The Handbrake-gctid259

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JamesF
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The Handbrake-gctid3694

Post by JamesF » Wed Aug 19, 2015 9:28 am

4D3349786A1D0 wrote: The beans were a device (I forget the name !) that was alleged to alter unleaded petrol to something suitable for leaded engines, thus causing less wear on the valve stems and seats etc.

My memory seems to recall something about the inventor originating it for the use in Spitfires using Russian petrol..........
Fuel catalyst. Broquet developed a method of stimulating fuel to allow a cleaner burn in the Russian Hurricanes. I put some in my Scimitar and reckon it did improve combustion slightly. By doing so the wear on valve inlets is reduced. Many folk claim waste of time. I found I needed more than the recommended. But loads of folk started producing them and I doubt if all are 'pukka'.



You still need to have the heads done really. Probably still better off to use an octane booster or lead free additive. I thought Redex helped keep carbon deposits down on the valve seats/valves which is what does the damage. Checked tappets and found after 20 thou miles that adjustment required was about one thou - that was in a scimitar with heavy towing.

RichardS
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The Handbrake-gctid3696

Post by RichardS » Thu Aug 20, 2015 3:30 pm

OK, I'm not sure I want to start this BUT as a retired lecturer in Motor Vehicle Engineering you have touched upon some of my favourite areas. There are several issues in this post;

1) Octane rating, the ability of any fuel to resist ignition in the presence of oxygen with increased pressure/temperature.

2) Valve seat "recension" caused by combustion by products.

3) The effect of additives to fuel.



Number 1, any fuel will burn releasing energy but the more it can compressed before burning,the more energy it will release, thus high compression ratios are desirable but if you over do it "detonation " can occur resulting in engine damage. To suppress this Tetraetholynelead was added to petrol, the effects were you can increase the compression ratio OR the boost pressure of an aero engine leading to greater output. This stuff came from the Americans in about 1941 so although the RAF could have it the USSR couldn't, hence their reliance on old types of aircraft/engines from lendlease.



Number 2, a by product of TEL is solid "salts", caused by high temp/pressure, these can get stuck around the valve seat/face causing erosion by exhaust gasses. The cure, make the valve rotate slightly to its seat as it shuts thus dispersing the by product. This is the alleged "valve seat lubricated", when "lead" was removed from pump fuels the rotating vales of older vehicle wore quickly. modern engines don't rotate the valves so they don't wear. And of course on diesel engines never did this and the valves last for ever.



Number 3, if it makes you feel good by buying additives then chuck them in your tank, but any materials they contain can only only have an effect (good or bad) if they are present at the molecular level and a bit of tin/lead/what ever won't do that.



So, if anyone is still awake I could tell you more....

Richard

JamesF
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The Handbrake-gctid3698

Post by JamesF » Sun Aug 23, 2015 9:02 pm

183927233E224A0 wrote: OK, I'm not sure I want to start this BUT as a retired lecturer in Motor Vehicle Engineering you have touched upon some of my favourite areas. There are several issues in this post;

1) Octane rating, the ability of any fuel to resist ignition in the presence of oxygen with increased  pressure/temperature.

2) Valve seat "recension" caused by combustion by products.

3) The effect of additives to fuel.



Number 1, any fuel will burn releasing energy but the more it can compressed before burning,the more energy it will release, thus high compression ratios are desirable but if you over do it "detonation "  can occur resulting in engine damage. To suppress this Tetraetholynelead was added to petrol, the effects were you can increase the compression ratio OR the boost pressure of an aero engine leading to greater output. This stuff came from the Americans in about 1941 so although the RAF could have it the USSR couldn't, hence their  reliance on old types of aircraft/engines from lendlease.



Number 2, a by product of TEL is solid "salts", caused by high temp/pressure, these can get stuck around the valve seat/face causing  erosion by exhaust gasses. The cure, make the valve rotate slightly to its seat as it shuts thus dispersing the by product. This is the alleged "valve seat lubricated", when "lead" was removed from pump fuels the rotating vales of older vehicle wore quickly. modern engines don't rotate the valves so they don't wear. And of course on diesel engines never did this and  the valves last for ever.



Number 3, if it makes you feel good by buying additives then chuck them in your tank, but any materials they contain can only only have an effect (good or bad) if they are present at the molecular level and a bit of tin/lead/what ever won't do that.



So, if anyone is still awake I could tell you more....

Richard
sorry folks - my mistake i commented on a 2010 post.

JamesF
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The Handbrake-gctid3700

Post by JamesF » Sun Aug 23, 2015 9:08 pm

Well I am interested in the topic. In a sentence; I understood that the lower octane fuel i.e. 95 cf with 97 meant that the burn time was shorter which meant spot welding took place on the valve and valve seat. With towing the damage is at a faster rate. Simple way of reducing the damage is to use super unleaded. But either fuel will still need 50,000+ miles to "need" new valves and seats.

RichardS
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The Handbrake-gctid3702

Post by RichardS » Mon Aug 24, 2015 12:41 am

OK, I knew someone would be brave enough to respond, first, separate the issues:

1, Octane rating is a scale using two chemicals, Heptane with a number of zero and Octane with a number of 100, ANY fuel can be rated against this scale as a measure of it's resistance to spontaneity burning, ie, before the spark occurs. With "straight" petrol having a rate of 60-70 ( think of "pool") thus to improve efficiency other chemicals are added especially TEL to rates of up to 100, Avgas is about 130 and available from your nearest airfield. Now that TEL is not used it is replace by a variety of chemicals based around benzine.

2, The speed of burning (burntime) of a air/fuel mix is dependant on it's pressure and temperature in turn influenced by load hence towing has an effect, the higher the Temp/press. the faster burns.

3, Exhaust valves are the hottest running component in the engine and often run at a "red" heat, however this below their upper critical temp (at which they would fail mechanically) and considerably beneath their plastic stage at which "welding" occurs.

And back to the question, any exhaust valve issues relate to it's true running temperature, the quality of the materials involved and it's design (rotating face/seat interface)

As an aside although motorcars suffer from (exhaust) valve seat recession notably BMC motorcycle engines don't because they are air cooled and require better materials.

ps. to anyone who want's to check this out I will willingly provide the appropriate refferenacies

JSalix
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The Handbrake-gctid3704

Post by JSalix » Sun Nov 29, 2015 2:02 pm

Strange problem last Friday. The main area above the windscreen demist vents collected a vee-shaped area of condensation, just about the opposite of what one might expect. I expected it to clear as things warmed up but on a 3/4 hour journey, including a five minute wait at a traffic light contraflow, it didn't alter much at all, even with the fan at full-speed. There is no significant coolant loss but I wonder if it might indicate a slight leak in the heater matrix so that we are constantly blowing fresh moist air. Before I start tearing things apart or decide to convert the Ranger into a sauna, does anyone have any experience of this?

JJ

PaulG
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The Handbrake-gctid3706

Post by PaulG » Fri Dec 04, 2015 7:46 pm

Sounds odd, I'd have thought if the matrix was leaking there would be very distinct anti-freeze smell in the car. Could there be water in the ducting?

JSalix
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Joined: Tue Jun 27, 2006 5:06 am

Re: The Handbrake-gctid259

Post by JSalix » Sat Dec 09, 2017 8:55 pm

Rickman Forum posting is definitely a habit that I lost. Yes I'm still an RCOC member and we now run the Handbrake as our main vehicle. When the new car proved reliable, Angie's old faithful Potting Shed went to a new owner in Eire, driven there (except for the wet bit) by the new owner. Of course there are always improvements to be made. I had a pair of cheap fixed mirrors fitted temporarily (two years) and this autumn I finally got around to bidding on an electrically operated pair. I'd been pleased with the Ford Sierra set on the Potting Shed Ranger, convenient since Angie and I share the driving but not the personal physical dimensions. The mirrors were rusty inside but with the plastic seals chiselled off I was able to do a refurb job on the mechanics and reassemble with self-tapping screws. A hole and grommet in the door for wiring and a slight trim of the triangular back plate suited them to the doors, fixed with three stainless steel dome-head nuts and bolts.
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JSalix
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Re: The Handbrake-gctid259

Post by JSalix » Sat Dec 09, 2017 8:57 pm

There were spare wires in the Sierra flexible connection and plug that I used to convey power for the door speaker and electric windows and locks, so all I had to do was pick these up inside the car and find a place on the Corsa dash for the control joystick, plus a fused feed and earth. Job done, and no more cold hands readjusting wing mirrors on the hoof.
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ABurgess
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Location: Tetney

Re: The Handbrake-gctid259

Post by ABurgess » Sun Dec 17, 2017 10:23 pm

Hi "J"

just so you know if you decide to get new wheel studs then they can be purchased from "MERLIN MOTORSPORT" I bought some extended ones when I fitted alloy wheels to my Ranger. you can get normal length and various different lengths. www.merlinmotorsport.co.uk/

Alan

Ps beware fitting wheel spacers as your insurance company consider this a modification and should be declared!

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