Don M

John,

Many Formula 1 and CART engines use a belt drive. I personally do not know of one engine that is now used in F1 that uses a set of gears. Take a look at the Mclaren V-6 used in the 80's, its belt drive. The TAG engine built for McLaren by Porsche used a belt drive as well. After the teams began to go to Mercedes, Honda, etc I lost track. I dont know what they run now. If it is gears I would be surprised. Several problems are apparent: first the weight of gears is high. The extra weight of gears is or could be a handicap. Second, the GMF is out of this world at 18-19000rpm (that is what the serious F1 engines turn now) GMF is gear meshing frequency made from the gear teeth meshing or banging together. These freq's can vibrate an engine valvetrain apart at 18,000rpm plus. We could still have the transmission of crankshaft vibrations to the camshaft too. Since many of the newer F1 engines are overhead cam I dont see them using gears at all. The distance from the crank to the cam is beginning to get pretty far away now. The gears would need to be pretty large. Belts absorb vibrations and many serious engine builders use them for this reason alone.

You may be correct that the newer Honda, Mercedes, etc engines use a set of gears, but it just does not make sense. Nearly every production engine from these manufacturers use a belt drive.

The nitromethane was an example only. Lets try the same scenerio in Pro-Stock. Remember, when the Aldermans were dominating the Pro Stocks a few years back? Noone could catch the Dodges. The other drivers were having fits. Spending tons of money to compete in races that were all being won by the Aldermans who were finally caught using nitrous. They had been cheating everyone for months. Not cool. So the terminology "cheater" fits them well.

Cummins felt extra strength was needed as the power was increased in the B series. The camshafts were increased in strength and the marine is the best one yet. Lets take the stock 12 valve 180HP engine with the weaker of the 12 valve cams and grind away some more material. Making it that much more weak, now lets go turn the power up to 500-600HP. You have effectively just lowered the tolerance to breakage of the camshaft by a large margin. I personally dont like the idea of an under engineered cam. Breakage can get expensive or even dangerous.

Flat tappets are not bad for the 4000-5000 rpms we would run. They dont cause the breakage at that rpm. Ours are very accurate and have very large base to keep them on the lobe. Another cool thing that Cummins did was surface harden the tappets. That was when Cummins decided to add the extra requirement for the oils they required to be used. I wonder if the surface hardening is being ground away with these re-ground lifters being offered with the Piers cam? Cummins was concerned with wear in this area enough to ask for a newer oil design so Im guesing only that the hardening is not deep. New lifters would be my axiom with all cam changes.

Could you give me some data on F1 engines that use a gear drive? Maybe they are composite materials or something. I honestly dont know, but from an engineering standpoint it sounds kinda backwards in technology.

One last thing I remembered was you stated that most cams were re-hardened after they are re-ground. Not so. The proper way to say that would be to say that most are NOT re-hardened. The overwhelming majority are not. They slap on a finish (phosphate or graphite)that helps the break in process and that is about it. Some re-grinders will/do, but not many.

Don~

banshee

Don,<br><br>After looking up quite a bit, it seems that the newest F1 motors are now running pneumatically actuated valves instead of running a standard valvetrain. The rpm limit is pushing on the 20k wall... good for 800+ hp out of 3 naturally aspirated liters. The V-6 engines you mentioned are a far cry from the motors used today. Those were turbocharged and turned much lower rpms. The only cutaway view I found of a CART motor indeed showed a set of cam gears, not a belt. I don't see a belt holding up to the force at those engine speeds. The weight of the valvetrain componets approaches tons instead of grams or ounces due to the accelerations. Also, belts are commonplace in modern production engines because of NVH concerns, and gears are just too noisy (not a problem on the cummins ).<br><br>I'm not at all arguing that nitrous adds power and can do it in a sneaky fashion, but it wouldn't do much good in a top fuel car. The cheater setups are quite popular on F-bodies, but the new trend is in a dual purpose fuel injector used for both fuel and nitrous that fits in the stock injector pot. I think it was Holley who introduced them a couple of months ago... pretty slick.<br><br>Can't say that one of these manufacturers (Piers or DD) are grinding what on the cams and lifters. I do know that most cams I have ever seen for sale have been hardened (especially by the big names... Comp &amp; Crane), but I also know that there are others that are not. I know you think that the flat tappet lifters are &quot;ok&quot;, but a roller would allow a much more agressive cam profile with faster ramp rates. IMO it is better to open &amp; close the valve as fast as possilbe (the newest XER lobes from Comp are perfect examples of this idea) and leave the valve at max lift as long as possible. Heck, the newest LS1/6 cams I have seen look more like a rounded square lobe than the traditional triangle <br><br>Basically, it's just my opinion that the combination of lifters (and thus rpm) combined with heavy valves, etc are not a good combo for high rpm use. But for us 3400rpm limited guys... i think it's a winner <br>

Don M

I called a few guys I know about this F1 stuff and found out that the valves on some of the newer engines are indeed actuated by nitrogen gas. Not all, but some. I also found out that 90% of CART engines use a belt drive system on their 10,000rpm engines. Followed by the Mclaren cars that use a chain drive. So, belts will and do work very well. Double overhead cams are pretty complex to drive from a set of gears. Think of all that vibration from that many gears. Think of the extra weight and balance problem you would have with the mes of gears rotating around up there. Those spur cut gears are nasty farm tractor stuff Man...too much vibration from that low tech hunk of iron. Thinking out loud here, but how much valve timing errors could/would occur with the lash required for spur cut gears in an 18,000rpm engine as the speed/load was changed? I just dont see it. Maybe some really trick composite helical cut stuff would work.

Here is a link some used CART engines for sale, they are nearly all belt driven. Yes the Cosworth V-6's are not the big screaming V-10's and 12's of Judd, Mercedes and Ferrari, but you mentioned CART earlier.

This one is a 2000 model:
http://www.race-cars.com/engsales/co...6/gaa-v6ss.htm

Here is another Cosworth with belt drive, this engine turns over 10,000rpm, you can clearly see the belt drive:
http://www.race-cars.com/engsales/co...1pa.htm#center

And finally, one more that uses a set of belts to drive all four camshafts on a quad overhead cam engine:
http://www.race-cars.com/engsales/co...6/gaa-v6pc.htm


A roller would be nice, but at the lifts we use in most applications just dont need them. Those big heavy roller lifters require an even larger valve spring to control them too.
Not sayning the idea is bad, its just beginning to get into the wallet a little further. Frictional losses enjoyed by the higher rpm gasser engines would not be found by a 3000rpm Cummins. Maybe we could see some gains at 4-4500 though.

I dont like our collets and retainers either, they are plain nasty farm tractor stuff that has no business on an engine that rotates at 4000rpm. The rockers are strong, but heavy, same goes for the push tubes. It could all use some upgrading.

I just weighed a pair of valves, intake and exhaust from a 12 valve. 112 and 114 grams. Pretty heavy for their size and the stem is not that big either.

Sorry you can only rev to 3400, that must be terrible.

Don~

Don M

I found a few more killer engines from infinity, etc.<br><br>http://www.race-cars.com/engsales/ot...1/irl991pb.htm<br><br>http://www.race-cars.com/engsales/ot...1/spiex1pa.htm<br><br>One more that was built for the McLaren M6B, it is a can am engine but still uses a belt drive. One cool thing is-it is a BB chevy. ;D<br><br>http://www.race-cars.com/engsales/ch...7/tra427ss.htm<br><br>Don~<br><br><br>

BigBlue

I know nitrous wouldn't be that cool on a top fueler. I just think it would be funny to see one running it. Even if it was just a single pass.<br> The 2000+ LS1's use the 6.0L truck cam. You can hear it in my dad's 02 vette. The idle is kinda choppy on the exhaust and you can feel the car kinda shake a little at the stop light. The LS6 a.k.a. Z06 uses a specially ground cam for just it. Could be wrong about the LS6 but I know I'm right about the LS1 (may be 01 up though).<br> The Holley system you are talking about banshee utilizes a nozzle attached to the tip of the injector. It squirts both fuel and nitrous directly into the cylinder. That way, on a wet kit, you don't have fuel puddling in the intake and a nitrous backfire or something. They are extremely expensive though. Like $1500 or something. More than I'm willing to pay. I'll just hook mine up the traditional way and be done with it. Besides, as long as you start spraying at 3000+ rpms, you don't have to worry about fuel puddling. It is a pretty slick setup (till you see all of the lines you have to run), but for the money they want, it is easier to hide the nozzle you get with the kit and it is a lot cheaper and easier to wire in.

nascar mark

You know very well that the cam grind is on the back side of the lobe which doesn't weaken the cam for breakage. If the cam is going to break its going to be between the lobes were there is much less meat. Most likely beside the #2 journal. Grinding on either cam would result in the same material removed give or take a few thou and result in both losing some of there heat treatment. Which won't shorten the usable life of either. No big deal.

As for the reason Cart cars are not using many gear drives is $$$$$$ only. Cart has mandated that the cost of parts be closer to stock so the low budget teams can stay in the game.
Nascar is doing the same as things were getting out of hand with custom heads,light weight gears etc. Heads were starting to cost teams $40,000 apair. F1 doesn't have a $$$$$ mandate on parts.

mark

Don M

If you begin with two cams and one already has a higher lift and longer duration than the other, which one will have more material removed from the base circle to get the same lift?

Answer: the cam with the smaller lobes to begin with i.e. the stock or standard Dodge/Cummins cam.

If your not grinding away much material on the stock cam, then the benifit is so small it makes it almost not worth doing anyway, IMO. You cant have it both ways. Grinding away a bunch of material will throw the valvetrain geometry off and not enough will not do much for performance.

It does not make sound engineering sense to run a set of vibrating gears on mid to high rpm engine. Bottom line. Belts cure this and so do chains to a lesser extent. I have diagram of a gear drive system here for a daul overhead cam engine. It is nasty and belongs on a tractor or low speed diesel engine only. Not a CART, NASCAR, NHRA, etc engine at all.
mark, some of those engines I showed in the thread are INDY engines, are they budget limited too

Look guys, I like Piers. I buy a ton of stuff from him. Probably more than most guys. When anything in life comes up I try and look at it with total objectivity. I leave my emotions at the doorstep and base a decision on facts. Not on who or what the guy is. Friend or Foe, I try and get to the bottom line of what is good and what is not. I dont like the idea of using re-ground lifters in an expensive engine. I dont like the idea of using a stock camshaft as the base to build more power and expect more from in terms of durability and longevity. It has nothing to do with Piers or his business. Nothing. He has been good to me and if I was to ask his opinion of something I would expect his real and honest answer as well.


Here is a dual overhead cam slow speed diesel. Everyone look at this mess and tell me it will all hold together at 10-18000rpm. Not in my opinion. It is heavy too. Not good for a car that is composed of mostly composites to be as light as possible.

nascar mark

Don, Nobody is doubting you like Piers or his products. We all know he didn't just fall off a turnip truck and then started selling parts and service.<br>The marine cam is a lousy street/race cam in stock form. Anyone that has tried it will tell you this. So you can't tell me DD didn't do its fare share of grinding on it to make it streetable which in your own words would throw off the valve train geometry big time to make it streetable. Thats part of the reason DD had to regrind so many cams to get it right. No! Not just alittle bit on lift and duration. If their enginering was even half decent they could have forseen this. This proves to me the marine cam blank is not the right blank to start with in the first place. The stock cam is already a good street/race cam but needed alittle help to make it better.<br><br>Not trying to make waves just trying to enlighten people to the fact that they don't need to spend more money for something that does the same job and compare apples to apples.<br>Don, You have alot of good information and are very helpful so no sweat if we don't see eye to eye.<br><br>mark

Don M

Mark, <br><br>The first DD cams were born from the ideas of other cam grinders. Guys that were supposed to know what the heck they are doing. It was joke to say the least. They have tried many different grinds and have been coming back to a few real good ones. They dynoed the heck out of their cams until they were happy with what they had. <br><br>Most others have installed the marine cam and had bad results because they failed to get it set up correctly. I know of one fella that did get it right and picked up HP.<br><br>You would rather run a stock cam with a press on gear and made from weaker material? ??? <br><br><br>I fail to see how DD's engineering is half way decent. They provide the strongest cam you can buy without going to billet steel. They have already gone to HP levels that exceed what Piers and others have done. They provide some of the best products you can get your hands on as well. <br>What could be considered half way is using old lifters that are reground in an expensive engine. These lifters do get a wear pattern on the sides of them ,not just the base. The base is the only part that is reground because you cant remove any more material from the sides or they would be too loose in their bores. IMO, the best way to go about building a durable high performance engine is to use at least as good a component as you had in it to begin with. <br>Piers cam does not do the same job if it is inherently weaker than the DD cam does it? The marine cam provides a margin of safety and durability over the stocker, it just cost more money to do stuff right. <br><br>We may not see eye to eye on this, but chances are we do on others. <br><br>In the end noone will change their minds. Most guys stand behind who they like or live in the same region with. Its natural. <br><br>Don~<br><br><br><br>

Sled Puller

I have bought parts all over the country, some have worked well, others have not.<br><br>I did learn a lesson though.<br><br>&quot;Engineering&quot; parts on a dyno vs pounding them at the track are two different things.<br><br>X hp on the dyno does not mean squat for durability.<br><br>Dyno tuning is fine, build your best, and THEN go pound that sucker 3 nights a week for several months.<br><br>I have ridden with Piers, he drives like a moron. If anything was going to break, he will break it. That is what I want to hear, I beat this truck for a year, new part &quot;go fast&quot; held, they work, now I am ready to sell them.<br><br>It does not really matter anyway, because anyone using a DD cam or Piers cam is not going to be into cam breaking rpm, they are not for that.

banshee

Well put Gene

BigBlue

What I'm seeing in the argument for the gear drives is about vibrations at high rpms. Well, unless the vibrations are unimaginably strong, then at 4000 or so rpm, they ain't that big of a deal on our engines. Got a buddy with a 400 small block bored out to a 409. 11.0:1 compression, sick cam (don't know specs but close to .600 lift with an extreme amount of duration and LSA), gear driven. It makes about 500 to the wheels. He spins that thing to 6500 without a single bit of vibration and the thing keeps on pulling. You don't even realize it's that high until you look at the tach. It is extremely smooth. He is also solid mechanical roller. No problems with vibrations or anything.<br> He did twist and bend two forged and shot peened rods and just bend another rod, but hey. I guess that's what you get for spinning it to 6500 rpm with 0 miles on the engine. He occasionally hits 7000.<br> My point is this (and I could be completely off), that if he can spin his engine that high with a gear drive and solid roller without any vibrations, then I think we can spin ours to 4000 without worry. Granted, our engines vibrate a little more than his. So this post might not have anything to do with vibrations and all but I thought that I might just share that little bit of info.

Don M

[quote author=Sled Puller link=board=7;threadid=5607;start=45#53481 date=1034770475]<br>I have bought parts all over the country, some have worked well, others have not.<br><br>I did learn a lesson though.<br><br>&quot;Engineering&quot; parts on a dyno vs pounding them at the track are two different things.<br><br>X hp on the dyno does not mean squat for durability.<br><br>Dyno tuning is fine, build your best, and THEN go pound that sucker 3 nights a week for several months.<br><br>I have ridden with Piers, he drives like a moron. If anything was going to break, he will break it. That is what I want to hear, I beat this truck for a year, new part &quot;go fast&quot; held, they work, now I am ready to sell them.<br><br>It does not really matter anyway, because anyone using a DD cam or Piers cam is not going to be into cam breaking rpm, they are not for that.<br>[/quote]<br><br>Funny you said that. I know of a fella that spun the front gear off a stock cam on a dyno runa t 2800rpm. It must have been enough of a load to do it. It roached some parts as well.<br>So much for that theory. NO the cam did not break, but that chessy gear twisted off. YUK. <br><br>Big Blue,<br><br>Gear drives transfer vibrations. How much depends on a million variables. Do you or your friend know what breaks rods? Inertia does in 99% of cases. Tensile stress is the highest at TDC on the exhaust stroke. The rod is being stretched from the weight of the piston being stopped at a sudden speed and being jerked back down toward BDC. Tensile or stretching force is the most dangerous. Do you want to guess as to why the exhaust stroke does this? <br>Lets look at an example of piston speed real fast:<br><br>Small block chevy with a 3.48&quot; stroke at 6000rpm has a piston speed of 3480 feet per minute.<br><br>Our Cummins with the a 4.72&quot; stroke and at 4000rpm has piston speed of 3147 feet per minute.<br><br>Do you see the problem here? Which one has the most force acting on the wrist pin? Hint: the smal block with an 8 ounce piston has nearly 2000lbs of force at 6000rpm.<br>Any guess what our stock piston weighs? <br><br>Do you think that crappy valve timing caused by vibrations acting on the springs could break a connecting rod? The answer is as a resounding yes. Do you know what undamped harmonics can do to springs that are vibrating and shaking? It does effect their ability to open and shut valves with accuracy. It can cause mucho problems. You cannot hear over 90% of valve float that occurs either. It can be watched on engine and chassis dynoes though. <br><br>High compression engines do not break connecting rods. The forces on the compression and power stroke are all compressive. Compressing the rod is not very detrimental to its longevity. <br><br>You guys are not gonna run any cam I tell you to anyway. I said earlier that Im not going to change any minds here. <br>Im just making some suggestions and throwing my two cents in the pot. <br><br>Don~<br><br>If anyone gives crap the formula for piston is:<br><br>Stroke length x rpm/6. <br>

TxDieselKid

Here is the sitution. DD offers a cam that is marketed as, &quot;The Best&quot;. Piers offers a cam that is marketed as, &quot;The Best&quot;. Now look at the play and, &quot;YOU MAKE THE CALL!&quot; <br><br>DD cam: Made of a harder materal. <br>Piers cam: Same cam that came on the truck.<br>DD cam: Press on gear<br>Piers cam: Same method that came on our truck<br>DD cam: comes with new tappets<br>Piers cam: comes with new tappets<br>DD cam: $1500 - over the counter, not installed<br>Piers cam: Less then $700 - over the counter, not installed<br><br>Think about it, and after this break, wwe'll comeback, and show you the right call.<br><br>______________________________<br>Hel lo friends. Do you suffer from a weak engine? Then come on down to Landmark Chevy, for a ride in the ALL NEW, Duramax diesel. It's so quiet that you'll swear it is a gas engine. And not to mention that it has all the latest styleing cues, as seen in the sports cars from Europe. So head on out to day, and get a free &quot;If it's too loud, it aint a duramax Tee-shirt&quot;.<br>_______________________________<br ><br>Welcome back to &quot;YOU MAKE THE CALL!&quot; Now rememebr the sitution, here it is again.<br><br>DD cam: Made of a harder materal. <br>Piers cam: Same cam that came on the truck.<br>DD cam: Press on gear<br>Piers cam: Same method that came on our truck<br>DD cam: comes with new tappets<br>Piers cam: comes with new tappets<br>DD cam: $1500 - over the counter, not installed<br>Piers cam: Less then $700 - over the counter, not installed<br><br>The correct call is, NONE!!!! That's right, it really boils down to who you want to give your money to. If you think DD deservies it, then call them, and start writing the check. If you think Piers is the man for the job, then call him up, and get your Visa/Mastercard ready. Both cams are ment to do the same thing; faster spool up, less egt's, and less smoke. So who do you want to give your money too? I would like to give mine to Dave Mitchell! ;D ;D ;D<br><br>Andrew<br><br>P.S. Sorry if this is a dumb post, but this thread is kinda comical to me in the first place. I view this debate as those old &quot;You make the call&quot; baseball commericals on TV during games. Boy do I miss being that young. 8)

Don M

Piers cam does not come with new lifters. They are re-ground.<br>Not new. He takes your old lifters and regrinds them.<br><br>Don~<br>