Are 1960 SR interference engines ?

[Macbeth]

I’m close to a 12 mth build ending. Any chance we can bend a valve here ? Yeah I’m a better cook than engine builder

[groily]

Any reason why you should?
(I like mine medium-rare please!)

[CheeserBeezer]

Highly unlikely assuming you've used original or well-sourced parts. Just make sure you've got your dots and dashes lined up properly on the timing gears and you should be good to go! Good luck!

[Triton Thrasher]

If the inlet and exhaust valve in a cylinder are both slightly open (exhaust valve closing and inlet valve opening), at top dead centre after the exhaust stroke, then your valve timing is not a million miles off.

If the engine turns freely when you carefully turn the crankshaft by hand, the valves are not touching the pistons.

If you reduce the valve clearances to zero, then screw the adjusters down another turn and a quarter to hold the valves open by about 0.050” on the base of the cam and the crankshaft still turns freely (be careful and slow and feel for resistance), then you have a fair clearance between valves and pistons.

Others may have better figures than 0.050” and 1.25 turns. I’m guessing that BSAs might have 26 tpi adjusters and 0.010” running valve clearance.  There may even be BSA recommended valve-to -piston clearance somewhere.

[Greybeard]

Just a thought: if a pushrod is not seated in the cam follower cup, ie., resting on the lip, a valve might be held open.
After putting the rocker box back one needs to be careful when rotating the crankshaft.

[sean]

i find a dab of grease on the end of the push rods helps keep them in place and a curved dental pick seems to work better for me than the comb tool .
but always turn the motor over by hand and check spring clearances  etc

[limeyrob]

Very easy to sit a push-rod on the edge of a rocker cup. Back off all the adjusters and go own very slowly checking all the way.

[Macbeth]

Tks heaps guys. This has been an absolute nightmare. Almost every new part (standard aftermarket suppliers) has been a mess re spec’s, wrist pin bushings so loose a breeze pops them out, rods that req case notching, valve spring issues etc etc etc . Anyway the day is nigh !  Going to feel like a rabbit in a greyhound pen on that very first ride

[berger]

Macbeth if you mean con rod little end bushes letting the pin slide through you are better off having a sliding fit and not a forced fit .i don't understand rod notching.

[Macbeth]

Yeah there slide & there’s flopping about loose. Notched as the new rods clipped the cases. I was on the side for most of this until now & the builder just kept rejecting out of spec parts but the rods had to go in (he showed me a few of his rejects & he was dead right in his explanations & expectations of parts). He is completely off the scale pedantic on everything which is both tiring & appreciated on my part. He has a hell of a good reputation (no shortage of work Trumpy, Douglas, Norton etc) so really my first dabbling in this old Brit bike engine build life which needed expectations adjusted. The $ is horrifying

[Macbeth]

She’s alive !! Mechanic has temp run it a few times & taken her for a run. Blew the head gasket on start up yet the 2nd gasket had a tad of compound added & it appears to work well as test ride went well.

Now just need to watch the temps on its first rides as I live in a CBD & it’s 35C atm. Will do a few late night laps of the city blocks when it gets back to mid 20’s & traffic dies off

Picked up a filter housing with Orb banjo’s to 6AN. Takes a very common bike filter. Took me a long time yet I located 6AN - 1/4” BSP female /male fittings/nipples so bike fittings stays 3/8 BSF with 6AN oil hose & reusable screw on hose fittings