[jakeshoe]

Using the .200 lift method we are showing ICL to be off 6* which is 2* different than we are seeing with the .050" method.

We'll retime the cam and see what happens.

[Stuckinda60s]

As I said, I wondered if it was retarded. Are you going to install it straight up or will you advance it. The recommendation is 4* advanced, isn't it?

[hal101]

i must say it's very interesting

[sportylemans]

This thread has me checking it every hour. I guesss I'll have to subscribe. Hell my 71 lemans w/350, summit 2801, and Carter AFB leaves a 15 ft black mark when I step on it. If I dropped a 455 in it I would expect a hell of a lot more.

[screamingchief]

Originally Posted by jakeshoe

I determine ICL by where the .050"events happen. There are other methods but because of the assymetrical cam lobes you get into, you can't assume it's exactly centered on the events.

It's because of asymmetrical lobes that folks began to use the intake centerline method,and that's also likely why Comp recommends using that method as well.

Asymmetric lobes can shift the events around in ever so subtle ways that the cam cards dont always reflect.

I gotta agree with 67bonnie455 that you should give that method a try here,just for the sake of being thorough.

It's not hard to do,and it only helps understand whatever else you've found.

There is little room for the lobes to affect those intake centerline readings,as your just looking at the very nose of the cam (.050" down on each side of the peak),not lower down on the ramps where you often will find some discrepancies.

Call me a back seat mechanic here if you want,but I do it both ways untill I can get them both to tell me roughly the same thing.



Bret P.

[tempest455]

I did not read through all of the posts but they probably suggested the same.

Degreee the cam. Install a little advanced with that gear.

More converter.

Gear change down the road when you can swing it.

[jakeshoe]

Originally Posted by screamingchief

It's because of asymmetrical lobes that folks began to use the intake centerline method,and that's also likely why Comp recommends using that method as well.

Asymmetric lobes can shift the events around in ever so subtle ways that the cam cards dont always reflect.

I gotta agree with 67bonnie455 that you should give that method a try here,just for the sake of being thorough.

It's not hard to do,and it only helps understand whatever else you've found.

There is little room for the lobes to affect those intake centerline readings,as your just looking at the very nose of the cam (.050" down on each side of the peak),not lower down on the ramps where you often will find some discrepancies.

Call me a back seat mechanic here if you want,but I do it both ways untill I can get them both to tell me roughly the same thing.



Bret P.

Yes,
we found it slightly more off that way.
I don't think a 4* difference is killing this engine this much but the 6* we are seeing off ICL certainly isn't helping.

I don't mind suggestions but when someone is telling me how to use a piston stop to degree a cam after we already have already posted timing events...
How would we have gotten there otherwise? I'm not going to stick the dial indicator down the spark plug hole at an angle to get TDC.

I run a shop that specializes in this type of work. See signature...

ICL should be in place if the .050 timing events are to the cam card. The intake lobe is 4* short on duration so that throws some confusion into the mix because we don't know where that 4* is at, on the opening or closing.
We checked the exhaust side and the duration is spot on and is 3* off on the timing, so that at least gives me a direction to go with.

We are going to advance it using the crank gear on the multi-keyway timing set and check it again to see where we land.

[Kyflier]

All day and no updates.........whats up?????

[jakeshoe]

Originally Posted by Kyflier

All day and no updates.........whats up?????

We're in a brainstorming session about keeping the current cam or going with a different grind.

I'm also busy with running a business. We have 6 200-4R transmissions in progress, 1 in the test car, 2 awaiting, and 3 to get started on.

Plus a cam swap on a 505 BBC in a '78 Z/28 going, shipping parts to France, MI, and KS.

Only 4 of us working it's all we can do

[Kyflier]

Just givin ya shyt my man......but hey, I'm glad you have the work to keep you busy and the doors open. And I'm sure the guy your helping with this Pontiac cam problem is paying you (well I hope he is anyway). Lots of places can't/don't stay that business very long. It's great that you have the reputation and skill to do what you do. We've lost a couple of great mechanics lately here at the dealership. it's hard to find and get good talent. Let us know how it all turns out, we're pullin for you to figure it all out.

[tr709]

yes I'm paying

[Kyflier]

At least now you'll be getting VALUE for your dollar

[chiphead]

Since you're in it that far, I'd likely change the cam. Something on a 112 lsa would spread the power band out, and since it's a roller you could get even more power with less downside. You could likely go a bit more duration with a wider LSA and not lose the lower RPM power. I like the XE274 in a HFT, but I'm guessing it would be too peaky in a roller version.

[tr709]

A little bit more of where we are at.

Jake and I talked this morning and basically my decision is, do I dial the current cam in based on jakes findings knowing it will improve things but not sure how much OR go with another hyd roller choice that preferably someone has run with a similiar combo so that I can get some real/proven numbers.

I'm leaning towards a new cam, problem is there are so many opinions out there who do you believe?

[guccieng]

you can reuse the lifters, so it's just the cost of the cam, right? i say go for tried and tested: new cam.

[Stuckinda60s]

If you go with a new cam, it doesn't work the way you expect, and you then find another problem, you'll never know how well the old cam would have worked. If you dial it in and it doesn't perform as you think it should, and then go with a new one and it works well, you have an answer. If it still doesn't work you can pursue it further.

What's the cost difference between dialing it in and a new one? If you dial it in, buy a new one, the new one works well and you sell the old one you can truthfully answer how it worked.

I would want to know whether dialing it in helped before I went with a new one. Of course, I would be doing it myself and not paying for it so it would be an easier decision for me to make as I wouldn't have to pay for someone else to do it.

[jakeshoe]

Originally Posted by Stuckinda60s

If you go with a new cam, it doesn't work the way you expect, and you then find another problem, you'll never know how well the old cam would have worked. If you dial it in and it doesn't perform as you think it should, and then go with a new one and it works well, you have an answer. If it still doesn't work you can pursue it further.

What's the cost difference between dialing it in and a new one? If you dial it in, buy a new one, the new one works well and you sell the old one you can truthfully answer how it worked.

I would want to know whether dialing it in helped before I went with a new one. Of course, I would be doing it myself and not paying for it so it would be an easier decision for me to make as I wouldn't have to pay for someone else to do it.

That's exactly where we are at...

Myself being the curious type, I would like to see what we can accomplish with the current cam before making any parts changes.

However we have the timing cover off, the timing set off, the drivers valve cover off, and the coolant drained right now.
Now is the time to swap a cam if we are going to do so and not create additional expense.

It's in Tony's hands

It is a difficult decision when it's your own car. Easier on me because I'll do what he wants.

Tony,
I tried to call SD today and left a message.
One thought is that you can probably sell the current cam and recoup some of the cost of a new cam.

[ta man]

What is the recommended ICL for that cam?What is the installed ICL?

[Cliff R]

Sucks not knowing which way to go? I'd be opting for a cam change. Moving a cam around in most cases just shifts the power curves. That cam is a TURD in a 455, from my direct testing. Some would deem it a good or even great choice, my direct experience tells me it's too small and LSA too tight for a big CID build with any kind of commpression in it at all.

The 428 is a different animal, but they LOVE to rev, much like 400's, but have cid to produce great mid-range torque. No matter where the cam is degreed, the short seat to seat and 224/230 duration just isn't going to make an strong top end charge in that big of an engine.

FWIW, we built a 428 here couple of years ago, unporte KRE heads, iron intake, q-jet, 10.6 to 1 SCR, 236/242/110 HR cam. 497hp and over 530ft lbs tq. The owner has it in an early GTO with 3.73's and a 4 speed. Has zero traction in low gear, and no problem busting the tires loose in the higher gears on the street. He absolutely LOVES the build, but keep in mid the drivetrain parts are well chosen for the engines power curve......Cliff

[GAGuy]

You have a tough decision to make and certainly plenty of opinions/advise here! This has been a great thread to follow. Any rate here is my personal 2-Cents worth.

I would change the cam, since you are already in there. Beyond that, if spending even more $$$ is not what you to do, I would recommend matching your camshaft to your existing combination. Enjoy the car for now, then later down the line, upgrade to better exhaust manifolds to further enhance what you have.

The old “Super Shops” way of doing things was: 1) First step, install too much camshaft only to find out you lost low end power and your car feels slower. 2) Next step, spend tons more $$$ changing everything else to match the new cam only to find the car is not that great to drive on the street anymore and certainly not on the freeway.

If you are building a car for max ¼ times, spend the extra $$$ and go that route, nothing wrong with that. Otherwise, if you just want a cruiser that is great on the street, save the $$$ and the headaches and match the camshaft to your existing parts. A more aggressive cam may make more peak HP but at a much higher RPM, but you will lose power in the RPM range that is most frequently used with normal street driving. A milder cam will give you more average HP/TQ from idle to 5500 RPM and be a better street driver.

My car weighs 4500lbs (with driver), has 3.08 gears, 27” tall tires, 2100 converter, 455 with mild custom HR cam (218/224 on 114). Over the weekend, I ran a 13.17 @104.95. Engine has a ton of torque, blows the tires off the car and still pulls hard past 5500RPM. A few more tweaks and I should be into the 12s soon. Your tires should be shorter than mine which would make your 2.93 gears roughly the same as my 3.08 gears. I would recommend a cam in the 212/218 to 218/224 on a 112-114 range. This would match how your car is currently set up. Sometimes less is more.