1200 short cylinder stud/bolt

  • Thread starter Thread starter lemonjelly
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Just looking at the valve timing figures for different cams. Using an A11 inlet camshaft on the exhaust side would be a close approximation of 4C valve timing, but with the lower lift of the A11. Should work OK as long as it's dialled in properly.

Cheers,
Cam
 
Racer boy me then,well I ve got 4C on the Sprint,this ones going to be standard workhorse  one day! :D
 
Nice one Cam  :)  

Shaun, I would think your greatest priority would be sorting out the cam pillar M8 Stud, the rest is anywhere from very bad to superficial. Technically, you could fit the correct cam but without dialling it in, "potentially " it could be no better than what you have in there.

I've learnt something, no need to carry 2 spare cams around, when one will do....
 
how about the blocks/cam bearings Rob? Keith is sending my the correct stud to see how I get on.

Shaun
 
Thanks Rob

Torque seems ok and the studs seem to be at 90 degrees still ,I ll sort the stud prob out and re evaluate.Need to get on with powdercoating fame really.

Thanks for your offer,being in Devon is a bit of a shit sometimes!

Shaun
 
I have a new billet type set of cam blocks on my Jota...one thing maybe worth checking is the straightness or otherwise of the cams themselves...I went for years struggling to get the things turning smoothly after shimming...one end always seemed to bind...suppose I should have realised but it took Keith to notice the slight bend and straighten it!Iremember when I got my head from Slaters I.e the new one from the display engine,that That fella Clem stopped Richard Slater from undoing the studs willy hilly and was most insistent on a sequence to avoid warp age.I suspect it is not difficult to bend the cams by inadvertence when undoing eg if they are loaded by a valve not closed.
Nick7
 
on a 180 all valves can be in the closed/resting position , before you break the chain and then release the holding down studs, so  o need to bend a cam with a valve open,and yes I do believe that if you release in the correct order, you will save yourself some grief, never, never ,never leave those two 7mm studs by the plug holes and the 8mm studs front and rear to last, do them first,then the 8mm cam studs/9mm cclinder studs in the correct reverse order and in at least two loosening torques, on "the way down"
CLEM
 
CLEMTOG said:
on a 180 all valves can be in the closed/resting position
Click to expand...

I remember someone mentioning that before. So last time I had the lid off the engine, I cranked it over slowly keeping an eye on the valves. At no point were all valves closed at the same time. I have 4C cams. Maybe it's different with A11.

Cheers,
Cam
 
Agree with Cam. Having just dialed in my cams it's fresh in my mind. At TDC the inlet valves are closed, the ex. cam, after breaking the chain will retard somewhat before closing all valves. What I did notice between the flat top pistons and the Ross H/C just fitted is that I now have to back the crank off TDC before turning the ex cam to line up with the TDC marks on the cam wheel and pillars, as the #3 valve will now kiss the piston where as before there was no clash.
 
Just did a quick think on this while scribbling some diagrams on the back of an envelope. I'm feeling more confident about it now, so I challenge anyone to find a crank position when all valves are closed on any correctly timed Laverda triple or twin engine with any camshaft installed. Unless I've cocked up my thinking entirely (always a possibility) there will always be some valve overlap between cylinders. The only exception would be something unusual like a twisted twin.

Cheers,
Cam

 
Perhaps being confused with each individual cam in a 180 having a spot where no springs are compressed and there's 30-odd degrees of free movement.  That's the spot to install cams and cam bearings in a 180, then having everything nipped up and pistons away from TDC, you then move the cams to their correct timing positions etc.  Also great for checking for tight-running cams.  Not the case with a 120.
 
Dellortoman said:
so I challenge anyone to find a crank position when all valves are closed on any correctly timed Laverda triple or twin engine with any camshaft installed.
Cheers,
Cam
Click to expand...

Challenge accepted - potentially anywhere in a 720 degree range on a SOHC 750
(you didn't mention anything about rockers being installed).
:D
 
There's always a smartarse  :D :D :D :D

But you're correct. Not being a 750 owner I hadn't considered leaving out the rockers (what are they?). Perhaps I should have said an engine capable of actually running, but someone clever dick is bound to find a loophole there too.

I should also have specified only Breganze 750 and 1000/1200 triple engine. I don't know anything about the smaller twins or Zane engines. If they're 180 degree cranks then there will be part of the 360o cycle when no valves are open.

Cheers,
Cam
 
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