S80
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Post by S80 on May 24, 2015 20:05:00 GMT -5
I need help getting my 307 derby ready and was wondering if any motor experts would be willing to answer some questions for me. Pretty much a noobie when it comes to motors. Would like to get working on it this week so the faster the response the better,
Thanks
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Post by seventyonehemicuda on May 24, 2015 23:45:49 GMT -5
From what I've seen from earlier posts made by yourself. I would say you pretty much have no clue whatsoever when it comes to engines (electronic carbs ect)
you are pretty much going to have to learn the basics on your own. I don't want to come off as an ass but nobody wants to spoon feed. you are going to have to find a friend that is willing to help you out or at least knows the basics. I've tried to help my wife over the phone to get a car to start only to find out 10 min into the conversation that the battery was dead. the person on the other end of the line has to understand basics in order to convey information back and forth effectively or its all wasted effort. spend some time looking up olds small blocks or even small block chevy's (basically the same thing)
Really what are you looking for? a recepie on how to build the worlds best 307? i know some great derby drivers that know nothing about mechanics. there is no shame in having someone else do your motor for you.
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S80
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Post by S80 on May 25, 2015 8:43:16 GMT -5
Not to be an ass back but I wasn't asking on help building the worlds best motor. I just needed some advice on some basic setup items to get it running. Basically a fuel pump question and then a explanation of how to switch over from electronic carb to non electronic. yes i do not know much about motors but I want to learn, I thought this was a website to do so. I do not want to have someone else do my motor because I want to know whats going on with it an why its not working. You are just discouraging the next generation from derbying by telling me to go somewhere else for help. I just have a few questions that I cannot find myself out and needed some help to get the motor running. not to be spoon fed a guide to a complete rebuild. So if you would or anyone else would be willing to answer a few simple questions it would be greatly appreciated because like i said before I have little to no knowledge on how to switch over carbs.
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Post by pasterofmuppets on May 25, 2015 13:56:00 GMT -5
What is currently not working on the engine? Fuel, spark, timing, air, parts missing or not operating? Or does it already run and you want to upgrade parts on it?
If you ask specific questions, many of us will give you specific answers. The olds 307 is a very weak engine for demo purposes. They have very low peaks on both the torque and horsepower curves. If your engine is not currently running well, it would almost be the same price to upgrade the engine to a chevy small block. But if you are set on using the olds engine, ask individual questions when you get stuck. Use Google also. Only way to learn is to try yourself or be lucky enough to have someone show you.
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S80
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Post by S80 on May 25, 2015 14:42:25 GMT -5
What is currently not working on the engine? Fuel, spark, timing, air, parts missing or not operating? Or does it already run and you want to upgrade parts on it? If you ask specific questions, many of us will give you specific answers. The olds 307 is a very weak engine for demo purposes. They have very low peaks on both the torque and horsepower curves. If your engine is not currently running well, it would almost be the same price to upgrade the engine to a chevy small block. But if you are set on using the olds engine, ask individual questions when you get stuck. Use Google also. Only way to learn is to try yourself or be lucky enough to have someone show you. I just got it running today, the guy i bought it off of had the fuel pump on wrong so I had to fix it. I know the engine is weak but its for stock class and I don't have alot of money to spend on a new motor. I heard that if tuned right they will run for days when hot, although I wont have the torque and horse power I should be able to keep her going and at least have fun right? My first major question is about switching the carb to non electronic. |
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Post by cheezwhiz31 on May 25, 2015 15:40:36 GMT -5
get a manual carb and change dist. too. to non computer one.
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S80
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Post by S80 on May 25, 2015 17:25:12 GMT -5
get a manual carb and change dist. too. to non computer one. Okay I assumed that is what I needed to do, will any gm four barrel carb work? or do I need a quadrajet? and will any cheapo ebay gm distrib work too? Or do I need to look for certain models? |
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Post by seventyonehemicuda on May 25, 2015 19:46:35 GMT -5
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S80
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Post by S80 on May 25, 2015 20:11:05 GMT -5
Yea I have been reading that website quite a bit, sounds like I need to swap the rearend. Can you help me with carb issue?
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Post by seventyonehemicuda on May 25, 2015 20:38:41 GMT -5
General rule of thumb for carb size is 2cfm per Ci of engine displacement for example:
a 600 cfm carb is about right for a gm 305, olds 307, mopar 318, ford 302 ect. ect.
an 800 cfm carb is about right for a gm 400, mopar 400, olds 403, ford 400. and on and on.
an edelbrock 600 cmf carb would be perfect for your engine.
pretty much any 4bbl from a gm 305 should do the job.
but without question and edelbrock 600 is the ideal carb for that size engine. also edelbrock carbs seem to react really well when the car is shaking and rocking all over the place. big hits, small hits. they don't seem to flood out like the carters or the holley's do. im not big on quadrajets because they have like 4 million vacuum lines coming out they look like a damn porcupine by the time you've got em all plugged off.
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S80
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Post by S80 on May 25, 2015 20:53:47 GMT -5
Will it edelbrock 600 bolt right up? what about distributor? anything gm?
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Post by seventyonehemicuda on May 25, 2015 22:36:37 GMT -5
you would need a 4 hole to spread bore addapter edelbrock part number #2696 (around 20 bucks) even if you can only scratch up a 500 cfm edelbrock you'd be just fine. im not 100% sure but i thinks all olds distributors are the same. 307 350, 403, 455... sould be able to pull an older distributor off a late 70's olds of any kind/shape.
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S80
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Post by S80 on May 26, 2015 6:34:00 GMT -5
Okay thank you for the help. Ill see what I can do
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n8
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Post by n8 on May 26, 2015 9:12:12 GMT -5
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S80
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Post by S80 on May 26, 2015 17:14:45 GMT -5
CFM required = (engine ci × max RPM / 3456) × volumetric efficiency of engine ^This is the equation I was taught. The volumetric efficiency of stock naturally aspirated engines is probably 0.85 on the high end. So if you were expecting to spin say 6000 rpm with a 307 - that would require approximately 453 cfm, and that's on the high side of everything. This is oversimplified, and there's lots of variables. For derby purposes, I'd be tempted to put a 2 bbl on there. -all just personal opinion, so take it for what it's worth. Why would you run a 2 bbl on it? I see they are alot cheaper then 4bbl so i might have to go that route, what the big difference? What kind of adapter would I need for it to bolt up? just trying to weigh all my options price wise as I am on a strict budget. Thanks! |
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