not do something similar. BTW the Toyota Twin cam engine was a copy of the Ford BDA – just 20 times more reliable!

1.    Why is it ridiculous exactly?
2.    Possibly something that could be worked on.
3.    Water pump driven by engine (jack)shaft means no loss of circulation when pulley drive belt snaps.  Good thinking of Triumph, not ridiculous.  Why the jackshaft?  To relieve the cam shaft(s).  Only one camshaft would have driven the pump which would mean a difference in load between the heads.  Look no further than the Lancia Gamma for proof how that can screw up engines.  What they should have done is not drive the jackshaft on the LH chain but dedicate its own drive.
4.    Chains are not longer than in any other overhead cam chain drive.  Duplex is indeed a better option though.  
5.    Too small?  They were on the 2.5 prototype V8s but they 3.0 mains are OK enough.  What wears them out so soon is not by being insufficient in size but rather the use of the wrong materials/processes due to a lack of tribological knowledge.  Trust me on this one.  I have one of the two Stags that probably will never need their cranks reground due to what I have done to it.  That simply wasn't available to anyone prior the mid 1990s.
6.    There are a lot of engines that suffer this.  Why not attack all the others?  It is possible to avoid valves hitting pistons but you might ask why so many engine designs are still capable of such self destruction.
382 wrote:
Yes, I know that nearly all the problems are now known and can be sorted, and IF you use an upgraded cooling system, and change the oil every few thousand miles, and drive the vehicle carefully, it can be reasonably reliable, BUT there is a reason why people do not even DARE to power tune a Stag engine (ported heads, increased CR, high lift / long dwell cams etc) – they are just too happy for the engine to stay in one piece in standard trim – around 145 BHP, which is pathetic for a 3.0 L V8.

Dunno about all that.  Mine and that of my employer have standard cooling systems and run brilliantly.  I intend to up the power in mine somewhat and I do not drive it slowly.  Has yet to go bang.  Tony Hart wouldn't agree with you either.
382 wrote:
I have read on the forums of people spending $4,000 Sterling on overhauling a Stag ‘thoroughbred” engine.

Who did the work?  If you get someone else to do it it will always cost a packet.

All my opinion, based on what I know and what is already known about Stags and their production.

Julian

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Don't see either why the Stag V8 or the Dolly/Sprint/TR7 are bad engines.
Ok some detailing could have been better, as seen from a servicing point of view.

But for reliability they are pretty good. I have done well over 200.000 km in two TR7’s without major engines problems.
A friend of mine did 300.000 km in a Dolly, on one engine. Only got very basic services over the ten years he used it.

Most important thing indeed with these engines is to service them properly  ;)

Biggest problem was the way they were put together by the very  ... euhh .. motivated BL workforce.
As an example another friend of mine owns an original un-restored Stag. Quite some years ago he got himself a brand new full engine for his car, still in the factory crate.
A few years later he thought it a good idea to dismantle the engine and wrap all the parts in oil paper.
When he had the head of the engine he found out that the block still had the casting sand in it ... no wonder BL got so many warranty claims, and the cars such a bad reputation :-/

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382 wrote:
I am of the opinion that the Stag V8 engine, and its close relative the 4 cylinder TR7 / SAAB slant 4 engine was the major cause of Triumph’s demise.


The Saab derivation of the engine was fantastic - so much so that Saab didn't stop production of the original 900 until 1993. I owned a Saab 900 Turbo T16 and it was the best non-Triumph car I've ever owned.

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I'd have a stag V8 over a Rover or old Ford one anyday......

Yes, they had issues, but isn't that part of the fun?

Anyway, of you build them right (clean the block of all the casting sand, use decent quality chains, proper oil,  etc) they are totally fine.

As said before, if they are that bad how come 90% of Stags still have the original engine in them?

Stag with proper engine is worth double one with a nonstandard engine in!!

Much as I admire your courage and free will and all that....... but personally, silly thing to say on here!!!!

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beans wrote:
Most important thing indeed with these engines is to service them properly

Very much the case for the Stag V8.  Back in the day the average garage service mechanic had to deal with Jags, Rovers, Morris, Austins, MGs and Triumphs.  Of those Triumphs, only a small portion would have been Stags.  It goes without saying that the knowhow on Stag service was lacking as many just did to it what they did to the other cars.
Example:  the only time I ever let my Stag get touched mechanically by someone else was when my mates dad (ex Rover/Land Rover mechanic) looked at it.  He was puzzled as to why the engine was running while the timing was so far off - he was trying to tune it to no.1 cylinder.  We know that it is timed on the no.2 cyl. but folks like him wouldn't have guessed that and would only find out after reading the service manual - and few ever did that.

Also once said is that if you treat a Ferrari engine in the same manner as those service mechanics did with Stag V8s, then you'll be in trouble very soon.  And here we are thinking that Ferrari makes good engines... at least Enzo always said the engine the most important part in the car and that handling for those who can't make good engines.
Being good doesn't necessarily mean maintenence free.  If you don't service a good aeroplane like the B737 then you'll have it in strife rather quickly.

Those who think that special attention is a waste of time are truely kidding themselves and shouldn't have Stags.

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I can somewhat agree with some of the points made. OK, we all now know about how to remedy / prevent these faults, and that good servicing is a must. BUT back in the 70s it wasn't the case, people didn't know. And to reduce the chain service interval to something like 20,000 miles IS rediculous on a production car.

However, if treated properly they can be a solid, reliable engine.

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382 wrote:
I may possibly own a Stag again in future – first order of business will be to fit a decent V8 engine – 4.6l Rover or Ford Windsor!


You kind of had me up until here. But come on, those are both dinosaurs in their design unless you are talking about a Boss for the ford, rather than a real Windsor. The 4.6 RV8 is still a pushrod piece of old junk that makes very average power compared to a more modern V8. And I am saying that even though I have one in my RR!

I have a stroked Rover V8 in my Stag but if I had a blank slate there is no way I would use something designed in the 1950s. There are Japanese and European small V8s with great gearboxes behind them that would be much more desirable.

I think it is fair to say that, even for its era, the Stag V8 was a pretty disappointing in both design and actual build. The benchmark should have been the Rover V8 and it is not really disputable that they didn't even make an engine as good as that, much less a better one.

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well my rover stag produces 260bhp and 270llbs of torque. could i get that from the tv8.
I dont have a problem with the tv8, but if you want a car to use and abuse a tv8 stag is not the choice.
Go through the soc forum and it is littered with tv8 woes.
shaun.

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I can only speek of the Stags I know of here.  For the American market the Stag had to have a V8 or very high horsepower 6.  The standard Stag engine had major cooling problems along with head gaskets.   The old Buick engne has such a bad rap no american would touch one ever again.  We knew Rover got that engine right but then only a few Rover takers here.  (We have Jeeps)  I woud take the Ford Winsor 302 over any Ford engine.  Most HP and Torque than even the 390 per cubic inch, and it would dileiver better gas milage.  Some day I might own a Stag, would use the standard engine till problems and then re-engine with a small block Ford or Chevy engine.

Yes I know the Range Rover sells well here but not the Land Rover of old.

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sax_player wrote:
Go through the soc forum and it is littered with tv8 woes.


Yea, that Stag-only forum is full of people with Stag V8 engine issues - must be crap.  I just took a look and there wasn't a single post from anyone having problems with the TVR AJP6 engine so that must be the most reliable engine ever...

Goody wrote:
...We knew Rover got that engine right but then only a few Rover takers here.  (We have Jeeps)...
Yes I know the Range Rover sells well here but not the Land Rover of old.


There was actually quite a demand for the old Series Land Rovers in the US - from people that knew about them and had encountered them over-seas.  Unfortunately they fell foul of US fender height regulations and the cost of redesigning to get them in to the US wasn't considered worth it and was spent on developing the Range Rover that had OK fender heights.

There may have been some personal imports before but it was only in the '90s that a dispensation was given for limited numbers of Defenders to be imported/sold and this made them the same price as a Range Rover.

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The Stag is a very rare car for its time - it was sold only with one engine size and type, with no variations. ( Discounting hard top/no hard top.) A one model range.

The car should have been launched with the 2.5 PI engine in 1969, and the V8 developed more to provide 200 bhp and more reliability.  If the V8 was unpopular, the car could still have been a big success.  It was obvious the TV8 had severe problems, and so the MkII should have had the RV8, and then the larger versions of that engine as they became available.

Almost all cars, then and now, are marketed with a range of engines and other options.  Why not the Stag?  It was like it was a pet project of a highly placed person in Triumph.

Brilliant car though.

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Sam_Russell wrote:
The car should have been launched with the 2.5 PI engine in 1969, and the V8 developed more to provide 200 bhp and more reliability.  If the V8 was unpopular, the car could still have been a big success.  It was obvious the TV8 had severe problems, and so the MkII should have had the RV8, and then the larger versions of that engine as they became available.



Would the PI engine have helped?  PI engined cars were regarded as pretty troublesome in their day too.  Most people I speak to who owned PI engined cars the '70s say that they were a bit of a nightmare.

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sorbs wrote:
Would the PI engine have helped?  

No, of course not.  The USA was the main market and remember that they never got PI equipped cars due to the emissions bla bla.  That would have meant the Stag with a 2.5 six would have been somewhat underpowered and therefore probably not sold well in such guise.  It would then have been comparable to a pricey, underpowered and overweight car such as the DMC12 - in contrast to its competitors is was sure to fail.  Though the Stags beauty may have given it a chance....

Julian

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Here in the mid atlantic US, by the time the Stag was interduced English cars were just not popular.  The MG midigt outsold Triumph by a wide margen.  I don't remember my local AMC/Triumph,/Land Rover dealer ever having a Stag.  I never saw one in person till a local show a few years back.  The TR6 sold well and that seems to be the most popular here today.  As I said before the TR7 laid an egg and after that most just never looked back.  Their are two Stags in my local club.  One has been re-engine'd.  Most I know want nothing to do with the engine.  

Sorry Mj17, Land Rovers did not sell well here in this area.  My local dealer (who I knew well) was forced to take at least 2 per year and most he had to DX elsewhere.  Not sure about the goverment regs but the LWB's could be classed as trucks and there fore would have been exempted.  IE: In 75 Jeep uped the GVW on their 1/2 ton pickups and were not under the hight, bumper, emissions regs.   By the way the goverment puts the little Jeeps CJ2 thorugh CJ5 as trucks.

Of course their have allways been some die-hards but, only a few around here.  I see Blake Discher has joined the forum and if he reads this he can give a number of how many Stags are still on the road in the US and how many belong to the National Club.

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sorbs wrote:


Would the PI engine have helped?  PI engined cars were regarded as pretty troublesome in their day too.  Most people I speak to who owned PI engined cars the '70s say that they were a bit of a nightmare.


The PI engine was producing the same power as the TV8, but was a reliable engine, at least in twin carb form.  The TV8 was still in development while in production, and had a heap of problems even before it was badly built by the labour force at the time.

The Stag could have been launched in 1969 with the 2.5 TC, 2.5 PI, and then a year or two later, had the V8 as an upgrade, top model.  The V8 would then be sold in small numbers while it was sorted.  The whole reason that the Stag failed to sell in large numbers was the poor performance/reliability of the V8.

The idea that Rover could not make enough V8 engines for the Stag is nonsense, if Triumph could build TV8 engines they could build Rover V8 engines.  They are not that different.

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