GrannySShifting

iTrader: (10)

Before they were camshaft guys LOL

A.R. Shale Targa

iTrader: (2)

Holy decade of hibernation.....

99Bluz28

iTrader: (35)

I think your brain must be granny shifting. Why would you bump a 10yr old thread only to LOL it?

A.R. Shale Targa

iTrader: (2)

Crazy thing is that whole first page could fit right in Martin's current valve events thread. Interesting read for sure.

DavidBoren

I read this and all of the lsa doesn't matter thread today. Learned a lot. Need to research more. Still have to do A LOT of reading and asking questions about resonance tuning in both the intake manifold/ runners and in the exhaust primaries/ collectors. But overall, I have a much better understanding of how this works.

I really like the cam discussions that talk about the actual valve opening and closing events.

And I think that when the time comes, I am going to take a stab at spec'ing my own cam. Obviously, I will need a much, much better understanding of what is going on. But I prefer to test my own potential for failure, before paying someone else.

BlwnLs1GTO

iTrader: (12)

Just 5+ years ago there were only 2 or 3 people around here that "Spec'd" out your cam for you if you wanted "the best".

5 year's later, everyone's a Cam expert...

DavidBoren

I doubt that everyone is a cam expert. It doesn't matter what forum or bar table you are talking around, pat g and Martin are the names people trust. Yeah, sure, you hear that you should call comp cams directly or whatever every once in a while. But when someone tells you to call a specific person, it's pat g or Martin.

But we live in an era of infinite communication. Every ounce of knowledge is available on a device that you carry in your pocket. I would sure hope that the overall amount of knowledge on ANY subject has vastly increased.

DavidBoren

I'm going to continue to research and read until I have a general idea of what I think... What I think... the proper cam events will be. I will have that cam, MY cam, made and install it. I will dyno and drive MY camshaft before I ask Martin or Pat G what they think my engine should have.

I will be able to email or explain every valve event and why I chose that "spot" for that event. My cam, along with every other aspect of my engine, will be the culmination of everything I have read, seen, learned. I want my first engine build to be and represent everything I deem right and well in an engine.

I'm willing to fail. I'm willing to pay good money for a **** camshaft... IF I am just flat out wrong and design a **** camshaft. At the that point, my pat g or Martin cam will show me the errors of my ways.

It will be a leaning experience, to say the least. But if I was satisfied with what the factory offered, I would buy a crate motor.

I want to test my ability to fail, or succeed, based on what I believe SHOULD work based on what I think and know.

Tony @ Mamo Motorsports

Holy Retro Batman!!

Damn.....kickin it old school

Its actually scary this thread is a decade old cause I still kind of remember it....LOL

Good information....and IMO everything matters concerning cam design including the LSA.

I try to envision all of it at the same time and use LSA at times to dial in the correct amount of good behavior (or bad behavior if that's what my client is looking for) but its all "intertwined".

LSA is great tool to help create a car that's friendly to drive and still make big power.....your trade off is some midrange torque but if your "streeting" it or drag racing....your either under 2500 most of the time or banging the gears at redline and capitalizing on the big power upstairs. I don't care about how much torque occurs at 3600 in that situation.....its no mans land for the most part and I emphasize/cater to the portion of the power band I want to accent (big power and reasonable civility). You cant have it all.....its like the pick two situation (fast-reliable-cheap).....LOL

Anyway....saw this thread and I was like WTF!

Gman.....where are you.....hop in and say hello....LOL

-Tony

DavidBoren

Lately, I have really been trying to understand camshafts. I know everything has to be approached as a system. From intake runner length and design to exhaust primary length, etc. And I had no trouble imagining it all together.

But, then I started reading about camshafts and quickly realized that I don't know **** about any of it.

I had the basic understanding of intake runner length and its effects on flow, same with headers, really generic borderline ignorant understanding of what was going on with all that.

I didn't know about sonic pressure waves, or any of that. And now, the more I read, the more I realize that I have so much more to learn. Every question answered leaves me with two more unanswered.

Like, Tony, how are those small bore mamo-fied 205's coming along?

Jimbo1367

DavidBoren,
I used to want to understand it, but its way too much to grasp for me. I have a hard time remembering stuff now.

I refer to leave curtain things to the pros. LOL

squalor

iTrader: (3)

DavidBoren, I felt the same way as you and I started this thread:
https://ls1tech.com/forums/generatio...ve-events.html

My suggestion to you is to limit your study to your own setup and needs. What you learn about camming a 346 w/243 heads will not apply to a LS3 or a 5.3 turbo. Be honest with yourself about what you want from your engine. For my situation, a light car with a m6, I want a cam that can be a daily driver and give up very little in drivability for the extra power I get.

So now that this old thread is alive again, I have something to add about exhaust valve opening points. Most think that a EVO of 50 to 55 is needed to turn 7000 rpm without exhaust contamination of the intake charge. If your thing is the fastest track time and you don't care about driveability, go for it. If you like to drive your M6 car at 1200 rpm in traffic on your way to work a cam like that will give up alot of low rpm torque. At low rpm you get less cylinder fill so you have less cylinder pressure. Your mix burns slower and you need a longer power stroke to squeeze all the btu's out of it. A EVO of 44 is what the old tr224 used.
Remember these valve events ? IVO>2 IVC>42 EVO>44 EVC>4
They describe a cam that made 446 hp @ 7000 rpm , 224/228 110+0
https://ls1tech.com/forums/generatio...change-15.html

DavidBoren

Keeping my studies to what applies to my proposed build is excellent advice, and honestly is the only way I can even begin to keep track of everything.

I just read an article about resonance tuning over on a gtr forum. Good information, but it's directed towards turbocharged dohc motors.

Keeping my research focus relatively narrow helps me not get overwhelmed... and I have an overwhelming amount still to learn.

In my particular application, I will need a relatively early exhaust valve opening event, because I want to have a static compression ratio of ~12:1 which necessitates an early EVO to bleed excess cylinder pressure.

My main concern is juggling the EVO to satisfy my high compression, yet not make it so early as to limit my useful powerband.

I'm still at the stage where I am trying to understand the terms, the individual events, and their relationship to one another. After I get a little better grasp on the big four events, and a generic idea of what changes to each equate to what changes in the powerband, once I understand that, I will start comparing dyno graphs of similar set-up's and cam-only dyno charts to start getting an idea of the specific timing of these events.

Darth_V8r

iTrader: (4)

David, I was looking at EVO the opposite as you. I'm not sure that the earlier EVO is necessary to accommodate the bleed down from higher pressure.

More like, the pressure bleeds down faster when it's higher due to compression, so you don't need to hold the valve closed to build torque. In other words, the work is completed sooner, so you may as well open the valve earlier to evacuate the cylinder sooner to make more room for fresh air/fuel.

That's one of the reasons you see people post comments like "larger cams respond well to compression". You plan your compression around the camshaft, if that makes sense. One of the many reasons heads and cam should generally be done together.

In your case, the compression ratio should help maintain a nice broad torque curve even if you use a larger cam.

Tony @ Mamo Motorsports

Very close....Looks like Im settling on 1.970 and 1.570 regarding valve size (subject to change slightly but so far that's the way its looking). Ports look great...chambers look great but Im working on better positioning the chambers for a better top cut to chamber transition. Im also targeting 60 cc's as my standard chamber volume knowing these heads will always be bolted on "displacement limited" applications that need a small chamber to get any reasonable amount of compression.

It looks really good....but I'm a perfectionist and want to get it really dialed in before releasing it. I'm probably a month or less away from pictures and an official product launch thread with all the details.

Thanks for hanging in there.....some of the delay is my hectic schedule....some of it is AFR's lag time.

It will be worth the wait....that's the only thing that really matters when its all said and done

-Tony

DavidBoren

Tony, thanks for the reply. I can't wait to see what a set of your mamo-fied heads are capable of. Might sway my decision to stick a 4" crank in the 4.8 and make a 359" undersquare stroker motor. And still put the lsa blower on it using third-gen's adapters. Talk about torque.

Anyways, I did word my previous post incorrectly. Yes, high compression allows an earlier exhaust valve opening. It doesn't require it.

J-Rod

Wow... Holy back from the dead thread.

Here is what I will say. You pick out your valve events, and that determines LSA. I have seen a lot of disagreement on which valve event is most important.

What I typically see people do is say I want this intake lobe, and this exhaust lobe, and this LSA plus or minus this much advance/retard. So, for many people, LSA drives valve events instead of the other way around. I know tons of folks who will look at LSA first, and let that drive their decision point. (112 is an N/A cam, 117 is a turbo cam, etc...)

Its a high level decision point (all things being equal) but it is less than ideal. That also leads to folks using too much lobe, and trying to fix it with a wide LSA and a lot of advance to fix bad valve events.

Yes, after 60+ years of dev on all the various SBC motors, you can with some degree of certainty pick a 224ish cam for a mmotor in the mid 300 inch range and know you can probably make 75-80% of the folks happy using some well know and accepted general rules of thumb.

After that if you need something because you are "special", you need to look at goals, drivability, etc... Those are subjective, and what one person has no issue with, someone else will find unbearable. Again, those goals drive the duration, the valve events, etc....

J-Rod

BTW, these threads should be duplicated in the Advanced tech forum, and you might want to post in there.

joecar

There's no way for most people to know where their engine's valve events should be located (they do not have the necessary tools, equipment and know-how)... so they have to rely on advice from the actual experts who have the experience of having done the tests and measurements (and analyzed the results of)...

then the "knowledge" is passed around in the form of "patterns" that are matched up to engine/vehicle requirements... this is mostly successful, and most times it is sufficiently "close", and for the majority of people (without access to equipment) this has to be sufficient (it's close enough, but no one can determine how much so or not so).

1FastBrick

iTrader: (16)

Glad to hear your still working on them.