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TR6 INJECTORS


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I am rebuilding 6 spare 1969 TR6 injectors. All dismantled and the O rings were like solid bakelite! So all cleaned up and lots of e mails and phone calls later, no one will supply the correct o rings. I know most charge about £20 for a reconditioned injector but you can do it yourself with a new (Viton) O ring for a few pence. The cross section of the ring is rectangular fitting in a 2mm x 1 mm deep groove. I can get 50 Viton O rings for about £3 but would prefer the original spec.

Can anybody advise on who might supply.?

Thanks,

Barry.

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Barry,

 

http://www.chriswitor.com/proddetail.php?prod=CW3354V​

 

These are round section but do fit and seal OK.

 

This is not sophisticated but, it's cheap!!

 

 

Do you have a an air line oiler? a standard UK 1/4" air coupling is the "right" thread and screws into a spare injector line. Fit an injector to the other end of the line The air regulator can then be slowly opened with the injector held over a bucket of water, when the injector opens the pressure can be read off the gauge and you can observe the "ripple" on the water surface to check the injector is producing a nice circular jet directly below the injector and not offset to one side if it does not open cleanly.

 

You can ensure all injectors open at the same pressure, the gauge on an oiler is not accurate but you can check the gauge later against a more accurate tyre gauge etc.

 

In the UK most injectors seem to be set at 40psi but Kinsler in the US sets them to 55psi.

 

 

 

 

a2T245014.jpg

Alan

Edited by barkerwilliams
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I would also suggest Eriks (seal centre) as a good source of o-rings as long was you know the inside diameter of the o-ring and cross section required.......you'll find your nearest centre here:-

 

https://www.eriks.co.uk/Locations

 

I do have a contact specifically for o-rings which I can email if you are interested?

 

I will be doing mine soon once I have measured up. There are various grades of Viton, however I will be considering a material called 'Perlast' which I have used a number of times in the Pharmaceutical industry due to the excellent chemical and temperature resistance properties, if of course they are available in the required size....this material is a lot more expensive however!

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Hi All,

 

Just been reading this post with interest.

 

My 6 (72) has been off the road for ages undergoing a full refurb and i am close (ish) to recommissioning the engine after its rebuild.

 

I was going to get all the PI gear new or refurbsihed, including the injectors, but i prefer to do as much as i can myself.

 

So how do injectors get refurbished, what has to be done and is it within the realms of a home rebuilder, is any specialist equipment needed, i do have a compressor as mentioned above.

 

For a bit of context i'm doing a full body off, nut and bolt job and the only things i have not done myslef are the gearbox/overdrive and the painting, so i'll giove more or less anything a go.

 

Cheers

 

Keith

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Keith,

 

I'm very much of the if it 'aint broke school.

 

All my working life I have had to develop diagnostic procedures and I enjoy testing out a mechanism to confirm if something is working correctly.

 

Before I had a pi my experience of injectors was of a complicated, very expensive device prone to failure coincidently with my funds being low.

In contrast the Lucas injectors are a simple device but were made to a very high standard and perform well even after very high mileages.

 

Injectors are easy to lift out of intake manifolds dangle over an empty container (disconnect coil - sparks!) crank the engine and look at the spray cone and check for dripping, a 5 minute job.

 

I have spent some time with a Dellorto balancer (my number one most essential pi tool) adjusting my butterflies ensuring that all my cylinders have the same volume of air at idle and throttle open. Then it was the injectors turn.

 

Not having a hydraulic tester I used compressed air to test the pressure at which my injectors opened, I was surprised to see one injector opened at a substantially different pressure to the others. Also I was intrigued that by holding each injector over 6" away from a bucket of water and observing the ripple. four injectors had a circular pattern centred on the injector, two injectors had the ripple offset to one side as if the injector was "tipping" open as opposed to dropping evenly, and the output was to one side. - Don't you just love my technical terms! It was easier to use air with a continuous flow than try using the pulse of petrol when the injector was in situ.

 

After blowing air through the two iffy injectors for perhaps a minute each not just a pulse, the output jet centralised. Was this a particle of dirt blowing out, or a sticky mechanism? I don't know but it cleared and then all were operating similarly.

 

Prior to blowing through the injectors my car usually started on perhaps four cylinders then after a couple of minutes the other two would drop in. After blowing through, and refitted to the car all injectors held over a bucket start to produce a jet after a couple of cranking revolutions and the car now starts on all six simultaneously.

 

I have subsequently sent away the injector needing a higher pressure to open away for professional re-calibration, I would not attempt that.

 

To be honest the whole thing took about half an hour, cost nothing and made a significant difference to starting my car, but perhaps more importantly has given my confidence that my injectors are good and all operate evenly. I now also have a useable diagnostic test for the future, when deciding if whatever problem I have at that time is caused by my injectors or something else.

 

 

Alan

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Thanks for the info,

 

Unfortunatley my car was a none runner when i bought it and is not going to run anytime soon, and we are talking last taxed in the mid 80's, so a while since it ran.

 

i can certainly clean the injectors up a little and do the air test but was thinking i would also need to replace anything that may have degraded with time, such as O rings, but not really knowing any methodology i'm not to sure what may need replacing or not.

 

Does anyone know of a method or seen a cross section diagram?

 

Cheers

 

Keith

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I will be going through a detailed explanation with photos when I have completed the exercise. If the injectors haven't been used for a good number years then the internal O rings will likely have hardened considerably.

Reconditioned units are about £20 each.

Replace the injector block to inlet manifold O rings also.

 

Barry

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Hi Keith,

 

Neil Ferguson will recondition a set of 6 injectors for £70 or thereabouts, and his work is excellent - injectors, prv, metering unit, Lucas pump alike.

 

The PI system doesn't particularly lend itself to diy engineering, and I've seen an awful lot of very expensive disappointments resulting from diy efforts over 45 years, it's one TR aspect I'd consider having effected by a pukka specialist . . . .

 

Cheers

 

Alec

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Hi Barry,

 

The original compound will not withstand todays petrol formula!!! There are Viton of certain grades for E5 & E10 Petrol the minimum grade Viton to use is 'B', this will go up to E15, 'C' grade will go in excess of E25.

 

N.B.: Viton 'A' is no suitable!

 

My advice is the same as others have stated above go direct to a specialist. But ensure that the nylon locking tubes are new or nylock nuts are used, as these now seem to be breaking up on the knurled face and the poppet valve un-screws.

 

Bruce.

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I shall be using Viton 75 O rings.

GENERAL PROPERTIES

VITON is DuPont-Dow Elastomer’s trade name for fluorocarbon elastomers. Mykin’s fluorocarbon elastomers exhibit excellent resistance to high temperature and low compression set. They respond very well with resistance to ozone, high temperatures, oxygen, mineral oil, synthetic hydraulic fluids, fuels, aromatics and many organic solvents and chemicals over a temperature range of -20F to +400F. Low temperature resistance for static applications is limited to approximately –40°F (–40°C) under special formulation. Under dynamic conditions, the lowest service temperature is between 5°F and 0°F (–15°C and –18°C). Gas permeability is very low and similar to that of butyl rubber. Special formulation can also improve resistance to water, steam, acids and fuels.

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I think Tim Sharp (former committee member of the Register who posts here as TIMS tracked down a source of the correct injector o rings and will happily furnish you with the size and they cost pence.

 

Rebuilding an injector is no big deal. Remove the circlip that stops the tip from entering the injector body then you just need an air supply to blow out the tip when you have done that to access the o ring.

Replace the tip, put the circlip on and check the opening pressure. If it's wrong undo, tighten (or loosen) the screw thread that tensions the spring on the inside of the injector. Reassemble and test again. (Lucas used to supply a tool to allow pressure adjustments without disassembly but an allen key will suffice.

The pictures will show a tiny filter that goes into the injector body but these have not been available for donkey's years.

 

The only spanner in the works is if the the injectors you have have tips that are crimped rather than retained with a circlip - if so they are not serviceable by you or the experts! Fortunately these are rarely found these days.

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