New 383 troubles
07-23-2014, 07:30 PM
#1
Burning Brakes
Thread Starter
New 383 troubles
New crate 383 wont idle in drive and seems weak out the hole. Idle is 9ish in park and sounds fine, drives fine at higher speeds but drops to 5K rpms and stalls when I come to a stop. I'm running stock torque converter with a th350. Could my torque converter be bad or do I just need to upgrade to a 2400 stall thats been recommended?
07-23-2014, 08:14 PM
#2
Safety Car
Not enough info , but I would say timing and carb are not set up properly
07-23-2014, 08:51 PM
#4
Burning Brakes
Thread Starter
2000-2400 stall converter is recommend for this 383. Anyone know what factor stall is for a 79 TH350? And does those numbers sound about right?
This is my engine http://www.summitracing.com/parts/mll-bp3830ctc1
This is my engine http://www.summitracing.com/parts/mll-bp3830ctc1
07-23-2014, 09:15 PM
#5
Safety Car
2000-2400 stall converter is recommend for this 383. Anyone know what factor stall is for a 79 TH350? And does those numbers sound about right?
This is my engine http://www.summitracing.com/parts/mll-bp3830ctc1
This is my engine http://www.summitracing.com/parts/mll-bp3830ctc1
07-23-2014, 09:33 PM
#6
Burning Brakes
Thread Starter
Here are some specs
Camshaft: Steel Flat Tappet
Cam Lift: .487” Intake / .508” exhaust
Cam Duration @ .050”: 234 deg. Intake / 244 deg. Exhaust
Lobe Separation: 112 Degree
Cylinder Heads: Cast Iron Vortec.
Combustion Chamber: 64cc
Valves: 2.02” Intake/ 1.60” Exhaust
Rocker Arms: Stamped Steel, 1.5:1 Ratio
Valve Springs: 1.25” Diameter
Balance: External
Ignition Timing: Base 10 degrees BTDC, 32 degrees total
I got this info from http://paceperformance.com/i-8396354...rear-seal.html
Camshaft: Steel Flat Tappet
Cam Lift: .487” Intake / .508” exhaust
Cam Duration @ .050”: 234 deg. Intake / 244 deg. Exhaust
Lobe Separation: 112 Degree
Cylinder Heads: Cast Iron Vortec.
Combustion Chamber: 64cc
Valves: 2.02” Intake/ 1.60” Exhaust
Rocker Arms: Stamped Steel, 1.5:1 Ratio
Valve Springs: 1.25” Diameter
Balance: External
Ignition Timing: Base 10 degrees BTDC, 32 degrees total
I got this info from http://paceperformance.com/i-8396354...rear-seal.html
07-23-2014, 09:37 PM
#9
Safety Car
Here are some specs
Camshaft: Steel Flat Tappet
Cam Lift: .487” Intake / .508” exhaust
Cam Duration @ .050”: 234 deg. Intake / 244 deg. Exhaust
Lobe Separation: 112 Degree
Cylinder Heads: Cast Iron Vortec.
Combustion Chamber: 64cc
Valves: 2.02” Intake/ 1.60” Exhaust
Rocker Arms: Stamped Steel, 1.5:1 Ratio
Valve Springs: 1.25” Diameter
Balance: External
Ignition Timing: Base 10 degrees BTDC, 32 degrees total
I got this info from http://paceperformance.com/i-8396354...rear-seal.html
Camshaft: Steel Flat Tappet
Cam Lift: .487” Intake / .508” exhaust
Cam Duration @ .050”: 234 deg. Intake / 244 deg. Exhaust
Lobe Separation: 112 Degree
Cylinder Heads: Cast Iron Vortec.
Combustion Chamber: 64cc
Valves: 2.02” Intake/ 1.60” Exhaust
Rocker Arms: Stamped Steel, 1.5:1 Ratio
Valve Springs: 1.25” Diameter
Balance: External
Ignition Timing: Base 10 degrees BTDC, 32 degrees total
I got this info from http://paceperformance.com/i-8396354...rear-seal.html
07-23-2014, 11:33 PM
#11
Race Director
Here are some specs
Camshaft: Steel Flat Tappet
Cam Lift: .487” Intake / .508” exhaust
Cam Duration @ .050”: 234 deg. Intake / 244 deg. Exhaust
Lobe Separation: 112 Degree
Cylinder Heads: Cast Iron Vortec.
Combustion Chamber: 64cc
Valves: 2.02” Intake/ 1.60” Exhaust
Rocker Arms: Stamped Steel, 1.5:1 Ratio
Valve Springs: 1.25” Diameter
Balance: External
Ignition Timing: Base 10 degrees BTDC, 32 degrees total
I got this info from http://paceperformance.com/i-8396354...rear-seal.html
Camshaft: Steel Flat Tappet
Cam Lift: .487” Intake / .508” exhaust
Cam Duration @ .050”: 234 deg. Intake / 244 deg. Exhaust
Lobe Separation: 112 Degree
Cylinder Heads: Cast Iron Vortec.
Combustion Chamber: 64cc
Valves: 2.02” Intake/ 1.60” Exhaust
Rocker Arms: Stamped Steel, 1.5:1 Ratio
Valve Springs: 1.25” Diameter
Balance: External
Ignition Timing: Base 10 degrees BTDC, 32 degrees total
I got this info from http://paceperformance.com/i-8396354...rear-seal.html
Here is a cam that has the same lift and duration as yours.
http://www.summitracing.com/parts/su...make/chevrolet
Notice the operating range of 3000-6500?
Notice it says this:
Lopey idle, mid-upper rpm power. Works best with 10:1-11:1 compression, 3,000+ stall, and gearing.
When you stomp on it from a dead stop how long will it take to get into the powerband? It sure won't roast the tires and get there quick. You asked before you bought this engine and these issues were brought up (see below)but you bought it anyway. Now getting the performance you expect will take a ton of work and a bunch more money. When you post a question you need to listen to the answers.
The Cam is the heart of the engine it controls the timing of everything. It can make a huge difference...Some can increase dynamic compression and some can bleed it off.
You can easily get larger HP numbers by swapping it out but at the same time you can easily hurt the actual power output in the actual rpm range you would use most on the street. There are a lot of guys that just don't get it and stick the biggest cam they can in the engine only to find out that 450hp at 6500rpm cost them a lot of torque and HP down in the actual range where they would feel and use it most in all situations except when flying at 6,000+ rpm. This is also why if the average person drove two identical vettes except one being an L48 and the other being an L82 that person would mistake the L48 for the stronger L82 because the L48 starts making power sooner and has more torque which throws you back in the seat. Basically everything is a trade off as you can tune it to make more power but at a cost somewhere else like torque at lower rpms and vs versa... things like increasing displacement and better flow are solutions around it this limitation to a point.
You have to make sure the cam you select is a good match for your gearing and stall/ torque converter. If not you will have a 400 HP slug that can't get out of its own way until it finally gets to 50-60 MPH.
You can easily get larger HP numbers by swapping it out but at the same time you can easily hurt the actual power output in the actual rpm range you would use most on the street. There are a lot of guys that just don't get it and stick the biggest cam they can in the engine only to find out that 450hp at 6500rpm cost them a lot of torque and HP down in the actual range where they would feel and use it most in all situations except when flying at 6,000+ rpm. This is also why if the average person drove two identical vettes except one being an L48 and the other being an L82 that person would mistake the L48 for the stronger L82 because the L48 starts making power sooner and has more torque which throws you back in the seat. Basically everything is a trade off as you can tune it to make more power but at a cost somewhere else like torque at lower rpms and vs versa... things like increasing displacement and better flow are solutions around it this limitation to a point.
You have to make sure the cam you select is a good match for your gearing and stall/ torque converter. If not you will have a 400 HP slug that can't get out of its own way until it finally gets to 50-60 MPH.
Last edited by 63mako; 07-24-2014 at 12:03 AM.
07-24-2014, 12:16 AM
#12
Race Director
Easiest, cheapest fix is to do this. It will cost you peak horsepower. It will be much quicker with your combination. This drops your cam duration 15 degrees getting you to the powerband your car can operate in at an RPM you will use and will run on pump fuel with your 9.5 to 1 compression.
http://www.summitracing.com/parts/lu...make/chevrolet
http://www.summitracing.com/parts/lu...make/chevrolet
Last edited by 63mako; 07-24-2014 at 12:19 AM.
07-24-2014, 07:38 AM
#13
Race Director
My stroker runs VERY well - WITH the stock 3:08 rear gear.
It lights the rear wheels very easy and pulls very strong
But I did install the stall speed torque converter as recommended.....
I think the stall speed helps a LOT....allows the engine to ramp up before launching.
But, kinda a PITA now that your engine is in. Either gotta pull the engine or the transmission to install it now.
Torque converter I used:
$211.97 Summit
http://www.summitracing.com/parts/sum-g2702-1/overview/
I'm sure your engine is putting out the full 405HP..... you just have some more tinkering to do.
It lights the rear wheels very easy and pulls very strong
But I did install the stall speed torque converter as recommended.....
I think the stall speed helps a LOT....allows the engine to ramp up before launching.
But, kinda a PITA now that your engine is in. Either gotta pull the engine or the transmission to install it now.
Torque converter I used:
$211.97 Summit
http://www.summitracing.com/parts/sum-g2702-1/overview/
I'm sure your engine is putting out the full 405HP..... you just have some more tinkering to do.
07-24-2014, 08:21 AM
#14
Burning Brakes
Thread Starter
I'm not sure mine has the 3.08. Its a 79 and all the info I've found says 79s have a 3.55 rear. But who knows, after 35 years whats in there. But if it does have a 3.55 would 63Mako's recommendation still be accurate? I also have long tube headers, no cats and true dual exhaust.
Anyway I'm gonna get the timing and carb checked today and see if it helps any.
I really appreciate all the help and comments I receive from this forum. Thanks
Anyway I'm gonna get the timing and carb checked today and see if it helps any.
I really appreciate all the help and comments I receive from this forum. Thanks
Last edited by Bloodzone; 07-24-2014 at 11:02 AM.
07-24-2014, 07:18 PM
#15
Race Director
I'm not sure mine has the 3.08. Its a 79 and all the info I've found says 79s have a 3.55 rear. But who knows, after 35 years whats in there. But if it does have a 3.55 would 63Mako's recommendation still be accurate? I also have long tube headers, no cats and true dual exhaust.
Anyway I'm gonna get the timing and carb checked today and see if it helps any.
I really appreciate all the help and comments I receive from this forum. Thanks
Anyway I'm gonna get the timing and carb checked today and see if it helps any.
I really appreciate all the help and comments I receive from this forum. Thanks
I got a PM that felt I went off on a rant and essentially called you an idiot. If it was taken this way I apologize as that is not what I meant to do. Your combo is not well matched. Tuning does need to be first on your list. If it does not get you what is expected further modifications will.
Last edited by 63mako; 07-24-2014 at 07:25 PM.
07-24-2014, 07:22 PM
#16
Safety Car
If it makes you feel any better I changed my mind and bought and sold a new cam 3 times as I was learning about how they work and building my engine... As mako said its a common mistake and one that's too often encouraged in forums like these.... BIGGER IS NOT ALWAYS BETTER guys!
Even when setup right, Some guys find that the car becomes too difficult to drive and end up selling it or afraid to to drive it after bumping the HP up in the 400+ range.
On a plus note a bigger stall will mask the problem and work as a partial work around.
Even when setup right, Some guys find that the car becomes too difficult to drive and end up selling it or afraid to to drive it after bumping the HP up in the 400+ range.
On a plus note a bigger stall will mask the problem and work as a partial work around.
07-24-2014, 07:52 PM
#17
Race Director
If it makes you feel any better I changed my mind and bought and sold a new cam 3 times as I was learning about how they work and building my engine... As mako said its a common mistake and one that's too often encouraged in forums like these.... BIGGER IS NOT ALWAYS BETTER guys!
Even when setup right, Some guys find that the car becomes too difficult to drive and end up selling it or afraid to to drive it after bumping the HP up in the 400+ range.
On a plus note a bigger stall will mask the problem and work as a partial work around.
Even when setup right, Some guys find that the car becomes too difficult to drive and end up selling it or afraid to to drive it after bumping the HP up in the 400+ range.
On a plus note a bigger stall will mask the problem and work as a partial work around.
http://forums.corvetteforum.com/c3-t...ys-better.html
07-24-2014, 07:59 PM
#18
Burning Brakes
Thread Starter
No hard feelings Mako I need all the help I can get.
Car is in shop getting timing and carb dialed in. They are also checking what rear I have 3.55 or 3.08 (hoping for 3.55) I talked to blueprint and verified stall of 2000-2400 for my engine. I need to decide between adding stall to my th350 or upgrading to a 200r4 or 700r4 with correct stall or switching cams.
This is what I'm thinking, you guys tell me if I'm offbase.
3.08 rear do cam first
3.55 do stall first
I'll know more tomorrow night. Thanks again for all the help.
Car is in shop getting timing and carb dialed in. They are also checking what rear I have 3.55 or 3.08 (hoping for 3.55) I talked to blueprint and verified stall of 2000-2400 for my engine. I need to decide between adding stall to my th350 or upgrading to a 200r4 or 700r4 with correct stall or switching cams.
This is what I'm thinking, you guys tell me if I'm offbase.
3.08 rear do cam first
3.55 do stall first
I'll know more tomorrow night. Thanks again for all the help.
07-24-2014, 08:24 PM
#19
Safety Car
If it makes you feel any better I changed my mind and bought and sold a new cam 3 times as I was learning about how they work and building my engine... As mako said its a common mistake and one that's too often encouraged in forums like these.... BIGGER IS NOT ALWAYS BETTER guys!
Even when setup right, Some guys find that the car becomes too difficult to drive and end up selling it or afraid to to drive it after bumping the HP up in the 400+ range.
On a plus note a bigger stall will mask the problem and work as a partial work around.
Even when setup right, Some guys find that the car becomes too difficult to drive and end up selling it or afraid to to drive it after bumping the HP up in the 400+ range.
On a plus note a bigger stall will mask the problem and work as a partial work around.