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Topic Review (Newest First)
12-04-2012 07:13 AM
Camaro_Nut2001
Quote:
Originally Posted by bygddy View Post
Or listen to people who have done it, built it, cruised it, raced it....as opposed to calling someone with a product to peddle.....that's the drawback to calling edelbrock, sure, you can buy a top end package, which is exactly what their going to reccomend, or you can mix and match, spend time and effort, not money, on something you did yourself with a little help from "real" people who understand budget and reality.....
After all, this is what hot roddin is all about, right.
10-10-2012 05:12 PM
techinspector1
Quote:
Originally Posted by bygddy View Post
Fair enough, I'm simply speaking from my own experience, in that the last 4 "stock" 70's 350's I took apart were exactly that, as were anyone else's I have helped or watched being taken apart....i, perhaps wrongly, assumed the OP knew exactly what he had before he started adding parts. You are fundamentally correct tho....I stand corrected
You are a gentleman of integrity and honor, something that is very rare these days.
10-10-2012 04:27 PM
bygddy
Quote:
Originally Posted by techinspector1 View Post
There are only two scenarios where you can safely say that and it be true.
1. You bought the motor brand new from the manufacturer and nobody has laid a wrench on it since then.
2. You have had the motor disassembled yourself and verified the pieces that are in it.

Otherwise, you don't even know the cubic inches of the motor, much less anything else about it.
Fair enough, I'm simply speaking from my own experience, in that the last 4 "stock" 70's 350's I took apart were exactly that, as were anyone else's I have helped or watched being taken apart....i, perhaps wrongly, assumed the OP knew exactly what he had before he started adding parts. You are fundamentally correct tho....I stand corrected
10-10-2012 02:10 PM
bygddy
Quote:
Originally Posted by hcompton View Post
Sounds great for the soap box but its not to difficult to find a cam for a mostly stock 350 in a heavy car.

Really... cruised it, built it, raced it. You think you might have went a little far on that one....

When you get done researching all the stuff that guy said you will have a cam very close to the performer cam from edelbrock.

Top end kit is not really needed in this case its for street use only.

FYI: I called edelbrock a few years back for a cam i liked. they told me it would not work well. The guy i spoke with told me to call Lunati or comp. Glad they told me not to buy from them. Lobe center was way off and wasnt listed in the catalog.

grandslam1991:

Be sure to read up on cam break in proceedures these days they ha
ve changed and its very important to follow them 100%. If they say to do it then do it. You will be much happier no matter what cam you choose.
You could count my experience on one hand, and even then, I'm far more hack then most people, my tongue and cheek reference was actually to the people on this site, you will find a myriad of people who have done it all.......and while I'm not bashing edelbrock products, I use them myself, I was stating they are still a buisness, and want, and need to sell their product, but I am glad you weren't one of those people that got advice they didn't need
10-10-2012 01:09 PM
techinspector1
Quote:
Originally Posted by bygddy View Post
he did say "stock bottom end" and its a 70's 350 so were fairly safe assuming small dish, 4 valve relief pistons.
There are only two scenarios where you can safely say that and it be true.
1. You bought the motor brand new from the manufacturer and nobody has laid a wrench on it since then.
2. You have had the motor disassembled yourself and verified the pieces that are in it.

Otherwise, you don't even know the cubic inches of the motor, much less anything else about it.
10-10-2012 12:57 PM
techinspector1
Quote:
Originally Posted by hcompton View Post
grandslam1991:
Be sure to read up on cam break in proceedures these days they have changed and its very important to follow them 100%. If they say to do it then do it. You will be much happier no matter what cam you choose.
Words of wisdom here.^^^^^^

I originated this wiki article, which has since been tweaked by other board members to its present form. I believe it to be the definitive tutorial for using a flat tappet camshaft......
http://www.crankshaftcoalition.com/w...ips_and_tricks

If using a mechanical or hydraulic roller cam, clean the preservative oil off the cam and lifters, oil them with engine oil, install 'em and run 'em. No special procedures are necessary.
10-10-2012 12:47 PM
techinspector1
Quote:
Originally Posted by vinniekq2 View Post
tech,I dont know why you posted that.If the cam is slightly more than he had and cr from 8.5 to 10 :1 a slightly bigger cam will improve the engines breathing.If his engine is 8:1 or 11:1 the cam will make a bigger difference and choice is more important.(The engine is mainly stock) was posted in OP,please tell me a slightly bigger grind that would make this engine perform worse?and
OK Vinnie, let's work through this. Please see the link I posted in post #14 of this thread, in response to the OP's post #10. If his motor is maxed out now for cylinder pressure, then it is at the highest level of efficiency that it's going to be for pump gas. If going with more cam (which will extend the intake valve closing point), the piston will be further up the bore when the intake valve closes, thus pushing some of the mixture back up the intake tract (trapping less mixture than it does now) and making less cylinder pressure. That's the whole big deal with knowing the static compression ratio, the fact that you can figure the dynamic compression ratio from it and maximize the cylinder pressure for the fuel you're using. Otherwise, it's just a guess. In the case of this young man, I would advise him that his combination is maxed and that the only way to go faster now is with more cubic inches, because more cam will lower cylinder pressure and the car will likely slow down. I am aware that there are fellows who have run over 200 psi cylinder pressure on pump gas, but they had to ditch PCV and EGR and de-burr and polish everything in the chamber and on the piston to prevent detonation.

I will agree with you that this thing of building motors is not rocket science, but there are laws of physics that have to be observed if you intend to hit a home run with your build. I certainly don't know all the answers and I'm no mechanical engineer, but I have been doing this stuff since 1958, when I was 16, and I have made many mistakes. When I finally got fed up with guessing, I began reading what the engineers and professional engine builders were writing and learned enough to get a lot closer on my choice of components to reach the goals I had set for the motor I was building.

Choosing components for a build just is not that difficult if you pay attention to what the experts/professionals are telling you. Again, I'm no expert, but I do listen to the experts and read what they have to say. If I say something on these boards, it is the result of either having done it myself or quoting an expert who has done it. No hocus pocus, no guesswork, just physics and reality.

One final thought. If you did not buy this motor in a vehicle brand new and you were the first owner, then you have no idea what components are in the motor or what machining has been done to it. Don't assume.
10-10-2012 12:09 PM
techinspector1
Quote:
Originally Posted by grandslam1991 View Post
I did a compression test the other day, all cyclinders were in the range of 160-170 PSI, although not sure of the compression ratio. hope that helps ill try get compression ratio numbers.
Crane Cams |
10-10-2012 10:36 AM
hcompton
Quote:
Originally Posted by bygddy View Post
Or listen to people who have done it, built it, cruised it, raced it....as opposed to calling someone with a product to peddle.....that's the drawback to calling edelbrock, sure, you can buy a top end package, which is exactly what their going to reccomend, or you can mix and match, spend time and effort, not money, on something you did yourself with a little help from "real" people who understand budget and reality.....

Sounds great for the soap box but its not to difficult to find a cam for a mostly stock 350 in a heavy car.

Really... cruised it, built it, raced it. You think you might have went a little far on that one....

When you get done researching all the stuff that guy said you will have a cam very close to the performer cam from edelbrock.

Top end kit is not really needed in this case its for street use only.

FYI: I called edelbrock a few years back for a cam i liked. they told me it would not work well. The guy i spoke with told me to call Lunati or comp. Glad they told me not to buy from them. Lobe center was way off and wasnt listed in the catalog.

grandslam1991:

Be sure to read up on cam break in proceedures these days they have changed and its very important to follow them 100%. If they say to do it then do it. You will be much happier no matter what cam you choose.
10-10-2012 10:03 AM
bygddy
Quote:
Originally Posted by hcompton View Post
You will need to do a search for a compression ratio calculator on google. FYI chevy 350 is 4.0 bore and 3.48 stroke stock.

Big car with gear and good intake/exhuast for low compression I would go with the edelbrock performer or the performer rpm if you find out you have high enough compression to run it.

Edelbrock could help you get the setup with the right stuff. Just give them a call.

You have got a massive amount of choices for cams. Edelbrock has shorten this down to a few good choices. Makes the selection easier.

Or listen to people who have done it, built it, cruised it, raced it....as opposed to calling someone with a product to peddle.....that's the drawback to calling edelbrock, sure, you can buy a top end package, which is exactly what their going to reccomend, or you can mix and match, spend time and effort, not money, on something you did yourself with a little help from "real" people who understand budget and reality.....
10-10-2012 09:54 AM
hcompton You will need to do a search for a compression ratio calculator on google. FYI chevy 350 is 4.0 bore and 3.48 stroke stock.

Big car with gear and good intake/exhuast for low compression I would go with the edelbrock performer or the performer rpm if you find out you have high enough compression to run it.

Edelbrock could help you get the setup with the right stuff. Just give them a call.

You have got a massive amount of choices for cams. Edelbrock has shorten this down to a few good choices. Makes the selection easier.
10-10-2012 08:10 AM
grandslam1991 I did a compression test the other day, all cyclinders were in the range of 160-170 PSI, although not sure of the compression ratio. hope that helps ill try get compression ratio numbers.
10-10-2012 04:18 AM
bygddy I reccomended the bare bones based on my head choice, he did say " stock bottom end" and its a 70's 350 so were fairly safe assuming small dish, 4 valve relief pistons. With a felpro 1094 gasket and a 60cc chamber (after de-shrouding) it gives you close to. 040 quench and a static of around 10.4 I believe.....or close to it.....
10-10-2012 12:00 AM
vinniekq2 tech,I dont know why you posted that.If the cam is slightly more than he had and cr from 8.5 to 10 :1 a slightly bigger cam will improve the engines breathing.If his engine is 8:1 or 11:1 the cam will make a bigger difference and choice is more important.(The engine is mainly stock) was posted in OP,please tell me a slightly bigger grind that would make this engine perform worse?and
10-09-2012 11:44 PM
techinspector1
Quote:
Originally Posted by vinniekq2 View Post
A small cam is not rocket science.I like cams with lower intake centrelines for stock compression engines.keep the duration short,220 or less and lift moderate.Yes ported heads work better.The heads you have would work better ported.dont expect huge gains in power just changing 1 item,,,
You cannot intelligently choose a camshaft for a motor until you know the static compression ratio. You might just as well write the candidates on little pieces of paper, tape them to the wall, stand back and throw a dart.

From Crane Cams....
"Why is it necessary to know the Compression Ratio of an engine in order to choose the correct cam?
The compression ratio of the engine is one of three key factors in determining the engine's cylinder pressure. The other two are the duration of the camshaft (at .050" lifter rise) and the position of the cam in the engine (advanced or retarded). The result of how these three factors interact with one another is the amount of cylinder pressure the engine will generate. (This is usually expressed as the "cranking pressure" that can be measured with a gauge installed in the spark plug hole.)
It is important to be sure that the engine's compression ratio matches the recommended ratio for the cam you are selecting. Too little compression ratio (or too much duration) will cause the cylinder pressure to drop. This will lower the power output of the engine.
With too much compression ratio (or too little duration) the cylinder pressure will be too high, causing pre-ignition and detonation. This condition could severely damage engine components."
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