rockers

Discuss mechanical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
philthehill
Minor Maniac
Posts: 11585
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: rockers

Post by philthehill »

After a bit of effort I now have the 1.5 rockers nicely centrally aligned over the top of the valve stem.
Note:- The valve stems seals are fitted to all valve guides as it stops the valve falling out when the head is lifted. Only fitted to inlet valve guides normally.
[frame]Image[/frame][frame]Image[/frame][frame]Image[/frame][frame]Image[/frame]

bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Re: rockers

Post by bmcecosse »

What cam are you running with these high lift rockers Phil?
ImageImage
Image
philthehill
Minor Maniac
Posts: 11585
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: rockers

Post by philthehill »

bmc
At the moment I have no idea what cam will be fitted but it will not be any thing like full race - more like standard - I am just in the process of gathering spares to add to the ones I already have and which will eventually be incorporated into the spare 1275cc 'A' Plus engine I am building / modifying in very slow time
These 1.5 rockers became available on 'e' bay so grabbed them whilst I could.
It has been as you said above a very satisfying job to get them over the top of the valve stem and the original post of this thread spurred me into getting the job done.
Phil

panky
Minor Legend
Posts: 2042
Joined: Wed Aug 20, 2014 4:12 pm
Location: Cheshire
MMOC Member: No

Re: rockers

Post by panky »

Looks a cracking job 8)
Oh for the days when I had access to a lathe :cry:
Image
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Re: rockers

Post by bmcecosse »

Those of us without access to machines - just have to make do with saw and file !
ImageImage
Image
panky
Minor Legend
Posts: 2042
Joined: Wed Aug 20, 2014 4:12 pm
Location: Cheshire
MMOC Member: No

Re: rockers

Post by panky »

That's how I did my rockers :)
Image
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Re: rockers

Post by bmcecosse »

Phil - I'm slightly surprised you can use standard pillars with the 1.5 rockers. Usually custom pillars are needed - to move the rocker shaft slightly away from the valves to allow the rocker pads to act directly down on the valve tips. Alternatively (but much less satisfactory) some drill out the stud holes in the pillars to allow them to move the pillars away from the valves - but how they stop them shuffling back is beyond me. Or -are these rockers just shorter than normal in the 'heel' rather than longer in the finger ?
ImageImage
Image
philthehill
Minor Maniac
Posts: 11585
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: rockers

Post by philthehill »

bmc
I was expecting the pillars that came as part of the 1.5 ratio rockers to be offset but they are of exactly the same standard dimension's as a sintered pillar but made of steel.
The only reference I have found so far as regards off-set pillars is with the Avonbar Racing 1.5 ratio rocker kit which was a virtual copy of the Speedwell 1.5 ratio rocker kit.
The Mini Spares 1.5 ratio rocker kit http://www.minispares.com/product/Class ... lassic/1.5 rockers.aspx|Back to search
makes no reference to using special pillars but the kit comes with steel pillars.
Mini Spares also supply individual 1.5 ratio rockers http://www.minispares.com/product/Class ... .aspx|Back to - again no reference to special pillars.
Back to the rockers in my postings above:-
They have been used - but so little that the anodising has hardly worn off the valve stem pad. The marking from the top of the valve stem on the pad is central on the arc but not central fore and aft; and there is no slide marking on the valve stem pad indicating the they may have been used with a standard cam.
I have measured the 1.5 ratio rockers against a standard ratio pressed steel rocker and these are the dimensions of each:-
1.5 ratio rocker
Centre of rocker shaft to centre of valve pad..................32mm
Centre of rocker shaft to centre of adjuster screw............24mm
Standard rocker
Centre of rocker shaft to centre of valve pad..................31mm
Centre of rocker shaft to centre of adjuster screw............25mm

So not a lot of difference but a small difference.
The listing on 'e' bay stated that they had come off a tuned 1275cc engine.
Phil

bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Re: rockers

Post by bmcecosse »

I guess that difference is enough to give the extra ratio - without seriously affecting the contact point on the valve tip. But you can see it obviously does - by that 1mm extra on the 'finger'. This is where I have seen advice in the past to move the pillars (and therefore rocker shaft) away from the valves. In fact - most of the advice I have seen is that these rockers should only be used as a 'cheap' way to effectively uprate a standard cam by 'one' (ie where the cam is not easily changed in a Mini 1275 engine without removing the engine - there being obviously no access from below in case the followers should drop - despite being held up by magnets - or - to get the very last gasp of air into a very large capacity engine when the head ports and valve sizes have become the limiting factor for air flow. Otherwise - it's generally recommended to change the cam.
ImageImage
Image
philthehill
Minor Maniac
Posts: 11585
Joined: Thu Jul 19, 2012 12:05 pm
Location: Hampshire
MMOC Member: Yes

Re: rockers

Post by philthehill »

bmc
I agree with your comments above.
I have a some good spare standard (AEG577/323/538) 1275cc camshafts so may try the rockers with one or other of those and see how I get on.
I was looking for a new set of rockers anyway so when these 1.5 ratio rockers came available so I thought I would give them a try.
They were less than half the price of a set of Mini Spares 1.5 ratio rockers (even though on reduced price at the moment) and less than a set of recon sintered rockers from ESM.
The exercise of aligning the rockers with the valve stem was worth the purchase even though I have done similar exercises in the past.
Phil

Post Reply