Unleaded Heads

[Flyin Banana]

is there an easy way of telling if the heads of a 2.8 v6 have been converted to using unleaded fuel or not

cherrs Rob

[MJG280]

H side of the engine block, towards the front, you will find the engine number. Nearby is the type code and for a 2.8i it's PR. If there's also a D or an E stamped on the cylinder head exhaust flange upper face near the middle spark plug, it's unleaded.

It is easy to confuse this with the TVR engine number and code which are located on one of the 4 upper flange faces and may also contain a letter D. The engine number is typically below the engine code, which also causes some confusion. Check both sides to ensure that both heads are unleaded friendly.

[mrzigazaga]

Hi mate..Found this if it helps..
http://www.shpub.co.uk/tvrbooks/faq_unleaded.html

[grahamw48]

Unless the heads have been converted/replaced since the car was manufactured, which may be what the OP meant.

Not sure how you would tell with those, unless there was a bill for the work.

[Flyin Banana]

thanks for all your help, bought a 280 last year tryin to get it back on the road, prooving harder than i thought

Cheers Rob

[hallsie]

Rob

Im in the same boat as you mate, I know the engine has been changed, so it does not have any TVR stamps on it, but there is a big 'EN' stamped on the drivers side rear exhaust manifold casting which I am assuming means that it has unleaded heads!

rightly or wrongly, I am also still using the fuel additive just in case.





I know it does'nt really help, but it might be something to look at.

Stu

[mrzigazaga]

Hi chaps..I think mine has EN stamped on it as well..ill have a look in a bit..Although im sure i read somewhere that they are casting numbers..E=Engineering dept..N=Design change..Maybe you can check your timming as its normally retarded a couple of degrees for unleaded..Mine is 12degrees and its definately leaded..Will take a pic..cheers..zig

[Flyin Banana]

so, is it going to do more damage if i run a car with additive that doesnt need it or no additive and does need it?

if the engine needs additive and i run it with out will it do more damage to the heads, or when they break just get them repaired to unleaded spec?

cheers Rob

[mrzigazaga]

Mine has EN stamped on both sides..

Apparently you can run a leaded car on unleaded for hundreds of thousands of miles..They have a lead memory that eventually will wear off and you will end up with receeded valve seats and no cylinder pressure..If yours is leaded and is being run continually on unleaded you should experience pinking,In which case use an additive and stick with the same brand..I think the other way round and you would end up with the valves sticking or burning the valve seats..Not totally sure about the latter..Hope this helps..will try to find out more,,or someone more knowledgable will reply..Cheers.. zig

[grahamw48]

Using the additive I'm sure won't do any harm.

It is my understanding that the valve seats will take 1000's of miles to deteriorate, as there is a 'memory' factor involved from previous use of leaded or additive.

I put Castrol additive in my 280.

Don't let this spoil your Xmas....haven't heard of anyone's 280 blowing up because of this yet.

[mrzigazaga]

Nice one graham..as you can see santas sledge is powered by methane (raindeer farts) the more they poop the more santa wants to get away from the smell..unfortuneately they are at the front..Its psychological..well most of the time..so dont worry too much..And if you are that worried after christmas im sure help will be at hand to physically examine your valves to put your mind at ease..zig

[Big Daft Lad]

My philosophy with old cars is why worry about changing the valve seat until you need to?

If you car is a Sunday toy you’ll probably run it for years before anything happens. Then you either get the valve seats changed or you’ve already got a set on unleaded heads sitting ready to plonk on. Let’s face it, how much are a set of heads off an XR4x4? 20-30 quid tops.

Don’t stress about it and just set the timing by ‘ear’ to eliminate pinking if it’s still running 4 star timing.

[grahamw48]

mrzigazaga said:

Nice one graham..as you can see santas sledge is powered by methane (raindeer farts) the more they poop the more santa wants to get away from the smell..unfortuneately they are at the front..Its psychological..well most of the time..so dont worry too much..And if you are that worried after christmas im sure help will be at hand to physically examine your valves to put your mind at ease..zig

Ayup...think he must have got my note !

[mrzigazaga]

I much prefer the old sleigh..this is what he done last year to my roof when he left...

[ROOODBOY]

Agree with the above, I ran my Capri 2.8I for 20,000 miles or so on unleaded petrol, never caused me a problem.