Triumph V8 Engine

Ticking LH Heads
Oil pressure, pumps and circulation
Water Pump + Cooling System
Automatic Gearbox
Which Gearbox?
Running Hot!!
Ticking LH Heads - index
Shortly after rebuilding my engine and with the cylinder heads coming up for 100,000 miles, I noticed a very loud ticking noise coming from the left bank (2,4,6 & 8). Initially I dismissed this as being a rogue tappet, but was surprised when the noise went away after 5 minutes.

After spending months pulling the heads off replacing guides etc I have come to the conclusion that it is one of those things that happens. HRS have only ever managed to successfully resolve the problem by swapping out the head for a known good unit.

Further research into the problem, undertaken by Mikki Stojanovic who submits to the Stag Digest Forum, has surmised that the problem could be caused by a lateral rocking motion on the tappet buckets for #8 cylinder. Wear in the bucket chamber has allowed the bucket to be slightly tilted as the cam lobe starts to open the valve. As the Cam lobe passes over the centre of the bucket it forces the bucket to tilt in the opposite direction. As the engine warms up and expands the tilting movement of the bucket is greatly reduced hence the lack of loud tapping. Mikki has proposed a fix which involves grinding away part of the valve spring chamber for the affected valve.

I suspect that I will leave this “feature” alone for the time being. I hope to prevent further wear by allowing the engine to warm very gently without resorting to higher rev ranges until the engine is in its non-ticking stage.

I guess that some enterprising individual may produce a sleeve that can be machined into the head to take up the play in the bucket chamber.

Oil pressure, pumps and circulation - index
Within the body of the pump is a pressure release valve, this is forced open when the oil pressure reaches a certain level and stops the oil pressure rising to high. I have had problems with very low pressure at low revs when this valve has stuck open.

The pump should be replaced periodically, they do not last forever and from my experience seem to wear out pretty quickly. Replacement is straight forwards, I find that to remove it I need to get rid of the RH exhaust down-pipe and the oil filter bowl. Note: when you remove the oil pump watch out for the hex drive that sits between the oil pump and the distributor, it normally comes out with the oil pump but if it doesn't make sure it does come out later and hit you in the eye!!!

I have been told that it is a fallacy that very high pressure is good for an engine. Too high oil pressure can force oil past bearings back into the sump, it can over tension the chains causing premature wear and also blow oil gaskets all over the engine. Oil flow is far more important than pressure to the health of an engine.

Oil pressure itself is something that keeps Stag owners amused while driving. Many, including myself, fit oil pressure gauges in place of the electric clock on the dashboard. I have found the mechanical gauges to be far more reliable that the electrical variety.

The gauge can be used to detect issues within the engine but only by studying trends over time. Low oil pressure at idle over a long period of time can be ok compared to dropping oil pressure at idle, which could be the indication of bigger problems.

On my engine when I first bought the car it seemed and sounded healthy enough even if the oil pressure was a little on the low side when warm.
3000 Rpm

After a while the oil pressure started to drop which worried me.
3000 Rpm

I then fitted a High Pressure Oil Pump of SAAB origin
3000 Rpm

I did notice that the oil pressure gauge used to slightly decrease under hard acceleration. But it wasn’t long before I first heard the dreaded death rattle. I didn’t really use it again until the engine had been rebuilt. On the rebuilt and run-in engine the figures are much healthier
>1000 Rpm
3000 Rpm

The cause of the dramatic reduction in oil pressure was worn main bearings, the main bearing caps then fractured causing further wear in the main bearings, it is a wonder that the engine ran in this state.. It certainly didn’t feel particularly nasty nor did it vibrate at all.

What I should have been on the lookout for was the initial progressive drop in oil-pressure. Ignoring this and hoping for the best probably led to the destruction of the engine block with broken main bearing caps and stress cracks in the crankcase. The dip in oil pressure when the engine was under load was possibly due to oil pouring past the worn out main bearings and straight back into the sump, thus causing further damage.

Water Pump + Cooling System - index
The cooling system does have inherent design faults, the water pump is located quite high in the block just under the thermostat housing. . i.e. the coolant level in the radiator doesn’t have to drop too far before the water pump runs dry and the engine over heats. The coolant expansion bottle is located low down in the engine bay and relies 100% upon a vacuum to suck the coolant back into the radiator as the car cools down. The slightest leak in the cooling system and this just won’t happen, before you know it the coolant level progressively drops until the waterpump runs dry. There are a four solutions;
  1. Make sure that the cooling system is leak free and 100%
  2. Check the coolant level everytime you use the car
  3. Replace the mechanical waterpump with an electric unit and locate it much lower on the engine, this will give you some safety margin
  4. Fabricate an expansion bottle that is located above the waterpump, this will allow gravity to keep the rad topped up in the event that you cannot 100% seal the cooling system.
There are issues with some pumps manufactured more recently where the skew gear on the pumps main shaft that meshes with the jack shaft is incorrectly hardened. Thus the thing wears out in a few thousand miles, filling your engine with shards of metal and possibly causing it to overheat!!! Think twice before fitting a new pump, ideally get the gear tested before installing it.

To remove the pump, I slightly unscrew the reverse threaded bolt on top of the pumps impellor and use a slide hammer to gently lift the pump out of the block, it may come out of the block leaving its outer brass ring still in place. This can also be gently removed with the use of a slide hammer. With the pump removed I make a point to check the bottom bush which sits in the bottom of the water pump housing in the block. I also replace the o-rings and then reassemble the pump back into the brass cage before refitting. The pump should twist into place using hand pressure on the impellor. Do NOT do what I did and attempt to apply any force whatsoever on the reverse threaded bolt in the top of the pump, it is softer than butter. I shimmed the pump cover up using the workshop manual, this is important! Too few shims and the bolt on the impellor could touch the cover causing failure of the water pump gears, and too many shims will cause the water to flap about inside the cover and greatly reduce the pumping efficiency of the water pump.

I have listened to many discussions of whether the 6vane or 12vane water pumps are better. I have seen no evidence to point to either one, it has been suggested to me that the 12 vane impellor moves ½ the water of the 6vane pump at twice the speed thus making it move the same amount of water as the 6 vane pump. It is important that whatever pump you have the cover MUST match it.

Automatic Gearbox - index
The only problems that I have encountered with the hardy Borg Warner 35 Autobox concern it being able to keep fluid inside itself. Shortly after putting my car back on the road the garage floor started collecting ATF by the pint. I soon discovered that the fluid was overflowing the gearbox dipstick tube, any rumblings of the gearbox being overfilled were quickly dispelled by the fact the gearbox was slipping due to the limited fluid available to it.

This problem was eventually solved by unblocking the gearbox breather tube (which runs over the top of the brake servo and into the o/s inner wing on UK RHD cars). Apparently some owners block the breather as it encourages the gearbox to hang onto gears a little longer!! This now allowed me to fill the gearbox up to its correct level and certainly stopped all gearbox slip especially when cornering.

Alas I am still experiencing ATF loss but now it happens after the car has been left for a week or so. This is possibly because the seal between the gearbox and Torque converter is failing thus allowing ATF to seep back into the gearbox causing it to overflow. Tony Hart of HRS was in contact with Borg Warner to identify the cause some time back and their response was to replace box and Torque converter. So I guess in conclusion is that some boxes do it and others don’t

The final straw for my BW35 Auto box was when I noticed a very high pitched whine / grinding noise while driving. It took me ages in tracking this down to the gearbox. The sound is very similar to that which a brake back plate makes when it is just kissing the front disc while driving, which is what I thought the noise was. The high pitched whine turned into a high pitched metallic howl and isn’t getting any better with time. My diagnosis pointed to the gearbox for the source of this noise when I noticed the gearbox growling away to itself while in Park / neutral. I disconnected the kick down cable from the carbs and the noise went away, still howls while driving though. If I tug on the kick down cable the growl gets louder. I found out that the kick down cables allows for an increase of fluid pressure inside the gearbox thus prompting it to change down a gear, I was helped to the conclusion by various experts that the front pump was on its way out. Nobody could predict how long it would last but could confirm a complete loss of drive when the pump fails. The only fix is to recondition the box and Torque Converter, which as I found out is a pricey option.. I looked at buying one of the many BW35 second hand boxes but as they can only be health checked when running I could waste my time fitting a bigger dud that I just took off!

Which Gearbox - index
When buying a standard Triumph Stag you are faced with one of three gearbox options, Automatic, Manual or Manual with Overdrive.

Having owned both a Manual o/d and automatic transmission Stags I have noticed advantages of both setups;
  1. The idea of selecting your own gears is too involved for what should be a laid back drive.
  2. The Automatics gearing is perfect for rapid acceleration when cruising at motorway speeds, its' higher gearing put the engine right in the middle of its power band.
  3. A good Auto box with clean fluid gives very very smooth changes both up and down the box.
  4. However some owners who have an auto BW35 Stag will tell you all about propshaft vibration. Tis a nightmare to do with the rubber connector between the main shaft and the trailing UJ section.
  5. A bad manual box feels and sounds fairly agricultural, I think mine on my first Stag was duff!
  6. The engine certainly needs exercising in 2nd gear to maintain acceleration in 3rd on a car equipped with the manual box. Good or bad you make up your own mind on that.
  7. The foot well can be too small for three pedals and a pair of clodhoppers.
  8. The Manual Gearbox works well when pressing on or when racing by allowing for better driving control at the limit of the cars handling.
  9. String Back gloves and an automatic gearbox look a bit blousey!
  10. The exhaust note can be made to sound fantastic if you can perfect the double declutched down change on your manual box.
  11. The Manual Overdrive option offers better fuel economy than Auto or non overdrive models. Many manual o/d equipped cars seems to achieve getting on for 30mpg on a run. My auto struggles at 21mpg
So apparently in conclusion, the Automatic gearbox saps the revs and guzzles the fuel but it seems so much better suited to the Stag. It makes the car easy to drive and leaves the driver with nothing to concentrate on other than whether it is going to rain or how much longer they can hold that inane smile for. Sure the Automatic BW35 could cope with an extra gear at about 60-70mph to keep the revs down but then the engine wouldn’t be at exactly the right revs for rapid acceleration at motorway speeds.

It is therefore with certain trepidation that I am planning to swap out my failing BW35 for a J-Type Man O/d… All I can say right now is watch this space..

Auto Gearbox was pulled out early in 2006 and a reconditioned Manual J-type Overdrive box was installed. The car behaves very nicely indeed though I have had to dramatically adapt my driving style of the car. The low torque at lower revs are easily dispatched with an auto as the TQ allows the engine to rev and slip the power gently through to the autobox, thus allowing for easy access to rapid acceleration. The manual box just doesn't do this, the wrong gear just gives pitiful acceleration regardless of how hard the throttle is shoved into the carpet, it may sound obvious but after 12 years of driving an Auto Stag it caused me some minor bother..

Driving round town is easiest in 3rd gear, flicking the overdrive in gives pretty much the same ratio as 4th gear so it is just no worth the bother going any higher up the box.

Which brings me onto my biggest bug of the manual o/d setup. The gearstick is like the Eiffel Tower which means that in fourth gear I cannot get my foot comfortably off the clutch. I have 34” legs and stand a shade over 6’ 3” tall. To combat this I have found the that 3rd O/D “in” to 4th O/D “out” can be done quite easily without the use of the clutch. Similarly down changes can be achieved by slipping out of 4th gear before depressing the clutch to engage 3rd. With practice I have this licked and probably won’t bother cutting and shutting the gearstick to shorten it..

So do I like the Autobox or the Manual O/D? Oh if only life were that simple, the Auto equipped car is certainly easier to drive, but I can’t do double declutched down changes using an auto and when you get one of those right you are totally addicted. (A bit like the guitar solo in Pink Floyds’ Comfortably Numb)

There are companies who offer a 4 speed automatic box, but it is expensive. There was at some time in the past a company who applied an overdrive for the tail end of the BW65 autobox.

If I was concerned about fuel economy, (which I am not with my limited annual mileage) I would consider installing an LPG kit into the spare wheel well, this would give access to ½ price fuel with all the advantages of the slushbox.
Running Hot!! - index
Since I rebuilt my engine, Rupert has had a nasty habit of running a bit on the warm side when on a motorway on a nice hot day. Although the car never actually overheated I did drive it with one eye on the temp gauge.

I think that the engine rebuild partly contributed to the running hot. i.e. the new engine will be tighter and thus more heat related friction will build up. The car is running unleaded which I heard burns slightly hotter. It is also likely that I drive a bit quicker now that I am less concerned about the oil pressure.

Facts The car seems to run at the same temperature unless ambient temp exceeds 20 degrees or thereabouts. Therefore anything below is classed as cold and any above as hot. Very Hot day is a one off where the ambient was about 30 degrees
Activity #1 Around TownCold DayHot DayV. Hot Day
1. Warming up from cold at idle758083
2. Driving Around Town808588
3. Switch off after driving around town8595>95
4. After 1 minutes driving after stopping808588
Activity #1 Motorway runCold DayHot DayV. Hot Day
1. Driving round town75-808588
2. Get upto motorway speed (3-3,500rpm)75-808090
3. After approx 5-10 miles of motorway driving75-808595
4. Exit Motorway and come to a stop85-9595100 #1
5. three miles of driving town and country80-8590
6. six miles of driving town and country75-8085
#1 When the car hit 100 I pulled over, switched off the engine and left the bonnet open for 15 mins. The car didn’t boil over and while it seemed hot, it didn’t seem “boiling” hot if you see what I mean.

Now I reckon I fixed the problem has been fixed and here is how;
Firstly and very early on I found that I was using the wrong thermostat. The correct item for the mk2 stag should have a plunger on it which blocks a waterway. I must have always had the wrong item in hence not noticing the fault when dismantling etc.

Next I found out that there are two temp gauge senders on the market. The one with the white insulation around the electrical connector is wrong for the car and allows the gauge to read high when running at just above normal temperature. Once I dispatched this unit into a field using my tennis racket I installed one with the correct black insulation.

The car was still running right up to the edge of the red sector on the temp gauge when I exited a motorway and queued at the junction. So I bought a Supergil radiator from HRS. The original was a bit bunged up so it was money well spent. The new rad allowed the car to run cooler in every example listed above except for fast running on a very hot day, under these circumstances the car behaved exactly the same and on one occasion sailed right into the red so I switched off and let it cool.

To be honest at this point I was seriously starting to think that there may be a localised hotspot inside the engine where perhaps a piston was scuffing the bore. Even though it made no unusual noises I was starting to consider an engine rebuild to ensure that the bores were all aligned exactly.. but then the autobox started to play up. It had been growling for some time and was costing me a small fortune in ATF which overflowed the dipstick tube when the car got lonely. But the growl had turned into a howl and while the box still worked well I was advised that the front pump was on its way out. Recon autoboxes are very expensive and I can’t see the point of an untested 2nd hand unit so I opted for a man o/d conversion which was duly effected earlier in 2006.

The difference in the cooling dept is significant; round town on all but the hottest days the car struggles to get past the first 1/4 on the gauge. On the motorway it runs between a 1/4 and 1/2 and on exiting nips just over the 1/2. On a couple of the hotter days this year, and there were a few, I managed to get the car up to 3/4 on stopping after a spirited run but this dropped back to 1/2 after a mile or so.

So has the lower revs solved the problem. Well yes, but not much, you see an engine running through an autobox might run at higher revs but I reckon it is under much less load than the manual, probably in the wrong gear most of the time, and all that additional load would not help a cooling system if it were struggling. Also I have been exercising the car quite a lot through the gears and thus, other than motorway cruising, it is probably running at about the same revs as it did with the autobox.

What I reckon has made the difference is removing the autobox cooler from the front of the engine bay. The cooler was a nasty looking bit of kit that was way past it’s best. Most of the fins were crushed but because it didn’t leak I assumed it was doing its job. So I reckon that a knackered and poorly efficient cooler, cooling a dieing automatic gearbox provided just enough heat to tip the marginal cooling system over the edge in extreme circumstances. Though now it would appear that the car is over cooled!!! Oh the irony.