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  #16 (permalink)  
Old 11-25-2008, 10:25 PM
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Originally Posted by eric32
Wow Fbird and other guys thanks so much for all the info man that is bad *** on the hp and torque numbers with that other cam you used in the simulation. I am still going to take the big mutha cam out next year its too much and is taking away the potential my engine can make and have. I am probably go with the 288HR is as its not too big and works with my setup that I currently have. I will have to get me a timing light and try your method Fbird and see how it goes but I will have to wait till spring time. My Garage is reall small and dont have room. I share it with a neighbor lady. Also Fbird on my carb here is what is on my carb. Idle Air Bleeds are.070 10-32 screw in type. High Speed air bleeds are .031 10-32 screw in type. Main Jet size is 72 and secondary is 80 with extensions. Power valve is a 45. Power valve secondary is plugged. Primarry nozzle is 33 and secondary nozzle is 33. Acc pump is 30 and pump cam is pink primary and secondary and in position number 1. That is what's on my carb spec sheet. Nothing has been changed and yes I have retuned my carb since changing cams. Thanks for all your help man you know your stuff. Thanks to everyone else too.
Eric
Ya give it another go in the spring.

Everything looks good on the carb. Is it a four corner idle carb or two corner idle carb? ( 4 idle mix screws or 2?) May/or may not need to fine tune the air bleeds. No way to know until the spark timing is corrected and the carb throttle blade opening/ idle transfer slot exposure is reset.
Try the locked out the mechanical advance timing first. Its fast and easy to do. Once the idle is all set up you can yank the distributor and create a proper timing curve. (its a bit of a job.) Or leave it locked out and install a dash mounted ignition power interupt switch to enable hot cranking and starting, while the motor is hot, with the increased base timing. You may need that also with 25deg of inital timing anyways. Doubles as a cool anti theft device.
At least you'll know how the motor is supposed to run with that cam.
The way it is set up now, with just 11deg of initial timing, it is a real pain to live with,with such a high overlap cam.

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  #17 (permalink)  
Old 11-28-2008, 01:25 PM
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Hello Fbird on my carb its a 4 corner idle control circuits. I am going to swap out cams anyways and go with the comp 288hr wich will give me some more hp and torque and somewhat a better idle and still be a choppy sound just not as bad as the thumpr cam. I will never recommend a thumpr cam to anyone.Thanks for your help. How do I advance the initial timing without changing my advance timing? thanks eric
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Old 11-28-2008, 01:40 PM
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id have to say that theres no such thing a a piece of crap cam, just a cam not matched to the engine its in. from the SOUND of your motor, id say that cam is just to big........ even your converter sounds a little to big, i wouldnt run much more than prob a 2200 in an s10. as far as your cam goes..... id run something more along the lines of that 292 you had. lunati makes the bmII series but it isnt roller. im sure you could find one tho with similar numbers. as far as your car dying, try adjusting your idle.... with a cam that big, its going to have a higher idle speed than normal.
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Old 11-28-2008, 02:09 PM
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This is a clear case of overcamming.
I wonder if CompCams recommended the BIG Muther? The biggest in their series.
I certainly wouldn't recommend a cam with 30* too much overlap for their combination.

A 350 cube SBC with real good heads will make a strong midrange and peak horsepower at 6100 rpm with a 224* @ .050 single pattern cam on 107* LSA and a mid 9s compression.

Unless you have very high compression and a desire to regularly turn above 7300 rpm, a cam with 236+ intake and a big exhaust blow out will be a pretty high rpm bugger.

Crutching a cam with more than 4* advance from straight up just says that it is the wrong cam for the combination in the first place.
Wide LSA and long exhaust durations need lots of advance to crutch the mismatch.
JMO FME, FWIW

Last edited by ScoTFrenzel; 11-28-2008 at 02:19 PM.
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Old 11-28-2008, 03:25 PM
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Quote:
Originally Posted by eric32
Hello Fbird on my carb its a 4 corner idle control circuits. I am going to swap out cams anyways and go with the comp 288hr wich will give me some more hp and torque and somewhat a better idle and still be a choppy sound just not as bad as the thumpr cam. I will never recommend a thumpr cam to anyone.Thanks for your help. How do I advance the initial timing without changing my advance timing? thanks eric
You have to limit the amount of mechanical advance travel.
Requires tearing downs the distributor to shorten the advance pin travel slot length.

The comp 288Hr will also require a modified distributor advance curve.
(If you like a sharp running motor) 11 initial is not enough for this cam either.

Here are a few ways to limit the amount of mecha adv travel to allow increased idle timing (24 to 26deg) without excessive high rpm max advance. (34 to 36)
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Last edited by F-BIRD'88; 11-28-2008 at 03:44 PM.
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  #21 (permalink)  
Old 11-28-2008, 05:18 PM
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Thanks Fbird I will try to do the lockout advice your recommended.
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  #22 (permalink)  
Old 11-29-2008, 09:47 AM
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I recomend filling it up rather than trying to make a bushing, seems to be the easiest way. And 24 initial with about 12 mechanical sounds about right.
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