Anyone else?

The point I was trying to make earlier is to do with vibration or frequency of vibration. If you drop a ball bearing on a steel plate it bounces. Strike two hammers together and they spring apart. Weld a big flat bastard file to a old flywheel or a bit of thick plate and film it with a high speed camera when it hits the ground, it will flick and bend like a fishing rod. If you tried to bend it that far it would be close to snapping. Some metal parts will make shapes like a guitar string vibrating. Everything vibrates, we just don't see it happening if it is not in our range of vision. A couple of classics are, one of the Holden tailshafts, which if kept at 120 or 140 kph will start to try and shake the car apart. Another is a bench grinder, when it starts up and stops it goes through vibration periods, that is why something that seems well balanced will shake the bench as it goes through these vibration frequencies that have nothing to do with it being balanced. If you've ever been in a shearing shed when the grinder used for grinding the combs and cutters is slowing down it will shake the shed if the mounts are in some way connected and you will hear it over 100m away, this is a balanced machine. Keep that picture in your mind of metal things vibrate at speeds which you cannot see, you usually just get to see or hear the effects of them doing it. Which was the reason for suggesting a high speed camera, then it would be possible to see if it was lofting, bouncing or something else. If things didn't vibrate you wouldn't be able to hear anyone speak, in some cases that would be an advantage.

Take a spring, if there was anything which was designed to vibrate it would be near the top of the list, somewhere near the guitar strings. The old fashioned way of trying to cure valve bounce was to use multiple springs of noticeably different rates so that there was one or more springs that were not in a vibration period at the same time. The solution was to make a spring of a varying diameter and spring rate so that no two parts would be in the same period at once. Then one spring can do the job of two or three springs with reduced spring pressure, wear and tear on the valve train. We have a spring, a valve, some metal parts all in a row, being impacted at 50 times a second near the rev limiter. Any play in the system is going to cause a party to happen at some point, multiple points more likely as each bit of metal tries to bounce off the other ones. Back to the first line again if your trying to picture what the valve is trying to do, the spring is trying to do and the pushrod and the lifter are trying to do all at once. If you dropped a valve on the floor, does it stay there, no it bounces. The thought of what the cam is getting at one end is not pretty as it is the one fixed thing in the system if there is any free play in it. Makes an overhead cam look really good in comparison, much less weight to push back and forward, a lot less harmonics to deal with. Sure if you spend enough you can make a Harley rev, but is it worth it?

How to cure what is going on, one option might be to adjust the lifters as per the instructions and then they will take play out of the system and also reduce the stress on the system with the dampening effect of the oil. No cam information supplied, so will assume that the cam is made to run with hydraulic lifters. Then cam manufacturer would then have made the cam profile to allow for the hydraulic lifters being used, hydraulic lifters are already factored into the profile. Is there any evidence that running a Twin cam (assuming that it is a twin cam as not stated either) with as little clearance as possible in the valve train can actually show an increase in the power output ?  Nothing to show it does from what I've seen so far. If your trying to get the valve to do something different, why not use a different cam that gets the valve to do what your trying to achieve and set the lifters as reccommended, everything might be happier in there. Was there something about instructions still being in the packet unopened.

Anyone else used the limiters and how did it go as its not looking good so far. Thats the problem with the net, one problem and every one hears about it, something goes right and not much gets heard.

Captain, as  you are aware the function of a Hydraulic lifter is to maintain as close as possible to zero valve train lash.

I'm absolutely positive that the function of a hydraulic lifter has very little effect on valve train harmonics.

As you mention, the spring would have the most effect, the very small amount of damping available in the lifter would be hard to measure.
Pushrod flex would have a more dramatic effect.

Solid lifters can be a good choice for the simple reason that they offer the best valvetrain control at high rpm, and suffer no problems with lifter fill, bleed rates or pump-up. But they will require constant adjustment, and that's where they fall down in a production vehicle.

I'm not sure if have taken into account that when setting a lifter near the bottom of it's travel when using a limiter, the lifter is still running within the designed adjustment
window, and when the engine warms up and the valve train clearance grows, the lifter will pump up to compensate.
What do we now have ?.................... A functioning hydraulic lifter.

Hoody has stated most of this in his earlier post.

This thread is deteriorating. The guys who make the lifters probably thought of that, after the first few hundred thousand units, that would have been well covered, if they are making or designing the cams as well it would have been well covered too. If the pushrods start to flex far enough to effect the valve lift, it might not be working anymore. Its interesting that all the S&S lifters are not fitted with the limiters, only one set is, and there were a couple of performance ones listed from the quick look I had the other day from the main page. A lot of their stuff is available if you have the right part number but not shown on the website unfortunately.

I tried to think of another example to try and make it clearer and the only thing that comes to mind is the toys that people used to have on their office desk, with about 5 ball bearings hanging from bits of string, Pull the end one out and let it go, they bang backwards and forwards for a while. The same thing in slow motion. As for the valve spring, a camera is about the only way I can think of to catch it in the act of dancing, or trying to slip a bit of paper under it with the motor running. If the bit of paper can be pushed under the spring, it has started to bounce away from the head and is not perporming its function properly anymore. Using heavier valve springs may not be fixing the problem. I haven't looked on Youtube for an example as there is so much junk on it and I see it the same way as I see facebook. Remember the old stereo type of going to someone's slide night of their holiday pictures, getting bored to death = facebook and much of the web. Most of the action stuff seems to be from kids who's biggest source of excitement has been a Nintendo or someone who doesn't get out much. Real useful content is nearly always missing. Was going to put a suggestion about something else to put on there but, sense of humor is unknown.

The original post was about how loud the valve train was, just tried to filled in a few blank spaces. Hoody had some good stuff, most of which is not new to me, but I don't agree with all of it.

Back to work...

edit in, look up; "Vibration, sheet metal hit at 1000 frames per second"

another edit in, went web searching; google search "valve spring float movie"   First one that comes up shows a valve spring going through a vibration period, not the best video to watch but it shows it really well, after going through the vibration period it goes on to higher revs working fine, it looks like they change the movie speed a bit which does not help. Can't see what the rest of the valve train is doing either. About the third video is one of a 14,000 RPM BMW bike engine, not the best video either as the the camera speed is not matched to the revs of the motor very well, so its hard to see if its going through any vibration periods other than possibly the speed of the spring rotation. Would show what the cams are doing as well if the camera speed was better matched up, notice the spring type/construction that they have used to get to the rev limiter of 14,000 RPM. Neither of these movies had a tacho in there unfortunately. Getting bored and distracted, must be time to knock off and go home.

Maybe I didn't explain what I meant very well. After thinking about it last night, the first little movie of the valve train with valve bounce, the guys said that they can cure the valve bounce with a heavier spring. If you went through a few springs that could be made to work. What is staring you in the face is that the spring only went into a vibration frequency at 6200 rpm, after that it worked fine. It would be a safe bet that the spring would continue working well untill the next vibration frequency. It might be 1 1/2 or twice the speed it would do exactly the same thing. Whatever it was, it would not take long to figure out a simple mathematical formula to predict exactly what rpm it would do it next. The trick with revs is to have a spring that is not going to have a speed where it will stop working and start dancing. if your after revs, higher spring pressure is not always the answer.

All I could think of is that sportsters have a similar pushrod system and some of the parts might swap as I think they get a few more revs than the twin cam, but don't know as I don't know anyone with one to check bits or revs with, never owned one. If I was wanting more revs out of my twinky (which I don't because of the huge costs involved), would be spending a few hours in a Buell parts catalogue or S&S buell parts or someone else who specialises in high performance Sportsters to see what bits or ideas could be borrowed from them for the valve train. Maybe spend a few hours reading at the NHRS website taking note of what they do, bound to be others out there who race their sportsters at the track or the drags.

Its off topic but I can't stop thinking that all that crankcase pressure from two big pistons coming down at once pressurising a tiny crankcase, robbing power from the engine could be put to good use if it was turned into a two stroke, they're not my thing but am sure it would work a treat. If it could be made to work it would make some serious power, the rest of the drive train and the bike wouldn't be able to cope with it.

Better get back to work or will still be here at 11 tonight again.

I could be completely wrong and your welcome to think that way, but I would be following the instructions.

The amount of expansion that the motor has as it gets hot is not simple. The top of the cylinder would be hot, the bottom would be closer to the oil temperature, the cases would be close to the oil temperature. The head would be hot but so would the whole valve train to the oil temperature, so every thing is expanding but only by the metals coefficient of expansion times by the difference in temperature + or -. The coefficients are tiny numbers and depend on the individual metal type. The exhaust valve would be one of the hottest bits and expand the most, reducing the clearance, not increasing it. Thinking that the whole valve train stays cool but only the cylinder expands would not be a good idea to follow when setting the lifter clearance. There are a lot of different pieces of different metal types between the cam and the valve going through the motor, or going through the valve train. Two different paths of expansion and not short paths either with the valve and seat at the far end on this vintage Harley system in an air cooled motor. The guys at S&S would have been through all this stuff until they were sick of it. By all means set your lifters how you want but I won't be doing it that way. If the threads are 32/inch, if 6 flats is one thread rotation the lifter will have 0.794 mm clearance, it might need that much space to work properly and do what its supposed to right through the rev range. If it doesn't collapse (and mine hasn't so far) then maybe everything is working as it should and how it was designed to. A lazy lifter will still get you home. Not seen a dyno graph or anything else proving its even worth reducing the clearance. Do what you want with your own motor. Nobody has even come close to convincing me that its worth doing, if anything I probably won't bother even putting the limiters in mine. They seem like a backup device in case a lifter gets lazy and isn't functioning properly.

My 2 cents, I'm done, back to work.

hi , name dyno , i have been building engines for these bikes for 6 years , i have  2 dynos , i spend a lot of time makeing changes to engine builds my own as test  benchs  , and re running them few hrs latter checking for percentages of improvement or losses or nill change , i have spent weeks playing with lifters depths , travel limiters ,settings  etc ,  hydraulic lifters are there for smooth running and reliability  at normal operating temps and  rpms , i have asked questions to manufactures about , what oil presure do they need to operate at ,what is best oil viscosity at 180 temp range  then if i increase  lift , what lobe profile what spring presures are they designed to handle , i dont get a answere , i did experiment at drag strip , set push rods to middle of plunger depth in lifter , ran bike at strip and it ran 11.20 down quater mile , reset lifters to 1/4 turn of bottom and bike ran 10.83  20 mins latter , i all ways adjust lifter to over bottom depth to let lifter  bleed out quickly while oil warm , then reset just of bottom , i have been doing this for years , hydraulic lifters set in centre will bleed down while rpm s 5500  thru each gear eventualy will bleed down causeing loses of cam lift and duration , hence , poor performance at end of strip , dureing normal rideing they will not exibit this ,i have found the s/s with limiters cover my needs best , engines do grow , alloy has growth rate 2.5 times of steel at same temp but the cast sleeve has almost minimal growth at  say same temps , it is a dead metal , i do work in metal trades , used to haveing materials heat treated , case hardened etc , the en series of alloy steels to 4140 h/t for shafts etc ,  engines i have been involved with for long time , but last 6 years doing my testing on my own bikes ,  you refer to that you havent seen a dyno graph show that it is worth doing , i have  imfo on that when doing all gears runs under load to show losses after 7 seconds of running , on normal dynjet 250 , a 100 rwhp bike may take in 4 th gear 6.5 secs to run , what the run wont show you is that sustained high rpm ,they will bleed down , then what you wont here is the damage of excess clearance will do or allow lifter to pump up and maybe piston touch valve , recently i have few bad manufatured lifters in sets , , my own car eng builds for performance aplications are solid roller for accurate constant control , any way , there are setting for general use of rideing , and if chaseing bit more , then these are some options to help keep gains ,these are things that i have found in this area ,  cheers guys

Thanks for the info Dyno, cheers