GB is not OK, again!

[bsa-bill]

just a thought, I recall striping my rocker box down due to the strap bit of the box that goes between the exhaust tappets (see pic), I had a spare box without rocker shafts (no apostrophe  ) upon stripping it down I found a rocker shaft broken, the bike had been running fine with the broken shaft, but it makes you wonder.

[chaterlea25]

Hi All,
Bill, I had that thought but dismissed it
Anyway I will include a spindle with the rockers that will be sent to GB


John

[berger]

greybeard, today I nipped up the rocker box and re set tappets. while doing so took some rough measurments, the bike has 356 cam with approx. 20 thou off the head and maybe 5to 8 off the top of the cylinder head where rocker box fits { just to clean it up after years of the dredded screwdriver treatment.}.... results of tappet height are ... inlets 1cm from the top of the  lock nut to the top of the square bit on tappet..... exhausts are 7mm from top of lock nut to top of tappet... this might help the next time your in there

[Greybeard]

...results of tappet height are ... inlets 1cm from the top of the lock nut to the top of the square bit on tappet..... exhausts are 7mm from top of lock nut to top of tappet.

Thanks for that Keith. Kudos given.

[Greybeard]

To recap: Since fitting a RR camshaft, the inlet rocker adjusters on my 1955 A10 semi-unit engine needed to be screwed so far down that I had to thin the locknuts.

ChaterLea25, (John) has very kindly sent me a set of Inlet rockers and shaft, so today I reluctantly took the rocker box off and compared the current rockers with the ones from him. I could not see any real difference but changed them over. The adjusters are now slightly improved so, a great result. Thank you Mr Chaterlea25, (John)!

I inspected the pushrods and found them all straight and the correct length.

[edboy]

hi greybeard, why not fit lash caps from a b31 to take up the space. also minimises wear to the guide and valve top. i think they are a straight fit.

[Greybeard]

hi greybeard, why not fit lash caps from a b31 to take up the space. also minimises wear to the guide and valve top. i think they are a straight fit.

Thanks, that has been suggested to me before. I'll get some.

[coater87]

Ok,

 Rockers are good, valves are correct length, push rods are correct length.

 That pretty much leaves two things, diameter of camshaft or WORKING length of lifters. If the pushrod pocket in your current lifters is different than your old lifters...

[duTch]

 I've just spent a few beers looking at some photos of my rockers/valves open and closed , as I have a similar issue-on the back-burner, but I have Socket-cap adjusters, so maybe different....I'm inclined to agree with Lee, and I'm not so sure that caps will sort it properly, but just be a smooth-over.

 Sure they may give more threads on the adjusters, but it won't change the angle that the adjuster strikes the valve tip which I reckon is critical  .
 As I interpret what Lee suggests, either the lifters need to be longer/higher/less deep pockets, or the pushrods need to be longer (in my case anyway, with ally head a different factor), but we have an agreed stock pushrod length, so the plot thickens...

 Edit; I chased up the B31 Valve Cap part, same as A7 Longstroke caps, part # 65-020...not cheap the little buggers, but for properly hardened steel, I'd expect that...one thing to consider as I was looking at my valves is the distance from tip to the collets needs to be more than the depth of the caps, or the thrust will be on the collets- not ideal metinks....

[edboy]

hi greybeard, the 334 is a strange looking cam and has a thicker base circle than a sporty one i think from memory. i dont think the valves open that much but have longer duration. any spitfire profile cam really needs mushroom adjusters and lash caps to spread the adjuster wipe over the valve stem whe the cam lifts. but  the adjuster musnt strike the side of the lash cap. so must be checked. the standard adjuster will work with lash caps but check the wipe on full lift of every valve. should be central. ive fitted lash caps to my triumph and now hardly ever adjust the valve clearances.
this is a seperate subject really