Yes sir. If it was mine 100-101 it would be. I’ve never installed a cam straight up In my life.
440 power gains/ aluminum head advantages?
- Thread starter NoahSewal
- Start date
-
Yes sir. If it was mine 100-101 it would be. I’ve never installed a cam straight up In my life.
NoahSewal
Well-Known Member
in your opinion you think i'll be missing a lot at 105? i plan on going to better flowing closed chamber aluminum heads at some point and i know that would run better with a more retarded icl like 105.
NoahSewal
Well-Known Member
how do you determine what icl you install your cams at? do you have a rule of thumb for duration/lift/lobesep compared to the intake centerline you would install it at? it would probably be different depending on the engine.
PRH
Well-Known Member
I’ll be looking forward to the progress report.
PRH
Well-Known Member
Ask 10 people………get 10 answers.
Advancing a cam has always given me better 60 foot times. I’ve had cars as fast as 1.20 in sixty foot. If I can get fast 60 foot times the rest is a cakewalk. But if you can’t set a chassis right this thinking could really screw you.
NoahSewal
Well-Known Member
yeah always true. every engine is different too so there's no hidden key to tuning an engine. i just didn't know if there was some secret rule of thumb i didn't know about. camshafts are always such a touchy subject to begin with because there's so much more to it than just what your lift/duration is. all of that aside i'm just excited to drive my dart again. in the past 2 years ive had maybe 50 drives in total on it. i always end up taking something back apart to do something. i need to take the advice "if it's not broken don't fix it" more seriously ha
Newbomb Turk
Well-Known Member
You go to an engine dyno and pay to figure out where the cam goes.
As an aside, if you are advancing the cam more than 4 degrees from split overlap you have the wrong cam.
In performance engines I always go in straight up. That’s where they make the most power. Not where the cam company says it goes. Split overlap or straight up.
Like I said if you need to go more than 4 ahead you have the wrong cam.
PRH
Well-Known Member
In two of the recent responses we have opposing views.
One view is to run 8 degrees of advance, the other is zero degrees of advance.
For most builds like yours I would typically be in between those two with 3-4 degrees of advance.
After you’ve done it for years, you’ll develop your own preference for where to start.
If you need to go 4 you have the wrong cam and combo.
NoahSewal
Well-Known Member
when you say 3-4 degrees of advance is that from the lobe separation of. 108 or the recommended icl of 105. i know icl and lobe sep have no relation because one is the distance between the two cam lobe centerlines and one is just the position of the intake centerline but i want to clear some confusion for myself
Generally, if the cam is too big for the intended use, advancing the cam can claw back some lost low end which is the usual result of the 'bigger is better' syndrome.
The other extreme, the cam is too small, retarding it can give a little more top end, 'little' being the operative word. Dozens of exceptions apply. That is why it is pretty useless trying to get a cam dialled in to the Nth degree, unless it is duplicating an exact, known combination.
The other extreme, the cam is too small, retarding it can give a little more top end, 'little' being the operative word. Dozens of exceptions apply. That is why it is pretty useless trying to get a cam dialled in to the Nth degree, unless it is duplicating an exact, known combination.
Carnut68
Well-Known Member
From the ICL.
I really don’t care what a dyno tells someone. I’ll go by what the ET slip tells me.
PRH
Well-Known Member
In general, when talking about cam installed positions, I try not to reference it in terms of “advance” or “retard”, because often times not everyone is not on the same page wrt what “straight up” is.
For me, straight up is split overlap, which I view as the c/l for both intake and exhaust being the same.
So, they will be the same as the lsa.
As in, a cam with a 108lsa would have the intake and exhaust c/l of 108.
However, if the cam card showed an intake c/l of 104, some people would call 104 as straight up.
I would call it advanced 4*.
So, to avoid any confusion I prefer to call out the numerical position of where the cam is.
With the example above, I’d say, “it’s a 108lsa, installed at 104”, with no reference to being advanced or not.
Newbomb Turk
Well-Known Member
^^^^ Interesting from you 2 engine builders above. I haven't installed nearly as many cams as you (I've probably done less than a dozen) but I've always considered "straight up" to be what the cam manufacturers' specify the ICL to be on the cam card. Any advance or retard comes from that defined position. I always assumed someone at the manufacturer deciding the cam lobes had a reason fir specifying the ICL where they did. Hence why as stated above it is important to factually describe where it gets installed in absolute terms.
Fast forward to my time spent on engine development with one of the Big 3 (40+ years). All of our cam positions were defined based on computer simulations and then dyno confirmation testing. We put a lot of time into that and designing the rest of the system and manufacturing capabilities to hit that number. But I don't know how every cam grinder out there specs theirs and whether it was known to be ideal.
And as we all know, nothing beats actual experience when we're dealing with these old engines and every custom build. I'm certainly not going to tell John (PBR) (or others!) where to index his cams for best performance!! His numbers speak for themselves.
Fast forward to my time spent on engine development with one of the Big 3 (40+ years). All of our cam positions were defined based on computer simulations and then dyno confirmation testing. We put a lot of time into that and designing the rest of the system and manufacturing capabilities to hit that number. But I don't know how every cam grinder out there specs theirs and whether it was known to be ideal.
And as we all know, nothing beats actual experience when we're dealing with these old engines and every custom build. I'm certainly not going to tell John (PBR) (or others!) where to index his cams for best performance!! His numbers speak for themselves.
NoahSewal
Well-Known Member
this is what i've always thought of it to be. although i haven't built a ton of engines this is just what my mind clicked with. i got it all together with the new ignition box and coil this afternoon and got coolant in it and took it for a drive. i'm not sure if it's faster or if i just haven't driven it in a while but it sure does run good. and hitting the rev limiter at 6k put a smile on my face ha. but when i pulled it in the yard there was a bad oil leak i noticed from the timing cover. specifically from the dowel pin in the cover on the ds. the bolts were tight so all i could do was take it back apart... and found i didn't line the dowel pin up with the hole when i put the cover on and it bent the cover out some around the pin and caused it to leak like crazy above like 4k rpm. i fixed the cover and i'll put it back together more carefully tomorrow. driving it again after a month or so made me remember how much cooler mopars are than your average chev ha
-
