Associate
As some of you know I purchased a 1967 Triumph GT6 last year with the view of learning some mechanics. I haven't really posted about it on here so I thought it was time to put up a ongoing progress log thread as you guys might find it interesting.
I am a complete novice when it come to car mechanics so this has been and continues to be a massive learning experience for me. I wouldn't have got as far as I have with the car if wasn't for some good (and much more knowledgeable) friends of mine so a lot of the credit should go to them.
So far I haven't really done much “mechanical” work on the car. The rear transverse leaf spring was replaced by a garage near me. I would have loved to do that myself however I don't really have the space or equipment to do it in my garage (lifting equipment etc...). Here is a list of thing that were done last year:
The opportunity to do some proper work on the car has now presented itself because in true Triumph and British Leyland style, the car has decided to break. One of the carbs had decided to start leaking fuel whenever the throttle is applied, resulting in a loss of power. When I asked a mate of mine about this he said it is probably because the fuel needle in inside the carb is sticking. Pressure then builds inside the carb due to more fuel being pumped into it and the only place it has to go is through a gasket or one of the throttle bars. Needless to say this isn't good as it makes the car completely un-drivable. So to fix this I had to strip the carb down, replace the gaskets that I break, determine and fix the problem (it may not be the needle) and put it back together. Unfortunately the carbs fitted to the GT6 were Zenith Stromburgs which are a lot more complicated than SU's (see exploded diagram). Anyway, here is the obligatory picture of all the new shiny parts that arrived the other day. (apologises for the poor quality phone pictures)
As you will be able to see from the exploded diagram below, the carbs on a GT6 are very complicated. The part that had broken was part 63 on the diagram. The one thing we didn't want to do was move the fuel jet (part 56). Doing this would adjust the amount of fuel going into the engine and either make it run rich or weak and it is a complete nightmare to get it right.
So we took the carbs off and took them apart so we could get to the float chamber to change the needle valve.
When we got to the float chamber we replaced the needle valve and we also noticed that the fuel floats were sitting far too high in their default position. The highest point on the float should have been 18mm from the joining seat around the float chamber. It was at 22mm, so we decided to put this to its correct height (which we later found out was a bad thing to do, I'll explain why in a bit).
This was then repeated on the other carb where float was also out by 3mm and was also “fixed”. Everything was then put back together and fitted back onto the car along with some new air filters.
We started the car up and it was running like a dream when it was cold – the smoothest it had ever run. So I decided to take it out to get the engine warm to see how it would go. All was well to begin with however as the car started to warm up it would no longer idle and would stall at every opportunity. At this point I knew something wasn't quite right so I decided to drive it back so we could have a look at it. On the way back after pulling out of a junction, at about 3200 rpm in 1st gear, it had the biggest backfire I have every heard come out of a car. It quite literally shook the whole car as if a firework had gone off underneath it, so I pulled over to take a look at the damage. At first I thought the bottom end had blow out but there was no oil leaks and everything looked good in the engine bay. That car just wouldn't idle at all at this point and it was a really challenge to get it back home. It was obvious now that the car was running far far to rich, which would explain why it was running so smoothly when we started it from cold and so poorly when it was hot. We hadn't changed the fuel jet setting so it must have been something to do with the floats. It then dawned on us that because we had altered the float level the jets would be out of alignment by the amount we had adjusted the floats by. As the floats are new closer to the top of the float chamber more fuel is getting pushed through each time. (I'm sorry for the poor description but it is very hard to explain as this is one of the most intricate designs of I device I have ever seen. You really need to see one to fully appreciate how it all works).
So this is where the car is at now as I didn't have any more time this weekend to look at it. The next job on it is to tune each of the carbs (something I didn't want to have to do as it is very hard) and then balance them so they are running in harmony with one another. This is done my screwing in or out the jet adjusting screw (part 59) and adjusting the two arms between both of the carbs. Hopefully I'll get to do that next weekend. I only need to be able to get it to a level where the car is drivable on the roads so I can take it to a rolling road and have it fine tuned by a professional as there is no way I will be able to get it at 100% with the tools that I have available to me.
I'll try and keep this thread up to date as I will hopefully be doing quite a bit of work on the car over the next few months so it is all up and running for the summer.
I am a complete novice when it come to car mechanics so this has been and continues to be a massive learning experience for me. I wouldn't have got as far as I have with the car if wasn't for some good (and much more knowledgeable) friends of mine so a lot of the credit should go to them.
So far I haven't really done much “mechanical” work on the car. The rear transverse leaf spring was replaced by a garage near me. I would have loved to do that myself however I don't really have the space or equipment to do it in my garage (lifting equipment etc...). Here is a list of thing that were done last year:
- Replace the rear leaf spring
- Replaced the radio with a genuine 60's unit (Which had FM on as standard) and place a speaker in the car.
- Re-trimmed the centre console
- Replaced the handbrake cable
- Refitted new locks throughout the car
- Swapped the number plates for some proper black as silver ones (This totally transformed the car)
- Refurbished the front triumph logo badge
The opportunity to do some proper work on the car has now presented itself because in true Triumph and British Leyland style, the car has decided to break. One of the carbs had decided to start leaking fuel whenever the throttle is applied, resulting in a loss of power. When I asked a mate of mine about this he said it is probably because the fuel needle in inside the carb is sticking. Pressure then builds inside the carb due to more fuel being pumped into it and the only place it has to go is through a gasket or one of the throttle bars. Needless to say this isn't good as it makes the car completely un-drivable. So to fix this I had to strip the carb down, replace the gaskets that I break, determine and fix the problem (it may not be the needle) and put it back together. Unfortunately the carbs fitted to the GT6 were Zenith Stromburgs which are a lot more complicated than SU's (see exploded diagram). Anyway, here is the obligatory picture of all the new shiny parts that arrived the other day. (apologises for the poor quality phone pictures)
As you will be able to see from the exploded diagram below, the carbs on a GT6 are very complicated. The part that had broken was part 63 on the diagram. The one thing we didn't want to do was move the fuel jet (part 56). Doing this would adjust the amount of fuel going into the engine and either make it run rich or weak and it is a complete nightmare to get it right.
So we took the carbs off and took them apart so we could get to the float chamber to change the needle valve.
When we got to the float chamber we replaced the needle valve and we also noticed that the fuel floats were sitting far too high in their default position. The highest point on the float should have been 18mm from the joining seat around the float chamber. It was at 22mm, so we decided to put this to its correct height (which we later found out was a bad thing to do, I'll explain why in a bit).
This was then repeated on the other carb where float was also out by 3mm and was also “fixed”. Everything was then put back together and fitted back onto the car along with some new air filters.
We started the car up and it was running like a dream when it was cold – the smoothest it had ever run. So I decided to take it out to get the engine warm to see how it would go. All was well to begin with however as the car started to warm up it would no longer idle and would stall at every opportunity. At this point I knew something wasn't quite right so I decided to drive it back so we could have a look at it. On the way back after pulling out of a junction, at about 3200 rpm in 1st gear, it had the biggest backfire I have every heard come out of a car. It quite literally shook the whole car as if a firework had gone off underneath it, so I pulled over to take a look at the damage. At first I thought the bottom end had blow out but there was no oil leaks and everything looked good in the engine bay. That car just wouldn't idle at all at this point and it was a really challenge to get it back home. It was obvious now that the car was running far far to rich, which would explain why it was running so smoothly when we started it from cold and so poorly when it was hot. We hadn't changed the fuel jet setting so it must have been something to do with the floats. It then dawned on us that because we had altered the float level the jets would be out of alignment by the amount we had adjusted the floats by. As the floats are new closer to the top of the float chamber more fuel is getting pushed through each time. (I'm sorry for the poor description but it is very hard to explain as this is one of the most intricate designs of I device I have ever seen. You really need to see one to fully appreciate how it all works).
So this is where the car is at now as I didn't have any more time this weekend to look at it. The next job on it is to tune each of the carbs (something I didn't want to have to do as it is very hard) and then balance them so they are running in harmony with one another. This is done my screwing in or out the jet adjusting screw (part 59) and adjusting the two arms between both of the carbs. Hopefully I'll get to do that next weekend. I only need to be able to get it to a level where the car is drivable on the roads so I can take it to a rolling road and have it fine tuned by a professional as there is no way I will be able to get it at 100% with the tools that I have available to me.
I'll try and keep this thread up to date as I will hopefully be doing quite a bit of work on the car over the next few months so it is all up and running for the summer.
Might just pre-emptively give up and get me a man with a van to deal with it