Cam lift

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v8ranger
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Cam lift

Post by v8ranger »

Is this to much lift for my setup, 5.0HO with GT-40 heads, ( Lift w/ 1.6 rocker (intake/exhaust) .542"/.563" ). Will the valves hit the pistons?
1986 Ranger with 1990 5.0 HO roller motor
Ported GT-40 heads
Duel plane air gap intake with 750cfm Holly
Paxton SN93 Supercharger with 3 1/2" pulley.
8 to 9psi of boost??
T-5 trans
Large tube shorty headers
Stock posi rear end
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faststang90
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Re: Cam lift

Post by faststang90 »

my ford book says with the f-cam thats .512 lift you check to make sure you have clearance.
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Re: Cam lift

Post by plowboy34 »

That much lift I would automatically do a PV clearance test. It's a bit of a pain but a broke off valve at about 5K would be too..... :shock:
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cgrey8
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Re: Cam lift

Post by cgrey8 »

It's not so much the lift as the lift in combination with duration. Wide duration cams are the ones with clearance problems. As long as .050" durations are in the mid 220s or less, you are probably ok. If it's more, you'll need to do the check for sure. My guess is you'll be more if this is an aggressive build.
...Always Somethin'

89 Ranger Supercab, 331, ported GT40p heads w/1.6RRs, Crane Powermax 2020 cam, ported Explorer lower, FMS Explorer (GT40p) headers, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, A9L w/Moates QuarterHorse, Innovate LC-1, James Duff traction bars, iDelta DC Fan controller

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v8ranger
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Re: Cam lift

Post by v8ranger »

Here are some of the specs on it.

Duration @ 050" (degrees) - 224 intake/232 exhaust
Cam Lift (intake/exhaust) - .339"/.352"
Lift w/ 1.6 rocker (intake/exhaust) - .542"/.563"
Lobe separation (degrees) - 112°
1986 Ranger with 1990 5.0 HO roller motor
Ported GT-40 heads
Duel plane air gap intake with 750cfm Holly
Paxton SN93 Supercharger with 3 1/2" pulley.
8 to 9psi of boost??
T-5 trans
Large tube shorty headers
Stock posi rear end
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cgrey8
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Re: Cam lift

Post by cgrey8 »

That's more aggressive than I would ever go in a truck, but I'm also more daily-driver minded. If you are looking for big power and 1/4 mile times from this engine, then that's a decent cam to go with. It won't kick in hard until 2500 but if you got strong valve springs, big flowing heads & intake, and an exhaust system to support it, the cam will still be in its optimal RPM range at 6500 and pulling strong. Since I tend to think in terms of 5500-6000 being redline for the street and solid performance at sub-2000 RPMs, I'm more inclined to always recommend cams that are below 218 duration@.050"...and if you want solid off-idle torque, you'll want to be below 214 (assuming an N/A 302).

Strokers and boosters change that some. Under ideal conditions, super/turbo setups tend to PREFER milder cams in the sub-220 duration range even when pushing big RPMs. But often people are boosting an already built engine and don't want to swap out pistons when they install a booster. So they HAVE to put larger cams in to lower the dynamic compression ratio to a level that the engine doesn't ping the heads off the moment the engine goes into boost. It'd suck to find you can't get above 3 PSI before the engine PINGS itself to head gasket death. So any time boost is involved, you can't talk generics anymore. You have to be much more specific about the build...head chamber volume, piston dome/dish CCs, boost pressure targets, presence of innercooler, and intended fuel to be used before a cam can be recommended.
...Always Somethin'

89 Ranger Supercab, 331, ported GT40p heads w/1.6RRs, Crane Powermax 2020 cam, ported Explorer lower, FMS Explorer (GT40p) headers, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, A9L w/Moates QuarterHorse, Innovate LC-1, James Duff traction bars, iDelta DC Fan controller

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Re: Cam lift

Post by v8ranger »

I dont take it to the track, but its not a daily driver either. Its just a fun truck. Im looking for something that will give me good mid range power. Im getting a new remaned block, bored 40 over with hypereutectic pistons, the rest will stay the same thats in my signature. The cam thats in the motor i have now doesnt give me mid range. What would you recomend for a cam that has good mid range power and a loppy idle that will work with my build? Im not looking for top end speed, its a truck, just looking for some good mid range power.. here are the specs of the cam I have now.
.512 lift, intake and exhaust
duration @ .050 intake 220 exhaust 220
lobe separation 110
firing order 1 3 7 2 6 5 4 8
1986 Ranger with 1990 5.0 HO roller motor
Ported GT-40 heads
Duel plane air gap intake with 750cfm Holly
Paxton SN93 Supercharger with 3 1/2" pulley.
8 to 9psi of boost??
T-5 trans
Large tube shorty headers
Stock posi rear end
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cgrey8
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Re: Cam lift

Post by cgrey8 »

Lopey is generally gotten from a wide duration cam. So narrowing the duration is going to smooth that out a bit, but will get you better low end torque.

One of the problems you run into with wide duration cams and boost is you wind up loosing a portion of your air (and fuel) out the exhaust because the booster is literally shoving it out during the overlap when the intake and exhaust valves are open at the same time. This is why I was saying that boosted engines generally "prefer" a milder cam. But if compression limits your options, you deal with what you got.

Now being you are getting a reman'd block with new pistons, do you have the option to choose the pistons? Or is that already being chosen for you? If you do have the option to choose, then NOW is the time to make that decision intelligently so you can optimize everything and run a cam that's going to work with you, not simply shoe-horn the booster onto your engine.

Also while I really like hyper pistons, I have to say the modern technology forged pistons are far better than they were even 10 years ago. It used to be that forged pistons had to be undersized so badly that you got bad piston knock when the engine was cold. But with today's metals, they can get clearances that are near hyper clearances so you don't get the piston slap noise. Mahle is probably the best piston out there for this although there are others that are good pistons as well...so I don't want to detract from them...just Mahle for the money tends to be the best since you get the rings with the pistons AND Mahle pistons come from the factory with teflon pads on the sides of the pistons where most other brands don't. When I was sizing up my 331, I started looking for hypers and was surprised to find that MOST of the options for hypers in strokers had dried up and most been replaced with forged. There were at least 10 different styles, types, and designs of forged pistons for a 331, but only about 2 for hypers and neither in the configuration I needed. At the time, I reluctantly went with forged, but now that the engine is built, I'm quite happy with them.

Anyway, the other info you'd need is the actual CCs of your combustion chambers. I'd like to say you can rely on posted info for a GT40 head, but if these were production heads from Ford, you can't do that. The actual cc of the chambers is not likely to be what you expect them to be. The only exception might be if they came off a Cobra 5.0L engine which means SVT was involved with their machining and they have FAR tighter tolerances than Ford production lines do. I thought my GT40p heads were going to be 58cc heads. From the factory, not a single compression chamber was anywhere near 58. They were closer to the 64 cc range. Even after I had the decks planed .010" by the machinist, the compression chambers were still in the 59-61cc range. I went around to EACH chamber, identified the largest chamber, and then machined off metal in the other 7 chambers to within .3ccs. You talk about time consuming filling and refilling those chambers with water and taking down the measures. But once I'd done it with about 2 chambers, I got a fairly good feel for how much grinding was equivalent to a .1cc so the other chambers went fairly quickly. The area I removed metal was around the spark plug boss and unshrouding the exhaust valve out to the gasket ring. I don't expect others to spend that kind of time with their heads, but you at least need to cc them once to know what you are working with. If you've already done that, then great. If not, then picking a cam and selecting pistons is going to be shooting from the hip.

And for that, I'd say your option will be a set of 16cc dished pistons, .039" head gasket, and a Comp XE264HR12 cam.
...Always Somethin'

89 Ranger Supercab, 331, ported GT40p heads w/1.6RRs, Crane Powermax 2020 cam, ported Explorer lower, FMS Explorer (GT40p) headers, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, A9L w/Moates QuarterHorse, Innovate LC-1, James Duff traction bars, iDelta DC Fan controller

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Re: Cam lift

Post by v8ranger »

My choices in pistons where stock and hypereutectic. I haven't CC'd the heads, don't know how to. I don't ever get that technical.. Maybe I should, I have all winter to do this.. I just want a cam that's better than what I have now. the mid and top end drop off. I'm not worried so must about top end and don't want a cam that doesn't come in strong till 6000rpm's, it will NEVER see that kind of revs. My truck may see 5000rpm's once and a while. I would like the power to come in around 2500 to 3000rpm's and keep pulling from there.. Its not a race truck or 1/4 mile truck, nor will it be. its just a weekend driver or nice days.
1986 Ranger with 1990 5.0 HO roller motor
Ported GT-40 heads
Duel plane air gap intake with 750cfm Holly
Paxton SN93 Supercharger with 3 1/2" pulley.
8 to 9psi of boost??
T-5 trans
Large tube shorty headers
Stock posi rear end
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cgrey8
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Re: Cam lift

Post by cgrey8 »

Based on your usage of the truck, the Comp XE264HR12 is perfect for that. The question is going to be how will it work with the rest of the engine and the booster. The only way to know is to run the numbers. And you'll need those numbers...including what the cc of the pistons are. Even if they are flat tops, the valve lashes count as "dish" and thus give it a dish cc number. Usually flat tops are in the 6cc range. If there are 2 sets of valve lashes, then you'll be up closer in the 10-12cc range. You really DO NOT want double-lashed pistons if you can help it. The additional lashes where valves aren't are right in the quench area and reduce the quench affect. My guess is the hypers are NOT double-lashed...unless they are KBs. Then all bets are off.
...Always Somethin'

89 Ranger Supercab, 331, ported GT40p heads w/1.6RRs, Crane Powermax 2020 cam, ported Explorer lower, FMS Explorer (GT40p) headers, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, A9L w/Moates QuarterHorse, Innovate LC-1, James Duff traction bars, iDelta DC Fan controller

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Re: Cam lift

Post by v8ranger »

Ok, maybe I'm doing something wrong. I found two cams with that number, but, they have two different lifts. one is 512 the other is 544.. And what kind of idle does that cam have? I know, to some people that's not important, but I like the loppy idle...
1986 Ranger with 1990 5.0 HO roller motor
Ported GT-40 heads
Duel plane air gap intake with 750cfm Holly
Paxton SN93 Supercharger with 3 1/2" pulley.
8 to 9psi of boost??
T-5 trans
Large tube shorty headers
Stock posi rear end
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Dave
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Re: Cam lift

Post by Dave »

I think the difference in the lift is just which ratio rocker is used. Summit says cam is for use with the 1.7's but don't know why. 1.6 ratio is .512 lift. YouTube has several clips of Mustangs running that cam (or the -14 instead of the -12).
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Re: Cam lift

Post by cgrey8 »

Here's the one I was talking about:
Comp XE264HR-12 Ford Roller

The other one is:
Comp XE264HR-14 Ford Roller

Basically identical cams with the expcetion of the Intake centerline which affects the LSA.
Here's another example of almost identical cams with the only difference being the 112 vs 114 LSA, but very different descriptions:
Comp XE270HR-12 Ford Roller
Comp XE270HR-14 Ford Roller
Notice how different the descriptions are on these two.

Despite the difference in lift, the difference is because one is being advertised to be used with 1.7RRs and thus they advertise the lift assuming 1.7, not 1.6. Notice the lobe-lift is exactly the same. So using the "larger lift" cam on 1.6RRs would yield the same .512" lift. My guess is they do that because the same cam with 1.7s will give you higher lift so on heads that CAN give you more flow at .54" rather than .51", then you get a slight performance increase by using 1.7s. So it reduces the number of actual cams they have to stock and a narrower LSA is generally more performance oriented vs the wider duration is better for torque and idle. I guess that's a good reason. With GT40 heads, .512" is more than plenty lift so I would stick with 1.6RRs particularly if that's what you already have on the engine.
...Always Somethin'

89 Ranger Supercab, 331, ported GT40p heads w/1.6RRs, Crane Powermax 2020 cam, ported Explorer lower, FMS Explorer (GT40p) headers, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, A9L w/Moates QuarterHorse, Innovate LC-1, James Duff traction bars, iDelta DC Fan controller

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Re: Cam lift

Post by v8ranger »

Yes, 1.6 is what I am running. I do have a set of 1.7 roller rockers. Those cams don't seam all that different than what I am running now. I don't know much if anything about the numbers on cams, but comparing those to what I have, doesn't seam like its worth spending the money for something I may not even notice a difference with.. don't know......
1986 Ranger with 1990 5.0 HO roller motor
Ported GT-40 heads
Duel plane air gap intake with 750cfm Holly
Paxton SN93 Supercharger with 3 1/2" pulley.
8 to 9psi of boost??
T-5 trans
Large tube shorty headers
Stock posi rear end
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cgrey8
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Re: Cam lift

Post by cgrey8 »

What you have is a cam that's 224/232 duration@.050". What I'm recommending is a milder cam that will kick in a bit sooner than that one will and give you more umph in the 2000-2500 range.

I don't remember exactly which cam brand you have and I couldn't find what your off-the-seat durations are. If it's an FMS cam, those ALL have very mild "stock like" ramp rates which means the off-the-seat duration (aka duration@.006") is much wider than it needs to be. Milder ramp rates are good for reducing the chance of valve float. But if you aren't going to be reving in the RPM range where that matters, then you are far better off going with a steeper ramp rate.

Wider duration at small openings there seems like nothing and it's considered negligible on N/A engines. But on boosted engines, you loose PSI in that range with unnecessarily wide duration due to the overlap. Comp cams are known for having quite steep duration which means they generally have much narrower off-the-seat duration relative to the .050" duration allowing you to go much more aggressive at .050" without the off-the-seat limitation. However, what I'm recommending is going to a cam with narrower duration on both .050" and off-the-seat, then you should improve things all the way around. With a milder cam, you are sacrificing HP in the 5800+ range. But what you are gaining is MUCH better responsiveness in the RPM range you use most.
...Always Somethin'

89 Ranger Supercab, 331, ported GT40p heads w/1.6RRs, Crane Powermax 2020 cam, ported Explorer lower, FMS Explorer (GT40p) headers, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, A9L w/Moates QuarterHorse, Innovate LC-1, James Duff traction bars, iDelta DC Fan controller

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