ET: Engine (Twin) ET38 Valve Circlip Install Tool, Collet Types and Pushrod Info

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Flo

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Well when you have heard the mechical din of a flat 12 cylinder Ferrari F1 engine (3 litre formula) you might think anew!
Off course once it fires the mechanical noise fades into insignificance.
 

royrobertson

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Just thinking about all this theory and calculations. Has an allowance been made for the valves getting longer when hot and closing any clearance up? perhaps someone can do an actual measurement on a cold/hot engine and then we will have a real life answer.
 

Cyborg

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Just thinking about all this theory and calculations. Has an allowance been made for the valves getting longer when hot and closing any clearance up? perhaps someone can do an actual measurement on a cold/hot engine and then we will have a real life answer.
The area between the valve seat and rocker pivot is also expanding. Trying to calculate the overall expansion is a nightmare. Much easier to measure when hot. Either a dial indicator with magnetic base or just count the adjuster revolutions required to get back to zero lash. Easier to check on the Honda because you can just shove a feeler gage in there. Although the book said set cold, you could establish the setting at operating temperature so you didn’t have to wait for them to cool off. Setting them cold was a better approach… more consistent (especially on some models) and less painful.
 

royrobertson

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In answer to the question. "why would you want to remove the rockers without the head? Some of us do not have the luxury of using all new parts and used rockers and adjusters can and do strip their threads in service, I have experience of this at an unfortunate time. I was so glad I was able to withdraw the pushrod and replace the rocker without dismantling the top end.
 

oexing

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Roy, as for me, I did not just get all new parts to complete lots of boxes of semi-scrap Argentinian B-Raps for finally have two fresh HRDs on the road after maybe 50 years in bits somewhere in the pampas. Instead it is a matter of checking all there is for defects and decide on repairs, fabricate new - or pay what suppliers are asking for. I tried best as I can to get around the last option, reasons the prices and more so my non-existent faith about acceptable products matching my expectations. So it is often my way to repair to my standards and fits than to pay for substandard.
When building an engine all parts require extensive checks of dimensions or damage. So in the end there should not be breakdowns from suspect parts and in consequence I do not especially prepare for easy roadside repairs like some here want to do and hold them from applying Loctite on clutch nuts and all. This brings up pictures from the fifties or sixties in me - well, photos. Born in 1953 I was too young to know and conditions in UK or Germany then were quite different. But in 2022 roadside repairs to be expected any day - really ?
You are not the same lot like the grey hair motorbike racers going to race courses with defective bikes and spend one day or two just to get the thing running - somehow, almost, for having 10 or 20 paddock parades at max. noise ?? Not surprising as the thing was never really fixed , sat in same place unrepaired for one year till next time - same joy . . .
Thinking about valve clearance hot or cold, in an all alu engine steel pushrods are not easily logic I´d think. Effects of heat in valves onto valve clearances appear to be less than expected when you look up clearances of , say, BMW 2 valve , maybe only 0.10-0.15 mm more for the exhaust which operates red hot. My view is the valve tulip gets red hot and increase in diameter . So it sits lower into the combustion chamber on its taper seat then, compensates a bit with the not so hot longer shaft. When looking at Vincents with all nil at cold and exhaust allright in hot condition it means cylinder plus head will have grown longer by a lot so the intake valve will be quite sloppy and noisy then. No way can you do anything with steel rods , no empirical preload in cold condition neither. You´d have no compression when kickstarting possibly and at least grind marks on follower faces from exactly same position on base circle grinding across the follower face. This shallow groove across the follower spoils the contact face with time with more grief to come.
With roller followers you want some light preload on them all the time for preventing slippage of rollers on oil so they stay nice much longer than get stuck for unknown times.
What´s to learn from discussions here: Try your best to keep valve clearance in hot condition close to nil , test with running engine and listen closely, some ticker is allright but noisy means components have a very rough life and a shorter one than necessary. Quieting ramps on traditional cams and more than 0.20 mm running valve clearance miss the follower which bashes the cam at the steeper acceleration curve - with excesssive loads into valve gear and the clatter.
With alu rods you may end up with some play in cold engine for having some ticker in hot engine to play safe and no burnt valves . My guess: Alu rods clearance nil in cold will be allright in hot engine as well.
Some years ago I did a 460 cc mod for a Horex single, new alu cylinder, alu head standard. Alu pushrods certainly and nil with cold engine. Alu pushrods are 280mm long - a lot, but in hot engine I´d want material with more heat extension than alu, with decent strength - but I cannot think of anything useful there, so it will remain as is. Else I´d have to do a roller follower mod for setting light preload at cold condition - ahh, no, not next time soon .

Vic
 

Bill Thomas

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Vic, Vincents are not that bad,
Driven nice they will last a long time, Even thrashed !, They are not bad,
If they were, I would have mine for sale, Very quick !,
I am not well and can't do waiting for the AA for 4 hours !,
I have had 2 bad break downs in the last 20 years,
Both really my fault,
A Fibre pinion that I have not changed for 38 years !,
And a broken cam follower, Standard type that had been stellite welded.

But the followers had been in my Special, Which I raced for 5 years !,
Then I took them out and put them in my L/ning rep, And raced that for 7 years !,
Then when I made the L/ning a Road Bike, Left them in for another 20 years !!,
I didn't know that stellite welding can make them a bit brittle ?,
But even so, I have heard some modern bikes are not as good ?.
Cheers Bill.
 

Simon Dinsdale

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I think this thread has drifted off the initial question of how to fit valve circlips (10 pages??) so time to move on.
 

oexing

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Seems some got the idea I was saying Vincents were unreliable from the start. I was answering Roy´s story of a defective rocker he had a chance to change on roadside as he kept the massive pushrods. That is why my view was assemble your engine with all due attention to all components for fitness and you should not be worried about roadside repairability - as hardly anybody today cares about that sort of maintenance at roadside.
So that is why it does not matter to me that my alu tubes prevent quick repairs as I don´t see the need for it. But I see an advantage of alu pushrods - from other engines I run and am a bit amused how Vincenteers seem stuck in the thin rod through thread religion. Assembly is different but no rocket science, not that nuisance like the string trick around rollers of inner mains through unchamfered outer races. THAT was something I was certain at first sight that I´ll never accept in my engine.
Anyway, it´s about discussions and finding new ideas and aspects that might come useful - or not, thankfully I learned a lot here about things you don´t necessarily find in books. Some may say I am a radical, well, more like liberal and not easily satisfied by what I find in engines. No limitation in Vincents in this respect, I am merciless in any poor details in any engine - well,that might be a brain defect as well - or just I get triggered for hours playing on the lathe or mill so I don´t have to ride motorbikes instead . . . .

Vic
 

BigEd

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I think this thread has drifted off the initial question of how to fit valve circlips (10 pages??) so time to move on.
I tried to make a little more sense of this thread by changing the title, it was too much of a jumble and complicated to split it up into individual several individual threads. Start a new thread with a specific title to have a better-focussed discussion.
 
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