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Discussion Starter · #1 ·
I really dont know if I dont have everything set right or if my set-up is just wrong.... I have the Edelbrock performer top-end kit with a 750 4bbl edelbrock carb. When I set the Timing the cam is @ 0* and my inition timing (harmonic balancer) is at 0*... When I give it gas really easy it takes it without falling off before picking up but say i just wanted to just stomp on it, it will sometimes cut off or bog way down till i let off and kinda baby it up in RPM's....

I adjusted the valves by ear and the carb was preset, I broke the engine in about 6-months ago and it sat up. does the carb need to be reset or what about the choke.... the electric choke isnt working b/c i didnt hook up the ground and fried it.... I think it should have alot more fuel response and power than it has.... whats wrong, can anybody please help me out.... I really put all my saving into this motor and its quit disappointing. Please help
 

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wild_man84 said:
I really dont know if I dont have everything set right or if my set-up is just wrong.... I have the Edelbrock performer top-end kit with a 750 4bbl edelbrock carb. When I set the Timing the cam is @ 0* and my inition timing (harmonic balancer) is at 0*... When I give it gas really easy it takes it without falling off before picking up but say i just wanted to just stomp on it, it will sometimes cut off or bog way down till i let off and kinda baby it up in RPM's....

I adjusted the valves by ear and the carb was preset, I broke the engine in about 6-months ago and it sat up. does the carb need to be reset or what about the choke.... the electric choke isnt working b/c i didnt hook up the ground and fried it.... I think it should have alot more fuel response and power than it has.... whats wrong, can anybody please help me out.... I really put all my saving into this motor and its quit disappointing. Please help
What motor do you have? What do you have your timing set at with a timing light? The electric choke is only used for cold starts until the engine gets to temperature then it should remain open while driving. List your engine combo.
 

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wild_man84 said:
Sorry,,

Its a 350 4-bolt main.. 4* advanced... its a 85 block with orig. bottom end

my rockers are 1.6 ratio
pushrods are + .100
h.v. oil pump
Depending on cam specs, I think you need more timing. Try more like 15-18* instead of 4* and let us know what it does. Don't get into detonation though.
 

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Discussion Starter · #5 · (Edited)
yesterday i went to my dads to get old school to check it out and two of my rocker arms were loos from where the threads were messed up ( all brand new parts) and when we tried to adjust them again he said that the lifter wasnt holding pressure.. that they were leaking down...... said i should buy new lifters.... i will redo the timing again before the lifters just to see what it does.. the part # on the cam is at summit or edelbrock is EDL-7102

so we put two washers and raised the nut above the recked threads and readjusted the rockers. we loosened them till clicking and tighened them to no lash and 1/4 turn more... when we shut the engine off it still had lash to it....

is this right or are my lifters shot....

also, i have a fuel pressure regulator but i dont have a fuel pressure gauge... could it be to much fuel pressure....
 

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Discussion Starter · #6 ·
S10 Racer said:
Depending on cam specs, I think you need more timing. Try more like 15-18* instead of 4* and let us know what it does. Don't get into detonation though.

what is detonation and how do i know/tell if that is what is happening?
is this the same as what i call spark knocking
 

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wild_man84 said:
yesterday i went to my dads to get old school to check it out and two of my rocker arms were loos from where the threads were messed up ( all brand new parts) and when we tried to adjust them again he said that the lifter wasnt holding pressure.. that they were leaking down...... said i should buy new lifters.... i will redo the timing again before the lifters just to see what it does.. the part # on the cam is at summit or edelbrock is EDL-7102

so we put two washers and raised the nut above the recked threads and readjusted the rockers. we loosened them till clicking and tighened them to no lash and 1/4 turn more... when we shut the engine off it still had lash to it....

is this right or are my lifters shot....

If you are going to use this method, I believe you will find that in order to get the lifter centered, you are going to have to tighten it down 3/4 turn from no lash. Where did the 1/4 turn thingie come from?

also, i have a fuel pressure regulator but i dont have a fuel pressure gauge... could it be to much fuel pressure....
I would suggest that you make life easier on yourself, and get yourself a motors manual & read. From your questions, it seems like you are having to struggle your way through this because your knowledge is a bit on the weak side.

People here are going to want to help you if you ask, but it is impossible to look over your shoulder and see what else may be wrong with your build, or if your stuff is put together correctly. I would be concerned about offering you advice because I am not sure as to what you are asking at times. I have never heard of timing a cam to zero degrees so I do not know if your cam is installed properly. This is a tough call for me, even if I want to help you.

Good luck with it.
 

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wild_man84 said:
what is detonation and how do i know/tell if that is what is happening?
is this the same as what i call spark knocking
I think detonation is spark knock and I think it is caused by spark timing being set too advanced. I have an edelbrock carb on my 355 Chevy engine and I set the timing at about 14 degrees. Note that reduced vacuum, as when you push on your gas pedal, causes the timing to advance. Setting the timing at zero when the engine is stopped must cause the timing to be quite retarded when the engine is running due to vacuum increase. Make any sense?

Also, the electric choke: black wire is for ground I think and other wire for 12 volts positive. I don't think it matters if it is hooked the other way around, but not sure...best to check Edelbrock web site for documentation.

Good luck

R
 

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Discussion Starter · #9 ·
DENCOUCH said:
I would suggest that you make life easier on yourself, and get yourself a motors manual & read. From your questions, it seems like you are having to struggle your way through this because your knowledge is a bit on the weak side.

People here are going to want to help you if you ask, but it is impossible to look over your shoulder and see what else may be wrong with your build, or if your stuff is put together correctly. I would be concerned about offering you advice because I am not sure as to what you are asking at times. I have never heard of timing a cam to zero degrees so I do not know if your cam is installed properly. This is a tough call for me, even if I want to help you.

Good luck with it.

I have set the cam with the timing marks strait up and down in a vertical position like your suppose to (like the manual says). it has 4* neg. and 4* positive i set in in the strait up and down.... So i would assume that would be @ 0*. I just let everyone know exactly what what I knew about the lifters B/C that is where im confused at as well as the spark advance... Dad is saying that i need new lifters b/c thery are leaking down..and now holding pressure...I read and read and read about the cam and its complicated stuff yesterday and learned the differance between spark advance and cam advance/retard.. but it doesnt say what the outcome of doing either one is....ALso, when i bought the distributor it came with 3-differant springs (soft..medium.. and hard) i used the med. Could that be my problem...
 

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You lifters and timing may be part of it, but you need to address the choke as well. If it's not hooked up and opening up, then you're starving it for air when you hit the gas hard. Think about what happens when you hit the gas, it's actually just opening the butterflies to let more air in, which in turn pulls more gas in. If the choke is still closed when you hit the gas, and the butterflies are trying to pull more air in, but can't because your choke is closed, then it's not going to get the air that it needs. Your accellerator pump is going to give it extra gas, but the extra air that it needs to burn the fuel won't be there, so it will bog.

The choke is easy to address. If the wires are shot, then just adjust it so that it's out of the way and open. As long as it's not cold out, you really don't need a choke. Take off the air filter and loosen the 3 screws on the choke housing. Turn the housing until it opens the choke all the way and just leave it. See if that helps at all...
 

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Discussion Starter · #12 ·
35pontiaccoupe said:
You lifters and timing may be part of it, but you need to address the choke as well. If it's not hooked up and opening up, then you're starving it for air when you hit the gas hard. Think about what happens when you hit the gas, it's actually just opening the butterflies to let more air in, which in turn pulls more gas in. If the choke is still closed when you hit the gas, and the butterflies are trying to pull more air in, but can't because your choke is closed, then it's not going to get the air that it needs. Your accellerator pump is going to give it extra gas, but the extra air that it needs to burn the fuel won't be there, so it will bog.

The choke is easy to address. If the wires are shot, then just adjust it so that it's out of the way and open. As long as it's not cold out, you really don't need a choke. Take off the air filter and loosen the 3 screws on the choke housing. Turn the housing until it opens the choke all the way and just leave it. See if that helps at all...

the choke is fried, i didnt have the ground tight when i hooked up the power wire. which fried my choke.... i know this because i was woundering why it wasnt working and bumped it with my hand and it was hot enough to burn me.. I will try the choke open and see how if it helps
 

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wild_man84 said:
and the 1/4 turn thingie "lol" came from the book, my dad, the shop i use to work at, and the internet.... Never heard of 3/4 turn.. the most i herd of is 1/2 turn
I would check with your lifter people and see if your 1/4 turn adjustment is still acceptable as far as correct adjustment goes. If the most you have ever heard of is 1/2 turn, would 1/4 turn be the least? C'mon, get those valve adjusted so we can get down the road to your other issues.
 

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Also, what distributor do you have? MSD? GM HEI? Vacuum advance?

Have you taken it apart and checked your that springs and stops are all ok?

As for timing, I'd stick with around 12* initial for a faily mild cam (less than 220 duration at .500")
 

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Discussion Starter · #15 ·
35pontiaccoupe said:
Also, what distributor do you have? MSD? GM HEI? Vacuum advance?

Have you taken it apart and checked your that springs and stops are all ok?

As for timing, I'd stick with around 12* initial for a faily mild cam (less than 220 duration at .500")

Cam Style............................................................Hydraulic flat tappet
Basic Operating RPM Range.....................................1,500-6,500
Intake Duration at 050 inch Lift................................234
Exhaust Duration at 050 inch Lift..............................244
Duration at 050 inch Lift.........................................234 int./244 exh.
Advertised Intake Duration......................................308
Advertised Exhaust Duration....................................318
Advertised Duration...............................................308 int./318 exh.
Intake Valve Lift with Factory Rocker Arm Ratio..........0.488 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio........0.510 in.
Valve Lift with Factory Rocker Arm Ratio..................0.488 int./0.510 exh. lift
Lobe Separation (degrees)....................................112

I have a Accel Distributor w/ vacuum advance ( not the best I know)
 

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Make sure that the timing advance is working; both vacum and mechanical.
You should get around 34*-36* at no more than 3000 rpm without vacum connected. Anything less, it may bogg down.
Second:
Make sure you don't have any vacum leaks anywhere. This is not a japcrap with a zillion hoses so it's easy to check.
Third (and this is not so easy): Make sure that markings on the damper is correct.
Fourth: Make sure the acc pumps are working in the carb. Stand looking down and open the throttle ;you don't have to have the engine on
 

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Discussion Starter · #18 ·
I have also been doing alot of reserch myself and this is also a question>???

Would my stall converter being to small cause this boggness ????

I have a 750 4bbl with a stock '90 454 ss silverado stall converter in a 400 turbo.....
 

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Decadent pianoplayer
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If you have a 454 the carb is NOT too big. Still it may need some tuning.
I've seen many carbs that has been tempered with so much it's a miracle they work. Usally for nothing because the timing was wrong or they had vacumleaks
 
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