Using the multi quote function looks neater, but it appears I'm too dumb to get it to work, hence the multiple posts to reply to one thread.

At least one of the cam suppliers is responding to you !

Yeah, fair comment about not sharing too much info until an order is placed.

That said, it looks like the advertised duration is 272/282, which provides a mild ramp rate, but more importantly, provides the acceptable estimated DCR based on a 9.76 SCR.

I agree that the lift is not excessive enough to be detrimental, or that there would be 'consequences'.

It's a bit like your truck having two gas tanks and mine only having one. Either works, and your extra tank is not too excessive. (I hope that makes sense.)

The Lykin cam would satisfy your needs just fine, but so too would the Crower cam assuming it's within the DCR limit.

The point I want to make is that you could be presented with 10 cams, each with different specs, but all 10 would work just fine.

Small differences might show up on a dyno, but you probably wouldn't feel any difference whilst driving, and the latter comment is my point.

 

Before I forget again, here's some more notes :

Whether the cylinder heads are assembled or not, you need to check that all 16 springs have the correct pressures at given heights, and that they match the pressure requirements of the chosen cam.

A tool is available to do the measurements.

Shims are available to set pressures where needed.

The spring instructions might say something like, ''For break in, heat the springs and let them cool down''.

That's easy enough, just run/drive the engine for 15 minutes with varying rpms, but also consider what the piston ring instructions say.

You might need to retorque the heads after cool down. The heads instructions should specify what's required.

See if you need hardened push rods. The heads might have push rod guides that require them.

Check that the cam supplier also supplies matching roller lifters. (He should also be able to give you the cam spring pressure requirements.)

Pre-load on the lifters might be 1/2 turn or 3/4 turn or whatever, so you'll need to know that too.

Mark the damper in 1/4's if you want to set the pre-load in the firing order.

 

Duration at 0.006'' lift, a.k.a. advertised duration (Without these figures, a cam cannot be wisely chosen. Period.)

Really? How does this take into account lobes that have a large amount of asymmetry? Does a cam lobe design with a quick opening and a slow closing appear to the engine as if it is longer or shorter duration when compared to a lobe that's symmetrical?

 

Yes !

Take the Crower cam specs in post one, use an ICL of 109, and calculate if 77FordExp would have an acceptable engine, or a pinging nightmare engine, if that cam were fitted.

The cams discussed thus far have equal ramp rates, but by all means you can use differing or equal rates in the calculation, as the answer will be the same.

I'll post up what my answer would be, after you've posted your answer, and yes, I have no problem saying my answer is wrong if it turns out to be the case.

 

This is my question.. Use the cams in the thread I did a year ago when I rebuilt the 460 in my '79 pickup.

https://www.ford-trucks.com/forums/1...-my-460-a.html

The engine had been built for about 20 years and ran fine but after I went to the E4OD transmission I felt that it was a little bit over cammed when running along in overdrive on the interstate pulling my trailer. The RPM level had changed about 1000 or so.

The first cam used the Reed Torque master lobes which are pretty much symmetrical designs. The first cam had more duration at .050 but actually less duration at .006 than the cam which I used as a replacement. The new cam is a brand new design that I had done and then made into a master. It has pronounced asymmetry as you can see in the graphs. The peak velocity is very high on this cam yet the peak accelerations positive and negative are not significantly different than the first cam.

The lobe separation on the new cam is 107 degrees and it is in the engine on about 104 vs the other cam which was ground on a 112 and in on 108. The intake opens 6 degrees earlier with the new cam at .006 and it closes about 5 degrees later. Does this make the dynamic compression lower? At first it would seem like it does but I don't think that tells the whole story.

Take a look at the exhaust side. The exhaust now opens about 6 degrees later and closes 13 degrees later. This later exhaust valve closing has a profound effect on the low speed cylinder pressure. It does give the engine more overlap at seat yet in this case less overlap at .050. This "tail" on the exhaust lobe really helps to fill the cylinder as soon as the engine is "on the cam". In this case the engine idles at about 750-800rpm or so with an idle that is slightly noticeable and with about 15 inches of manifold vacuum but as soon as the speed increases even 100 rpm it becomes totally smooth and manifold vacuum jumps up about 4 numbers. That's all it takes to get the velocity high enough in the exhaust port to allow it to help pull in a fresh intake charge and thus increase the VE of the engine. it make more low cylinder pressure and torque does this mean that the dynamic compression ratio has increased?

 

I had to go eat lunch so my post ended up getting cut off. I wanted to write something about the intake side closing with the new lobe. The closing event appears to be later with the new lobe that's smaller at .050 by 5 degrees. At first it would seem that this would tend to reduce the cylinder filling capability at lower engine speeds but I don't think that's the case. As the intake event gets close to its end the piston has already slowed way down, stopped and is now starting to come back up in the bore. At first it would seem that having the valve still open later would really eat into the compression stroke but what I think tends to happen is that if the valve's closing rate is just right it presents an area to the the gasses that's progressively becoming smaller and smaller. Even at low speeds engines can develop some inertia ram effects in the intake tract but for this to be effective the velocity at the valve seat has to be maintained. This drops the pressure and allows it to keep on filling for a longer period even though the piston is moving the wrong direction. A lobe that seats too quickly can limit this effect.

 

I put a Crane "Fireball" torque type cam in my truck's 351M over 30 years ago, new stock lifters and timing set, it uses just plain OEM non rotator valve springs, stock rockers and push rods. It owes me nothing, it pulls good, Idles a little lumpy but it pulls 12-13 inches vacuum at idle when warm about 900 rpm. I'd use the same again if I ever use my 400. I don't think Crane makes it now, they may be out of business for all I know, but others have the same specs like Edelbrock's 2172. I verry seldom ever see tach over 4K even. It's just a cast iron flat tappet cam.

Operating RPM Range: Idle-5,500
Intake Duration at 050 inch Lift: 204
Exhaust Duration at 050 inch Lift: 214
Advertised Intake Duration: 282
Advertised Exhaust Duration: 292
Intake Valve Lift with Factory Rocker Arm Ratio: 0.484 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.510 in.
Lobe Separation (degrees): 112

Just throwing it out there. I know the "hot tip" today is "riollers rule". I've only ever had cams wipe lobes after high miles and or a lot of heat and both those were OEM cams in OEM engines . I have used soft OEM springs to breack on in qafter checking for coil bind, just keep rpms down and change the springs later.

 

I didn't see a yes or no in the above posts (20 and 21) as to whether the Crower cam would work or not in the OP's engine, but here's my answer as promised anyway :

I cannot say whether the cam would work or not as I do not have enough information about it. I therefore would not give an opinion.

(I.E. Duration at 0.006'' lift, a.k.a. advertised duration (Without these figures, a cam cannot be wisely chosen. Period.)

Tbear853's cam would work just fine.

 

I guess I didn't understand your post when I put up my example about cams but maybe if you read what I posted you would understand that the concept of dynamic compression doesn't tell you much about engine operation. How can it possibly have any meaning if the cam lobe has any significant asymmetry? Using my truck cam as I did in my example: the centerline of the lobe(max lift point) happens at 104 degrees after top dead center. If I figure the lobe center using the events at .006 that centerline is now 110.8 degrees ATDC. Where does the Crower lobe go into the engine when it comes to figuring dynamic compression? It could be significantly different that it appears by just looking at the numbers.

 

That's ok, I'll clarify.

This thread, and I'd guess 99.9% of all cam enquiry threads in FTE, would be referring to typical cams with symmetric lobes.

As such, the typical question is, what will the DCR be so that one can avoid detonation.

Using the Crower cam specs in post one, we'd need the ICL and advertised durations to calculate when the intake valve closes. Once we had that number, we could calculate an estimated DCR number to ensure a correct cam choice.

Hence my comment about the numbers being needed for all cams period.

Given the context of this thread, I don't believe I'm wrong.

You've introduced asymmetric cams which is outside of this thread's context, but fair enough, if I were having a cam custom built to that degree, I would want the advertised durations, and then some. (Still ''period'', LOL)

 

I did read it, found it interesting, opened the link, scrolled down quickly, found that it looked interesting too, and then logged out due to time constraints.

The posts and thread look like they warrant reading with full concentration and no interruptions.

When I'm afforded time to do that, I will.

 

It is always an interesting question, "what cam should I run in my engine build". A couple of months ago I discussed this with David Vizard the author who's written tons of books on engine related subjects. I told him that I felt that camshaft selection was the most misunderstood part of engines. He felt that it was cylinder heads but it sure seems to me that cam selection is a real puzzle.

The problem I have with doing a calculation to determine dynamic compression ratio is simply that those sorts of calculations use the intake closing event to determine how much the static compression ratio is reduced. This should be pretty true when it comes to cranking compression but as soon as the engine is running other factors immediately come into play.

For what it's worth I've built quite a few 408 Cleveland engines mostly for Pantera applications. While I've built them with more cam most customers want an engine that's mild, idles well and makes lots of mid range torque. I usually shoot for about 10:1 compression with a TFS or similar cylinder head. I normally like to use a hydraulic roller cam from Demos' Cams, HR3-7A1 which ends up being 220 @ .050 intake and exhaust on a 107 lobe sep in the engine on 105. That makes .565 lift on the intake and exhaust side. These will typically make 535 horsepower by about 5800rpm and 530 lbs/ft at 3500rpm with a peak torque of 535 @ 3900. This is with a Perf RPM air gap intake with the divider welded up and a 4 hole 1 inch spacer under a 750 Holley. Pantera exhaust system will shave about 15lbs/ft off of the torque but HP stays about the same.

Cam events @ .006: Int open 34.8 BTDC, Close 71.9 ABDC
Exh open 69.1 BBDC Close 36 ATDC

While this cam works very well in a Pantera and will pull 5th gear without chug-a-lugging I think that it is probably a bit too much duration for a pickup truck. I think that I'd drop it back to around 214 to 216 at .050.

How does that cam sound?

 

I can't hear it !!!!

Sorry, I couldn't resist that.

I read David's book ''How to build horsepower'' about 15 years ago, and I enjoyed the book immensely.

I don't know which is more misunderstood, cams or heads, but you could maybe add ignition timing to the list.

Yes, agreed, I understand what you're saying about IVC, DCR, and changes in cylinder pressure, but using the engine in this thread, IVC is probably the only 'safety' measure we have.

Ok, given the OP's driving style and requirements, I'd say that the cam is not suitable based on the peak torque rpms alone.

220 would work ok, but agreed, a drop in the range could be more suitable.

Using 220, 107, and 105, I don't get your cam event numbers without using differing durations ranging from 280 - 292. (Haha, I think you knew that.)

 

Vizard's books are very well done. I've always liked how he shows a lot of things that are helpful yet that can be done on a limited budget. His advice can be really helpful when it comes to selecting the right parts for a build regardless of the make of the engine. I enjoy his information on porting both from the books and from what he puts on YouTube.

An application like this one is tough to cam for because the usage scenario of the engine somewhat contradicts certain aspects of the build namely the relatively high static compression ratio. 9.7:1 is pretty high for an engine that's going to pull down low with a 3.0 gear ratio and a low stall converter. I think that having an aluminum head with a nice modern combustion chamber will help a lot when it comes to fuel choice but I think that it will still possibly require premium fuel.

I think that you're 100% right in that the cam has to act as sort of like a pressure regulator but it probably doesn't have to put the intake valve closing event super late to work. I think that a 112 LSA is probably wider than it needs to be to make this work. It would use something tighter with the cam straight up or nearly so.

Here's what the engine sounded like when I was running it on the dyno. I ran it with a bunch of different exhaust, a Pantera setup with ANSI mufflers, his exhaust with the BHA mufflers and a set of Hooker headers that fit a Mustang chassis. The BHA setup didn't sacrifice a whole lot of performance and sounded good. One of them had been filled with antifreeze when the engine had cracked a cylinder and it took forever to get that burned out but it finally quit smoking after about 6 pulls or so. There's also some steam from the dyno cooling tower and absorber drain.

 

Good morning Dave,

I just re-read your posts from post 20 onwards including the thread linked in post 20, and thoroughly enjoyed the read. .

I fully understand everything you said and it's incredibly interesting.

I am Mr Boring, and would have been happy with a normal symmetrical cam, coz I know one would be easily available which would have given me the torque/HP requirements I'd need.

That said, if I had a friend who could make asymmetrical cams, and I had my own dyno and machine shop, things might be different ! LOL

Your comments about oil viscosity and oil loss and engine vacuum, 400 grit hone, 3sp to 4sp tranny swap, valve spring corrosion, oil pan louvers, and air gap manifold, caught my eye for varying reasons.

I agree with you aiming for 10:1 SCR on engine rebuilds and using closed chamber heads. I wouldn't entertain anything else for my own engine to be honest.

Years ago, I had a chat with one of Edelbrock's technicians about the cam they recommend with their Cleveland air gap manifold and ally heads, coz I thought their claimed power figures were a bit ambitious.

He didn't convince me otherwise, and I never get around to trying that particular cam 'just to see'.

And talking about Edelbrock, they do a cam with the exact same specs as Tbear posted recently, and they too state an operating range up to 5,500rpms.

Yeah, it's more like 5,000 rpms !

The questions on my plate at present, to which I want answers, are, 'How exactly do CoQ10, triglycerides, and vitamin E, influence each other ? Can CoQ10 increase triglycerides ? Can CoQ10 raise vitamin E to a level of toxicity ? Is Lipoprotein (a) as a cardiac marker, utter bollocks ?

Hence my lack of in depth discussion on cams.

Today's rhetorical question is, ''Why the f$$k did an American Medical Journal, supposedly reputable, allow a Canadian paper to be printed, on the subject of unvaccinated people being more likely to have a car accident ?'. Here : https://www.amjmed.com/article/S0002...822-1/fulltext

Utter, utter, BS !

@ 77FordExp, I hope you don't mind the .