need a new cam

[v8ranger]

What do you all think of these cams?? What kind of idle and improvments would they be over what I have now???

http://www.summitracing.com/parts/EDL-2221/

http://www.summitracing.com/parts/FMS-M-6250-F303/

http://www.summitracing.com/parts/LUN-51026LUN/

http://www.summitracing.com/parts/TFS-51402000/ I think this one wont be any better than what I have now? But figured I would throw it out here. I am running 1.7 RR. How much lift can I get away with and still be safe with my setup???

[cgrey8]

http://www.summitracing.com/parts/EDL-2221/
This is an Edelbrock 2221 Performer RPM cam. Reading Edelbrock's specs for this, they say this cam is good from 1500-6500 on a 289 & 302. However its specs say a different story. The off-the-seat duration as well as the .050" duration are pretty wide. This cam does NOT suggest low RPM torque at all. The Edelbrock info also says this cam should NOT be used with 1.7RRs...only 1.6s. The reason is this cam has a performance oriented ramp ratio which would be exaggerated by 1.7s. Also, this cam lifts to .520" on both valves. 1.7s would push the lift to .552". You'd need to be sure your springs could handle BOTH the lift and faster ramp rate.

IMO, these details nix this as an option for you.


http://www.summitracing.com/parts/FMS-M-6250-F303/
This is the FMS F303. Being an FMS, it is going to have a lot of the same problems the E303 has mainly a stock-like ramp rate...again to work with stock valve springs although this cam has enough lift that most stock springs are going to be bound. So other than valve-float avoidance, I really don't know why they went with such a stock-like ramp rate. But ALL the FMS cams have stock ramp rates. The F303 is a wider duration than the E303, but has a wider LSA than the E303. One looses torque, the other gains it torque. The F303 is a higher lift than the E303 and the wider LSA are both improvements over the E303. The wider duration would make it lopey, but again the wider duration would also kill low RPM torque. The supercharger should make up for that but may cause you to waste more fuel shoving more unburned air/fuel out the exhaust during the overlap period. I don't know anybody that runs this cam. Although I expect it would serve you OK.

The one thing you have to be aware of with FMS cams is they aren't made with nearly the accuracy than other cams are. You should always degree your cam to make sure your lobes are aligning where the cam card says they should. If they aren't, then you need to know which way to degree it to get the cam timed where the cam card says it should be. That's where the degree wheel comes in. MOST of the time, Comp, Crane, and similar cams won't need adjustment. And if they do need adjustment, they only need 2° one way or another. I've heard stories from engine builders that FMS cams are notorious for needing more than that...and that the accuracy from cylinder-to-cylinder isn't that great either. I cannot say whether these claims are founded or not. But there does seem to be a general mistrust amongst engine builders when it comes to FMS cams. Take that for what it is worth.



http://www.summitracing.com/parts/LUN-51026LUN/
This is Lunati's version of the E303. With a few very minor differences, this is an E303 that has 4° advance "built-in". Advancing a cam is usually good for adding torque, at the expense of top-end RPM. The more it is advanced, the affect is exaggerated. The jump from being installed straight-up to 2° may barely be noticeable. Going to 4° will be much more noticeable. Going to 6° will be VERY noticeable, but will also quickly kill high RPM performance. 4° is probably about right for and E303 to regain some torque that the E303 looses due to duration. So if I had to choose between this cam or an E303, it'd be down to which is cheaper...assuming you have a timing chain kit that allows you to advance/retard a cam you can make either cam behave VERY close to the other. If your E303 wasn't advanced when it was installed before, a 4° advance may be just what you want to get some low end torque. The biggest problem with this cam is the price.

On a sidenote, the Crane Powermax 2040 is Crane's replica of the E303.




http://www.summitracing.com/parts/TFS-51402000/
This is the Trick Flow Stage 1 cam I was mentioning earlier. It is TFS's version of the E303, but with "upgrades". And you are right, the performance difference between your E303 and this cam wouldn't be huge. But it would be an improvement. IMO, this cam would improve over the E303 in both performance and lower RPM torque. It has a smaller off-the-seat duration and wider LSA. Both are low RPM torque builders. It has wider .050" duration and lift that will help your high RPMs a tad. And it's only $180 from Summit...the cheapest of all the cams you linked to.

___________

For your intentions with this truck, any of these cams would fit the bill I think. It's just a matter of which you choose. This is my assessment on each. One thing I will say. If you weren't boosted, I would be recommending milder cams to you...cams that would serve better in the low RPM and fuel economy area. But that can be dangerous with a boosted application. Milder cams will increase your Dynamic Compression Ratio by "locking in" more air in the compression chamber. With lower compression NA engines, this is almost always a performance increase in the "street" rev range. However with a boosted application, you could over-boost the engine and cause detonation where you didn't have detonation before at the same RPM/Load/boost conditions. As you know, detonation on a boosted application is a great way to crack piston rings, pit pistons, and blow head gaskets. So without knowing more specifics about your build, I'm very hesitant to recommend something milder than the E303. But if I had to, that'd be the Comp XE264HR12 or XE264HR14. The only difference in the two is the LSA. The HR14 has 114 LSA which would give you slightly better low RPM torque. Either of these are normally great middle-of-the-road street cams for 302s.

[v8ranger]

Thank you cgrey8 for all the great info. Im thinking I will go with the trick flow one then. Now I was trying to look up valve springs, but didnt have much luck. Then I remember, crap, I cant look them up for a 1990 mustang gt. The heads are GT-40. What is your thought on valve springs? When I looked them up, they where $300-$400... So Im not looking something up right. I cant believe the springs would be more than the cam. So should I look up springs for a 97 Explorer/Mountaineer??

What about these springs? http://www.summitracing.com/parts/TFS-51400413/

[cgrey8]

Email this guy with what you have:
arkhighroller@sbcglobal.net

He sells spring packages on eBay under the name Alex's Parts. I bought my GT40p spring package from him customized with exactly the spring retainers I wanted made for GT40p's valves for $100 shipped. See what he can do for you. He really knows his stuff. He'll know exactly what you need. But before you do that, get a pic of your springs and retainers. It'll be obvious if you are using stock retainers or aftermarket retainers. If you are using aftermarket equipment, you shouldn't have a problem reusing them given its similarity with the E303. If they are stock, talk to this guy about what you would be best using. You'll get the best price from him than you will anywhere else.

[v8ranger]

Is the idle on that stage 1 cam about the same as the E-303, ruffer or smoother??

[cgrey8]

It's going to be in the same realm as the E303 although just looking at the specs, I suspect the idle will be slightly smoother with this cam. I don't know that for sure, but that would be my guess. Doing a detailed differential of the two cams, here are my comments:

• The off-the-seat duration of the TFS Stage 1 is less than the E303. This will have the effect of improving low RPM torque, slight improvement of idle, and possibly a slight improvement of fuel economy at the low RPMs.
• The .050" duration of the TFS Stage 1 is greater than the E303 which, combined with the the above note, means it has a faster ramp rate and holds the valve open wider, for longer. That will make the TFS Stage 1 flow better at higher RPMs. The E303 shouldn't have had any issues with this on aftermarket heads to start with. But on stock heads (I consider GT40 heads stock), the TFS Stage 1 would probably produce just a tad more power. The faster ramp rate is what requires stiffer springs.
• The TFS Stage 1 has higher lift, but only by a tiny amount .498"/.498" vs .499"/.510" (assuming 1.6RRs). With 1.7s, the numbers increase to E303's .529"/.529" vs TFS S1's .530"/.542". Even with 1.7s, I wouldn't expect any noticeable gains from this modest difference. Far more gains will come from the faster ramp rate than will come from the slightly higher lift.
• The TFS Stage 1 has an LSA of 112 vs the E303's 110. Wider LSA generally improves torque at lower RPMs.
• The TFS Stage 1 has a built-in advance of about 4°. Remember when I said people often install E303's with 4° advance to get better low RPM torque? TFS seemed to agree that this was a good idea, and built that advance into the TFS's grind. So when the TFS is installed straight-up (no advance/retard), you get the 4° advance automatically.

Like I said in every way, the TFS Stage 1 seems to be an upgrade from the E303. But all these differences, with the exception of the ramp rate, are fairly minor. Most people would call improved idle, while improving low RPM torque and not sacrificing high RPM HP an improvement all the way around. However it sounds like you view the slightly calmer idle as a downgrade.

[v8ranger]

What is your opinion on this cam? http://www.summitracing.com/parts/CCA-35-351-8/ is it better than the trick flow? I wish they would give more info on all there cams. Only some say what idle they have and if you need stall convertor, headers or any other after market stuff.....

[cgrey8]

This cam, a Comp XE270HR-14, is gravitating towards the conservative side, but only slightly. It has a higher LSA (114) than either the E303@110 and TFS@112. The wider LSA is usually good for improving vacuum and thus idle and off-idle torque. Although you can't say that with Comp cams. Comp widens their Extreme Energy (XE) cam selection by offering the same exact cam-grind in LSA of 112 and 114. So, I'm sure there's an XE270HR-12 version of that cam as well. Comp is also really good about granularity in duration as well particularly in the 260s and 270s, which is where 95% of street cams need to be. This offers the number-crunching engine builders off-the-shelf flexibility, and thus affordability, in cam selection without going with a custom grind to get exactly what they need.

To accurately place this cam relative to the others discussed, I should probably group the various cams into some kind of logical order so you can see the progression from mild-to-wild.

For my tastes and intentions for an engine, I always prefer lower RPM performance over high RPM scream just because low RPMs is where I spent the vast amount of my driving. I don't race (street or strip), so I'd rather have the umph in the RPM range that I use the most. So I gravitate more towards the truck/RV cams. The cam I have for my 331 build is a Crane Powermax 2020 (pn 444211). Comp's version of this cam is the XE258HR-12. Both have conservative durations, an LSA of 112, and big lift to help extend their effective RPM range higher than it otherwise would with a shorter lift. These two cams are examples of the most conservative you'd ever want to go on a 302 rollerblock. They generally have the smoothest and lowest RPM idle, get the best fuel economy, and the best responsiveness at typical street RPMs. They are strongest in the idle-4500 RPM range and continue to pull to 5000 RPMs, but are falling fast by 5500. The only other cams that I know of that are more conservative are the stock Explorer cam and some custom grinds. There may be other off-the-shelf options with similar characteristics, I just don't know about them. BTW, these are the cams that most budget-builds should be using, but are rarely chosen...same reason people put 750cfm carbs on 100% stock engines.

Now, the average engine builder is not as interested in being conservative. They build for moderate performance which means they are willing to sacrifice off-idle performance to get more umph at WOT. Although they still want idle quality, driveability, and some sentiments of fuel economy. For them, the Crane Powermax 2030 or the Comp XE264HR and XE266HR are a better fit. For those that stroke their engine, they can get away with an even more aggressive cam and get the same idle and driveability performance that the above cams give on a 302.

The XE268HR or this XE270HR would be an excellent street cam for a 331/347/351w. In a 302, it's about as high as you want to go without running a higher idle and loosing some off-idle thrill. These cams have no problem reving past 5500RPMs, but are usually done by 6000. With a supercharger helping things out, it will probably have no issues off-idle. It's certainly going to be a better performer than the E303 off-idle. The only concern I have with this cam is if it will introduce detonation with boost. I doubt you'll have any issues, but detonation is always a concern when toying with cams and boost, particularly when you go to a more conservative cam and you don't know what your engine specs are. However the XE270HR is not that much less duration than a TFS, so I doubt you'd have any issues with it that a twist of the dizzy wouldn't fix. However the price difference between it and a TFS Stage 1 is right around an addition $100 or so. Is it worth the difference in price? It wouldn't be to me. The only way I could justify the difference is if I was doing serious number-crunching to target a very specific Dynamic Compression Ratio (DCR) and the XE270 got me there and the TFS had the DCR just a tad too low for my target.

In the lineup of cams, the E303 and TFS Stage 1 are next. They are still classified as street cams, but they are for optimizing HP in an engine that isn't expected to have great off-idle torque or a steady (stock-like) idle. They generally require the idle RPMs be kept in the high 700s to 800s. Engines running one of these cams on the street benefit by being higher compression engine or boosted. They generally don't "kick-in" until about 2500RPMs so you'll have to size a torque converter and/or rear gears accordingly. IMO, these are the most aggressive you'd ever want to run in a daily driven 302.

The next level above these cams is the Comp XE274HR12 and XE276HR12. These are the big displacement engine's moderate-aggressive street cam. I can't remember which of these 87ranger runs in his 347 twin-turbo with AFR185s, but they are so similar, the average person probably couldn't tell one from the other. Off idle torque is not going to be a problem in that engine...in fact, this cam probably makes the engine more drivable/controllable by throttling it back at the off-idle and cruising RPMs. A 302 with one of these cams is either a weekend warrior or purpose-built strip engine. While I'm sure there are some people that do daily-drive these cams in a 302, I can't imagine them actually getting decent fuel economy unless they are also running ~11:1 static compression ratio.

The next level up are cams like the TFS Stage 2. Unless you are all-out racing, this is not a good fit for a 302. Can it be run? Sure. But I wouldn't want to drive back home with eggs in a 302 with this cam. Although this caliber of cam works well on the street in a 347 stroker, a 351w, or larger mid-to-high compression engine. In a larger displacement engine, a TFS Stage 2 performs about like a TFS Stage 1 in a 302. Adam McLaughlin just rebuilt his 351w with one of these cams. He'd run a poorly constructed high compression engine with a Comp XE258HR and then later a Crane Powermax 2020. In fact, the 2020 I have for my build is his old cam. He never took the time to size everything out right and maintain a tight quench. So the engine suffered from detonation most of its life. Add to that, California's highest octane pump gas is only 91 octane. His DCR was simply WAY too high. When he rebuilt the engine, he went to the opposite end of the spectrum with a cam...a TFS Stage 2 along with dished pistons. He's never been happier with the build. The more aggressive cam does keep his idle up high, even on a 351w, but he says otherwise the engine has decent enough off-idle torque and hauls tail like never before on regular 87 octane. He also smogs way below the California limits for HC/CO/NOx.

I will say though I personally would NOT have chosen the TFS Stage 2 for his build. He took the advice of his machinist, he's happy with the results, and I'm glad he is. But given the limiting components on his engine (stock 351 upper/lower & cast iron exhaust manifolds), I would've chosen a more conservative cam that will get him a lower idle-RPM and caters more to the limiting components he has on the engine. But it was his intention to be able to burn 87 octane and the TFS Stage 2 and dished pistons allow for that due to the DCR. Point being, installing a more aggressive cam in an existing build lowers Dynamic Compression Ratio (DCR). Likewise, installing a more conservative cam increases the DCR. Most of the time an increase in DCR is better for performance. But there is a limit. Tight quench can increase your engine's DCR threshold at the lower RPMs, but even the tightest of quenched engines will still butt-up against a DCR limit. Adam was way over that limit with his conservative cams and had to revisit the build to correct it. So just be careful which direction you go when making a cam selection when you don't know your engine's exact quench, compression, and capabilities.

So, does all that help?

[v8ranger]

How is the idle of that cam, is it best to use the stock 1.6 or am I ok with useing my 1.7rr?? would this cam be even a better upgrade from the Trick Flow?? I know I dont want to go with to much lift, but at the same time I would like to get more lift than the E cam.... Is the cam above still a good street cam with my setup?? Thanks for all your input... When it comes to cam's, I'm pretty lost at what all the numbers mean, I just know more lift is better, but to much for the wrong setup is bad. Thats about all I know... What numbers on a cam make up the idle they produce??

[cgrey8]

BTW, I just updated the above post. I submitted instead of previewed. I've made lots of edits to the post, so re-read over it and ask questions...

[cgrey8]

How is the idle of that cam,...

Without knowing the compression ratio of your engine now, that's difficult to say. Comparatively speaking, I would expect the XE270HR14 to have a smoother idle than the E303 though.

...is it best to use the stock 1.6 or am I ok with useing my 1.7rr??...

IMO, 1.7RRs are only to be used on stock and FMS cams. They benefit these cams by artificially increasing the ramp rate, .050" duration, and lift without actually swapping the cam out. They can be used on aftermarket cams, but they generally just complicate things more than help on aftermarket cams since most non-FMS aftermarket cams have more than plenty of ramp rate for 1.6RRs. If swapping to 1.6RRs is an option, that's an option I would recommend for sure. You may find you can keep your spring package and replace the 1.7s with 1.6s for about the same price. And unlike used spring packages, you can resell 1.7s relatively easily.

...would this cam be even a better upgrade from the Trick Flow??...

I don't know that upgrade is a good term. It's more conservative. To me, that's better. But without having all the details and facts about your engine, I can't say that with any confidence. What I can say is that quality/feature-wise, the TFS and this cam are comparable. They both have good lift and a fast ramp rate...both of which ARE upgrades as compared to the E303. The TFS has a wider duration and narrower LSA than the XE270HR-14...neither of which I call an upgrade or a downgrade, but rather I call more aggressive compared to the XE270HR.

...I know I dont want to go with to much lift, but at the same time I would like to get more lift than the E cam.... Is the cam above still a good street cam with my setup??...

Lift is always a good thing. The more you can get without binding the springs, the better. With the exception of running the valves into the piston, lift is rarely a bad thing. In fact, the only negative side to high lift is that you get more valve movement. Greater movement means more wear on the valvetrain and more chance of floating the valves. But if you are going to float at .550", you were probably going to float at .500" in just a few more RPMs anyway.

I wish I had more info about your engine such as head cc, gasket thickness, and piston deck height. With those pieces of info, I could give you a much more informed response as to which is "better" for your application. But you already have a conflicting intention which is a lopey idle with better off-idle torque. More aggressive will get you lope, but reduces off-idle torque. More conservative gets you more off-idle torque, but will also smooth the idle.

...What numbers on a cam make up the idle they produce??

There's no single number that does that. It's a combination of the intake duration and intake lobe centerline. At low RPMs, the lift has nothing to do with idle or performance. The benefits of lift aren't realized until you get into the higher RPMs. The duration and centerline are values that cam grinders use because these are specific specs to grind to. However specifically what affects idle is the intake close event. You get that value from both the duration and intake lobe center value. The quicker the valve closes, the less air the piston pushes back into the intake as the piston rises in the bore for the compression stroke. More aggressive cams delay closing the valve for much longer. At lower RPMs, this has the effect of shoving a LOT more air back into the intake...a condition called reversion. Cams do this because at higher RPMs, the air velocity and inertia is so great that the air traveling through the intake runners literally shoves more air into the cylinder even though the piston is rising in the bore. So the longer they can hold the valve open, the more air they can get into the cylinder. But the optimal RPM for max cylinder charge rises as the delay in valve-close rises. The side-effect is that at low RPMs, the air doesn't have nearly enough inertia and velocity to overcome the rising piston, so you get reversion, which is the piston shoving part of its cylinder charge back into the intake. This is what kills vacuum and requires that you keep the RPMs high at idle. Carbs need vacuum to atomize the fuel into the air. If you have cylinders shoving air back into the intake, that lowers the carb's ability to atomize and eventually the carb fails to atomize at all. At that point, the engine doesn't get the fuel it needs to stay running and conks out completely. EFI can keep an aggressively cammed engine running at lower RPMs since injectors don't require vacuum to fuel the engine. But there's still a limit to how low you can maintain a stable idle even on an EFI engine.

There's also such thing as exhaust reversion. This happens when you have a cam that opens the intake valve too early in the exhaust stroke. The piston is still rising in the bore for the exhaust stroke, and the intake valve is opening. This shoves exhaust into the intake also lowering intake vacuum.

In a V8, you ALWAYS have at least 1 intake valve open. However during the transition from one cylinder to the next, you have 2 valves open at the same time...one closing and the other opening. With aggressive cams, it is possible to have the opening intake valve's cylinder shoving exhaust into the intake while the closing valve's cylinder is or will soon be shoving part of its intake charge into the intake. During these brief periods, you theoretically have zero vacuum. It doesn't last for long, but explains why aggressively cammed engines play hell on a vacuum gauge's needle at idle, bouncing it back and forth. To combat this, you can get dual plane intakes which separate sequentially firing cylinders into two different plenums. Using a 4 barrel carb, a primary and secondary are dedicated to 1 plenum, and the other primary/secondary pair are dedicated to the other plenum. With separated plenums, you still have vacuum instability in the intake due to reversions, however you've isolated the problem so that a cylinder with a dropping piston can produce full vacuum on its side of the carb. With this setup, the carb can atomize the fuel more effectively at lower RPMs allowing an aggressively cammed engine to idle at lower RPMs with a carb. These are also the intakes that "lope" an engine best since you can get the RPMs low enough to lope while still keeping the engine running. So if you want to lope the engine harder, get a dual plane intake and lope-away with a TFS Stage 1 barely holding onto idle at ~650RPMs.

[v8ranger]

The pistons and head gaskets are all stock. The block is all stock with GT-40 heads that have been lightly ported. I am running a duel plane intake.... So you think the trick flow stage 1 is my best bet then? Should I use my 1.6 rockers and take out the 1.7's with this cam??

[cgrey8]

Ok good, you have a dual plane intake. Although, I'm a little surprised you couldn't get a harder lope with the E303. In that case, I'm not going to tell you the TFS is going to lope harder since the duration and the wider LSA would suggest it will not.

So now you got a decision to make. This is your chance to change-it-up if you weren't perfectly happy with the engine the way it was. However be careful with that thinking. You can quickly fall down the rabbit hole. First its just a cam replacement. That requires different rockers. But then you get to thinking about the pistons, compression, and the deck height. Should you do machine work while the thing is apart to improve quench and compression? With a tighter quench and a lower compression, you might could run a smaller pulley and up the PSI of that blower a bit. But with higher PSI, you might need an innercooler. Before you know it, what could've been a $200 cam, cam bearings, some coolant, and gaskets, has you in for a few grand in parts and service you talked yourself into. Its this kind of thinking that maxes out Credit Cards if you aren't careful.

So for your 1.7RRs, I probably wouldn't bother swapping them if you go with the TFS Stage 1. The lift difference between the E303, which you know worked with your springs and the 1.7RRs, and the TFS Stage 1 is so small, I can't see the springs having a problem. If you do bind with the Stage 1 cam, it was because you were right AT bind with the E303 and never knew it...the difference being .529" lift vs .542" lift with the TFS on the exhaust valve. To me, it'd be worth the effort of trying 1 cylinder and seeing if it bound. If it didn't, the move forward with the other cylinders. If it did, then revisit the spring package vs 1.6RR option.

If you went with any of the higher lift Comp cams, I would say plan on ditching the 1.7s, not so much because of lift, but because of the ultra-fast ramp rate Comp grinds into their cams. The TFS is a typical aftermarket fast ramp rate, but still capable of tolerating 1.7RRs. But Comp grinds a fierce ramp into their lobes.

Knowing that the engine is 100% stock allows you to assume you probably have a piston-to-deck clearance height of .015" and no thinner than .040" head gaskets. That means you don't really have any quench to speak of. My 97 Explorer engine I'm stroking had .016-.017" deck clearance on its pistons and the gaskets were .047" crush thickness. But if the engine could run with a stock cam and 87 octane fuel, you should have no problem running 87 octane on a TFS Stage 1 cam. What could push you to premium is the boost.

The X-factor is the GT40 heads. Were they sold new? Pulled from a 96 Explorer, or are they from a Cobra?
Aftermarket and stock Explorer GT40 heads are generally in the 65cc range, closer to what the E7TE heads are in stock form.
However SVT shaved the GT40 heads they put on the 93-95 Cobras to give the Cobra engines a higher compression. Cobra GT40 heads are in the 60cc neighborhood. A difference of 5cc is huge when calculating compression ratios.

[v8ranger]

The heads where fresh rebuilds I bought from someone off E-Bay quite a few years ago. I dont remember what he said they cam off of. Not even sure he said, lol.... I know the holes where bigger and so where the valves when I compaired them to the E7 heads. The truck even sounded differant out the tail pipes when I put the GT-40 heads on... More air in and out mad it a little louder out the tail pipes..lol.... I think the valves are 1.94?? something like that I think, if memory serves me right.....
After checking the rod and main bearings, I didnt like what I saw on one of the rod bearing. So I had to order a new crank... Not what I needed to find, but I guess better to find these problems now then at WOT.... I would love to put a stroker in it, but unless I get lucky in the lottery, that wont happen anytime soon... Untill then, I have to keep what I have... So a $40 gasket change is now turning into a rebuild...... At least its winter and I have time to do it... Just go to get the money now, lol....

[cgrey8]

If you need a 302 crank, I got one sitting on the floor of my garage that will likely never be used in any of my engines since I am replacing it for a stroker. If you haven't already bought a crank, this one looks pretty good. I can get you pics if you want/need.