Budget 383 dyno results! Couple issues...
03-06-2014, 09:08 PM
#41
I don't know how demanding those Voodoo cam lobes are on valve springs, but those 918 springs sound marginal to me for those cam specs. I wouldn't use those springs for much more than a CC503-ish cam.
I'm running about 160 on the seat with beehives. On paper, my cam doesn't look much different from yours .. 228/234 .617 lift w/1.6's. It peaks at 6400 (in a 350) but pulls cleanly past 7000.
BUT..... with that said, I see in your post just above from last July that the car pulled cleanly to 6500. So......if you trust your tach, I'd say it's more likely that something went south in the ignition rather than in the valvetrain.
Are you running stiffer pushrods and NSA rockers?
I'm running about 160 on the seat with beehives. On paper, my cam doesn't look much different from yours .. 228/234 .617 lift w/1.6's. It peaks at 6400 (in a 350) but pulls cleanly past 7000.
BUT..... with that said, I see in your post just above from last July that the car pulled cleanly to 6500. So......if you trust your tach, I'd say it's more likely that something went south in the ignition rather than in the valvetrain.
Are you running stiffer pushrods and NSA rockers?
03-06-2014, 09:14 PM
#42
Definitely get a stiffer spring and lighten up the valvetrain if you can. Titanium retainers are always good.
I have the Crane 10308-1 kit with 130 seat @ 1.850 and 400 open @ 1.150 and have read that they're on the edge with something like a cc306. Granted, the steel retainers are dual springs are heavier but I think those beehives you're using aren't enough.
I have the Crane 10308-1 kit with 130 seat @ 1.850 and 400 open @ 1.150 and have read that they're on the edge with something like a cc306. Granted, the steel retainers are dual springs are heavier but I think those beehives you're using aren't enough.
03-06-2014, 09:20 PM
#43
"My" new MSD Opti proved to be the source of my high RPM stumble, car would just nose over around 5200-5500 RPM. Chased springs, injectors, plugs/wires, tune (and Ed was gracious enough to look at data even though my issue was not tune related). Put back on my used AC Delco Opti and it has been on years now.
On the valve seals for the CM heads. You say the LSx ones fit fine, but any machinest would mic the stand and order the size. Summit, JEGS, etc all have them from various (Trick Flo) brands. I get the full jacket Viton seals. Can't remember size but just mic your heads to find out if the LSx ones are not spot on.
springs, I have the Comp 918's on ported AL heads w 2.02/1.60 Ferra valves in a small XFI cam 383.
On the valve seals for the CM heads. You say the LSx ones fit fine, but any machinest would mic the stand and order the size. Summit, JEGS, etc all have them from various (Trick Flo) brands. I get the full jacket Viton seals. Can't remember size but just mic your heads to find out if the LSx ones are not spot on.
springs, I have the Comp 918's on ported AL heads w 2.02/1.60 Ferra valves in a small XFI cam 383.
We'll see what a new opti does first...
03-07-2014, 07:23 AM
#44
Village Troll 
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I too had a bad opti that I thought was valve float at first, however it wouldn't hurt to get the springs tested, or at least get one of these and test as many springs as you can reach:
http://www.summitracing.com/parts/mor-62390/overview/
http://www.summitracing.com/parts/mor-62390/overview/
03-07-2014, 09:54 AM
#45
I too had a bad opti that I thought was valve float at first, however it wouldn't hurt to get the springs tested, or at least get one of these and test as many springs as you can reach:
http://www.summitracing.com/parts/mor-62390/overview/
http://www.summitracing.com/parts/mor-62390/overview/
Does anyone know if the high rpm miss issues are caused by the optical sensor portion; or the cap and rotor?
I may just put the LTCC conversion on my existing MSD with some LS1 or Northstar coils to be done with the high voltage going through the opti....I don't want to be one of those guys putting new optis, cap and rotors, on every 6 months...it's a PITA! And no, I'm not going to spend $2200+ on the 24x conversion, that cost more than my entire forged 383 shortblock and would have to pay AGAIN to get it tuned...no thanks! I'd get a junkyard LS before I did that 
03-07-2014, 11:25 AM
#46
Village Troll
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With mine I had a Delco opti. Changed it with a Delco cap/rotor and it did not fix the problem. Put in a Delphi and the problem disappeared, therefore I think mine was a sensor/wheel issue.
03-07-2014, 02:45 PM
#47
WTF?!...I may just end up with a Duralast opti from autozone (with lifetime warranty) like so many other opti horror threads and be sentenced to a lifetime of hard labor opti replacement lol....I can't see spending nearly $500 for a craps shoot and then being told to go f@&K myself if it's a bad opti
03-07-2014, 03:18 PM
#48
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For whatever its worth I run the Manley Nextek 221438-16 springs as recommended for my cam with fairly aggressive lobes and 614 lift intake and exhuast
The specs on those are 150 lbs at 1.8" installed height and 375 at 1.150" and the rate is 353 lbs per inch.
I spin my 355 cleanly past 6700 with no problems, I highly doubt the lunati lobes are more aggressive than mine
The specs on those are 150 lbs at 1.8" installed height and 375 at 1.150" and the rate is 353 lbs per inch.
I spin my 355 cleanly past 6700 with no problems, I highly doubt the lunati lobes are more aggressive than mine
03-07-2014, 06:16 PM
#50
And for that very reason, I just bought a Duralast Gold opti from autozone to be installed in the morning....It's a roll of the dice for sure lol....I'm feeling lucky though
Going from a $500 opti to a $159 autozone special with lifetime warranty....this should be interesting. I'll post my findings upon the dissection of the MSD opti....who wants to buy a lightly used MSD opti?
03-07-2014, 06:34 PM
#52
Yea, it's getting rough out there for a LT1 lover....PCM for less also mentioned they no longer have the software to dyno tune LT1's anymore after the PC with that program crashed. I feel fortunate to be one of the last. At least they still do mail order tunes by Brian in the Ohio location.
03-07-2014, 09:21 PM
#53
Question for valve spring experts:...how much more could I possibly shim these 330# seat pressure springs over installed height (1.8) to add more seat pressure (135-155#) ?
Type: .600" Lift Ovate Beehive Valve Spring
O.D. Big End: 1.290"
I.D. Big End: 0.885"
O.D. Small End: 1.055"
I.D. Small End: 0.650"
Coil Bind: 1.140"
Seat Load: 130@1.800"
Open Load: 318@1.200"
Rate (lbs/in): 313
Type: .600" Lift Ovate Beehive Valve Spring
O.D. Big End: 1.290"
I.D. Big End: 0.885"
O.D. Small End: 1.055"
I.D. Small End: 0.650"
Coil Bind: 1.140"
Seat Load: 130@1.800"
Open Load: 318@1.200"
Rate (lbs/in): 313
03-09-2014, 04:35 PM
#55
Well, the past couple of days have been quite the opti adventure I have good and bad news about Autozone "Duralast gold" optis. First the bad, I drove to my buddies house for some help since he seems to enjoy these sorts of things...my car is even more of a PITA than normal, due to having an electric WP, the fans have to come out because the electric WP butts right up against it, and we decided might as well pull the radiator too for ease of access. The first replacement opti was a complete dud....no spark to the coil at all Luckily we were smart enough not to put the WP on and just test it by attempting to start the engine a couple seconds, no matter what we checked or fiddled with NADA! It was just one of those defective optis I've heard so much about, of course there's only one other full complete opti (cap and rotor included) on the other side of town and it's getting late, so had to leave the car in his driveway dead. Oh yea, the MSD opti had a crack in the billet case very close to the driveshaft, and one of the rotor screws was not tightened at all....not sure if that would be causing a high RPM breakup or not. Otherwise the MSD opti looked clean inside, no other obvious issues.
Today, returned the defective opti for another brand new Duralast gold opti, (every other one in town was only the optical sensor portion, cap and rotor sold separately, and there was a $40 core charge...total ripoff) Luckily, this next opti would start the car, so reassembled everything, my friend supposedly labeled the wires correctly, anyways, the car ran like absolute garbage on the way home, misfiring, backfiring at low rpm, down 200hp, just terrible...he kept insisting the wires were on correctly, and blamed another bad opti but I had to double check once home and sure enough 6&8 wires were crossed
I've beat on it like a rented mule for a bit today to 6500 RPM and it seems to be pulling stronger at 5000+ RPM, although I'll admit it's hard to tell if it's 50hp stronger than before or if there is valve float just by the seat of my pants; this is the fastest car I've ever driven so hard to tell. Bottom line, AZ optis have a 50/50 success rate in my experience.
I may just take the advice on here to step up to a better valve spring....Question: if I put on these other dual LS valve springs, do I have to re-measure pushrod length? Their installed height is only .010 higher
Would this crack in the MSD billet opti housing and the untightened rotor cap screw cause upper RPM issues?
Luckily we were smart enough not to put the WP on and just test it by attempting to start the engine a couple seconds, no matter what we checked or fiddled with NADA! It was just one of those defective optis I've heard so much about, of course there's only one other full complete opti (cap and rotor included) on the other side of town and it's getting late, so had to leave the car in his driveway dead. Oh yea, the MSD opti had a crack in the billet case very close to the driveshaft, and one of the rotor screws was not tightened at all....not sure if that would be causing a high RPM breakup or not. Otherwise the MSD opti looked clean inside, no other obvious issues.Today, returned the defective opti for another brand new Duralast gold opti, (every other one in town was only the optical sensor portion, cap and rotor sold separately, and there was a $40 core charge...total ripoff) Luckily, this next opti would start the car, so reassembled everything, my friend supposedly labeled the wires correctly, anyways, the car ran like absolute garbage on the way home, misfiring, backfiring at low rpm, down 200hp, just terrible...he kept insisting the wires were on correctly, and blamed another bad opti but I had to double check once home and sure enough 6&8 wires were crossed
I've beat on it like a rented mule for a bit today to 6500 RPM and it seems to be pulling stronger at 5000+ RPM, although I'll admit it's hard to tell if it's 50hp stronger than before or if there is valve float just by the seat of my pants; this is the fastest car I've ever driven so hard to tell. Bottom line, AZ optis have a 50/50 success rate in my experience. I may just take the advice on here to step up to a better valve spring....Question: if I put on these other dual LS valve springs, do I have to re-measure pushrod length? Their installed height is only .010 higher
Would this crack in the MSD billet opti housing and the untightened rotor cap screw cause upper RPM issues?
Last edited by ahritchie; 03-09-2014 at 05:00 PM.
. Can't hurt to have a spare opti on hand!
03-23-2015, 09:10 AM
#58
**Update** Well it's been a year my autozone Chinese optispark experiment ended as could be expected back in January; and it self destructed in a loud and embarrassing fashion with a shotgun like backfires in front of a carwash, which resulted in tow home, not before some high school kids from the car wash came over to check out the car and give me their pity, condolences, and advice assuming I blew the motor... I told them it was probably just the optispark and they looked at me like I'm crazy. 
Anyway, it sat a couple months as it's been too cold to be fooling with opti replacement until yesterday. Good news is I had MSD rebuild the old one I had (that had a high RPM misfire) and got them to send me the fresh air hoses that was missing on mine before. This new MSD they sent me fired her right up and eliminated a pesky low RPM sporadic stumble/backfire the autozone one had before it finally kicked the bucket 10 months and about 2000 miles after install...POS! This being the 6th optispark over my car's lifetime it finally seems like I have a decent opti! Only time will tell...I'm feeling good about this one though and it's fully vented from in air intake/engine vacuum now.
I told them it was probably just the optispark and they looked at me like I'm crazy. Anyway, it sat a couple months as it's been too cold to be fooling with opti replacement until yesterday. Good news is I had MSD rebuild the old one I had (that had a high RPM misfire) and got them to send me the fresh air hoses that was missing on mine before. This new MSD they sent me fired her right up and eliminated a pesky low RPM sporadic stumble/backfire the autozone one had before it finally kicked the bucket 10 months and about 2000 miles after install...POS! This being the 6th optispark over my car's lifetime it finally seems like I have a decent opti! Only time will tell...I'm feeling good about this one though and it's fully vented from in air intake/engine vacuum now.
03-23-2015, 11:55 AM
#60
Negative....This cam only peaks at around 6400RPM, (probably more like 6200 on a 383). I have not really beat on it just yet; the roads were damp when I test drove it, so did not push it past 5k. I still need to get my new Lunati dual springs installed and hardened pushrods ASAP now I've got my opti woes behind me. (knock on wood) It is pulling and running smoother though for sure...
I'll definitely post another update once I get the valvetrain redone; I'm going to get JHR Performance in Mooresville NC to do this for me soon!
) It is pulling and running smoother though for sure...I'll definitely post another update once I get the valvetrain redone; I'm going to get JHR Performance in Mooresville NC to do this for me soon!
