Fuel Additive + Paint Question

[badshead]

Hi

 

Just got my first TR6 after wanting one since the early 80s. Having just taking possession I'd appreciate some advice on fuel additives. I've got the Bosch fuel pump conversion but as far as I know the head is not converted for unleaded (bills for major engine rebuild early 90s, but not specific). I'm planning to use normal unleaded plus Castrol Valvemaster Plus (with octane booster) - is that likely to cause any problems with my Bosch set up? The car is running great at the moment and I want to keep it that way.

 

Also, original colour was Mimosa Yellow, but resprayed during body off restoration to, what appears on the documents supplied as Mallard Green (it's a sort of British Racing Green look-a-like), is that a standard TR colour?

[Rex Wyer]

Hi badshead and welcome to the forum

The additive should not cause any problem with the bosch pump, i think its more important that your metering unit should be compatible with unleaded fuel.

Mallard is a standard colour ( 106 ) used between 73 and 74

if you have a Moss or Rimmers catalogue look on the back inner page it gives all the colour and trim codes

[jean]

I'm driving my TR6 now for 5 years lead free without any additive and this with a standard unmodified cylinder head.

Up to now no sign of valve seat recession.

Jean

[Don Elliott]

When I finished the 3-year total body-off restoration of my TR3A in 1990, during which time I totally re-built the engine with new valve guides and 2 new valves, I had the head skimmed and then re-assembled it all.  Then in 1990, Canada (where I live) passed new laws that leaded petrol would be no-longer available - as of 1990 !!!

 

What was I to do ?  I could re-do the head with zero miles on it for un-leaded.  Or I could wait and see how long I could run with an un-converted head.  I chose to run the experiment and find out.  Some of those valves had already run 80,350 miles since the car was new in 1958.

 

To check for valve seat recession, I checked the valve gaps every 3000 miles.  At 110,000 miles after having driven 30,000 miles with un-leaded, I started to notice that the valve clearances (gaps) on the exhaust valves were closing down to almost zero every 3000 miles.  So, at 123,000 miles with 43,000 miles on the head - running with un-leaded petrol, I pulled the head and had the 4 exhaust seats bored for new inserts, put in 8 new valve guides and 8 new valves.  The edges of the old valves were as sharp as razor blades.  But full compression was still there.  The cast iron seats in the head were eaten back about 0.025".  I did all this in 2000 and since then, I have driven "TRusty" another 35,000 miles with the converted head.  During this period, I have never had to re-gap my valves.  But I still check them every 3000 miles.

 

So, as far as valve seat recession is concerned, you might be able to drive the same distance.  But your compession ratio is probably higher than the 8.5 to 1 in my TR3A.  Do you know the mileage since the last head and valve job was done ?  If not, keep checking the gaps every 2000 or 3000 miles (or sooner) and when the gaps start to close down too close to zero, have the head converted.

 

The survival of a petrol pump in a TR6-PI running on un-leaded is another story, well documented in the archives here and elsewhere.

 

Don Elliott, Original Owner since 1958, Montreal, Canada

TR Register member since 1987

http://mysite.freeserve.com/trebor/don3a_big.JPG

[badshead]

Thanks for all your advice, I think I'll use the additive anyway for the octane boost.