Maximum lift of custom cams on stock valves/retainers.

[fredio54]

I just measured the movement limits of the inlet and exhaust valves, and this is what i found :

the maximum movement till the stem seal is hit by the retainer is 11mm on the exhaust side, and 11.5 on the inlet side. at these lifts there is room for 19.75mm of spring on the exhaust side, and 20.75 on the inlet. that means that with the vr6 springs which would be needed for a lumpy cam, the lift is limited by spring binding to about 10.75 on the exhaust side.

to exceed these figures, longer valves and thinner solid lifters would be needed. these amounts of lift should be ok for up to around 220hp NA anyway, so only those who are crazy (and require no bottom end) will need more.

my measuring was done with the same dodgy s/s ruler that i measured the springs with, so once again, not entirely accurate(worse this time due to limited visibility). if you are seriously getting cams made measure it again yourself more accurately and tell me and i'll edit this, and give you credit.

for dutch (and other NA fans) enjoy,

Fred.

[steveod]

So with 11mm and 11.5 available at valve max and the stanard lift of 9 .17mm this doesn,t leave us with much to play with.has anyone ever tried a regrind on the standard cams for say an extra 1mm and more duration,if so how much can be removed off the base circle before we run out of lifter and can we get away with the standard ecu with a mildly uprated cam (or have I missed a post somewhere)

[DRAG323]

The hla don't take more .040 or 1.0 mm if you regrind the base circle
of the cam.

The max duration when you regrind a cam is: 262
Nose of the cam is more round
the lift stay the same: .354

Eric

[fredio54]

stock lift is more like what dutch said 8.855 or so, not 9.17, but thats splitting hairs... what eric says sounds plausible in terms of using the stock cams. eric : did you mean starting with 3n or 5a? surely the 5deg difference or something vaguely proportional will still exist afterwards?

given the rate of decreasing returns of flow when adding lift, there isnt a huge amount to be had by going larger without bigger valves. you pretty much never want to exceed 1/3 of the diameter of the valve head anyway.

moral of the story, it doesnt take much extra lift to make good NA power, but it probably will take custom made cams rather than regrinds.

kiwi626 : what specs did your perf guy say the cams in the NA motor he built were?

fred.

[fredio54]

here are numbers which illustrate what i was saying about lift and flow. very manifold dependent. you'd want ITBs on a serious NA fe3 anyway though...

http://forum.miata.net/cgi-bin/ultim...=1;t=014474;p=

i may bother to graph these numbers for a visual representation of a good place to stop with lift. if getting a custom cam made, you could go higher in lift with the extra duration without infuencing float. then again, youd likely be getting bigger valves for it anyway and thus could get longer stemmed ones to allow extra lift.

fred.

[veltpak6]

why not just larger diameter valves - simulate more lift, without the excessive lift. Much safer and rpm friendly imo. You'll want RPM's in an NA engine if you wanna generate Horsepower. But going NA on an FE3 is like going NA on a Supra 2JZ... it just doesnt make sense!

[fredio54]

it makes a lot of sense in a mx5, and i know someone with a 2jz with vvt and it makes a lot of sense too. it depends on your application. my ute weighs 1600kg unladen, and needs to pull from 1200rpm : supercharger! a lighter ute, without f-in heavy hydraulic tipper would be fine turboed. i also like to have consistent throttle control, so big turbos will always be out for me.

with regard to the bigger valves thing, lets do the math :-)

its all about curtain area. 33mm intake 9mm lift stock for arguments sake.

33/2 times PI = 51.8362788 from my favourite calculator.

times 9 = 466.526509 sq mm

change lift by 1mm and you get 518.362788

change valve head by 1mm and you get 480.663676

i know that this isnt the whole story, but to pick up more flow by going bigger in a valve you also have to increase the port diameter in the bowl, and get a valve job(that you would be getting anyway) or you will LOSE flow,whereas to get more lift with the custom cams that you are already getting made with more duration takes a few quick words to the manufacturer, and stiffer springs/stronger valves.

this isnt about cost/return, its about what people want, and how they should get it. dutch is doing it. good on him. if i had a light vehicle, i'd jump in headfirst too.

have a good day.

Fred.

[veltpak6]

change both and what do you get? we can calculate area all day long and it still is hardly comprehensive to the application. this isnt water flowing at 5gpm, and the flow of gas is hardly laminar. this isnt about looking smart either. why dont you calculate inertial forces on the valvetrain with extremely wild cams, the type of spring pressures needed to acheive 7500-8500rpm safely, the type of mass reductions to the entire valve train? I mention the FE not being the wisest choice for N/A power due to its design. Cast iron block, beefy, heavy rods, heavy iron crank. I mean, if you wanna change everything in side it, sure go for it... but thats not what makes the FE shine IMO. There are a ton of other engines out there better suited for n/a rpms but then again this is venturing into personal preference. FE doesnt have VVT. I guess you've already considered your intake manifold plenum volume and runner length/diameter with your proposed cam profile

[fredio54]

In something that resembles your order :

534.070751

To use the word comprehensive in an incomprehensible way, a work of genius.

Gasses have the ability to flow in a laminar state to a far higher velocity than liquids in general. certainly air out flows water every time. Futhermore almost all forms of flow start off laminar and at some velocity break point become turbulent.

Definitely not about looking smart, if it were, i would capitalise my is, and check my spelling more often.

we could indeed get heavily into the maths behind valve physics, hell, we could rig up a testing device consisting of an fe3 head with no block and an electic motor to spin it up. however i posted this here as a source of information for others, not to discuss what cams and springs and lifters to use while reaching a lift of X.

the design of the fe motor is not well suited to high rpm, with a single camshaft, and either 8 or 12 rockers, they cough and weeze by 5k. the fe-dohc on the other hand has the perfect design for revving hard, and producing NA power. the direct acuation cam over lifter over valve is the best possible choice for revving hard, the springs used in our motor are very soft because they can be, thus with only moderate seat pressure(well below a 2v per cyl design) a lot of revs can be achieved.

i'd really like to hear exactly how the material the block is made of or how heavy the crank is effects an engines chances of revving hard... perhaps you could send me a pm to explain those ideas, and keep it the hell out of this one.

may i ask what you think honda and 4age and motorcycle crankshafts are made of?
how light do you think they are?

the weight of these small engines cranks is determined by there smaller stroke, smaller bore spacing, and smaller journals. the weight of the pistons etc doesnt even come into this at all (we arent talking about v6s or v8s).
i wonder what the weight of an h22/23 crank is? they rev pretty hard...

the rods on the other hand face a dificult challenge, to be strong enough to handle those revs, whilst being light enough to not flog big ends faster than you can say "why does my sr20 make that knocking sound", and also to be more smooth, and absorb less power by there reciprocating motion.

inside to make big power, changes that are needed are as follows : rod bolts(min)/rods(max) pistons, cams springs, maybe lifters, maybe valves, but neither of those last two are strictly necessecary.

Its all very well to have personal preferences as to which engine is "well suited" to NA, however it wont help you when you decide to put a 4age in your mx6 will it? this is the engine that has the most potential for rpm that fits into the cars that all of you love(or at least have) thus if one wants to not have a turbo for one of many possible reasons, then who are you to say that they should stay stock or buy a honda?

who said that the fe3 does have vvt? either way, its just another method to have your cake and eat it to, if you are serious about high rpm torque, then you already know that you aint going to have a bottom end, vvt or no vvt.

you would be a complete shmuck to put a plenum on a high reving heavily cammed engine. ITBs with short runners are the only way. i drive an engine like this everyday and damn it sounds good at the end of its torque curve at 7600 or so. it especially sounds good just before the speed cut at 190 in fourth :-)

the point here is, if the thread is about discussing maximum possible lift on the fe3 with stock valve gear, to quote john cleese "what is the bloody point" in saying you could do x y or z else instead. start a new thread entitled "use bigger valves OR more wild cams?"

please stay on topic.

Fred.

[veltpak6]

I'll tell you one thing; youre taking this far more seriously than I. By FE, it's obvious I'm speaking of the FE-DOHC... not figuring that out? a work of genius in and of itself. Anyhoo... tell me how heavy rods and crankshaft, heavy hydraulic lifters and valve retainers make this engine suitable for N/A RPMs (you remember, your NA powahz is going to have to come from excessively high RPMs... right?? of course!) So yea, consider the rods and most of the valvetrain completely replaced, and you might want to consider a longer rod, with a shorter piston. If I were doing this, i would be aiming for a good 8500/9000rpm redline. Stock IM is NOT going to support that, hell the ports will have a hard time feeding the cylinders at that rate. Have you seen a smalldisplacement HONDA port lately? After that, you might just want to knife edge, lighten and balance the FE (dohc sohc tohc) crankshaft. What a waste that massive rod journal diameter is going to be, considering the low (read: yawn) crankpin forces you'll be generating. Wow, suddenly those giant journals just amount to unnessecary rotating mass. Considering you dont change the rod length, and lighten/shorten the piston, the existing 1.75:1 rod stroke ratio is pretty nice. Gives a decent balance of piston dwell and TDC accleration which will help midrange breathing (provided it's matched with a suitable intake manifold). But again, youre going NA, so it would probably be prudent to lengthen and lighten that rod and shorten that piston, inturn increasing your R/S ratio which will help reduce the angular thrust of the piston into the cylinder wall and increase TDC dwell to make efficient use of the power stroke at extreeeeeeme high RPM, yo. The H23 crank, I can nearly guarantee you, is lighter than the FE3 crank (have u seen the counterweights on it?) albeit, yes it "revs hard" to a whole whopping 7000rpm (oOooO!!) and that thing has an absolutely retarded rod/stroke ratio of 1.45:1... FRM cylinder wall lining, short skirt, lightweight pistons and A BALANCE SHAFT seem to help it get there to its astounding 160hp *yawn*. The torque is nothing to scream about either, despite its long stroke and r/s ratio. (must be that the piston out acclerates the combustion flame front close to redline.. thats smRt) ok so H23 is a bad example. No wonder Honda shortened the stroke, increased rod length and increased bore size with the higher-na-powered H22. So to sum it all up, unnessecary rotating and reciprocating mass on high RPM NA engine = BAD. Have fun porting to support your wild cams, make sure your valves can return to the seat without destroying something (see point#1), . 'Laminar flow does occur in situations with fluids of greater viscosity' and yes air is teh very low viscosity, especially travelling in a round tube to a very abrupt low frequency. Finally, you should be a bit more selective in who you are rude to, ya never know what they could end up knowing and finally the FE-DOHC fuggin rawks in forced induction applications

Good Luck, Peace!

[fredio54]

with regard to the fe - fe-dohc thing, i was just pointing out that other people in the future may be mislead by this ambiguous name calling. is the 3 on your keyboard really that hard to reach?

"tell me how heavy rods and crankshaft, heavy hydraulic lifters and valve retainers make this engine suitable for N/A RPMs"

please leave the crank off of this list, yes reciprocating mass is bad, however the only thing a heavy crank does is add more inertia to the engine, just like the flywheel bolted to the end. the lifters are likely fine to 8k or even a bit more with the stiffer springs(that dont fit properly), and have you weighed that retainer lately, compare that figure to the valve itself. not nearly as signifigant. as the valve is it? so we are left with the rods... with better bolts they will take 8k just fine, however if going further a lighter set of expensive titanium ones would be preferable.

9k or even 8.5k is just not necessary to make 200hp, only required if trying to make say 240odd... and thus the rods will do nicely. pistons probably should be changed, but even those would probably hold on ok at 8k.

arguing about intake manifolds is just not going to work for us, i keep saying "independent throttle bodies are the way to go" , and you keep saying "the std manifold wont be any good", these two statement boil down to the same thing.

knife edgeing isnt necessay at 8k either, it isnt even necessary at 9k. a better designed windage tray, and oil scraper would be just as effective.
i would be looking to balance the crank anyway, so theres no big deal there.

those giant journals arent just there for the power stroke you know, they have to contend with the acceleration at the bottom of the stroke just as much as at the top, now although the forces on the big end at tdc are partially balanced rod inertia vs. combustion pressure, at bdc things are not so rosey. they wont be wasted.

the rod ratio will be just fine the way it is. although improvement could be made, it isnt feasable to do it inside an fe-dohc block, it would be better to do it the hard way and use the f2 block if longer rods were a requirement. all that is required to do that is have the head drain holes welded over, and fittings installed in the side of each, and in the sump, or dry sump tank to take the oil in.

so in summary the bare minimum to get a good amount of power would be 275deg cams, stiffer valve springs, new pistons with 11:1 comp, a decent extractor system with tuned to rpm lenbgth runners, some mild porting, and ITBs hanging off of the side. 8k with this setup should yeild 200 hp, and keep a grin on the front of the drivers face.

once again, laminar flow is the default, it occurs all the time, all over the place, have you heard of a peak flow meter? you blow through it, and it measures... now what happens when you have some mucous in your throat? your potential flow rate falls through the floor. because turbulence sets in earlier, and regardless of how hard you blow, you cannot get it higher. have you ever seen a hydraulic jump? water (but not necessarily) travelling down a stream at a certain speed meets a corner, and when it does, turbulence breaks out, and at that instant, the water goes up vertically, and then moves more slowly and with lots of swirls at a much greater depth. quite something to see on a big scale. obviously in a cylinder head, the "stream" has a contained top, thus when turbulence does break out, the same flow rate isnt maintained, and airflow suffers. the entire object of porting is to put off that point of turbulence, by eliminating those sharp edges that start it occuring in the first place.

the lower the viscosity of the fluid(in this sense it includes gasses) you are studying the later the onset of turbulence will be. this has to do with the inter molecular forces in the outer layers of the flow.

i dont believe that i have been rude, just stating fact and opinion rather than vague statements about a perfectly suitable engine being no good for NA power. i agree that the fe3, and most other dohc direct actuation engines rock with forced induction, however fi is the easy option, and it also will rock when someone(probably dutch, hes serious enough) puts together a good package.

please dont polute this thread any more. once again, its about providing info on what is possible, and how to go about it, not about saying it shouldnt be done.

peace indeed.

Fred.

[veltpak6]

Good work dude, you'll be fine for 200hp. Couple things I didn't know you were aiming for; 200hp and indy throttles. Have Fun!

[Dutch]

anymore input on this??

im thinking about a lift 10 and 275 duration.
this after reading a lot on cams specs. im not really a mathematics guy...so calculation stuff isnt really my thing. i like to try and measure on a dyno (see the chip thread.)

ive spoken about 280-290 cams with another fe3 owner here.
also 256 with a lift of 9.5

i need input and i want it fast

[fredio54]

from those old numbers that i had forgotten i'd say 10mm is a good number on both sides to give a little bit of clearance. it would be wise to check the head you intend to run your cams in to see if it matches the one i measured.

the std. size for performance lift is 1/3 the diameter of the valve head, exceeding that is pointless, and comes with very rapidly diminishing returns.

with regard to the cam duration heres a guide to the 16v 4age

http://www.billzilla.org/4agmods.htm#160hp

160hp from that is same as 200 from the fe3, and having seen both side by side (small port 4age vs. fe3) they are very very similar in design (just smaller). eveything in here is probably true for the fe3 too, and at least very close.

good luck :-)

fred.

[cam22t]

Stock cam specs here .... http://www.mx6.com/forums/showthread.php?t=135223 (FE3N Inlet and exhaust cams Dial up.) In detail.