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Ye Spawnne of ye Deville, or normal?


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Been helping a friend with a Land Rover restoration; engine out today, and spotted this (pic)

After all the misguided external oil supplies to Triumph cylinder heads (YSoYD) and Landie's do it all the time!

John

post-535-0-05947300-1494938555_thumb.jpg

Edited by john.r.davies
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Been helping a friend with a Land Rover restoration; engine out today, and spotted this (pic)

After all the misguided external oil supplies to Triumph cylinder heads (YSoYD) and Landie's do it all the time!

John

So do XK engined Jaguars but the pipework is of the correct size and drawn from a better place on the oil system

Stuart.

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My TR6 when I brought it from the USA had the rocker oil feed mod fitted, and by the look of the gunge on the pipe, it had been there for years.

 

But even with this fitted the rocker shaft is heavily worn and needs replacement.

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I've got 115K miles on a TR250 engine with the rocker feed line. Rockers were re-done to better than original standards with bronze bushes and hard chrome plated shaft, and show no detectable wear in that time. Oil pressure is at the high end of the specified range ( 65 psi @ 2000 rpm when hot - yes, it has a 16 row oil cooler with 'stadt ) and consumption at 3-4K miles per quart depending on driving style. No valve guide seals.

 

So it's been a complete success in my experience. The only difficulty is getting the installation leak tight.

 

Cheers,

Tom

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Done properly with a restricted pipe and the oil way in the head blocked off so that it only feeds enough oil to the rockers then fitting one probably isn't going to do any harm. The trouble is that many/most aren't installed correctly.

 

And then you get back to the issue that the standard rocker gear doesn't need much lubrication to operate satisfactorily to quite high rpm's and believe it or not the standard system is designed to deliver the correct amount for the rpm that the engine is doing, not squirt as much as it can up the pipe into the rocker chamber based on the oil pressure i.e. with an external feed you will get as much into the rockers at 65psi 2K as you will at 65psi 6K (give or take)

 

All too much oil in the rocker box is going to do is try and be sucked down inlet valve guides, and leak out the gasket, and blow out the PRV.

 

Rocker shafts are cheap and you can change them by removing the rocker cover, steal oil from the oil gallery and accidentally starve one of the critical bearings fed from it and you have an expensive engine out problem, and why? so you have a piece of blingy pipe on the engine that says "Race".

 

If you have needle roller rockers I understand the external feed is nearly essential.

 

My 2.0 6 pulls silly revs compared to most 2.5's and after 4 years on this winters rebuild there wasn't the slightest trace of wear on the rocker shaft.

 

Alan

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Took mine off as recommended by many here and now I can sleep at night :rolleyes:

 

There still appears to be plenty of oil floating around under the rockers cover from what I can see.

 

Gavin

Edited by KiwiTR6
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Peter W,

Even the owner doesn't know what those bolts are for, or why they are wired, so probably from the history were original production feature. What's wrong with the wiring, to deserve the name "knitting"? The wires are properly angled to prevent them undoing.

 

Menno,

You are right about the Spawnne being popular among Spitfire owners, and when you describe it as an "off the shelf kit", but it's a thoughtless and exploitatative bit of kit, marketed as 'competiton' but in fact pure bling! It can be added if properly fitted and restricted as said above, but when a riocker shaft needs so little, why bother?

 

John

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Even the owner doesn't know what those bolts are for, or why they are wired, so probably from the history were original production feature. What's wrong with the wiring, to deserve the name "knitting"? The wires are properly angled to prevent them undoing.

 

 

Interesting point on wiring things. At a competition the other weekend whilst being scrutineered (and we know they all like to find something) it was suggested (not required) that in the future I might like to consider putting a large jubilee clip around the oil filter canister and wiring it off to another point to prevent it undoing. Now not actually a bad idea but had a few other experienced competitors scratching their heads as they had never had it suggested to them.

 

Of course when you go around a car there are many things that might be safer if wired. I was always amazed on the XJS how many bolts were wired straight out of the factory!

 

Alan

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It is a personal thing....

I am originally from the UK civil aircraft world so single strand wire locking was only used in special situations. Twisted double wire was the norm.

This link gives a view of the technique most commonly adopted and specified in The Civil Aircraft Inspection Procedures published by the CAA.

 

http://byrongliding.com/technical/lockwiring/

 

Peter W

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Interesting point on wiring things. At a competition the other weekend whilst being scrutineered (and we know they all like to find something) it was suggested (not required) that in the future I might like to consider putting a large jubilee clip around the oil filter canister and wiring it off to another point to prevent it undoing. Now not actually a bad idea but had a few other experienced competitors scratching their heads as they had never had it suggested to them.

 

Of course when you go around a car there are many things that might be safer if wired. I was always amazed on the XJS how many bolts were wired straight out of the factory!

 

Alan

 

Several years back I had the unfortunate experience of having the oil filter partially undo itself on my Buell whilst out riding. It had been done up good and tight, but was a new long-body version which because of the extra length was apparently more prone to the considerable vibration from the Harley engine.

 

Fortunately I managed to stop before it came off completely and lost all of the oil, but it made one hell of a mess. Subsequent to that I fitted a jubilee clip and lock wire and would probably do the same on a competition car just for peace of mind.

 

Gavin

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Interesting point on wiring things. At a competition the other weekend whilst being scrutineered (and we know they all like to find something) it was suggested (not required) that in the future I might like to consider putting a large jubilee clip around the oil filter canister and wiring it off to another point to prevent it undoing. Now not actually a bad idea but had a few other experienced competitors scratching their heads as they had never had it suggested to them.

 

Of course when you go around a car there are many things that might be safer if wired. I was always amazed on the XJS how many bolts were wired straight out of the factory!

 

Alan

Thats because Jaguar used to do a lot of racing.

Stuart.

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For bolts which require tightening to more than 50% of their proof load ( 80% is pretty typical ) lockwiring serves no technical / engineering function except perhaps as a visual protocol signifying said tightening has taken place. Absent such tightening, bolted connections subjected to cyclic loading will fail in shear before lockwires are affected. Where the design diligence is complete, the specified torque will ensure the bolts never loosen in the application.

 

If there is any current justification for the practice I'd like to see it. Here in Cincinnat, Ohio, formerly the world's headquarters for machine tools, the practice disappeared before the start of my career almost 40 years ago.

 

Cheers,

Tom

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