[Moreirdan]

I have just installed a new set of cams from Hitchcocks in my 2014 GT. I have not yet started it so these are preemptive questions. It had the hydraulic lifters and I assume these have drained down whilst the bike has been empty of oil. I have refilled it with oil, but do not see anyway of "priming" the lifters with oil. Will the engine sound a bit noisy as oil circulates to the lifters? Should I turn the engine over a few times to get oil around the system? Any other things I should be looking out for?

[jez]

What else have you installed to go with the cams?

[Moreirdan]

The Hitchcock kit included new pushrods, valve springs and collets. I also have installed the Carberry anti-vibration plate.

[gashousegorilla]

I have just installed a new set of cams from Hitchcocks in my 2014 GT. I have not yet started it so these are preemptive questions. It had the hydraulic lifters and I assume these have drained down whilst the bike has been empty of oil. I have refilled it with oil, but do not see anyway of "priming" the lifters with oil. Will the engine sound a bit noisy as oil circulates to the lifters? Should I turn the engine over a few times to get oil around the system? Any other things I should be looking out for?

   What happens when you remove the rockers and push rods, hydraulic lifters will pump up and go to the top of their travel . There is a plunger , an oil filled cavity , check valve and a spring inside it.     So the insides just rise all the way to the top.   And they will stay like that for a good long time, oil primed without the valve spring  pressure applied ... through the rockers and push rods.  Over time, if the motor has been sitting like that , without valve spring pressure , some oil will drain out, but they should stay primed. 

 Assuming you checked pre-load at TDC after installation, and confirmed that the lifters bled down and settled into pre-loading the lifter. When you start the motor, you may get a bit of noise for a couple/few cycles until oil pressure builds and totally refills those lifters, and keeps them cycling properly.


 

[Moreirdan]

Checking the preload? How do I do that?

[gashousegorilla]

Checking the preload? How do I do that?

   Well.... if you have it all back together already, it's a little late now !      You would have to pull back off the tank, the rockers covers and the side cover .   BUT, you are probably OK.   Assuming the kit of parts  you have there are matched to work together, provided you did not change the deck height .  That would be things like...Thinner head or base gasket , or  a shaved  barrel and etc.  AND when the valve job was done, the valve stem height was corrected to match what you had before, or to work with the kit you have.     All these things can and DO effect push rod length and getting the correct pre-load on the lifter.    The amount of pre-load .. or the amount the push-rod pushes the plunger down into the lifter at TDC.... should be given to you by the cam supplier.   And it is dependent in large part to the about of total valve lift.

 If your rod length and preload  wind up being too long and too deep ?   Should valve train control be lost ... like if you over rev the motor or the valve spring gets too weak.   The lifter will pump up and  you could smack a valve into a piston crown.      If they are too short and pre load is not deep enough ?  As the top end  heats up and things expand , the lifter cant do it's job of taking up lash, and the rod will sit in there loosely .. or worse. 


  This is why good chromoly adjustable push rods are nice .   So you can compensate for things , and get your rod length and pre load perfect.
 

[Moreirdan]

This was a kit from Hitchcocks and they did not say to make any other changes. There was no engineering work to alter compression ratios or flow the head or anything so it looks like it is all ok. Thanks

[gashousegorilla]

   Yeah... I believe what they say to do in their instructions , regarding pre-load.  Is to measure the gap under the rocker block before it is tightened down .   So the rod would be sitting on top of a pumped up lifter , and in the rocker arm up top, without any play and not pushing down into the lifter.   At this point you would have a gap under the rocker block.... because the rod is not yet being forced down into the lifter, pushing oil out and preloading it.  That gap... before the rocker block is tightened down , would represent the amount of preload into the lifter.   Those lifter's have about .100" of travel on that plunger inside them.    Preload is usually set at 1/2 the distance of the travel or LESS.    Less, especially if the cams will push the valve deeper into the chamber.   In any case , your preload should not be more then the distance it would take , to cause a valve to hit a piston , should the lifter pump to the top of it's travel.

[ace.cafe]

I like to use about a half-mm(.020") of cold preload into the lifters.
On iron barrel engines, the vertical casting expansion was about .3mm (.012") when hot. UCE engines are probably not much different. Maybe a tad more because of the alloy barrel.
So, that leaves maybe .008" hot preload, which is plenty, considering a 1.2 rocker ratio would give about .1mm(.0096") additional intrusion into the chamber at full hot lifter pump up worst case. The typical safety margin for piston-to-valve clearance is 1.5mm (.060"), so there should be no chance of clashing from lifter pump.

[gashousegorilla]

I like to use about a half-mm(.020") of cold preload into the lifters.
On iron barrel engines, the vertical casting expansion was about .3mm (.012") when hot. UCE engines are probably not much different. Maybe a tad more because of the alloy barrel.
So, that leaves maybe .008" hot preload, which is plenty, considering a 1.2 rocker ratio would give about .1mm(.0096") additional intrusion into the chamber at full hot lifter pump up worst case. The typical safety margin for piston-to-valve clearance is 1.5mm (.060"), so there should be no chance of clashing from lifter pump.

 Yeah... on the 500 uce's I noticed 6-10 thou. expansion with solid lifter.   The top ends stay pretty cool.     Nothing wrong with running the pre load up high on these motors.   I believe HC recommends 1-2.5 mm with their cams.....039"- .098"!?  IS deep !    Sounds like they are banking on HEAVY duel rate springs with that set up... 

[ace.cafe]

 Yeah... on the 500 uce's I noticed 6-10 thou. expansion with solid lifter.   The top ends stay pretty cool.     Nothing wrong with running the pre load up high on these motors.   I believe HC recommends 1-2.5 mm with their cams.....039"- .098"!?  IS deep !    Sounds like they are banking on HEAVY duel rate springs with that set up...

Yeah, that is really banking on the springs.
IMO, it is not good practice to have more preload distance than p/v clearance, regardless of springs used. If you over-rev on a missed shift, you trash the engine. I would never recommend that to a customer. Prudence would dictate keeping the preload less than p/v clearance. I just don't see a good reason to do otherwise.

[gashousegorilla]

  It's just crazy... run a lighter valve spring and a shorter rod and make more power.  Those springs have to be brutal.     I measured .364 lobe lift on those cams.    At 1.28 rocker ratio... that's what I usually see.  And it's a safer number.   That puts valve lift at .465.   Add to that up to .090 pre-load ?   In the neighborhood of .556, without valve reliefs  ?     That is nuts...  WHACK !   

[ace.cafe]

  It's just crazy... run a lighter valve spring and a shorter rod and make more power.  Those springs have to be brutal.     I measured .364 lobe lift on those cams.    At 1.28 rocker ratio... that's what I usually see.  And it's a safer number.   That puts valve lift at .465.   Add to that up to .090 pre-load ?   In the neighborhood of .556, without valve reliefs  ?     That is nuts...  WHACK !   

I don't know what springs they are supplying with that kit. Whatever they are, the advised installation methods don't seem to align with things I am familiar with.

Our springs go 252 lbs at .500" lift. They seem to control the valve train fine at the rpms and ramp rates we use.

[gashousegorilla]

   No... me neither.   That is not how hydraulic's are set up , especially for performance IMHO.   And if the aim is, to do all you can do with spring pressure to prevent lifter pump ?   They are robbing power , and possibly excessive and unneeded stress, hammering the seats and valve train.  From what I have seen with those Cams , you'll float a valve at around 6000... with the stock springs.  With a .030 spring seat shim,  they were good up to 6500 as test , no problem.   Stock valve train and hydraulics with adjustable rods and a lite pre-load  on that bike.    On that bike ,  I re-tuned and reset the rev limiter at 6250  for a safety margin.   

  But as you know ... if one gets nuts with the throttle and is not paying attention and especially if they do not have a Tach on their bike like the 500's ?!  Knowing your piston to valve clearance  and adjusting your rod length and pre-load is a  MUST.  So if a valve floats a bit and a lifter pumps, nothing bad is going to happen. The lifter will just recycle and reset preload  when the RPM's drop.

  We have been using beehives with our cams.   Great spring design !   You can run a liter spring , keep better control of the valve train and put less stress on it.   Good to at least 6500  with Solids or Hydraulics.   I run around  90 at the seat and 190's open.   At a stock 1.28 ratio and .4736 total lift.   At still good at a ratio 1.5 with  .555 total lift.

[ace.cafe]

We also run Beehives at around 90 on the seat. All the Fireballs have them since the first one. Love them!