The Triumph Stag V8 Engine - A Turbulent Journey?! 

I have done 330,000 kms in my Stag, and from 93 to 2000 was my only car. From 2000 to 2013, it then shared daily driving with a Dolomite Sprint. Since then it is driven on sunny days (Dolomite is retired) and shares duties with my "newish" car (2006 Chrysler 300C) and an old Jag. From 93 to 2000, every year for 7 years I drove it home on Xmas leave (for 4 weeks at home, our summer) from Melbourne to Perth return. I am from Perth, but back then I was posted to Melbourne (I was in the Navy for 40 years) The trip is 3500 kms one way, so 7000 kms return. Temps from mid 30's to 48 degrees (C). Melb end leave Melb lunch time Friday, arrive in Perth Sunday arvo. The other way I would leave Thursday morning, arrive Melb Saturday arvo. I did it once in the Dolomite from Perth to Melb return in 2003 to get a manual Gbox to replace the auto in the Stag, and has been a manual since then. The Stag was an auto for all the cross Oz trips. I used to change my timing chains every 40,000 kms, so have done it 8 or ten times. Compared to new cars, it isn't a big deal.I used to use AE chains, and always measured how far out the tensioners were on removal/recorded it, to see "trend". They were always the same, ie chains had worn/"stretched"/elongated the same amount. Then about 2005 or so I researched IWIS chains. I contacted IWIS in Germany, and also the Australian rep. He said they use them in drag cars and have no drama. I fitted them then, and while I don't do the miles I used to, I haven't touched them since, and don't expect to ever have to, but if I am ever worried, I look with a bore scope (take tappet cover off) can see how far tensioner is out = shows how far they have to go. So much about the Stags "problems" really are rubbish. The early cars got bad write ups, and they have just been repeated again and again. I can give countless examples..................... but most have made their minds up. Honestly, back when the Stag was new, BL couldn't put together a Marina and other cars with cast iron heads, HOW were they ever going to assemble an alloy head OHC engine????? And the penny pinching was ludicrous. I have a copy of a BL service bulletin that says "Due to a shortage of anti freeze, dealers are to re use old anti freeze drained from other cars until further notice... " NONE of us would do that. How reliable is a new Honda or Toyota???? That story about "sand left in the engine blocks". That made people think "Stags were rubbish". Ok, put a handful of sand in a new Toyota or Honda (or any OTHER car) and that means "they are rubbish as well?" They have a lot of niggles and silly things on them. All cars do. But nowhere near the bad press they get. But once a legend starts, people LOVE to keep it going. That show "for the love of cars." Ant hated it, but even he had to admit there was little wrong with it. Their viscous fan drive failed (they are rubbish/bad batches, I have been through 3), but apart from that, nothing. But it's a Stag - it HAS to break down!!!! Can't disprove the legend. So he goes for a drive with Alexi Sayle. I watch and wonder why he is driving on a sunny day/idling in stop and go traffic WITH HIGH BEAM CONSTANTLY ON!!!!!!! So then they look at each other in surprise and "Oh no, it's broken down!!!!!!!" and they call the AA. Who turn up and get out a jumper battery. They idled it with the high beam on (and most people uprate the high beams) and ran the battery flat, "because a Stag has to break down." More about theatrics than reality. Idle any 70's car in traffic with high beam on = that will happen. I bought mine 16 years old in 1993 for $15,000 AUD. It was the only V8 touring convertible I could buy for anywhere near that price, it has served me well, and I will have it FOREVER. :-) Each to their own.

Just a small comment as far as I know the stag engine was developed by Triumph, as a v8 that could be cut in 2 to become a 4 cylinder, not the other way round. It was not a Saab engine, Triumph sold the right to the 4 cylinder to Saab, it was always t Triumph engine. I just suffered the budget cuts that hammered the rest of BL. If Triumph had the resources to sort it out properly it would have been a fantastic engine. The same happened to the PI engine in the 2500. One big problem with both the stag and the PI was the dealer service department had no idea how to look after these cars. No One knew how to tune the PI and no one knew job to look after the cooling system of the stag.

@brianwhittington5086 is correct about the engine, I don't know where the idea that this was a SAAB engine, originally if I recall it was Triumph Standard castings and as Brian describes was then made into a V8 to try to avoid the use of the Buick Skylark Rover V8. The SAAB engine was the left hand side of the Stag V8. The SAAB 99 Combi Turbo was the same block but SAAB built the head and the engine was mounted with the clutch forward so the head was to the O/s. I worked on Stags in the late 80's and had a SAAB 99 for Rally, and 900 Turbo. My chum still has a Stage I worked on then. I eliminated overheating by ironically fitting a SAAB header tank on the bulkhead above the water pump, fit electric fan and most important an oil cooler. Never had a Stag overheat since. Put a half penny under the pressure relief valve on the oil pump to bring the pressure up 5 psi. My engines hit first time which was not wanted from cold so I wired the oil pump switch to short out the points so it will only fire after oil pressure is satisfied. Check the head bypass pipes are not crushed and watch for leaking vacuum which will screw the carbs operation. Use SAAB 2.L turbo bearing shell and bucket shims as they are sized better than the BL parts. Also use SAAB suspension shims to sort out front en geometry. An oil cooler on the PS pump won't hurt. Spark-right TAC ignition helps a great deal. Don't follow the Triumph head tightening sequence it is stupid as the head drifts away from the angled bolts and is stressed and warps, slacken the vertical bolts a quarter turn then back down. Thanks for the video but I cant agree with your interpretation of the Stag engines evolution. PS, it was LUCUS that killed the Stag in the US along with many other good British cars.

I had done 180k in my Stag in hot AUS summers went across the country twice and finished 3rd in a tarmac classic rally and still running the original engine. Must have got a good one it was the last production run. Just meticulously maintained and everything is fine. 😂 never had an issue. 👍 Actually one issue that I did suddenly developed is smell of fuel in the boot once full. Replaced everything with new even the fuel tank, but still have the smell. Drives me crazy. 😀

Here in Western Australia Stags are very popular. The TSOA (Triumph Sports Owners Association) alone has 62 Stags amongst it's membership, many of which are in regular use. There was a large turnout of them (and other Triumps) on November 19th to celebrate 100 years of Triumph car production. Despite our hot climate overheating problems are now very rare as the causes are understood. Well over 100 Triumph cars attended and a grat day was enjoyed by all

The Torquatrol unit is a sealed, oil filled viscous drive that can be unreliable or fail completely. The best solution is to remove it and fit a temperature controlled electric fan. You must ensure the electric fan polarity is wired corectly, for how it's mounted, it must spin to draw air from outside, inwards to the engine bay, or you'll get engine overheating. The Torquatrol unit was designed to provide a varying viscous drive to the fan blades, almost solid when cold, stationary, or in slow moving traffic. As road speed rises, air flow through the front grille, and hot viscous oil in the unit, should gradually give less drive to the fan blades as air flow begins to overcome the viscous drive and stall the fan. It was designed for making less high-speed rasp from the fan blades, saving engine power as the revs rise. The unit bearings can wear, seize, or leak oil with age, leading to loss of viscous drive and a real possibility of the fan and worn out drive unit breaking off the engine and causing catastrophic radiator, engine bay, and bonnet damage. When working correctly, it should be quite stiff to turn the fan blades on a cold engine, but easy to spin when hot, with no sign of bearing wear or oil leaking.

Spot on comments Tony. Totally agree with you regarding the Stag with service products we use. As you may remember I’ve had my Stag for 44 years now and it’s used a lot and drive’s really well. All the best Bob

The noise that you keep hearing is the timing chain, it caused from the top bracket that holds the gear, the bracket that holds the gear just needs to be bent back a little bit so it's not catching

I used to work on Stags for a living back in the 80s -and owned one myself for 5 years. The viscous coupling mentioned in this piece could on occasion fail to the point that it parted company from the front of the crankshaft and tore into the radiator core. I used to recommend to customers that it was better for the car to remove the viscous coupling - and replace it with an electric fan - in those days a Kenlowe fan, now no longer made. In some cases, including my own Stag, it would be a 12-inch Kenwloe that was selected and fitted neatly between the radiator and the front grille. The 12 inch fan was fine, my Stag had one for 30,000 plus miles and was still spot on when I sold the car. There was a 14.5 inch option also - which came in a bright orange colour - when I asked Kenlowe why the garish colour, they said it was due to it being 'capable of taking fingers off'! We fitted quite a few 14.5 fans to Stags largely for customers who wanted extra peace of mind. The fan was so powerful it sounded like a hovercraft starting up - and would blow the dust off the workshop floor everywhere! One customer I remember booked his immaculate, low mileage stag in for new timing chains saying he was going on a summer European tour of 2,000 miles including crossing the Alps. We recommend the removal of the viscous and the fitting of a 14.5 fan - which was done. After the trip, the fellow came in clutching a pack of German beers saying his stag had done really well - and he'd enjoyed the trip that much more as he wasn't worried about his engine overheating. These days, Revotec fans would probably be the go-to brand. I agree with the views mentioned in this piece, the stag is often unfairly maligned - people like to sound off and exaggerate because they think they sound good - but actually, they don't know what they're talking about. These days, things like larger-capacity aluminium radiators and turret-mounted expansion tanks provide further peace of mind against overheating. Always run with a 50/50 antifreeze/demineralised water mix in the cooling system. Change your oil and filter every 3,000 miles, change the timing chains, tensioners and guides (and inspect the sprockets) every 25,000 miles and the engine is well capable of running beyond 100,000 miles.

I had 2stags I loved them bit of a money pit used to tow a caravan with mine no overheating 👍👌

Wow.Nearly half ever built are still on the road.Thats incredible.The thing is as a kid I loved them because of their design so engine issues that plagued them aside its a true test of a timeless design and simpler times engineering wise.If I had the chance to get one it would have to be the period yellow or brown because men of a certain age basque in nostalgia for cars we grew up with.I would equally love a mk 1 granada preferbly in green.

It seems that these days, these cars could be more reliable than they ever were, and equally as reliable as other classics. All of these mods and maintenance procedures are standard fare on e.g. a fairly mildly modified Ford Escort - improved water pumps, bigger radiators, frequent fluid changes.

Having rebuilt several Stag engines, I am very familiar with it's construction and I am very conversant with its problem areas also, whether they are true or have become slightly mythological and exaggerated over the years The single most effect thing to do after rebuilding one of these engines, I cannot stress how important it is to retouque the head bolts after 500 miles and again at a similar interval. This is crucial in preventing head gasket failure. I believe many Stag engines fell foul to this oversight, either by enthusiastic but unknowing private owners or garage repairs that just weren't followed up on. Stag engines are not alone in requiring this procedure. Many engines with alloy heads and iron blocks can suffer similar issues because of different expansion coefficients of the materials. Head bolts need retorqueing after initial ' stretching' too. Assuming correct assembly and all that concept entails. Subsequently followed by proper maintenance, my experience leads me to believe the engine should remain as reliable as any other.

Great info, thanks

The proven engine, used in the Land Rover, was a Buick Aluminum V8 that was sold to Land Rover. In the US it was used in the Spark and an Oldsmobile of the same size. It was underpowered by American standards but good enough to be used in some Kit Airplanes. Now if you find one of those cars it’s best to restore it because of the restoration craze.

I seem to think a lot of Stag owners are quite aware of the sand being left in the steel block from casting, it was a nice easy way to sabotage the stag !.🤔🤔🤔

Well said that man, You're spot-on Tony the Stag is now a well sorted car and just great fun to drive, been out in 'The Red Devil' today and it's run like clockwork (it cheaper than a petrol engine). Have a great week . Bob

Thanks Tony for another lovely video! Another fact for you: The hard work of late John Powell (Stag Register creator) established that 57% of Stags imported into Australia have survived. Not a bad record for a snag! And more evidence for you of the real capability of the design of the car when the poor production and quality control problems which plagued the car initially, are eliminated from the equation.

Very informative, I've been a big fan of the Stag since i was a kid, hearing my late uncles Stag, getting him to rev it up!

It would be interesting to have a comparison of the survival rate of the Stag compared to other vehicles. Apparently the Land Rover series and Defender is one of the highest.

Problem with sand in the block is sooner or later it end up in the coolant. Plugs up the radiator and the engine overheats. Shop replaces head gasket and the poor owner drives away again with a plugged radiator.

Also the 6th vein pump is much better than the 12 vein, I actually had this tested by a water pump specialist !. 🤔🤔🤪

thanks for the vids always an enjoyable watch

i think that noise is a bad bearing in the water pump

May I correct you. The Triumph Stag V8 engine was the first in Triumph' modular engine concept. The slant four is, in fact, half of the V8. Keep up the great work on the videos. 🙂 Paul 😎

My first thought fan had similar problems on v6 ford

Interesting. Glad to see that these cars can be kept running reliably and achieve high mileages without issues.

Mine I used an airline on the head waterways as you could see a build up of sediment in the rear waterways when I had the inlet manifold off, use safety glasses....! Also flushed out using the block drain holes. All back together, and the viscous coupling was shot. Always after a drain and fill, the temp will go three quarters of the way up, then bounce down to normal, and stay there never getting that high again. Assume its the last of the air being flushed out. I have the external Ford water pump installed low down where the alternator used to live. The standard Triumph water pump location is dangerously too high running the risk of running dry with little water level drop. I've also got a Volvo header tank mounted high up, the aftermarket aluminium ones look too bling for my aged engine bay.

We all no the early problems repeated time and again , most good stags well sorted years ago , no body maintained them properly in the day , who is responsible to check and maintain and service your vehicle ,? I now have one mk 1 it's super , thanks for the viscous fan tip , can be tricky finding where certain noises are comming from , always look forward to your videos

Surely the Triumph Slant 4 - not SAAB (but used by SAAB before Triumph)