Fuel?

Sanjøy · Post by **Sanjøy** » Wed Jul 19, 2006 11:33 am

The range things does actually work. I could get significantly more miles using Ultimate and the price diff still made it more economical than the std fuel.

Rich H · Post by **Rich H** » Wed Jul 19, 2006 11:34 am

Leaner means the fuel burns more completely but isn't as efficient use of the induction charge (As you will have an excess of unusable air) I'm pretty sure that this means a faster flame front and a quicker burn (And higher temps)

My old 1.1 Nova

used to pink all the time, sounds just a bit (more) rubbish, not knock you would know about that.

For those that don't know the followers are a little hydraulic piston that fills the gap beween the cam follower and the valve. Engine oil is used underpressure to fill the follower piston and this adds a little bit of damping into the system as well as accounting for cam and valve wear to some extent. This all means that when there is no oil in the follower when it has been standing for a while (It naturally drains, it's supposed to) you will get a pronounced rattle for a little while on initial start as they all fill up with oil.

If you want to hear a rattly engine, just liten to Shugs....

Post by **Shug** » Wed Jul 19, 2006 11:49 am

RICHARDHUMBLE wrote:Leaner means the fuel burns more completely but isn't as efficient use of the induction charge (As you will have an excess of unusable air) I'm pretty sure that this means a faster flame front and a quicker burn (And higher temps)

My old 1.1 Nova used to pink all the time, sounds just a bit (more) rubbish, not knock you would know about that.

For those that don't know the followers are a little hydraulic piston that fills the gap beween the cam follower and the valve. Engine oil is used underpressure to fill the follower piston and this adds a little bit of damping into the system as well as accounting for cam and valve wear to some extent. This all means that when there is no oil in the follower when it has been standing for a while (It naturally drains, it's supposed to) you will get a pronounced rattle for a little while on initial start as they all fill up with oil.

If you want to hear a rattly engine, just liten to Shugs....

Shut yer hole

You want to hear a really rattly engine, you should have heard the last one!!!!

This is a facking Lexus in comparison....

I think it's actually valvetrain clatter through the TB's (sounds daft, but it was the addition of the DTH TB's on the last engine that really pronounced the rattle - I ran the same cams with a plenum while I waited for delivery of the TB's)

I guess the volume of air in the standard plenum may damp the resonances of the valves opening and shutting. (wild extrapolation, but it's possible)

It was a little low on oil at the Dukes Pass though, so was deffo noisier than usual

Rich H · Post by **Rich H** » Wed Jul 19, 2006 11:55 am

With the lift you are running and the DTHTBs it to be expected I suppose. It still sounds like my Landrover though, but your gearbox is quieter (and it probably has oil in it...)

mac · Post by **mac** » Wed Jul 19, 2006 12:57 pm

I use supermarket stuff - it the engine is running rich then I'd look more to the air filter being clogged that the fuel your running.

Mac

Sanjøy · Post by **Sanjøy** » Wed Jul 19, 2006 1:04 pm

All this talk and popped out at lunch and bought Redex Petrol Injector Cleaner 500ml for £4.99.

Rich H · Post by **Rich H** » Wed Jul 19, 2006 1:05 pm

A few years ago there were reports of Vaxhalls (IIRC) suffering with injectors getting blocked, linked with extended use of supermarket fuels. No idea what happened in the end as supermarkets just buy the cheapest fuel they can...

Rich H · Post by **Rich H** » Wed Jul 19, 2006 1:06 pm

After Sanjoys dirty NAF filter escapade you have checked your filter recently haven't you.....

Rich

tenkfeet · Post by **tenkfeet** » Wed Jul 19, 2006 1:07 pm

Shug wrote:
tenkfeet wrote:"The short explanation is that the ignition timing is out (too advanced) and you'll hear a tinkling sort of sound from the engine. Sometimes more prone to happen when it's hot. "

I was trying to find a rattle on my engine yesterday when I started it from cold . Sounded like two bits of metal rubbing together. Took it out for a short run and when I got back it had gone. If it was pinking would it be more prone to do it at start up as they mixture is richer ?
Erm, IIRC no - it's more likely to pink when leaner... Pretty sure that was my personal findings when tw@tting about with mine.... Leaner mixture burns quicker than richer one, as there's more oxygen. Please someone tell me I'm talking pish, if I am!

The rattle was probably just a dry tappet - as soon as the oil had thinned and filled it, it would quieten down.

Makes sense , that will be why it sometimes pinks when you open the throttle in the too high a gear . My car has been thrashed quite hard of late so I am a bit paranoid.

Sanjøy · Post by **Sanjøy** » Wed Jul 19, 2006 1:08 pm

Fuel filter ?

Post by **Shug** » Wed Jul 19, 2006 1:10 pm

Sanjoy wrote:Fuel filter ?

He said it was running a bit rich, clogged fuel filter would make it run lean.

Post by **Shug** » Wed Jul 19, 2006 1:15 pm

tenkfeet wrote:
Shug wrote:
tenkfeet wrote:"The short explanation is that the ignition timing is out (too advanced) and you'll hear a tinkling sort of sound from the engine. Sometimes more prone to happen when it's hot. "

I was trying to find a rattle on my engine yesterday when I started it from cold . Sounded like two bits of metal rubbing together. Took it out for a short run and when I got back it had gone. If it was pinking would it be more prone to do it at start up as they mixture is richer ?
Erm, IIRC no - it's more likely to pink when leaner... Pretty sure that was my personal findings when tw@tting about with mine.... Leaner mixture burns quicker than richer one, as there's more oxygen. Please someone tell me I'm talking pish, if I am!

The rattle was probably just a dry tappet - as soon as the oil had thinned and filled it, it would quieten down.
Makes sense , that will be why it sometimes pinks when you open the throttle in the too high a gear . My car has been thrashed quite hard of late so I am a bit paranoid.

Yup - if you park it up toasty warm, the oil will be really thin and will drain out of the followers more quickly. No odds either way

GregR · Post by **GregR** » Wed Jul 19, 2006 1:21 pm

on a slightly related note, I parked mine up toasty warm, on 'Refill' and on a hill the other night. Would she start? Would she buggery!

Still - I now know that the fuel drains from the rear of the tank, and I have a nice green gerry can for future trackdays

tuscan_thunder · Post by **tuscan_thunder** » Wed Jul 19, 2006 1:46 pm

I use Esso 95 most of the time, Optimax when it's nearly empty and I happen to be going past a Shell station.

I run a bottle of that Redex stuff through every 6 months or so - dunno if it does anything at all but for the sake of £4 I reckon it's worth a shot.

(I know the Redex diesel injector cleaner works VERY well after seeing first hand the before and after results of it)

robin · Post by **robin** » Wed Jul 19, 2006 2:15 pm

In scotland the (95RON) petrol always comes from the same old place, just different additives for different retailers.

Now I don't know about the source and composition of 97/98/100 RON stuff and whilst all these fuels will have improved knock resistance there *may* be measurable differences in energy content and thus power output between them and they will probably all contain more energy than 95RON. As I understand it improved knock resistance comes from slower burning fuels which means longer CH molecule chains which in turn leads to higher energy density in the fuel (more C-bonds).

So whilst a standard K doesn't advance it's ignition timing/fuelling to take advantage of the better knock resistance of higher RON fuel, it may well reap the benefits of the higher energy content when running closed loop using the lambda sensor output to trim fuelling. Thus your motorway mileage might improve but peak power output will not (wide-open-throttle == open loop running).

Petrol does "go off" (though I don't know how - I assume it partially oxidises when in contact with air?) so you want to buy whatever it is you buy from a busy retailer if at all possible (freshest fuel).

2p

Robin

Scottish Elises

Fuel?

what fuel do you use?