Power Tec 10 lifter Tec

hi david vizar here and you are watching power tac 10. give me a few minutes of your time and i'll give you the benefits of my 50 years of race winning experience and that's not just at national level that's international level so what's our subject today well it's going to be one that's going to affect most domestic built v8 engines and that is predominantly lifters which are hydraulically adjusted there's a lot of misconceptions going around about lifters and hydraulic ones in particular so now it's time to put you in the picture for real i have to say you're probably going to hear a lot of contradictions to some of the things that you'll see in this video my answer to this is i have tested so many cams that i probably be in the guinness world book of records on the number of pulls i've done on camshaft testing let me give you some relevant numbers here for about three years i was testing cams for harvey crane did about 8 000 meaningful tests or meaningful test pulls on the dyno on just small block chevy cams for kent cams in england i did honor several engines about 11 000 pools and designed them a range of best-selling cams so i'm not coming from a journalistic point of view here where i ask somebody else i'm coming here as somebody who is an accredited research engineer that's me you're getting this story with no middleman so trust me if there is a mistake it's mine but i'm more inclined to think that whoever contradicts this will be making the mistake but anyway that's open from conjecture so let's get on with the story first let us look at why we have hydraulic lifters the reason we've got hydraulic lifters is to quiet the engine down big v8 engines can make big v8 valve train noise with solid lifters and detroit was hell-bent on having the luxury aspect of owning a detroit built engine that is it had to be good on performance and run very quietly so the hydraulic lifter came into being just because of that solid lifters because of the lash in the valve train tend to make quite a bit of a clatter the hydraulic lifter has the intent of removing the clearances between the working components of a valve train now i want you to remember that bit because it's very important in what i'm about to say noise however wasn't the only criteria that detroit was concerned with the american public at large or in general were not too good at servicing their cars the service intervals were often overrun by quite a bit also if we're going back to the era when hydraulic lifters were introduced the oils weren't so good as they are now and that 3000 mile oil change was a damn good idea if you wanted to keep that engine running so durability of the valve frame was also a factor as performance enthusiasts we need to look at our hydraulic valve trains in terms of not just noise but reliability and performance and that's just what we'll get on to now let's make our first move cutting the distinction between a solid roller sorry a solid cam and a hydraulic cam what i've got here is a set of conventional solid lifters now that they don't look much different to a hydraulic one they're called solid because there is no motion of the plunger in the body also they're easy to to determine that they're solids because a good solid lifter will have a circlip in this groove in the top instead of just a cheapo wire grip right so when this takes up the lash that valve train's opening right now deflections or no so it can be noisy but it's a good performance item now let's have a look at a typical factory hydraulic cam right this might be too far away for you to see but it's just got a round wire clip in it and that's fine they don't come out very often unless you've beaten the valve train to death by running into valve float or valve train control issues now it doesn't take much to convert one of these factory hydraulic lifters into a performance lifter but we'll go into detail on that later let me tell you a little story about hydraulic rollers right when i was doing a lot of testing for crane they decided to introduce hydraulic lifter cams now at the time crane did not make the lifters they simply acquired them from a well-known oe manufacturer well here's the deal these hydraulic rollers now i need to emphasize that rollers the early ones had a propensity for collapsing the factories using them as the the oe stuff they weren't testing them at rpm that you and i as performance enthusiasts are likely to turn our motors to but even so at about 4 500 rpm they could start to lose lift by virtue of the fact that the roller lifter was collapsing now you might ask does this happen to a flat tappet lifter no if we look at the geometries involved a flat tappet lifter has very minimal side loading all the loading is in the direction of the plunger i say all of it there's a small component due to friction on the flat face but compared with other loads it is very small so we might as well say it's inconsequential now with a hydraulic roller lifter we get side load if you look at my how to build horsepower book you'll see there's a diagram and it shows a cam profile coming around and it puts a side load on the lifter which distorts the body and under these conditions the lifter leaks far more than you'd expect it to what happens the lifter collapses now things have got better but they didn't get better overnight a few years ago i was running with a friend of mine a late model stalker and when we were on the dyno one of the things i noticed were and it was a sealed engine deal one of the things i noticed when on the dyno was that the power seemed to drop off very quickly at about 55 5600 and i suspected lifter collapse so since we couldn't get into the engine we had to cure it from the outside how do we do that well i had this idea and it came in the form of a simple phrase long chain polymers right so what happened here is amongst my group of die-hard racers one of them knew an oil scientist up in canada so we called this guy and had him brew us some various oils with different amounts of long chain polymers in now a long chain polymer it vastly reduces the amount of leakage you can have in a lifter the downside is is too many or too much of the long chain polymer stuff is going to cause the viscosity of the oil to increase result viscosity induced power reduction becomes very noticeable at high rpm so we had to find a happy medium between leakage in the lifters and viscous drag now now here's an irony for you i'm just going to back step here i called the manufacturer of the lifters right and it's not it's not gm they buy their lifters out and i spoke to one of the engineers responsible for designing this and i said is can you advise us anything we can do to prevent lifter collapse on your lifters and he said to me what lifter collapse and i said well when you get to about 57 5800 they start to collapse oh well we never go that high so i said you've never experienced on your spintron or test data any lifter collapse no and i thought there's a fine bunch of engineers for you but but i'm being critical here now this was before the long chain polymer idea so anyway we finally after testing a bunch of different mixes we finally settled on an oil that had us the right balance between viscous drag and lifters and the amount of horsepower that we picked up over a well-known and very well-respected race oil was 14 horsepower that is a lifter which is not collapsing let's go on with another story here right and you'll you'll understand the severity of the situation with roller lifters at least when they were first introduced and i'm dwelling on this now because roller lifters are such a popular um type of lifter to go with and hydraulic lifters are really ruling the roost here so the first lifters that came out were so bad that rather than have a hydraulic roll track roller valve train i would opt to have a street roller type deal which is a solid but quiet ramp street roller and and this is where i got my experience using some of comp cams street rollers and i was well pleased with how low the noise level was not quite a hydraulic intensity but certainly close to it now so how bad were the rollers the hydraulic rollers well here's the story i just built a very stout big block and i have this friend of mine who was a engine builder and he built engines for off-road racing and i believe he won the um big off-road race they have in baja the baja 500 and the thousand at least once so he's an experienced race engine builder however just because you're a race engine builder doesn't actually qualify you or doesn't necessarily qualify you as an all-round race as an all-round engine builder right and so i said to him well here's the proposition he came to me with he would do all the work on the engine any parts i could get that for him uh for test purposes and publicity that would be good but if not he would buy them now the idea was is that he would do all the engine building in my shop with this engine so that i could go on working on my engine whilst just over the other side the shop he worked on his so i was getting the work done on two engines to do two articles instead of one great twice the output of editorial material but still only about 1.1 times the amount of work now he insisted on having a hydraulic roller and i said now you won't like it he says look that's what i want and i said okay i tell you what i will call and see what i can do for cans well i called comp and they were gracious enough to let me have a hydraulic roller for this guy's engine build right and just so that i had a backup when this cam failed not because it's a bad design of profile bad lifter i could still get a story because i was going to put comps solid street rollers right now this guy chose a cam he wanted about 280 degrees of duration right the cam i picked i believe was 264 degrees of advertised duration at 15 000 so it was quite a bit shorter not as much as it sounds in there because it takes the lash up before that 15 so the reality is it was about eight degrees shorter well we dynoed the engine on this guy's hydraulic cam and i said well what do you think and yeah yeah it's okay and i said no you're not really happy about it are you well no i guess not i'm just right so we swapped over his cam which by the way i specked out he just chose a hydraulic roller and we put my solid roller which i spectate so how much difference do you think there'd be in horsepower and torque i know you'll find this hard to believe but it was a solid 105 foot pounds and 120 horsepower if you think you can afford to throw that away because you want a quiet valve train then you can't really qualify as a performance enthusiast now fortunately we don't have to put up with that trash these days hydraulic rollers have become very effective thank goodness let's put a break on these the storytelling for a moment and look at some of the details on flat tapping cams well first off flat tappet cams aren't flat they've actually got about a hundred a hundred inch radius on the face of the lifter and this combined with a heart about a thousandth taper across the profile causes the lifter to spin in the bores now if it doesn't spin that is absolute sure fire move toward lifter destruction as well as cam in most cases now the uh thought that these lifters actually rub one on the other at the speed the cam's going out is kind of um misleading because the lifter rotates the velocity between the surface of the cam and the lifter itself is a lot less than it would be if the lifter didn't rotate and the cam was in the middle if you look at the profile you'll see it's offset one side now um let's look at another aspect back in the early days there was something that a lot of racers suffered with called lifter pump up now you might think well that's obviously a lifter problem well actually isn't this is one of the most misunderstood things there is the fact of the matter is that the lifter is doing exactly what it should do and that is take up excess lash in the valve train so if we go into valve bounce or we lose control of the valve train because of spring surge and it opens up gaps what happens is the lifter pumps itself up to take up that lash or that unwanted clearance well the lifter doesn't know it's unwanted its job is to take up excess clearance and it did just that now some smart alec in the camp business and i know this gentleman well came up with the notion that he was going to market anti-pump uplifters which is exactly what he did and do you know what an anti-pump up lifter does it leaks down so fast that it can't pump the system up or in most instances it can't then well that's not what we want if your engine is experiencing what we call lifter pump up it is not the lifter at fault it is the spring that's being used springs go into surge or they go into valve float or they surge and then float now spring surge well i'll tell you what we should do here go and watch my video on springs it's going to go across the bottom of the screen here the the site for it and you'll understand better what spring surge is and how to get rid of it so that's the first thing now then if your valve train is suffering from collapse that's a lifter problem you might have too much spring usually it's a combination of both spring too much spring and an inadequate lifter the key here is to use no more uh valve spring than is necessary to get the job done so let's take a quick look at that i'm not going to go into too much detail here because i went into a lot of detail on on the spring video but here is roughly what i want to talk about first off you don't need to pay an arm and a leg for a spring you just need to know what springs work and what don't and when i say don't there's a lot of springs in out on the market which they'll work but they're mediocre right you may pay more than you need to to get that performance now if you want a cheap upgrade on your chevy ford or chrysler erson has a very good single spring as do pack again it's in my spring video but here's what i mean by buying the right spring for the job now this is a pretty good spring here it's exactly the same specification in terms of stiffness preload on the seat and over the nose load as this one this spring here weighs in at 150 gram 145 grams this spring here which will do a better job is only 132. this spring here is almost equal to running titanium lifters this will perform as well with the steel retainer as this one does with titanium retainer now you're better off with buying a spring like this again for details go to my spring video it goes into a lot of detail there now here's something that we can consider for our hydraulic valve trains first off let's look at spring rate we don't need a spring any stiffer than about 300 to 330 pounds for a flat tapping hydraulic cam and we don't really need anything stiffer than between 320 and 350 for a hydraulic roller that's a spring spec that will turn some pretty decent rpm now the up-and-coming spring for hydraulic roller camshafts is this beehive spring there's a version made by several companies the ones i use are by made by pack or comp cams comp has a new one out of this under the same part number it's magic this here is a spring of the future note that is conical this is where we're going in the future a lot of spring in terms of performance but unfortunately still quite a bit of money you want a big block beehive spring this one from comp will get the job done big blocks by the way with the flat tappet cams can be a problem it's a heavy valve train it has a one seven lifter on it so it puts even more load on that camshaft and lifter so you need to be particularly careful about the spring you select it's not just an expensive spring it needs to be a spring that's efficient that is it gets the job done with the least poundage what else can we talk about here well here's something i'm dying to tell you about let's talk about zinc

Channel: David Vizard Performance

Views: 5,833

Rating: 5 out of 5

Keywords: Wondershare Filmora9

Id: Jl4vjIrwZzE

Length: 24min 17sec (1457 seconds)

Published: Mon Dec 14 2020