This is not a definitive nor technical guide to working on your car, and many may disagree with what I’ve written. What has been typed is thoughts and opinions based on a mixture of common sense and personal experience.
This is an attempt to answer may of the common questions from people who are considering buying a Triumph or who have just purchased one. It is aimed towards the small chassis Triumph cars (Spitfire/GT6, Herald/Vitesse) but is relevant to many other models (Dolomite, Big Saloons some TR’s). Over time it will hopefully expand.
What engine oil should I use?
You need a good 20/50 oil. Without going into the specifics, you want something designed for “classic cars”, not the 20/50 motorway use oil you’ll see in a service station. This is the bare minimum to keep in mind when choosing which to buy and is absolutely fine for anyone just using their car to get from a-to-b or the odd jolly out. For the people who like to push on a bit more or have a habit of spending hours on long journeys then you may want to consider a 20/60. You’ll also see 15/50 for sale, but unless you’re getting a good deal or your car is going to see Arctic temperatures then it’s not worth it and you may find you’ll start to get leaks you didn’t know you had.
Good brands to use are Valvoline, Fuchs/Silkolene and Millers. On the cheaper side you have Halfords, Comma (which are the same) and Castrol. Again, fine to use but not considered to be as good.
What gearbox oil should I use?
First off, stick to a GL4. There are people who swear GL5 is fine and technologies have moved on, but the original specification is for GL4 which is easy to get so why take a risk on the word of a pub expert? This is true for gearboxes with overdrive as well – use the original specification which has been is use with nor problems by most people for over 40 years. Yep, people happily use others fluids such as 20/50, various grades of ATF and other GL’s and even the people the company who built the overdrive suggest other fluids when used on other cars but the people who designed and put the car together also knew what they were doing.
In an ideal world you want EP90 GL4. However, EP80 GL4 and EP80/90 GL4 are both find to use. Put in what is most convenient to you and you won’t have a problem.
What differential oil should I use?
Exactly the same as the answer for gearbox oil.
What brake and clutch fluid should I use?
This largely comes down to the choice between silicon (DOT 5.1) or mineral (DOT4).
I personally prefer DOT4. I find is nicer to use when driving, but it has the downside or stripping paint it comes into contact with. In an ideal world this won’t happen, but spillages when topping up or flushing, leaks and non-original master cylinders can, will and do happen. The fluid is also hygroscopic – meaning it absorbs water. This can lead to soft feeling at the pedals and rusted parts – but only as a result of poor servicing schedules.
DOT 5.1 is used and loved by many. It won’t absorb water so reduces the chances of rust and increases the service intervals. It also won’t strip paint which is absolutely brilliant. On the down side people often complain that it leaves the pedals feeling dead or soft. However, this can also be caused by air in the system or worn flexible hoses.
Make yours choices based on your needs and desires. No-one can really form a true opinion unless they’ve tried both are happy which what they’re currently using to the extent that they feel no need to change. The most important thing is no to mix the fluids. If your fluid is a light golden colour then continue to use DOT4 and if it’s purple use DOT5.1. If you wish to switch from one to the other then you will need to change your rubber components – slave cylinder seals, master cylinder seals, flexible hoses. This absorb traces of whatever fluid is in there and leaving them in can cause premature failure.
Should I oil or grease me trunnions?
Oil. EP90 GL4. It’s what Triumph told you to use, it has and does work. If a vertical link has failed it’s because it’s been in use for over 40 years or it’s a poor quality reproduction part. Some have moved to grease and modern ones are better than what was around and there may indeed be some which are suitable. But there aren’t any which have used modern greases for such a period of time, so there is no definitive proof that it is as good or indeed better. You’re also going to have plenty of EP90 GL4 around as it’s what you use in your gearbox and differential.
How often should I service it?
At least every 4000 miles or once a year, whichever comes first. Triumph often stated every 6000 miles and most of the fluids you buy now will last even longer than this, but I have my reasoning for this statement. The 6000 mile service was the thoughts of a new engine and car, not one which has been around for so long. And the more often you have a good tinker with your car the sooner you’ll spot problems. Yes, this will mean that some of us will have to service their car at least three times a year but for most this won’t be the case. I also suggest putting aside a good morning to do your service. Don’t limit it to just an oil and filter swap. Oil your trunions, flush your brakes and clutch, flush your coolant system, inspect and replace the air filter and check your gearbox and differential. Change your gearbox oil every couple of years or 24000 miles. Most differentials don’t have a drain plug which means the fluid in there is old and you’re buggered if you can get it out. So when you get the chance and feel brave get it out, change its bushes and fit or get a drain plug fitted and use the same intervals as the gearbox.
Back-flush your cooling system with the heater open to get all the crap and debris out and top it up with a good quality blue anti-freeze in a ratio of one part to two parts water. Don’t go this extra step and after some time you’ll be complain that your heater isn’t very good, that your car is running a bit warm or that your heater valve is stuck/leaking.
What fuel can I use?
Any petrol you like. There is no need to use lead replacement petrol unless you’ve had the head off and re-lapped the valves and seats. Over time use with leaded fuel builds up a memory and have been smashing together for plenty of time through lots of heat cycles. This protects them. And if you have had the head off you may as well go to the extra effort of getting it converted.
Triumph engines are hardy items and it’s not until they start to show signs of needing to be converted that they need to be. Before this there is no need to worry.
The signs you are looking for are valve seat recession (VSR). This is when the gap between the pushrod and rocker arm decreases as metal in the cylinder head gets burnt away bringing the two items closer together. And even when this starts to happen you still have plenty of time before it gets too bad – so it isn’t a case of instant panic when you spot it. Spend time and miles getting to know how bad it is before ripping the engine apart.
Now, octane. Your standard car can perform absolutely fine on cheap supermarket fuel. If it doesn’t, then something isn’t right. I’ve never known a Triumph engine to have problems with lower octane fuel without having over faults on the car. This could be porn/worn ignition components, the timing set incorrectly, air leaks, poor fueling settings, carbon build up in the cylinder head, etc. What I have experienced first hand is people stating that their car will only work correctly on higher octane fuel and ignore any and all advice or suggestions and then as time has gone on they have done general tinkering or servicing and eventually all the suggestions have been used – but not for the reason of using lower octane – and then I take it for a drive, throw in cheap fuel and hey presto it magically runs fine.
What tyre pressures should I use?
This is never a straight answer as there are many factors at play – brand, compound, weight of car, driving style, personal preference. The only true advice is to pump them all to 26PSI and have a play over time to see what suits you best. Pressure will be lower than on modern cars due the lower weight. Generally speaking, most people enjoy the front being around 2PSI lower than the rear.