Baby cam for 383
12-15-2016, 11:13 AM
#1
Baby cam for 383 Most of my recent threads have related to a bucking issue while cruising and this one is no different. Basically the car has this light back and forth jerkiness under low load cruising and I can't make it go away. I've been tuning myself for over 2 years now and have managed to dampen a lot of it but I think what I really need is less cam. I think my idea of smooth is more strict than others.
Engine has stock heads with bowl and slight runner porting, 3 angle valve job, 11.5:1 compression.
After a bunch of reading it looks like people like DD cams with low duration and high lift. One cam in particular that popped up often was Lingenfelter's 211/219 .530/.560 112LSA. People were putting down horse power numbers similar to what I have now with a cc503 (about 350whp). Looking at AI and Lloyd's offerings, they have cams that follow that theme. AI has a 220/226 .560/.560 and Lloyd has a 218/224 .570/.565 and a 212/222 .563/.562. Anyone have experience with these cams?
And I don't fully understand how these numbers relate to driveability if someone could help me out. I know higher duration equals more top end performance at the sacrifice of low end torque. I know overlap also increases top end performance at the sacrifice of a smooth cruise and low end torque. What does a higher lift sacrifice besides valve spring life? What difference would I notice between AI's 220/226 .560/.560 and their 220/230 .560/.555 cams that look so similar? I've emailed Phil at AI and he's been polite but not super helpful and not very quick to respond. He essentially said get the tune and sensors looked at otherwise he would recommend a hot cam
And what if I were to get a larger cam like 226/234 but have them put a 115LSA on it so there's no overlap? I just want a smooth cruising DD, thanks guys!
Engine has stock heads with bowl and slight runner porting, 3 angle valve job, 11.5:1 compression.
After a bunch of reading it looks like people like DD cams with low duration and high lift. One cam in particular that popped up often was Lingenfelter's 211/219 .530/.560 112LSA. People were putting down horse power numbers similar to what I have now with a cc503 (about 350whp). Looking at AI and Lloyd's offerings, they have cams that follow that theme. AI has a 220/226 .560/.560 and Lloyd has a 218/224 .570/.565 and a 212/222 .563/.562. Anyone have experience with these cams?
And I don't fully understand how these numbers relate to driveability if someone could help me out. I know higher duration equals more top end performance at the sacrifice of low end torque. I know overlap also increases top end performance at the sacrifice of a smooth cruise and low end torque. What does a higher lift sacrifice besides valve spring life? What difference would I notice between AI's 220/226 .560/.560 and their 220/230 .560/.555 cams that look so similar? I've emailed Phil at AI and he's been polite but not super helpful and not very quick to respond. He essentially said get the tune and sensors looked at otherwise he would recommend a hot cam
And what if I were to get a larger cam like 226/234 but have them put a 115LSA on it so there's no overlap? I just want a smooth cruising DD, thanks guys!
12-15-2016, 01:20 PM
#2
While I have a small cam in my 383 (218/224) it was more for smog compliance. Slight idle note and makes grear TQ down low and flat accross the rpm band (I have a 4200 lb car) Your bucking issue with the 503 is likely more to do with your tune
12-15-2016, 02:55 PM
#3
This is what I've been hearing from everyone for years. Two professionals couldn't smooth it out. The only way I've been able to is by running open loop with an afr of 12.5-13 and inject the fuel onto an open valve. I don't want to have to do that. Maybe it is the tune and I need a cam that's more within my skill level...
12-15-2016, 03:14 PM
#4
TECH Regular
The CC503 has been known to have some cam surge. (LINK) and LINK2. I'm running a custom grind that's real close to the 503 and the surge is very much there when just touching the gas at 60-65 mph or so. Three tuners have not been able to get rid of it, but Moe has gotten it the smoothest. The cam was spec'd by Lloyd: 224/230 .560/.544 112 LSA
Given how little time it spends on the hwy, its not something I'm letting keep me awake at night.
Given how little time it spends on the hwy, its not something I'm letting keep me awake at night.
12-15-2016, 04:06 PM
#5
IDK what about the CC 503 vs other 224/230 grinds makes it more prone to surge as noted by OP and in the links Atlanta posts, above my pay grade.
The 503 is a fairly common cam for a LT1 motor and I would think the qualified popular tuners are familiar enough to get it to behave without surge. IDK if any of the 3 tuners Atlanta used was Ed Wright but I have had perfect results on a few motor combs over the years from Ed. Mail order. But not with a 503 as I have never run one.
Maybe higher stall TC make it more prone...
Would also be good to know what IAC counts are under this surge condition to see if they are pegged at 160....
The 503 is a fairly common cam for a LT1 motor and I would think the qualified popular tuners are familiar enough to get it to behave without surge. IDK if any of the 3 tuners Atlanta used was Ed Wright but I have had perfect results on a few motor combs over the years from Ed. Mail order. But not with a 503 as I have never run one.
Maybe higher stall TC make it more prone...
Would also be good to know what IAC counts are under this surge condition to see if they are pegged at 160....
12-15-2016, 04:29 PM
#7
I know the Linginfelter cam made great power in my friends LT1 (B-body).
Hard to say anything bad about a grind from LE
Your IAC at 60 ish is good. Was just thinking if it was pegged during your surge issues...than something to look at (IAC hole in TB) but in your case, no.
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12-15-2016, 04:43 PM
#9
12-15-2016, 04:55 PM
#10
OP
If you are considering changing cams, LE would get my vote. IDK what his 218/224 cam is but I thought he used the XFI lobes, IDK. The XFI lobes are somewhat aggressive over older grinds. LE's lift specs are what my 218/224 466 cam is (.570 in/.565 ex) with 1:6 RR But I believe LE has a slighter tighter LSA over my 113
I did kill a set of Comp 918 springs in 20k mi (read one broke) with the 466 (fortunately no damage) and went with a Lunatti spring kit I got from Lloyd. He said those springs would last at least 50k miles on my motor
If you are considering changing cams, LE would get my vote. IDK what his 218/224 cam is but I thought he used the XFI lobes, IDK. The XFI lobes are somewhat aggressive over older grinds. LE's lift specs are what my 218/224 466 cam is (.570 in/.565 ex) with 1:6 RR But I believe LE has a slighter tighter LSA over my 113
I did kill a set of Comp 918 springs in 20k mi (read one broke) with the 466 (fortunately no damage) and went with a Lunatti spring kit I got from Lloyd. He said those springs would last at least 50k miles on my motor
12-15-2016, 08:40 PM
#11
OP, what kind of RPMs do you consider typical when cruising around?
The LPE cam is a step in the wrong direction. You are taking a pretty big duration hit across the board and there will be an appreciable loss of power over the 503 despite slightly larger exh lobe. I could see you going to a smaller duration cam like the XFI 466 with faster/taller lobes with little or no loss in performance, but I think your problem may be elsewhere. I had the 503 on my stock cubed motor with no surge if I kept the revs above 1800 on the cluster (horribly inaccurate). Was my daily for a few years.
The LPE cam is a step in the wrong direction. You are taking a pretty big duration hit across the board and there will be an appreciable loss of power over the 503 despite slightly larger exh lobe. I could see you going to a smaller duration cam like the XFI 466 with faster/taller lobes with little or no loss in performance, but I think your problem may be elsewhere. I had the 503 on my stock cubed motor with no surge if I kept the revs above 1800 on the cluster (horribly inaccurate). Was my daily for a few years.
12-15-2016, 08:52 PM
#12
TECH Regular
Mine surges at 1600-1800 or so @ 65'ish. (3.08 on 3k stall) I'm running way too tall of a gear and I'm sure that's part of the issue in my car. The 3.42's are in the garage - just no time to install em yet.
12-16-2016, 05:25 AM
#13
OP, what kind of RPMs do you consider typical when cruising around?
The LPE cam is a step in the wrong direction. You are taking a pretty big duration hit across the board and there will be an appreciable loss of power over the 503 despite slightly larger exh lobe. I could see you going to a smaller duration cam like the XFI 466 with faster/taller lobes with little or no loss in performance, but I think your problem may be elsewhere. I had the 503 on my stock cubed motor with no surge if I kept the revs above 1800 on the cluster (horribly inaccurate). Was my daily for a few years.
The LPE cam is a step in the wrong direction. You are taking a pretty big duration hit across the board and there will be an appreciable loss of power over the 503 despite slightly larger exh lobe. I could see you going to a smaller duration cam like the XFI 466 with faster/taller lobes with little or no loss in performance, but I think your problem may be elsewhere. I had the 503 on my stock cubed motor with no surge if I kept the revs above 1800 on the cluster (horribly inaccurate). Was my daily for a few years.
I wasn't planning on going with the LPE cam because it's so old, just used it as an example/starting point for the type of cam I think I want based on what I've read. I'll most likely go with something from AI or LE when the time comes.
12-16-2016, 06:52 AM
#14
I use to run the cc503 with stock cubes and I didn't get any surge when lightly cruising so I feel like your surge might be tune related. I do experience exactly what you describe with my current cam which is also a 224/230 duration cam but it has 13 degrees of overlap which is what I attribute that to. The cc503 with 3 degrees of overlap should drive great with a good tune and proper converter/gearing and especially so with the additional cubes and compression you have so something must be up.
12-16-2016, 08:12 AM
#15
0* overlap with 226*/234*, 115* LSA
-3* overlap with CC-503, 115* LSA
In my '96 Impala, I ran a high-lift Comp Cam, 224*/230* (like the '503') on a 114* + 4* LSA (-1* overlap). This was in a 396ci. I had no cam surge at all, very slight lope with that cam going through the 3L60E and a 3000 stall converter. Loved that combination.....gobs of torque.
Personally, I wouldn't go with the additional duration; I'd stay with the 224*/230* lobes and increase the lobe separation.....I might also consider a bit LESS duration.
Now....for my question: Do you still have the 4L60E or have you converted to the T-56 already? Also.....what gears are you running?
KW
Last edited by KW Baraka; 12-16-2016 at 08:29 AM.
12-16-2016, 10:29 AM
#19
OK. I saw where you have about 11.5:1 compression; didn't notice this before. Would you happen to know what your quench is?
IMO, that much compression will require a bit MORE duration versus less duration; you'll want to bring your Dynamic Compression Ratio down a bit from where it is.
I would consider a cam in the 230*/234* range with a 112* to 114* + 4* LSA.
This will result in a bit more overlap (about 5* to 8*).....but really, it ain't the overlap that's causing your issues. The cam in my 398ci has 18* overlap and I don't get anything like what you describe.
You either have an ignition/detonation issue, or a bad tune. Did the two professional tuners do work via mail order, or did they actually road-tune your car? If they didn't road-tune it, then you need to have that done. If they did road-tune the car, then you most issues outside of the tune.
KW
12-16-2016, 10:44 AM
#20
Village Troll 
iTrader: (2)
Don't install gears until you select a cam, get it on the dyno and find out where power peak is. BTW, as far as the 211/219 goes, I forgot to mention, even though it's a good cam and was initially designed for a 383, the profile was meant to pass smog in a CARB engine that was legal for sale in all states. It was meant as a boost in power while pretty much keeping the stock power curve while making more power and torque. I ran the cam for years, but there have been lots of changes since then. Just FYI.