While pricing a new cam - the DC engine book says I need these springs.

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abdywgn said:
Joe, I ran the 484/284 hyd. cam with stock rockers arms and Comp springs/steel retainers in a very close set-up to yours. It would run lo 13's at 108. Bob
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abdywgn- Thanks for the input. I want to go further away from the hydraulics as Float is a possibility over 5,500rpm. I'm looking to shift now in the 6,500 range to take advantage of the 3.91 rear. I will also need it on the highway with the street tires (off track driving)
 
MOPAROFFICIAL said:
These work, I've used them with that .528 solid, but the real drop in spring is the mp#847 spring.
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MOPAROFFICIAL- what did you mean- "but the real drop in spring is the mp#847? What is that? I assume P5249847 spring I was also looking at the P3412068- a bit more spring pressure but a bit more $ too.
My dealer says he can get them for about $8.00 per spring next day. seems a bit inexpensive to my memory.
 
i'm having issue with springs touching the stock 273 , but when i measure the spings install dia is 1.49 od . engine builder install them . went in to readjust the valves do to noisy operation of the valve train . this cam is little , idle to 5k . just a driver . wounding why such a big dia springs .
 
ir3333 said:
if the valve is wide open and passes all the air the port can flow then
will opening the valve further accomplish anything?
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I know or believe you know this already, you've been here a while ;)
In flat tappet cam as well as cylinder head world we know a few things...like the valve will sit at its full lift about a blip, about next to no time meanwhile the opening and closing rams have more area and the lifter/valve hang around and revisit those ramps aka spend more time there in comparison. So let take say the head does stall at .460....I myself will pick a cam lift about .060-.080 more to better utilize the flow in those lower lifts/hang the valve longer in the peak flow of the head. I know you're gonna say "well what about stall and the port backing up once you go beyond that peak lift?" well... Again remember the peak lift is only there for not even half the time the lifter/valve is on the ramps...so any backing up is gonna be micro...unless you lift the valve 'way into reversion' and in some cases the motor will still make some power...but nothing what it could be and lower under the cam operation will be crap, the intake gets blackened etc.

Let the ones who own a flow bench talk about what a head does, otherwise you're getting hot air and confusion from a guy who acts like he knows some secret when he really don't know **** and if he really did and was here to help, he wouldnt be telling you he can't help because it cost him too much to find out himself.
 
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Syleng1 said:
MOPAROFFICIAL- what did you mean- "but the real drop in spring is the mp#847? What is that? I assume P5249847 spring I was also looking at the P3412068- a bit more spring pressure but a bit more $ too.
My dealer says he can get them for about $8.00 per spring next day. seems a bit inexpensive to my memory.
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The 5249847 works great , set it up at 140 seat...they like to lose about 10 lbs after some use...it'll be around 290 open, if you go less it will be between 265-275 open. This spring needs no spring seat cutting, but you want to trim the guide so you don't pinch a seal. Mp cams are hit and miss, some don't last...so I like to try run only the amount of spring needed to control the valve at the rpms I run it. You want just enough, anymore is just wear and resistance/drag. 130-140 seat and about 290 is right on for that cam.
Springs lose their pressure anywhere from 7-12 lbs with cycling/use...so always figure that in.
The comp dbls are okay...but they don't seem to last more 4-5 years till they end up about .075 shorter inst height to keep the advertised. They had two versions, one was 140 seat...the other 110 or something....I don't like comp cams very much. I like kmotion,crane,Herbert,Engle, .....Isky is too much money, talk about paying for a name...
 
hey guys...i sure don't profess to know this stuff beyond basics or what seems to be logical.
..just here to learn or help.As for the valve only briefly fully open that makes sense,but shouldn't the events leading up to fully open be decided by designing the appropriate ramps rather than too much lift to increase the opening at half lift?
 
ir3333 said:
hey guys...i sure don't profess to know this stuff beyond basics or what seems to be logical.
..just here to learn or help.As for the valve only briefly fully open that makes sense,but shouldn't the events leading up to fully open be decided by designing the appropriate ramps rather than too much lift to increase the opening at half lift?
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ir3333 said:
hey guys...i sure don't profess to know this stuff beyond basics or what seems to be logical.
..just here to learn or help.As for the valve only briefly fully open that makes sense,but shouldn't the events leading up to fully open be decided by designing the appropriate ramps rather than too much lift to increase the opening at half lift?
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Being very general here... ramps can only be so fast in the flat tappet app...say lower at .050 you might be inclined to maximize lift or if its aggressive/faster not worry about it so much. Rollers arw where I do not go much beyond where a head, if the case, stalls..saturates..goes backwards or what have you, thats just my prefererence. There is more to it and other factors to consider, its not cut and dry unfortunately.
 
pomonamissel said:
i'm having issue with springs touching the stock 273 , but when i measure the spings install dia is 1.49 od . engine builder install them . went in to readjust the valves do to noisy operation of the valve train . this cam is little , idle to 5k . just a driver . wounding why such a big dia springs .
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pomonamissel - im not sure how old your heads are or what has been done but if your engine is a 273- im sure it does not have hardened valve seats unless you had them done.
From the factory the 318 and 360's - SOME newer models had it done but not a full hardened valve seat, just induction hardening. This is where they harden just the edges of the valve seat and not any more. in a production head- that would cost a lot of $$$'s for the manufacture to do. Anyhow if the valve over time has sunk deeper from wear at the seat, the valve stem moves upwards (closer the the valve cover) as well. Now your rocker arm is sitting at the wrong angle and the geometry is off. The wear on the rocker tip is greater as less surface area is touching the valve and the more noise is made.

Large diameter springs are used for longevity- if you are using factory springs. Sorry if this is actually not fitting your topic- your post was kinda vague- more information is help full.
Besides this is a post about my information on my car..LOL!:lol:
Joe
 
I think I got a set of the valve springs on the shelf.....
 
installed in factory j heads with 340 springs, the spring are 1.49 in dia . my old ones were 1.46 in dia . i'm just going to grind a bit more off the rockers . # 1 exhaust got a bit of a mark on it from the rub , it was hitting the spring and would spring back n forth , thats the worst one . a few more have a witness marks . but just the one exhaust has a groove cut in it . hoping it did not wreck the guide and valve stem . and of course the machinist is not returning my calls . what an ***...le . i guess sending 5k does not with him wasn't enough to get after sale service . think he should stick with building chevies . sorry about hyjacking your thread , just tired of fitting someones over sights .
 
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MOPAROFFICIAL said:
I know or believe you know this already, you've been here a while ;)
In flat tappet cam as well as cylinder head world we know a few things...like the valve will sit at its full lift about a blip, about next to no time meanwhile the opening and closing rams have more area and the lifter/valve hang around and revisit those ramps aka spend more time there in comparison. So let take say the head does stall at .460....I myself will pick a cam lift about .060-.080 more to better utilize the flow in those lower lifts/hang the valve longer in the peak flow of the head. I know you're gonna say "well what about stall and the port backing up once you go beyond that peak lift?" well... Again remember the peak lift is only there for not even half the time the lifter/valve is on the ramps...so any backing up is gonna be micro...unless you lift the valve 'way into reversion' and in some cases the motor will still make some power...but nothing what it could be and lower under the cam operation will be crap, the intake gets blackened etc.

Let the ones who own a flow bench talk about what a head does, otherwise you're getting hot air and confusion from a guy who acts like he knows some secret when he really don't know **** and if he really did and was here to help, he wouldnt be telling you he can't help because it cost him too much to find out himself.
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Nice dig I'll take as a back handed compliment.

When you start writing checks, I'll tell you want you want. In fact, for you it's straight cash homie. Then I will tell you what you want.
 
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