Let's talk camshafts

[chiplee]

Boy you're right Shelby. There's a lot of great info here.  I'm really only posting so I start getting notices of new posts in this thread but here's something I still wonder about after reading all this.  What do we really know about the performance of the currently available cam profiles if we don't dial them in.  Am I the only one who just laid my cam in the head and lined up the little roll pin and bolted it up?  I don't know? here are some directions for installing a cam from Crow cams.  Do you guys do this?

 

(1) Find top dead centre on the number 1 cylinder using a dial indicator. Mark this position with a pointer mounted on the flywheel or bolt to the front of the crankshaft.

(2) After setting the dial indicator to zero on the back of the cam inlet lobe, rotate the crank until the pointer indicates the piston has reached top dead centre.

(3) Read off the figure on the dial indicator and compare it to the figure shown for inlet lobe lift at T.D.C. on the cam data card supplied with the new cam. The figure shown on the cam data is a minimum and may be up to .005" more. Advance the camshaft to increase the lift at TDC retard the cam to decrease the lift.

 

Also I feel like what happens to typical engines when you increase duration seems desirable for our engine.  In dyno charts like this one

http://store5.yimg.com/I/supra_1708_20034511

you see that as the cam duration increases the power curve basically just slides to the right, effectively increasing HP without really increasing torque.  I for one, want that.  I want to make torque longer to get the big HP number. and have an engine that gets more work done over time and gets me down the track faster.  I'll be the guy that sticks with the schneider 292 for now for comparison and we'll see how all this comes along (especially since they made me a new one for free).  I think we're addressing all the important issues that have gone pretty much undiscussed over the years so this is good.   Please tell me what's wrong with my thinking, I'm out to learn not to say who's right or wrong.

 

 

 

 

http://store5.yimg.com/I/supra_1708_20034511

[Boosted_One]

The profiles on the cams need to be seperated as Tim is doing.

 

When I spoke to my machinist he did say Schneider makes good cams, but he thought it was odd the profiles are the same on both sides. He said less open time with the exhaust valve in his opinion because the cam has too much overlap allowing boost to go out the exhaust. On the other hand he did say without the cam timed he could not say for certain. BUT by the looks of the cam profiles of my 284F he did make comment as above.

 

I am not a cam Scientist but there are several knowledgable people I have asked info from and it all points the same way, less duration and split profiles. I thought about it quite a bit and I understand where Tim is going with his cam(s).

 

I think Tim is on to something big guys.  ;D

[chiplee]

I hope so.

 

 

I can't find a split profile turbo cam anywhere.  The HKS supra cams are the same intake and exhaust.  The RPW turbo cams the same in. and ex., Schneider cams are the same.  I just would have thought someone would have gotten "on to it" sooner if it's needed.  Again I hate to sound negative about it.  I hope he is indeed onto something and I know the split profile isn't the only trick he's using to tweak this cam.  From what I've seen though, this would be ground breaking stuff for ALL turbo engines not just ours.  Someone tell me it's common in several kinds of turbo applications to have split profile cams so I can shut up.

[Boosted_One]

http://www.holley.com/HiOctn/ProdLine/Prod...ECC/Buick1.html

 

http://www.grapeaperacing.com/GrapeApeRaci...h/turbocams.cfm

 

just a little bit of info.

[mikec]

Any of you guys ever hear of Jim Fueling?  He's got a really funky idea for a cam; he doesn't know why it works but he claims it helps a ton.  He's one of those guys doing the Bonneville type speed records and was hired by Oldsmobile a bit before the Quad 4 engine was made public... back when Olds was advertising "a new engine made in America that'll send the imports back to Japan."  Haha...  Anyway, Olds made two "Aerotech" cars: kinda like streamliner meets CanAm cars.  Both were powered by "modified" Quad 4 engines.  Jim was hired to build one of the 2 engines.  His "Quad 4" had the same bore centers as the GM engine; that was the ONLY thing common with the GM engine.  This 2.something liter 4 cylinder engine pounded out something like 800HP on 50 to 60psi boost (Jim is nuts by the way).  One of his tricks was his "special" cam, he's got patents on this thing he calls a "bump cam" or "pulse cam" - I forget which exactly.  Basically, on the valve closing side of the cam lobe, he puts a wart.  Something that knocks the valve open again as it's trying to close.  It works on either the intake or exhaust valves but not on both at the same time... he doesn't know why it works, nor why it won't work on both valve sets simultaineously.  I found this in Automobile magazine or something like that; it was many many years ago.

 

I've met his test crew at the Southern California Timing Association (SCTA) lakebed runs at El Mirage about 10 years ago; he was doing some stuff on a "stock bodied" car.  For this monster, he had a Cutlass Calais with a modified Quad 4 - a real one this time.  And a turbo darn near as big wedged in there.  I'd guess the compressor housing was around 12 inches across (!).  This car had a pulse cam on the exhaust and it made serious HP as well, and seemed to have a decently wide RPM band from the way it accelerated.  It was also REALLY LOUD.  If you've never been to a lakebed event, let me summarize: guys get push-starts from pickups or whatever and just accelerate in a straight line for a few miles.  Eventually they zip through traps where their speed (hopefully top speed) is measured.  Then they repeat the exercise going the other way and the speeds are averaged - to cancel out wind effects in theory.  Well, when most cars start up, 5 or so miles from the traps (where I was) you can hear them if you listen... then you hear an increasing roar as they approach.  Kinda like a jet fighter.  When Fueling's car starts, everybody turns and wonders "what?..." since it's so much louder - it sounds like he's a few hundred feet away, not 5 miles.

 

See if Google can find anything on this guy or his cams.  Or find stuff on the Olds Aerotech.  You guys might get some info on turbo sizes, cam setups, whatever that let these engines pound out race level HP on 4 cylinders with big boost.

 

mike c.

 

that Calais by the way: in a later event, it turned 200+mph one way, then on the return leg the front lifted slightly... enough that the front wheels lost traction and the RPMs skyrocketed.  Tranny grenaded.  Engine survived.

[importwarrior]

correct me if im wrong, but

judging by this paragraph below, it sounds like a little overlap of the exhaust valve helps the turbo keep spooling, with escaping turbo intake pressure, out the overlaping exhaust valve helps the turbo,spool,

 

i also get that we definatly have too small of a exhaust shell on stock turbo's

 

it also stated in there that less back pressure the better, so it sounds like 3 inch is the better way to go,

 

http://www.grapeaperacing.com/GrapeApeRaci...h/turbocams.cfm

 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~``

 

If you have a well matched turbo for the engine and application, it is a different deal altogether. A well matched turbine housing on the turbo will usually work well with cams with a lobe separation in the 112-114° area. If there is more pressure in the intake than in the exhaust, a camshaft suited for superchargers or nitrous will usually works well. When the exhaust backpressure is lower than the intake, reversion is not a problem, actually just the opposite is a problem. More pressure in the intake can blow fresh intake charge right out the exhaust valve. This can be a serious problem with a turbo motor since the charge will burn in the exhaust raising temperatures of the exhaust valves and turbo. This is also a problem with superchargers, which is why supercharger cam profiles usually work well with turbo's. In this type situation, the power required to turn the turbine is nearly 100% recovered energy that would have normally been dumped out the tailpipe, basically free power. Many will argue that nothing is free and you need pressure to spin the turbine and this must make pumping losses. They are wrong because a turbo is not getting anything for free at all, it is just making the engine more efficient. It is true that there are pumping losses, but on the other hand there are pumping gains as well. If the exhaust back pressure is lower than the intake, the intake pressure makes more force on the intake stroke to help push the piston down. At the same time another piston is on it's exhaust stroke. So the intake pressure is more than canceling out the exhaust pressure. Not free, just more effecient.

[TainterRacing]

Well the I order my cam for my car/Drag car should be fun.... it was well some what of a #4 cam But I chnaged a few things... well I all most got the Drive train done... Hope to get it on the dyno and see how it does yet this winter...

[Rusky]

Wow, just started reading these cam threads.  So much info, so little time.  Thanks once again to Tim C. and the other moderators for all their hard work, time, effort, and of course mullah.

 

I too value Tim C.'s info and advice and look forward to seeing a solid roller cam for our cars.  

 

Tim's specs are exactly what I am looking for in a cam.

 

Thanks again.

 

Russ

[Boosted_One]

My machinist says Tims cam is definetely going the right way. Says it will be a better cam with less duration, less overlap and split profiles.

 

My machinist word means a lot to me.

[Sarc]

It looks like Crane Cams is starting to/has picked up on some of the general ideas you guys have been talking about.

 

On this page check out the correction:"Stage 3, #14" cam. It has what Crane is calling "Features our unique "split duration" lobe profile design (exhaust duration is less than intake duration)"

 

"Unique" huh...

 

Too bad they don't make anything for our 2.6's.

[Grey_Wulf]

wow!  so much info.  I'm just a know-nothing kid from the midwest trying to stay outa the big boys way here but i saw something a while back that might help.  I was reading all of the is thread and when i got to a longer post about "split duration" cams I remembered a while back in a Ricer Magazine that i had seen a 1000hp Skyline with totally different intake and exaust cam specs.  I went and found this mag and looked it up.  It's the Hirata Engineering R33 Skyline GTR.  It has custom cams with a 291-degree intake and a 308-degree exaust.  this is the backwards of everything i've read here so far.  I'm not trying to throw a wrench into the gears here but what now?

[Tim_C.]

wow!  so much info.  I'm just a know-nothing kid from the midwest trying to stay outa the big boys way here but i saw something a while back that might help.  I was reading all of the is thread and when i got to a longer post about "split duration" cams I remembered a while back in a Ricer Magazine that i had seen a 1000hp Skyline with totally different intake and exaust cam specs.  I went and found this mag and looked it up.  It's the Hirata Engineering R33 Skyline GTR.  It has custom cams with a 291-degree intake and a 308-degree exaust.  this is the backwards of everything i've read here so far.  I'm not trying to throw a wrench into the gears here but what now?

Well, it depends on when the valve opens and closes too. What they are doing is running a very large amount of boost to need a set up like that. They are wasting some spool-up since their RPM range is so much higher than ours. Those engines can go to 8500 stock. Ours is more like 6500 stock w/o balance shafts. With big boost, on a big turbo, and a hi-rpm engine, there is a need to get the exhaust out faster, thus the huge exhaust duration. What that does is throw out any usable power under 4000RPM. We can't afford to do that on these engines. A better way to accomplish that is to go with a bigger exhaust valve. Then it does more work with the same cam. I recommend that for anyone running a big turbo (T3/T4 or 20G & bigger). The bigger duration will always raise the RPM range some, and we really need to get things happening faster than that.

It also makes it hard to do with a factory regrind cam. Getting a big duration means reducing the base circle more, so I am opting not to do it because we don't need it to get a lot of performance out of our engines. So, a new billet cam is needed for big duration, and that increases cost more than what most of us want to pay. Also, the bigger duration cams will tend to freak out the computer, especially if the lobe separation is wide too, which most big duration cams are. You would need an aftermarket computer.

We can go big duration cams and get good results, but the other mods needed is a long list that is carefully matched to each other. Then you will still have more lag that means you need more top end RPM capability to keep a good usable power range. A 292+ duration cam will not come on until after 3200RPM, no matter what your other mods are. More like 3500. That reduces your power band a good 1000 RPM. You really need at least a 3500 RPM band to work with, so the engine keeps pulling after shifting. The bigger the band, the faster, and longer it will stay in it.

That's just been my experience, subject for debate with other people's experiences.

[Mark_T]

Tim

Do you see any problem with using the grind you are testing in a 3 Lt V6 with a blow thew carb set up like George used on his 2.6.  I am not looking for the fastes car anymore my racing days are over , but I do like a car to respond when ask to.

Have fun

Mark T

[Tim_C.]

Well, That one is over my head right now. I wouldn't be the one to ask. My cam research experience is really somewhat limited. I've been in on several SBC cam projects, and my own 2.6 L ones. The other stuff I know is from the guys in the local car clubs, and guys at the track, and what they say, which is many times flawed somewhat.

The blow-thru forced induction thing has always had me scratching my head, and I have never thought much about the principle. All I know is that George has some very impressive numbers with his. 25 PSI boost!, etc..... My friend with a blown Monte Carlo, and his dad (60+ yrs working on cars), both are not familiar with the blow-thru concept. They don't see how the carb will do what you want, unless the blower is under it? I told them about George, and they admit, they are not familiar enough to know how that is accomplished. We haven't put our brains in that direction.

However, forced is forced, but now we are talking V6, and DOHC (4 cams), or SOHC? Anyway, it is more of the same philosophy I would think. But, that does open up quite a few more variables, and possibilities with them. I think my grinder has cams for v6 turbos, so I could try and get some info from him. He's hard to talk to for long though. He always has the machine going, and the phone beeps every couple of minutes!

Your experience is more than mine it seems. You have a few more years at this, and are one who makes his living in the auto industry, so you probably know more than what I can tell you?

[Mark_T]

I have 3 single cam engines and like what I have seen inside them they really look like a race engine.   As far as the blow through method of turbocharging.  there are two ways 1 blow the turboed air through a monified carb, The float bowls , throtle shafts  and other parts of the carb are modified to handle the pressure  and the carb is rejetted.  2  or you car put the carb in an air tight box and presurize the box ,  no need to modifie the carb.  But the box has to be farlly large to make it work right.  With this set up you elimanate the computer control, so I beleive that to make it safe a knock sensor hooked up to a combanation buzzer and lite display are very inportant, along with waterinjection.  to reduce the chance of detonation th out haveing to dump a lot of fuel into the engine.

What I am looking for in a cam is a lot of low end torque so the power is coming on with out havin to rev the engine .

One of the big advantages to a V6 is it is easier to keep the carb under the hood.

Have fun

Mark T

[fasteddy]

I'm not running the same road as you guys (turbo montero), because my brick will never turn good #'s in the quarter, but have any of you ever run the Magna roller cam on the turbo 2.6? Results? It's the only stock 2.6 cam I've ever seen with different specs than the stock Starion cam.

[Tim_C.]

No, I sure haven't. I didn't know the Magna came with a roller cam?

[Jozel]

Tim your thread would enable everyone to have a degree! ;D

Really great know hows!!! ;D Anyway w/c intrigued me to a point I had pretty much did some mods for my car I can call it modest but not in the NIRVANA state as Chiplee's Frank's Mike K's etc. I have to make a big decision and a conclusion now that I've absorbed all this valuable info to, make it short so you and or anyone can decide w/c cam is best for my engine I have a quick spec:

 

Forced Performance 18g ported turbo,Modified 1G Mas on K&N Filter Open Airbox , Jet Valves Removed, Balance Shaft Eliminated, Extrudehoned intake matched 52mm to TB, Cartech BCFR, MSD 6A Ignition ,BlasterSS Coil, Magnecor KV85 Wires ,HKS Elbow,BOV ,EVC PRO,Greddy Strut bar,Hayden Flexfan and Auxilliary Fan,Eibach/Tokico combos,ACT Extreme clutch/Fidanza Flywheel combo,TEP OVC Pipe and Shelby 2.0 IC Steel Pipes ,3 wire02 sensor on 2.5 TEP downpipe and HKS Hiper 120 mm. exhaust muffler,Schneider 284 cam,No a/c, cruise,Bain short shifter

3 inch exhaust/headers coming sooon!!!

 

This is just engine and drivetrain mods...to help anyone tails,. so my question is I don't honestly know if my cam has benefitted from it unless I reinstall my stock cam,...and I am using hydraulics,.. again I never knew that solid cam have higher lift w/c I cannot afford right now to change it, so I have to work with my baseline here and what would be the best cam for my setup? I also have the HD springs w/c I have not yet installed so I cannot differentiate it should I do that first before returning to my stock cam, or use a different cam? ???

The only thing I noticed is that my Vacuum guage registered at -15 w/c normally is -22 on stock cams..I think?? and then they said it's normal..I hope...

I noticed a lot of improvement regarding power band on my car but maybe because

of all the mods I made but I cannot pinpoint what the cam benefitted.

Thanks for listening guys,

Joe

[fasteddy]

TR Magna had Astron3 with roller rockers, larger combustion chamber (looks same size in pics, but who knows), bigger valves (in pics, exhaust looks bigger and intake same size), better cooling, per a set of shop manuals I got from an Aussie friend. Cam was different on specs than any other 2.6 cam I've ever seen. Every 2.6 I've ever read specs on gave the cam timing as 25-59-64-20. The TR Magna is 25-61-66-20. I think stock 2.6 vavle lengths were intake 107.96 -exh 105.86, and TR magna is the same - both use 102 link timing chains, and both have the same valve installed height of 40.40mm (+ 1mm).

 

You've obviously done a ton of cam research. What are you thoughts on using the Astron3 Magna cam with what should be steeper ramps with the roller rockers on a 8.2:1 turbo motor running a 14G? I'll probably be using a Magna manifold with either SDS or Megasquirt, and low end torque is my main goal, with a 5500rpm redline. Would like to see 300ftlbs of torque - hp is almost immaterial due to low redline with the long stroke motor.

[Tim_C.]

Jozel: The Schneider 284 is a decent cam, but it is also hard to keep passing emissions with, and they made the grind generic to save money.IMHO They widened the lobe separation to help with spool, but left the INT & EXH lobes the same. It really isn't the prefered way to grind a Turbo cam for just about any application, be it race, street, or both. It will certainly give more power than stock.

My roller cam requires roller rockers. So, you would need them. I do have a performance hydraulic grind for hydraulic sip rockers. However, the Schneider 284 will give a tad bit more power than it does. Mine will pass emissions much easier, and it will spool the turbo faster. The mid-range is a little less.

My roller cam will outperform the Schneider 284 hands down. I have not compared dyno runs or anything, just my opinion. The advantages of the roller lobe can't be beat.

 

 

fasteddy: I really don't know about the Magna cam. Was it a turbo engine? If not, then it for sure won't be what you want. If so, then it will still be too small for a performance application. The OEM's have their hands tied when it comes to something that affects smoothness adversely. They just can't sell cars that shake, so they don't put performing cams in them. The difference you see in the opening & closing specs are to accomodate the slower acting roller contact patch compared to the faster acting slipper. I doubt very seriously that the stock Magna cam is very good?

Tim C.

[Jozel]

Tim, what would the price be for a roller cam complete with roller rockers and also for a hydraulic setup?,.. if I opt for the rollers can I still use the HD springs from Schneider and it should be bolt on right?

I have thought of that before when I saw it at MS recycling,..I think :-/  and yet I thought that it still on it's early stage of R&D

By the way what's IMHO if you don't mind me asking?

I also can't wait for the TEP IC I got from ebay,..I just had to sell my old laptop to afford it w/c is not bad for 515.00 new plus selling my stock IC for 150 to 175 from ebay

do you think I can help further the efficiency of my engine on top off all the mods I did? I'm really aiming for it to be free flowing as I can then head for the MPI setup.

Thanks for listening,

Joe

[Tim_C.]

IMHO=In My Humble Opinion

 

$225+ core = roller cam shipped.

$70 = NEW lifters

$140 = NEW roller rockers

$40 = Schneider HD Springs

_______

$575 if you go with new parts. I usually only supply the cam, but if you need me to get everything in a kit, then my kit would cost a little more than that, since I would have to ship everything to me, and then to you.

 

You can find used rockers fairly cheap(M&S has them). They will work fine with my shim set-up.

You can use used lifters, as long as they don't stick.

E-Mail me for the info sheet I have on the cams & set-up.

Yes, it will help most all engine performance mods to increase more.

The cam is a bolt-on. The springs can be replaced in a few hours (3 or so).

Much more cam than my roller, will need pistons flycut, and special length valves. That increases the cost dramatically.

Thanks,

Tim C.

[morganf]

I am in the process of installing a non jet valve caravan head on my conquest but the cam is a different size. has any one else run into this problem , and what are the differentces, I must go back to the junk yard for the right cam and don't want to get another incorrect one, is there a difference between nonjet and jet or caravan and conquest?

Thanks.

[fasteddy]

The caravan cam will fit if you cut off the rear "tail", or use the rubber donut seal for the caravan instead of the StarQuest rear plug, but with a pressurized engine, I'd cut off the tail (or have a machine shop do it for $15).

[pure_insanity]

guys, im wanting to change to a solid lift cam and rockers. my question is this, can i use the truck, n/a, cam and rockers. i do know that the heads will swap but what about the cams and rockers by themselves. also i know from past exp. with truck motors, the 2.6and 2.0 are vrtually the same engines, but does anyone know that the cams are the same. im highly inclined to believe so but im not sure.  according to my machinist, the early trucks used the same parts dor some years,79-83 2.0 and 2.6 had the same heads as mits. had built the bigger internals but not a head to match. in 84 they made the 2.6 head and it was different but i dont know how much. my machinist told me to use the 2.0 head on all the 2.6 blocks and it would give more power with increased resistance to cracking. so what do you guys think about all this, which cams and rockers from the truck engines will fit in my quest head . ive got several truck engines laying around and they are a dime a dozen in parts yards.