The BSA A7-A10 Forum

Technical (topic titles must be descriptive) => A7 & A10 Engine => Topic started by: DaveB500 on 12.10. 2009 13:33

Title: Push Rods what B**ch of a job
Post by: DaveB500 on 12.10. 2009 13:33
Decided to cure a small oil leak from my rocker cover this Saturday.
Involved removing the rocker cover and applying a new gasket and sealant.
simple I thought.

all you experainced guys will know what came next.

1 hour to remove, cover, clean, fit new gaskets.
6 hours cursing the desginer for bringing the push rods up through the centre of the engibe, and at an angle.

After looking at the design of comb on ebay, and measuring the rocker socket positions, a piece of thick card and a pair of scissors hay presto job was done.

What a bitch of a job though. Next is the Primary side oil leak, what horrors are lurking on that job I wonder.
Dave
Title: Re: Push Rods what B**ch of a job
Post by: RichardL on 12.10. 2009 13:59
Dave,

This tip is too late to help you, I think, but here is what I did when I misplaced my factory-made comb. From eBay, copied a photo of a comb for sale; using AutoCad, scaled the photo to the correct size between mounting bolts (absent CAD program you could just resize the photo); print the picture at the correct scale; cut out and paste picture on sheet-metal scrap; cut shape in sheet metal - voila! pushrod comb.


Richard L.
Title: Re: Push Rods what B**ch of a job
Post by: mike667 on 12.10. 2009 14:03
Dave,

This tip is too late to help you, I think, but here is what I did when I misplaced my factory-made comb. From eBay, copied a photo of a comb for sale; using AutoCad, scaled the photo to the correct size between mounting bolts (absent CAD program you could just resize the photo); print the picture at the correct scale; cut out and paste picture on sheet-metal scrap; cut shape in sheet metal - voila! pushrod comb.


Richard L.

damn Richard!  ;) i think their under $10 bucks,
Title: Re: Push Rods what B**ch of a job
Post by: tombeau on 12.10. 2009 14:37
I've got skinny fingers. I can line 'em up through the inspection ports.

Cheers,
Iain
Title: Re: Push Rods what B**ch of a job
Post by: RichardL on 12.10. 2009 15:39
Right. Under $10, but days, not minutes (say, 60), away.

Richard L.
Title: Re: Push Rods what B**ch of a job
Post by: mike667 on 12.10. 2009 17:14
Right. Under $10, but days, not minutes (say, 60), away.

Richard L.

 you must of never been a boy scout "always be prepared"....

still nice to have the equip to do it though! *smiley4*
Title: Re: Push Rods what B**ch of a job
Post by: beezalex on 12.10. 2009 19:03
Dave,

with the aid of a hooked dental-type tool, it's a little fiddly but not THAT hard.  Just rotate your rockers so that the sockets that engage on the pushrod tubes are down all the way, then drop the box on slowly.  There should be enough friction on the studs that it will stay at whatever position you lower it to.  Bring it down until the rockers start contacting the tubes and use the tool to guide the pushrod tubes into place.  you should have at least a 1/4" gap to put the tool through and since the rocker arms won't be engaged you can do them one@ a time.
Title: Re: Push Rods what B**ch of a job
Post by: muskrat on 12.10. 2009 19:45
G'day Dave, yep the hardest part of a rebuild. I had to modify the comb to fit the tapered alloy push rods I use. i also use a piece of elastic string wraped around under the rocker arms and over the top of the rocker box to keep them up ( I use shims rather than springs on the shafts, less drag ). I recall a post about a rocker box with a hole in the top, to make that job easier.
The primary should seem like a piece of cake compared. Other than cover gasket look at the sliding plate felt and the joint between the inner cover and motor.
Cheers
Title: Re: Push Rods what B**ch of a job
Post by: rocket man on 12.10. 2009 20:27
i was looking for my comb then i remembered  i dont have eny hair *smile*
Title: Re: Push Rods what B**ch of a job
Post by: RichardL on 12.10. 2009 20:41
Well, I thought I was prepared until the manufactured one I own (which, I have since found) was not where I thought it should be. So, the "be prepared" still applies, but goes to having a peferctly clean shop where everything is in exactly the correct place at all times. I know I am the only one here for whom this does NOT always apply.

Richard L.

edited
Title: Re: Push Rods what B**ch of a job
Post by: olev on 12.10. 2009 21:28
Gday Muskrat,
Tell us about your alloy pushrods.
Why are they good and where did you get them?
cheers
Title: Re: Push Rods what B**ch of a job
Post by: BSA_54A10 on 13.10. 2009 02:34
I cut one out of stiff plastic ( front of a shirt box ).
Held em in then being flexiable just fell straight out.
Title: Re: Push Rods what B**ch of a job
Post by: muskrat on 13.10. 2009 08:19
G'day Olev,
               put one in a press and see where it bends. In the middle. Alloy is lighter, less reciprocating mass, thicker in middle stronger. Down side, ends wear faster so adjust every 10,000. I have another set to use in 50,000 but I can't remember where I got them, will have to go back through my records.
Cheers
Title: Re: Push Rods what B**ch of a job
Post by: DaveB500 on 13.10. 2009 10:59
Thanks for all the replies.
In the end I did copy a picture from ebay, and with measurments taken from rockers made my own cardboard comb. all lined up at second attempt.
I had tried dental hooks, but after 3 hours, i gave in.

Nearly didnt have any hair left myself for the comb....

Dave
Title: Re: Push Rods what B**ch of a job
Post by: snowbeard on 19.10. 2009 00:23
I ended up using a magnet on a stick to hold each one in place with the cover just a half inch up, then push each rocker down onto them to hold in place and seat the box. 

then I found out there was a tool available!! ;)
Title: Re: Push Rods what B**ch of a job
Post by: duTch on 05.05. 2012 09:52
I dug up this thread from an in house-site search for rocker shaft shim info(can't remember what now,but close to Muskrats post-probably need another topic).
 While I'm here though,will throw 2bobs worth+gst,vat,gdp,cpi.....! but first- Muskrat did you dig up the info for Olev where you got your fancy ally pushrods they sound good, one of my ex. ones has a bit of a chicane in it, and with the new springs figure may not take much to make it a hairpin! reckon I need newies
Burtons have ally ones not sure if 16gbp is for one or two, or four??
 SRM have CrMo one 12~gbp looks like ea??
 

Now to push rod fitting- I am soon to do mine for the first time in a long time, have usually done it a combination of most methods mainly Beezalex......
Quote
with the aid of a hooked dental-type tool, it's a little fiddly but not THAT hard.  Just rotate your rockers so that the sockets that engage on the pushrod tubes are down all the way, then drop the box on slowly.  There should be enough friction on the studs that it will stay at whatever position you lower it to.  Bring it down until the rockers start contacting the tubes and use the tool to guide the pushrod tubes into place.  you should have at least a 1/4" gap to put the tool through and since the rocker arms won't be engaged you can do them one@ a time.

.........and Snowbeard
Quote
I ended up using a magnet on a stick to hold each one in place with the cover just a half inch up, then push each rocker down onto them to hold in place and seat the box.

 Never used a magnet yet, good option.
 Something I noticed just now though is that the Exhaust rod cups are visible over the top of the rocker shaft if the adjusters are wound right back and sitting on the valve tip, and the inlets opposite, still wound right out, but way off the valve tip, are real easy to see (as you probably know).
      Admittedly it's out of the bike, on a (bench) and relatively easy to see and no frame in the way, but Ive done it in situ and still a bitch, but not that bad, and with a small mirror ('virtual magic') may just be ........?.............easy?
   Also small digital surveillance cameras/monitor can enhance that 'virtual magic'- I've used one for bolting a tie down eye bolt in where I couldn't see.
 
   I was looking for info re-rocker shaft shims  Might be a different topic will have a search or start again
   
Title: Re: Push Rods what B**ch of a job
Post by: kiwipom on 05.05. 2012 10:13
hi guys/Manosound, have`nt got to that stage yet but would`nt mind a copy of that cad drawing if you still have it,cheers,Bob
Title: Re: Push Rods what B**ch of a job
Post by: muskrat on 05.05. 2012 11:40
G'day Dutch,
                 Whatever you do, don't use a bent rod. There's a few on epay, thought I saw a alloy set with steel ends.
For the life of me I can't find where I got the tapered ones. I need another set.
 Found it. Kidderminster 20/08/93 $27AU. Think they might be a tad more now :(.
I remove the shaft springs and make shims to fit. Less drag on the rockers. I use a rubber band around the tappets and over a cover stud to hold'em up, cups down. the ex rods always find their way into the cups and the ins only need a pull rearward a few mm with a dentists hook to mate with the cups.
Cheers
Title: Re: Push Rods what B**ch of a job
Post by: duTch on 05.05. 2012 12:05
Thanks Musky, yes even though those are the rods I was using, with the extra spring am not optimistic. 20/08/93- is that a date??  that's last century! *eek* $27AU presume for the set?
 This could be a different topic that I was trying to get my head around earlier, but Yes I put the new shims in, but they're thinner (~0.027thou the odies are ~0.047) even had to dress the pressing dags off, but before I put 'em in had a play, put 1 each side inboard and about 5 on the outside, just a few thou tolerance, and compared to with the thackery springs, I realise how much drag there is(not).
 How much tolerance do you give them?? I figure it could cope with a bit but not too much.
Got a head scratch too about the old ones  but later ,cheers
 

 
Title: Re: Push Rods what B**ch of a job
Post by: muskrat on 05.05. 2012 12:49
'bout 5 thou Dutch. That's the date, gettin' old aren't we, and yes $set.
I just emailed them to see if they have more, not hopeful.
Cheers
Title: Re: Push Rods what B**ch of a job
Post by: muskrat on 05.05. 2012 13:20
A scan and measurements of a comb.
Cheers
Title: Re: Push Rods what B**ch of a job
Post by: duTch on 05.05. 2012 23:24
Yeah  I googled them up and emailed them last night too no word yet(weekend though). website been 'under construction' for 3yrs! I'll have a poke around the emarket
Title: Re: Push Rods what B**ch of a job
Post by: duTch on 06.05. 2012 15:04
Ok so  am on the hunt for new pushrods.
 Muskies Tapered pushrods sound good, sure I'm seen some before, but am checking other options in case of supply isssues.
 
Any known problem with stock dural ones, or does anybody have other ideas re- value/quality for money??

  Thanks ,duTch
Title: Re: Push Rods what B**ch of a job
Post by: mfhutchins on 09.05. 2012 01:23
i am trying to fit the rocker box and i am pretty sure i have the pushrods aligned in the sockets on top and bottom.  the cover does not sit flush on its own and i believe this is partially due to one of the pushrods being slightly longer than the rest.  is this correct or is something amiss?  should it sit flush on the head?  im nervous and dont want to do any damage.

by the way, i have been reading lots of posts here over the past few months and am rebuilding a 63 super rocket, my dream bike.

mike.

oh, and muskrat, thanks.  i used that jpeg of the comb to make my own.
Title: Re: Push Rods what B**ch of a job
Post by: muskrat on 09.05. 2012 07:43
 G'day Mike,
                there will always be at least 1 push rod on the cam. At TDC on the left the rods on the right will be up a bit, about 1/8".
Glad the pic worked for you.
Cheers
Title: Re: Push Rods what B**ch of a job
Post by: mfhutchins on 09.05. 2012 18:05
that makes sense.  thats about how far off the head the rocker box is on one corner, 1/8".
Title: Re: Push Rods what B**ch of a job
Post by: RichardL on 09.05. 2012 19:37
The popular theory and, I think, a good idea is to loosen the adjusters.

Richard L.
Title: Re: Push Rods what B**ch of a job
Post by: duTch on 09.05. 2012 23:59
Heck  RL, I wish I said that !! ;)

Hey Muskrat, I emailed Kidderminster, but monday being a holiday, ended up phoning tuesday-much easier, but Shaun(spell?) didn't know about the tapered rods, so I just ordered some pattern dural ones hope they're ok he reckons sold lots and no probs, but it could be worth sending him a photo of yours and an invoice scan, something might come to light??

 Also I noted that Burtons have 'alloy' ones,no elaboration, but haven't yet investigated but if I come up with anything I'll give a holler.
Title: Re: Push Rods what B**ch of a job
Post by: duTch on 25.05. 2012 01:16
Well, the pushrods that I ordered from Kidderminster arrived the other day (21 GBP landed-au), but am I on something in the water??    The ends are not nice and hemispherically machined as I'd expect, but look more like roughly carved hard chines on a primitive boat hull!? ,sorry but not very clear in the low res photos.
 Is that normal??  I expected something I could 'plug n play', now I need to sit and lap them I guess.

   Just thought I'd use this old Tee shirt as a background, never noticed the 'BrotherS in Arms'-before but think it's fitting- Sorry Cockroaches- too bad about the footy huh?
Title: Re: Push Rods what B**ch of a job
Post by: muskrat on 25.05. 2012 08:03
 Yep the ref was on the take !! Our good one disallowed and your dodgy one was. *dunno*
Two trains of thought about the rough ends. 1 they hold oil in the scratches = less wear. 2 smooth has no ridges to wear.
Cheers
Title: Re: Push Rods what B**ch of a job
Post by: terryk on 26.05. 2012 12:01
Musky you are just a sore blueser. Go Queensland!!!!! 7 in a row.
Title: Re: Push Rods what B**ch of a job
Post by: duTch on 27.05. 2012 15:32
Glad you said that Terry *eek*. Good one? Dodgy? All looked ok ta me *smile*, but have you seen the bumper stickers six yrs ago said 'it's official-NSW sucks'? But that was 6 yrs ago!

 Moving on, I sorted my pushed tips-remember them? I put one end in the drill in a table vice, and ran the other end through a small bearing in another vice, spun it in reverse and profiled the other end with the dremel. Will post a picture when I get home later.



OK here's later-
2 pics >first one is just the profile gauge I made that's a bit hard to see in > pic.2
I use this method for a lot of things, usually with an angle grinder and got the idea from a guys letter/story in a custom ragazine back in the eighties.
 Also interesting to note, being 'dural' they (rods) are not at all magnetic, so the idea of a magnet to do rocker box is out.
Title: Re: Push Rods what B**ch of a job
Post by: Butch (cb) on 29.05. 2012 11:57
Wasn't there another method for settng the pushrods correctly mooted in one of the Classic glossies some months back? Short bits of fuel line poked down to hold the pushrods in place whilst the box is bolted down and then pulled out after - maybe with long nosed pliers. Meant you didn't get your gasket goo all over the alignment tool.
Title: Re: Push Rods what B**ch of a job
Post by: jfligg on 02.06. 2012 22:12
Well guys I am 2 hours into this pain in the a$$  job.  I had to stop for a break.  I have done this job a couple of times and I dont remember being this fustrated.  Almost thinking of selling up.  Jeff
Title: Re: Push Rods what B**ch of a job
Post by: bikerboy on 03.06. 2012 14:37
At the risk of annoying some I have never had a problem fitting the rocker box even in situ. I dont use a comb like others I just use my fingers and a bit of a bent coat hangar.

I will say the alloy heads when the engine is in situ are a bit more tricky due to the longer rocker box studs but maybe I have just been lucky.

Mind you to be fair when I was about 18 I probably had my cylinder head off about every 20 minutes so it may just be a case of practise  *smile*