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  #16 (permalink)  
Old 02-20-2010, 09:42 PM
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Quote:
Originally Posted by 68stang73
thx... i understand the rudeness at times but i have read enough on these forums that it seems tht there is more arguing and i know more attitude than what this is intended for. i dont care what ya run heck i owned 1 of everything at one point. i dont like to play games just honest answers. i dont bash anything anyone uses but give my advice as i have experianced it and nothing more. anyways....im stuck with what i built. i dont have the money to do swaps at this time so im in the RUN WHAT YA BRUNG club right now. just wanna get it running good and if its less than what i expected then i will be the first to say so. im not taking it down the track just street use and hwy. cruz nights etc. but i do like power and the occasional race but i also wanted a sound that knowone else has around here and so thts why i went with it. i may change it down the road but im stuck now...lol! NOW im looking at my msd chart and if i get this right from what is mentioned i shld use the silver stop bushing and the light silver and light blue spring. i dont know if this is right im trying to figure it out. looks like it will stop @ 2800 rpm and have about25 26 degrees??????????????? any help wold be great..thx guys..
well i used the stuff i mentioned i dont know if its perfect for my motor or not but it sure sounds and runs a ton beter. good responce and no more spitting and sputtering as it climbs in the rpm range. i didnt touch the vacume adv yet but i will. lil baby steps works best for me... so anyways guys thx for all the advice even you f-bird 88! if what i used isnt what you were talking about plz let me know. thx again!

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  #17 (permalink)  
Old 02-21-2010, 08:48 AM
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It's really not hard to get the timing dialed in-- provided your dist. will allow the range of centrifugal adjustment that the cam needs.

Say you see that it starts and idles good w/22 degrees of initial. An additional 10-14 or so degrees should be provided by the centrifugal advance. This should be all in by 2500 or so RPM.

Another 10-12 degrees of vacuum advance (hooked to manifold vacuum, would be my choice), and you're basically done except for fine tuning things to match your exact set-up.
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Old 02-21-2010, 10:05 AM
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Hello Stang do you have the thumrpr, mutha thumpr, or the big mutha thumpr cam? The reason I ask is I had the big mutha thumpr cam. The thumpr cam the first one should work with a 2500 rpm stall and if your able to get it into gear and out of gear with out your rearend sounding like its shooting out the back and no issues when your at a stop sign etc then it should be good but that is just my opinion.

I have went through different stall's over the years with different cams so I have some experience. Yeah its best to do with what you got and if your happy with it and you get it all done and running good then your fine.There is in my opinion never a perfect engine combo when it comes to performance. You have some things and not others and vice versa. Well have fun with your build.

I only got rid of my big thumpr cam not because of how it performed but because of all the overlap it had. It was too much for me and street driving. Yeah it performed pretty well for what it is but my lunati voodoo does better but its a little bit smaller too so it will give me better response on bottom end anyways but that was my personal choice.

Just not a big fan of the thumpr cams just because of my experience but not bashing them, I just hate the exaggerated amount of overlap they have to give the sound. I like my cams with smaller split profiles.
Take care
Eric
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Old 02-21-2010, 12:28 PM
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Quote:
Originally Posted by eric32
Hello Stang do you have the thumrpr, mutha thumpr, or the big mutha thumpr cam? The reason I ask is I had the big mutha thumpr cam. The thumpr cam the first one should work with a 2500 rpm stall and if your able to get it into gear and out of gear with out your rearend sounding like its shooting out the back and no issues when your at a stop sign etc then it should be good but that is just my opinion.

I have went through different stall's over the years with different cams so I have some experience. Yeah its best to do with what you got and if your happy with it and you get it all done and running good then your fine.There is in my opinion never a perfect engine combo when it comes to performance. You have some things and not others and vice versa. Well have fun with your build.

I only got rid of my big thumpr cam not because of how it performed but because of all the overlap it had. It was too much for me and street driving. Yeah it performed pretty well for what it is but my lunati voodoo does better but its a little bit smaller too so it will give me better response on bottom end anyways but that was my personal choice.

Just not a big fan of the thumpr cams just because of my experience but not bashing them, I just hate the exaggerated amount of overlap they have to give the sound. I like my cams with smaller split profiles.
Take care
Eric
i have the stage 2 cam the Mutha Thumper. and i did go with the 2500 stall they recomended and where im at its cold and snowy so the stop light thing is a no go. had snow since dec. lol! but in the garage i have it idoling @ about 1000 and it goes in and out of gear great i idoled it down when in gear to about 500 rmp and yes it was choppy but it went in and out without stalling so then i bumped it back up to where i think it should be. so for street driving i dunno..i hope it will react like it is in the garage. i do need to remind ya all but im running all ford..lol! c4 auto 351w. i know most or all of ya are chevy guys and maybe that what ya say about the stall is correct with th350 or 400's i dunno. so yeah with the pro billit med i used the chart and used light silver and blue spring as well with silver stop bushing and it cleanded up so well my wife could tell from the kitchen and gave me thumbs up..lol! i do know that im in the right direction but is it right????hell i dunno... thx again for all ur help.
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Old 02-22-2010, 04:31 PM
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Yeah it sounds like your in the right direction. The idle at 1000 rpm sounds good and where it should be. I have a smaller cam then that and it idles at 1000 rpm. If you can shift it into gear and it does not stall and quit then there is one good sign of your stall being enough. The big mutha thumpr cam I had was so big that my stall was not enough at 3000 to 3500 rpm.

My flash stall is 3 grand and every time I popped it into gear it would just quit. Going to smaller cam got rid of that issue and all others associated with it. Keep it up and once you get it out and drive it then you will no how well it does. You don't know until you drive it. Have fun with it and Ford or Chevy different design but same concept. Post a youtube vid with your build would love to hear it.

Eric
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Old 02-22-2010, 06:07 PM
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Quote:
Originally Posted by eric32
Yeah it sounds like your in the right direction. The idle at 1000 rpm sounds good and where it should be. I have a smaller cam then that and it idles at 1000 rpm. If you can shift it into gear and it does not stall and quit then there is one good sign of your stall being enough. The big mutha thumpr cam I had was so big that my stall was not enough at 3000 to 3500 rpm.

My flash stall is 3 grand and every time I popped it into gear it would just quit. Going to smaller cam got rid of that issue and all others associated with it. Keep it up and once you get it out and drive it then you will no how well it does. You don't know until you drive it. Have fun with it and Ford or Chevy different design but same concept. Post a youtube vid with your build would love to hear it.

Eric
thx...i will post one when i can.
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Old 02-22-2010, 07:04 PM
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Eric,I have a 351w with a street/strip cam 70* overlap almost 240 duration. Speed Demon 650V I have a MSD pro billet street dist. I went with profile C (MSD Chart) and a Black bushing. This Black bushing gives 18* of mechanical advance which will give you 16* initial and 34* total with Vacuum blocked off.
16+18=34. If you use the silver bushing(25* advance) and you have 34* total advance your initial advance is only going to be 9* which is not enough initial for a street/strip cam. You will end up opening up the butterflies on the primary side too much to keep the engine idling and your idle screws will not respond to adjustment[even with using the secondaries for adjustment]. This will also cause your engine to run hot at idle. and rich too.
Lou
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Old 02-23-2010, 09:41 AM
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Quote:
Originally Posted by Cobra720
Eric,I have a 351w with a street/strip cam 70* overlap almost 240 duration. Speed Demon 650V I have a MSD pro billet street dist. I went with profile C (MSD Chart) and a Black bushing. This Black bushing gives 18* of mechanical advance which will give you 16* initial and 34* total with Vacuum blocked off.
16+18=34. If you use the silver bushing(25* advance) and you have 34* total advance your initial advance is only going to be 9* which is not enough initial for a street/strip cam. You will end up opening up the butterflies on the primary side too much to keep the engine idling and your idle screws will not respond to adjustment[even with using the secondaries for adjustment]. This will also cause your engine to run hot at idle. and rich too.
Lou
hey cobra? thx ill tryit and see how it responds..the only pain with chainging that stuf is not loosing the washer...tight fit with the fingers.
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Old 02-23-2010, 05:33 PM
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I tried it with the dist. in the block my fingers were too big. It was much easier when I took out the dist. and turned it upside down on a workbench with good lighting. Take an open end wrench that will fit the nut and bend it at the neck a little. Use needle nose pliers to get everything in place.
Don't forget to mark the rotor in relation to the cap as it is installed, and when it releases from the cam gear as you bring up the distributor, and the cap in relation to the block. That way it drops right back in with the twist of the gear. Start out with TDC and rotor pointer at #1 on compression stroke, its just keeps better order.
Good Luck
lou
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Old 02-23-2010, 06:46 PM
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Quote:
Originally Posted by Cobra720
I tried it with the dist. in the block my fingers were too big. It was much easier when I took out the dist. and turned it upside down on a workbench with good lighting. Take an open end wrench that will fit the nut and bend it at the neck a little. Use needle nose pliers to get everything in place.
Don't forget to mark the rotor in relation to the cap as it is installed, and when it releases from the cam gear as you bring up the distributor, and the cap in relation to the block. That way it drops right back in with the twist of the gear. Start out with TDC and rotor pointer at #1 on compression stroke, its just keeps better order.
Good Luck
lou
thx for the tip...but my fingers must be a lil smaller. i used a lil vaseline on fingertip and wala everything went together like ive done it for years..lol! (lucky)!!!! the roads dried off enough for a lap or 4 and it drove nice. tires didnt want to stick...lil too much power and cold pavement...lol! but its good enough for now till i get some road time in it and then fine tune it. i may have some questions along the way but thx guys..
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  #26 (permalink)  
Old 07-16-2010, 01:48 PM
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Hey F-Bird I know this post is old but just wanted to say THANK YOU for this information. I just set the timing on my zz502 (has the smallest thumper installed) and I thought I was seeing things when the initial timing was 25 degrees.. I've never had a cam that required much more than 8-10 initial so I was really spinning my wheels.. Even broke down and called Dad for his advice knowing full well he is a "factory original" type of guy haha..

I guess I will shamefully admit I didnt even know you *could* set initial timing that high until now...

Quote:
Originally Posted by F-BIRD'88
The biggest mutha thumper cam requires a lot lot lot of initial spark timing at idle.
Lock out the distributor mechanical advance and set the idle timing at 34-36deg BTDC.
Install the lightest/lowest tension edelbrock metering rod/power piston step up springs.
Be sure the PCV system is hooked up to the base of the carb and is functional.
the opposite valve cover needs a breather.
Edelbrock carbs do not idle off the secondaries like a holley does. They will be closed at idle.

Once you've modified the distributor and replaced the power piston step up springs and reset the carb idle mixture and idle speed adjustment the idle will be much cleaner. The throttle response will be much better.
A 3500stall torque converter is required. (10" th350 converter) (9" th700r4)

There is no proper carb adapter for the square flanged performer carb on a factory Qjet manifold.
Change the intake manifold. A edelbrock performer RPM is what you need.
Way to much fuel distribution upset with any adapter on a Qjet manifold.
Stop fooling yourself.

If when the motor is hot, the motor is hard to start with the timing locked out, install a SPST switch on the distributor (HEI) or external spark amplifier box power switch on wire to kill the spark during cranking.
Kick it over with the spark switch off, then throw the switch and it will fire right up. Any 10A or more rated automotive grade SPST switch will work.
Mount it on/under the dash where you won't kick or knock it while driving.

Which cam do you have and what distributor? What model # carb?
Get the proper intake manifold.
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