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

[delboy]

Ta Bill.
I seem to recall reading somewhere, PEI got the valve circlip idea from JAP? I might be wrong?
My own view is, we are some 75 years into the experiment and most of his ideas work pretty good.

I remember getting my valve circlip putter-onner tool from Clevtrev back in the early 80's. Similar to the one in the photo.
Still works brilliant.
Delboy.

 

[oexing]

Still no good reason for the wire circlips. You need split collets the same to go with these, so why not bin them and have collets for one groove, same shapes. Just care for suitable taper angle for collets, minimum 6 degrees, else they will stick a lot.
How do you disassemble the wire circlip lot ?? Fussy, I´d think, or maybe worse . . . .
For a few decades it was common on cars to replace valve seals when they started smoking in overrun. No question about letting the head untouched for seal changes. You just did the Magic Rope Trick for keeping valves up while compressing valve springs, taking out collets and spring cups with springs to access the hardened seals. Certainly no press in this operation - and no wire circlips there. Would be cathastrophic in real garage life with them flying in all corners - with offensive language the next second - a lot more than anyway all the time.
The magic rope trick consists of a length of small rope you feed into the spark plug hole for compressing it up the valve by turning the piston up. Then the valve is held up for knocking the collets loose and compressing springs for disassembly - easy .

Vic

 

[bmetcalf]

Some of us are so used to flying clips that we don’t curse anymore!

 

[davidd]

I have been using Gold Star valve springs and titanium retainers for so long I consider them to be stock. The valve locks or collets are one bump. RD spring always supplied the parts.

Pat Manning did have the circlip fall of his front exhaust valve on his trip back to DC from California. He used a bungee cord to hold the valve up while the reassembly took place. I suppose that is the reason that no racers use the circlip system.

David

 

[vibrac]

Well I did acknowledge that some folk install them with their thumbs. Just thought there might be folks out there with thumbs that aren’t quite as well developed as yours.

To be honest just having done the job there is the matter of a bit of pressure from a flat side of a screwdriver for the last push, age and lockdown seems to have rendered my thumb less 'horney'

 

[delboy]

Like it or not, in 45 + years of dismantling and building, I have never come across a failure on road bike of circlip, collets or cap.
Delboy.

 

[Gary Gittleson]

Instead of the "rope trick", which works for sure, I once removed the rocker arms of the engine on an electric generator (not a Vincent) and applied compressed air to the plug hole. I used a compression-test adapter screwed into the hole and connected to the compressor. Of course the air pressure moved the piston to the bottom of the stroke but once there, I was able to do the work. Maybe it wouldn't have, had the spring caps been really stuck causing the valve to open a bit. By the way, the reason I had to do this was that the generator which was given to me by a neighbor wouldn't start. It had no compression. The problem turned out to be that the collets on the intake valve (the three-groove type) had come out. I don't think the engine had been worked on since new. My neighbor never did any mechanical work.

 

[Bill Thomas]

I changed valve springs with just a bent rod though the plug hole.

 

[vibrac]

Ah! if we could change those push rod bottom seals effectively in the same way without taking the head off

 

[oexing]

. . . . or more likely the monkey who assembled the engine did not check the correct seating of collets in the spring cup.
I know the air pressure trick for changing valve seals but the safer way is the rope trick. Once the air supply breaks or any other bad move opens the valve a bit it may drop inside so you are in a situation. Anyway, the wire circlip in the postwar Vincent is a silly complication when all other engines got their safe collets . Still no good argument from anyone why they decided on this. And no reply to the question how to remove the circlip for disassembling the lot. Fussy at least and an extra complication for no good reason.
Desmo Ducatis had their wire circlip halves for keeping the closing collet on the valve stem. But then these were not famous for longevity or practical maintenance. The silliest version of valve components is by far the prewar A Rapide contraption, just to be different, while other brands stayed with more common split collet type. Well , on A HRDs you may want to keep standard as the lot is in open air - for those who give a sh** about concours judges - not my concern at all.


Vic
Ducati Desmo wire collets

TRW valve end types: