Ten CR Corrective measures

[Nick Jones]

GT6_Don wrote:

There seemed to be so many problems with fuel and poor running it might be better to ask who didn't have problems and why they didn't? At Last year's Classic Le Man there were so many poor running cars in all that heat...come on who has cracked it?

My EFI Vitesse worked without temperment in spite of the heat and altitude.  Most will consider this a mod too far I suspect! It always gets 95 fuel and therefore has been exposed to 5% ethanol regularly (It has seen E85 in the past too, but it didn't think alot of that!).  

You will have almost certainly encountered 5% ethanol in the UK unless you religiously use the premium fuels of just one or two suppliers, so I'm not sure that is really the issue, although there is no doubt that the ethanol content tends to dislodge the fossilised hydrocarbons lurking in the fuel system.  The comments about the blue colour are interesting though - could well be that there are formulation differences.

Suspect that the main problems are:
- higher than usual ambient temperatures
- higher underbonnet temperatures, partly as the result of the above, but also due to working hard at relatively low speed on long steep hills (!)
- altitude.
- Modern petrol containing more volatile components than the 60s/70s stuff the cars were designed for.

All of this conspires to cause fuel vapourisation and rough running.  We discussed this with Mike and Libby and the conclusion was that on the carb equipped-sixes, it is as if they are designed to promote fuel vapourisation with carbs over the exhaust, mechanical fuel pump and fuel pipe between the two hugging the hot block and thermostat housing.  Solutions discussed included an electric fuel pump mounted somewhere cooler, re-routing the fuel lines and heat shields for the carbs.  A fuel return line to allow fuel to recirculate rather than hanging around in the hot engine bay was also considered.

Nick

[Beans]

No issues with the engine in my TR7 (mildly tuned 2 litre (8 valve) on SU's);
Ran faultless with the temperature steady irrelevant of load or outside temperature.
Made sure I filled the tank with unleaded with a minimum octane rating of 98 RON.

[yamapinto]

It would be nice to just blame the fuel, but it's more likely thats just the common element in a lot of other problems.

Blocked and dirty fuel tanks/filters etc it could just be the first time they've been full to the brim in a while and the debris has come from there.

Carbs and fuel etc getting to hot, from the description above in moderate temperatures it was never a problem and willl have actualy helped prevent carb icing in cold weathers.

Overheating always seems to be a common problem but with a well flushed and prepared system with no airlocks, a good ducted electric fan with reliable fan switch (not sure Kenlow stats always are!) in the right place and air channeled so it has no option but to go through the radiator it shouldn't be a problem.

Now the fuel pump on an Acclaim failing there is a Mystery!

[Howard]

beans wrote:

No issues with the engine in my TR7 (mildly tuned 2 litre (8 valve) on SU's);
Ran faultless with the temperature steady irrelevant of load or outside temperature.
Made sure I filled the tank with unleaded with a minimum octane rating of 98 RON.

My 7 was similar - ran on 98/100 octane in Europe and had no troubles with vapourisation even when giving it plenty of right foot up the passes. in normal driving the temperature was about 1/4 but never went above 1/2 however hard I drove it :)

[Beans]

Howard wrote:

...  the temperature was about 1/4 but never went above 1/2 ...

Do you still have the original fan + viscous coupling?
If so your viscous coupling looks suspect as the temperature should be steady on a TR7.

[Jason]

Could the fuel issues be down to the contents of the tank being sloshed around a damn sight more than usual?

[mpbarrett]

as Nic said we spent a lot of time talking and thinking about the fuel problems...

I had this problem before the 10CR, broke  down on a very hot day on the M25 at the tunnel.
The problem is the fuel vapourises and the pump will not pump it and the carbs will not work.  The pump (all metal on my car) gets up to engine block temp so the fuel gets very hot (I think the glass topped ones might be better), there is no insulating block between the block and pump that does not help.
The fuel from the pump now travels around the block to the carbs and picks up more heat from the hot air from the radiator. Finally the carbs get soaked by heat from the exhaust even with a heat shield. This gets worse when stationary. This is not helped on my car by having K&N filters, thus the air thats goes into the carbs is already hot.....

I have an electric fan on my car so I can keep the enigne temp down, but then we are moving a lot of hot air down past the engine (into carbs, over fuel pipes etc...)..

On the 10CR the problem would be a misfire that got worse and worse. The solution was to pour water over the pump and carbs bowels and everything would be fine again.
Our short temp solution was a water feed to  top of the fuel pump which helped cool the fuel, this worked quite well.

My solution before the 10CR was to fit an electric suction fuel pump in the cold air at the front of the engine, but the 3 month old new pump started to fail before the 10CR and I went back to the mechanical pump....

My plan over the winter is to:
fit electric pump at rear of car
reroute fuel pipe over bulkhead to carbs (away from engine)
Improve heat shield (make a double skin one).
Build an airbox so that the carbs gets cold air from the front of the engine.

Remember that the fuel is now quite different from the fuel in the 1960/70 when the cars were designed and has a tendency to vapouris at a lower temp, a bit of googling shows that it is not just triumphs that have this problem, its very common problem.
Sorry this is  a bit long...

Mike

[Nick Jones]

Jason wrote:

Could the fuel issues be down to the contents of the tank being sloshed around a damn sight more than usual?

Could be a factor in some cases.  Mine gets thrown about fairly often which may help to keep things clean.....  :P  Another reason to use them properly on a regular basis  :)

Nick

[rotoflex]

mpbarrett wrote:

The solution was to pour water over the pump and carbs bowels

That never would have occurred to me, but if it works, I'm all for it.

Did you have the cardboard engine valances in place?  Can a comparison of vapor lock issues be made among GT6 Mk3's that ran, differentiated by whether the engine valances were in place?

[mpbarrett]

rotoflex wrote:

That never would have occurred to me, but if it works, I'm all for it.

Did you have the cardboard engine valances in place?  Can a comparison of vapor lock issues be made among GT6 Mk3's that ran, differentiated by whether the engine valances were in place?

I have removed the exhaust side one, near side is still in place.
My gt6 is a 2.5L so generates even more heat than a 2L....

mike

[tiggrr1]

We had a glass top mechanical fuel pump and no cardboard sidepanels fitted.

On the back of the radiator I have a very powerful 12" Spal Fan fitted and we had no fuel evaporation problems on standard air filters and Stromberg CD150SE carbs.

1971 GT6 MK3

[rotoflex]

Leon Guyot insulated his fuel line, as well as added a heat shield between the carbs & exhaust:

http://club.triumph.org.uk/cgi-bin/forum10/Blah.pl/Blah.pl%3Fm-1267839478/Blah.pl?m-1305719993/s-15/#num29

[SteveJP]

Andy had this fuel vapourisation problem with his Toledo on the passes as well. I didn't experience it on the Stag, despite the carbs being in the centre of the V, but I did drive most of the passes with the bonnet cracked open, the only problem with this was that all the released hot air from under the bonnet went straight down the cabin fresh air intake - Doh!  Well at least we didn't need to use the heater ;D

[heraldhabitat]

MOE runs on standard glass pump and HS6's, no problem with vapourisation just a vacuum that developed in the fuel tank that ground us to a halt just as we were towing an estate out of a tunnel, just got out before we were both sitting ducks, what are the chances two cars grinding to a halt with two different fuel problems within 200 metres of each other!!

Other things to do, find occasional fuel leak in tank area, adjust/bleed brakes, check CD player keeps blowing fuses, adjust PAS belt and over the winter due a head job including valve stem seals. used 4 pints of oil, couple of cups of power steering fluid and lots of petrol.

Just added a trip to the welsh coast and back.

[Howard]

beans wrote:

Do you still have the original fan + viscous coupling?
If so your viscous coupling looks suspect as the temperature should be steady on a TR7.

Thanks Theo, but am running these days with a Kenlow electric fan set to cut in at 50%.

[TimW]

I didn't have any fuel problems.

I have an electric pump fitted on the chassis at the rear, fuel lines routed on bulkhead, stainless heat shields between manifold and carbs and a very large ali heat shield between carbs and K&N filters with a 3" cold air pipe from rad cowl to heat shield in an attempt to duct cold air to the carbs.

GT6 MK3 with 2.5l and HS6 carbs

[Velocita Rosso]

339 wrote:

I didn't have any fuel problems.

I have an electric pump fitted on the chassis at the rear, fuel lines routed on bulkhead, stainless heat shields between manifold and carbs and a very large ali heat shield between carbs and K&N filters with a 3" cold air pipe from rad cowl to heat shield in an attempt to duct cold air to the carbs.

GT6 MK3 with 2.5l and HS6 carbs

....oy! side issue ,you should be in bed!

[don cook1]

I had considerable problems with my fuel mixture, it seemed to run richer and richer the more the engine had to work... vicious circle! One of the reasons why I cut the number of passes. However, at Cavalese, after breakfast, we had a real attempt at sorting it out. Some of you may also have spotted that my engine was now enjoying external oil lubrication, so co-driver John re-assembled my engine breather. I checked over the carbs, swopped over the diaphragms  and re-assembled but leaving off the air filters. Car immediately ticked over fine and off we set...only to run out of fuel after 1/4m - ahem!

With the car running very well we set off for Stelvio (a day after you lot) and went up the northern approach, much more fun. On the ascent I constantly asked John if the old girl was running ok "Pulling like a train" was his constant reply! Atop Stelvio she ticked over nicely, so did we after a nice lunch with beer. After that we cruised in the mid 80s and for quite a while ran at 90mph. The engine decided to stop lubricating externally and she has settled down nicely since our return.

Reading others' problems, or not, leads me to believe that a combination of things causes our problems. I'm inclined to think that the  approach by Mike is a good start. However, we have a major fundamental issue with the GT6: the heat under the bonnet is far too high and considering that these have been around since 1966 we haven't been able to solve the problem. Fed up now, more so as I won't be able to use/tinker/play with my GT6 for a couple of months as tomorrow I get my naff knee ripped out and a plastic one (from Rimmers) inserted!

[Goody]

DollyRoo with her 2L TR7 engine did very well. Only slight temp rise when pulling hard.  Good running, no fuel or mixture problems.  In fact with our speed limited due to both temp windscreens we were getting over 38mph!  Used less than a 1/16 qt of oil on the entire trip.  

[Beans]

Started on the preparations for when the car gets back home ...

[Tim Bancroft]

Mike,

I have been using a Huco engine compartment pump in my mk2 GT6 for sometime and must say I am happy with the thing-its mounted on the engine valance, not the block. Have'nt used it in the Alps, but good whilst in Scotland in June before the accident. I will change the route of the fuel pipe and stick that onto the engine bulkhead when I get the car back.

Very pleased to hear that you completed the event, I reckon the car is a beaut! In fact pleased that all GT6s completed the 10CR-still my fave Triumph! Really missing mine now!

[mpbarrett]

Tim
thats interesting! I mounted mine at the front on the outside of the engine valance (in the cold air) shame it started playing up before the run which is why I went back to the mechanical one! Do you have an air box on the carbs?
Anyay here is a picture of Libby demostrating the fuel pump  Water cooling system on available on the later Mk3 GT6's...

With the pump she was able to pump water along the orange pipe onto the top of the fuel pump.!!

[Beans]

beans wrote:

... Now I'll have to wait till car gets back ...

Got the car back today, but not happy.
They managed to chip the paint of the nose panel and bonnet somewhere between Austria and home   :'(



All other damage was to parts that could easily be removed, but this one isn't  :(

[Velocita Rosso]

Well the Spifire made it back OK....but Id heard a couple of knocks from rear nearside on the way back from Germany
Then after only 10 miles,the other day coming from 4 wheel aligning, I heard loud knocking.
We were lucky to get back from the run(albeit I had the spares and ability to do it roadside) removed Nearside UJ, two cups/brgs at 180 degs not looking good and the two  at 180.degs .....one shaft had a flat on it and only half the needle brgs and the the other cup had no bearings in at all ??)
Now all done inc trunnion refurb and ready for Bovingdon....... :X

[Velocita Rosso]

beans wrote:

Got the car back today, but not happy.
They managed to chip the paint of the nose panel and bonnet somewhere between Austria and home   :'(



All other damage was to parts that could easily be removed, but this one isn't  :(

...back to the insurers !