I am not sure if my rocker spindle bolts are original as the previous owner made alot of parts on his lathe and mill , my oil feed hole is .025" in the banjo bolt , very very small, and when I look at new replacement bolts (small hole) they look alot bigger, like about .060 , my exhaust valve had got stuck , I pulled the rocker and it all looks OK, it's got a brass fat spacer at the feed end , I've added a internal groove and filed some slots around it to pick up the end of the slot , I've re orientated the shaft to pass the valve side hole , I've ordered some new bolts as they are not very expensive. I held my finger over the return pipe in the oil tank and have got oil coming out . Any information greatly appreciated. Cheers
After alot of searching , i found this so I've copy and pasted it in all credit to John .
Hi MM,
The Physicist in you is taking over and running amok (again) laughing
Your post above caused me to go and search out all the rocker feed bolts I could find in my possession without dismantling any from running bikes
I also looked through the 49/53 parts book and the later 58 DBD book
65-317 is shown as the bolt for inlet and exhaust on the iron engine B31/33 but is also shown as fitted to the BB inlet and exhaust for 53
65-318 is the exhaust side bolt for the DBD
The bolt you have with the large hole c5mm. is either a B31/33 head drain bolt or has been drilled out
I measured the oil restricting holes as best I could with small drills and a gas nozzle cleaning set +micrometer
B33 iron head with its original looking bolts, measure 1.1mm - 0.044in. so presuming ? 3/64in.
New DBD bolts from Autocycle measure, inlet 1.1mm. exh 1.6mm - 1/16in.
Webco "Gold Star" oil feed manifold and bolts measure, inlet 1.1mm. exh 2.4mm. 3/32in.
A10 "Dow" bolts both measure 1.1mm.
John . This was from britbike forum .Cheers.
Quote from: Bigsingle on 22 Sep, 2024, 21:00
I am not sure if my rocker spindle bolts are original as the previous owner made alot of parts on his lathe and mill , my oil feed hole is .025" in the banjo bolt , very very small, and when I look at new replacement bolts (small hole) they look alot bigger, like about .060 , my exhaust valve had got stuck , I pulled the rocker and it all looks OK, it's got a brass fat spacer at the feed end , I've added a internal groove and filed some slots around it to pick up the end of the slot , I've re orientated the shaft to pass the valve side hole , I've ordered some new bolts as they are not very expensive. I held my finger over the return pipe in the oil tank and have got oil coming out . Any information greatly appreciated. Cheers
Hi did you reach any conclusions with hole sizes? I've just measured mine and they are between 2 to 2.5mm diameter (2mm is loose fit;2.5mm is too big for the small hole - not sure what that is in old money?) My B33 has a history of exhaust valve seize and pushrod jumping off. Spring on exhaust is considerably shorter than inlet. Maybe getting too hot = seize because of weak spring. Head currently off in the hope to find a final solution
Hi , just to be sure we are talking about the same thing , the b33 rocker spindle bolts pn65-317 or 65 -0317 and I am referring to the hole just below the taper , if your having issues with valve nipping up with 2mm to 2.5mm or .080" and .100" thou hole , try placing the oil groove in the spindle to align withe the rocker hole on the spring side , you can check flow with finger covering oil tank return pipe hole . Mine has a .040" hole now and is aligned , valve not sticking any more . Cheers .
Quote from: Bigsingle on 05 Oct, 2024, 19:30
Hi , just to be sure we are talking about the same thing , the b33 rocker spindle bolts pn65-317 or 65 -0317 and I am referring to the hole just below the taper , if your having issues with valve nipping up with 2mm to 2.5mm or .080" and .100" thou hole , try placing the oil groove in the spindle to align withe the rocker hole on the spring side , you can check flow with finger covering oil tank return pipe hole . Mine has a .040" hole now and is aligned , valve not sticking any more . Cheers .
Get some new terrys valve springs they don't have alot of spring pressure from new I tested them and they have approx 60lbs on the seat which is pretty low , my bike has been pretty modified and has big valves 45 mm ex 47mm in different keepers , it was difficult to bring my spring pressure up a little because of the limited height between the seat and the retainer , I changed out the inner spring .Things to look out for even in your stock configuration are, retainer to guide clearance, it's supposed to be about .060" , you could feed some chainsaw pull rope into the cylinder and then bring piston to TDC, easy enough to get springs off ,a simple lever and a notched pipe for acess to keepers . Hope this helps .
Quote from: Bigsingle on 05 Oct, 2024, 19:30
Hi , just to be sure we are talking about the same thing , the b33 rocker spindle bolts pn65-317 or 65 -0317 and I am referring to the hole just below the taper , if your having issues with valve nipping up with 2mm to 2.5mm or .080" and .100" thou hole , try placing the oil groove in the spindle to align withe the rocker hole on the spring side , you can check flow with finger covering oil tank return pipe hole . Mine has a .040" hole now and is aligned , valve not sticking any more . Cheers .
Yes referring to the little holes below the taper. 65-317's. Except on inspection I don't think I have the correct ones fitted as the holes are from what you've said are approximately twice the size than they should be. Could this be my problem? I'm no expert but if you compare say an adjustable nozzle on a garden hose you can increase the pressure by closing the hole. So comparing that scenario, whilst I'm getting oil through the rockers it's not being forced through due to the hole being too big. This of course, again using my theory, would reduce oil pressure for the whole engine? There is a is a return flow in the oil tank. Head is off now so cannot do any further checks but will bear in mind what you've said about alignment thank you
Hi,
As the rocker feed is taken off the return to the tank it does not really have any affect on the engine pressure. The idea of the smaller dia. pipe is to reduce the amount that goes up there as the rocker do not need loads of oil.
The size of hole in the banjo bolt is probably again, to not let too much oil in to the rocker box. I believe that the idea of the smaller holes on the inlet is to bias the supply of oil to the exhaust.
As you now have the head off you will probably strip the rockers to clean and check everything. When reassembled use an oil can to push oil through to see that it is getting to the rockers. Also, check to see if the rockers have any small drillings as on A10/A65 to take oil to the adjusters or valve stem.
Dave.
Thank you, I'll try those tests. Rockers still intact so I can squeeze some oil into the feed to see what happens. Once it's all back together (not for a while yet) I can try the different banjo bolts with rocker covers off to see if the is more/less oil going thro'
Regarding smaller hole on inlet feed as far as I'm aware both banjo bolts (65-0317) have the same size hole, they are often sold as a pair as per this link to Dragonfly
https://draganfly.co.uk/product-category/bsa/sparesparts-for-bsa-a710-b3133-c101112-m202133/engine-gaskets-gearbox/cylinder-head-barrel/rocker-box/pre-unit-b-m-group-rocker/
Hi,
In a previous thread I think it was established that the banjo bolts for B33 had same size hole and Gold Star had the exhaust a bit bigger. So same size probably correct for your bike but the slightly bigger one could well be beneficial.
Dave.
Slightly bigger would make sense to me to give greater oil flow.
Quote from: RichardAB on 06 Oct, 2024, 09:14
Thank you, I'll try those tests. Rockers still intact so I can squeeze some oil into the feed to see what happens. Once it's all back together (not for a while yet) I can try the different banjo bolts with rocker covers off to see if the is more/less oil going thro'
Regarding smaller hole on inlet feed as far as I'm aware both banjo bolts (65-0317) have the same size hole, they are often sold as a pair as per this link to Dragonfly
https://draganfly.co.uk/product-category/bsa/sparesparts-for-bsa-a710-b3133-c101112-m202133/engine-gaskets-gearbox/cylinder-head-barrel/rocker-box/pre-unit-b-m-group-rocker/
I think if the oil feeds were too big then the oil drains wouldn't cope and it would smoke , also ? If so much oil was in the head and draining to the crankcase the scavenge pump would have plenty of work to do and be constantly flowing oil , I think there is still some restriction because of the rocker spindle shaft/ clearance , but aligning that hole so that during the valve lift opens the hole and let's oil dribble out to cool the spring and lubricate the guide is the trick , I wouldn't worry too much about the 2mm hole at the moment unless you get excessive smoke . While your head is off polish your valve stem and or check for galling and stem clearance and replace as required , fit new springs .Cheers .
Ok thank you. I'll try all that's been suggested