engine performance
11-27-2015, 12:36 PM
#21
Le Mans Master
If that is a 12" jeggs stall converter those are pretty low quality.
I found out from a torque converter builder that the way those stalls are reached is by bending the fins and not adjusting the stator. This almost entirely eliminates your torque multiplication, the really nice thing about a torque converter.
A better 10" torque converter will give better results.
I found out from a torque converter builder that the way those stalls are reached is by bending the fins and not adjusting the stator. This almost entirely eliminates your torque multiplication, the really nice thing about a torque converter.
A better 10" torque converter will give better results.
11-27-2015, 12:41 PM
#22
Racer
If that is a 12" jeggs stall converter those are pretty low quality.
I found out from a torque converter builder that the way those stalls are reached is by bending the fins and not adjusting the stator. This almost entirely eliminates your torque multiplication, the really nice thing about a torque converter.
A better 10" torque converter will give better results.
I found out from a torque converter builder that the way those stalls are reached is by bending the fins and not adjusting the stator. This almost entirely eliminates your torque multiplication, the really nice thing about a torque converter.
A better 10" torque converter will give better results.
11-27-2015, 12:47 PM
#23
Drifting
The cam specs match an old Wolverine grind from the 70's. It was used on Fords and Chevy's. With that large of head with that camshaft it is going to be lazy. A pump gas 383 combination of parts and a hyd roller will make 500HP/500#/ft of torque easily.
11-27-2015, 01:44 PM
#24
Race Director
Hey guys , I built a 383 for the 76. It dyno at 425hp and 418 torque, I have 3:73 rear gear's and th350 trans with a 2700-3000 (jegs) stall. The car is not as fast as I would have thought. My first thought it was the cam, and a friend thought it was the convertor cause the motor made pretty good hp and tq. Just not getting it to the rear. Timing is 18 and all in at 50 at 2500-2700, the motor temp are 175-180 in the summer heat. A little more on the motor 10.5 comp. rpm air gap in take, pmb profiler alum. heads, 2.10 intake 1.600 exhaust, 210 intake runners, howards flat tap. cam .488 intake 509 exhaust intake 234 @50 and 244 @ 50 780 quick fuel vac. secondary. and thoughts Thanks
Disconnect the vacuum advance and rev it to 3000 RPM and shoot for 32-35 degs. total advance and let the rest sit where it is. On a chassis dyno you would only make about 300RWHP and you would need a matching stall converter to smoke the tires. I had a 355ci that made 300Rwhp and was a blast to drive and would spin the tires in second gear ( be it on crappy hard BFG's )
So the first thing I would do is disconnect the vacuum advance and time it for 34 degs at 2500-3000rpm. I would leave it disconnected and take it out for a spin and see what happens. 210 heads are not too big for properly sorted 383ci engine.
One thing missing, what is your compression ratio ?
Last edited by MotorHead; 11-27-2015 at 01:47 PM.
11-27-2015, 05:02 PM
#25
Advanced
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11-27-2015, 05:31 PM
#26
Instructor
Thread Starter
The dog ate the dyno sheet, peak tq was at 3800rpm and hp was at 5500rpm and still going up. Told operator that was good. Just a little nervous. I think to keep the peace with you know who, I'll do the convertor 1st and see, maybe the cam next. The timing was done with a advance timing light. First with vac. plugged I think it was around 18 and then it hooked up and engine to 2500 rpm that's were I'm getting 50 total. I'll check all that before I do anything. This all so may help it is a jegs hei
11-27-2015, 06:25 PM
#27
Race Director
You make that sound like there is no arguing the point. I happen to think there is no mismatch with parts. He still has over 400HP and I think there is something wrong elsewhere. I would like to know the advance at 2500RPM without the vacuum advance.
11-27-2015, 08:40 PM
#28
X2 Timing needs a fine tune to begin analysis.
11-28-2015, 10:37 AM
#30
Instructor
Thread Starter
Hey guys , I built a 383 for the 76. It dyno at 425hp and 418 torque, I have 3:73 rear gear's and th350 trans with a 2700-3000 (jegs) stall. The car is not as fast as I would have thought. My first thought it was the cam, and a friend thought it was the convertor cause the motor made pretty good hp and tq. Just not getting it to the rear. Timing is 18 and all in at 50 at 2500-2700, the motor temp are 175-180 in the summer heat. A little more on the motor 10.5 comp. rpm air gap in take, pmb profiler alum. heads, 2.10 intake 1.600 exhaust, 210 intake runners, howards flat tap. cam .488 intake 509 exhaust intake 234 @50 and 244 @ 50 780 quick fuel vac. secondary. and thoughts Thanks
11-28-2015, 10:44 AM
#31
Drifting
To give you that seat of the pants acceleration the can needs to be shorter on duration.
11-28-2015, 12:18 PM
#34
Race Director
425hp @ 5500 RPM, given a modest 25HP gain at 6500RPM that is 450HP.
The question remains, what is the timing at 2500RPM with the vacuum can disconnected ? If you could answer that then that would help instead of blaming the heads or cam without all the information needed to properly diagnose engine performance (101).
The question remains, what is the timing at 2500RPM with the vacuum can disconnected ? If you could answer that then that would help instead of blaming the heads or cam without all the information needed to properly diagnose engine performance (101).
11-28-2015, 01:17 PM
#35
Le Mans Master
All good points that need to be looked at. The torque converter for sure and the timing as well. The combo, may be mathematically wrong, but to start over again, would be the worse of two evils. Might as well wait for the next rebuild or just pull it out and put it together as a more viable option, up to the OP.
A lot of recent threads here concern the carb and how to get it right and that cannot be overlooked. How it's set up, jetting, accelerator pump, cam, opening of the secondaries, how big of a squirt it gets and on and on, make a huge difference in how it runs.
We'll spend thousands and thousands of dollars on a highly modified engine, but won't spend less than $200 on an reliable A/F meter, which in my opinion, is a must-have, because it will save you countless hours guessing or reading the plugs (like who wants to pull plugs on a hot engine?). Super easy to install, super easy to read and along with the torque converter and the timing, this should be the next step.
Even with the wrong combo, the OP will know what's going on, at least with the A/F mixture and then eliminate the other factors from there. Just my $.02. Glad I have mine, it's been very helpful.
A lot of recent threads here concern the carb and how to get it right and that cannot be overlooked. How it's set up, jetting, accelerator pump, cam, opening of the secondaries, how big of a squirt it gets and on and on, make a huge difference in how it runs.
We'll spend thousands and thousands of dollars on a highly modified engine, but won't spend less than $200 on an reliable A/F meter, which in my opinion, is a must-have, because it will save you countless hours guessing or reading the plugs (like who wants to pull plugs on a hot engine?). Super easy to install, super easy to read and along with the torque converter and the timing, this should be the next step.
Even with the wrong combo, the OP will know what's going on, at least with the A/F mixture and then eliminate the other factors from there. Just my $.02. Glad I have mine, it's been very helpful.
11-28-2015, 05:47 PM
#36
Instructor
Thread Starter
the car is kinda put away for the winter, however if I can I will check the timing, I can go and get another dyno sheet printed off. I'm, pretty sure I was fat on the runs and I down sizes the jets and it runs better. I think a new convertor is were to start, I called TCI and they gave me their into he stated it should make a difference
11-28-2015, 06:56 PM
#37
Burning Brakes
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2020 C3 of the Year Finalist - Modified
do yourself a favor. save your money for the time being. If you do decide to purchase a converter look at ATI. They will build your converter for your application and per your engine specs. If it has the wrong stall speed generally they will change it for free of charge for what you need. At least thats the way its always worked for me and it does not cost extra for a custom converter....converters are not one size fits all and need to be custom for each application.
A bbc with a given ground cam and a sbc with the same grind will have two totally different stalls using the same 3500 stall converter.
while your parts may not be matched perfectly you cn tune to give you the optimum performance...unless you have money to burn by all means rip it apart and change the cam. comp makes a real nice billet core.
Here is a real world comparison I've got a 350 true 11:1 aluminium headed pump gas motor.431 hp@6000 and 445 ft/lbs@4000 I use a stock converter and it does not creep in gear at lights.yep even a small roller cam 218/224 @.050 RWHP is probably only 300 lol
A bbc with a given ground cam and a sbc with the same grind will have two totally different stalls using the same 3500 stall converter.
while your parts may not be matched perfectly you cn tune to give you the optimum performance...unless you have money to burn by all means rip it apart and change the cam. comp makes a real nice billet core.
Here is a real world comparison I've got a 350 true 11:1 aluminium headed pump gas motor.431 hp@6000 and 445 ft/lbs@4000 I use a stock converter and it does not creep in gear at lights.yep even a small roller cam 218/224 @.050 RWHP is probably only 300 lol
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11-28-2015, 09:01 PM
#38
Drifting
TCi would not be my 3rd or 4th choice for a converter.
11-28-2015, 09:19 PM
#39
Performance Torque Converters (PTC) in Muscle Shoals, Alabama is very hard to beat when it comes to torque converters. Give Kenny Ford a call, he is very knowledgeable and easy to talk to.
11-30-2015, 11:02 AM
#40
Safety Car
Now
Can all of you who keep saying he needs a new cam or his heads are wrong please explain to me and others what problem he is having.
