help with 509 mopar cam

[mick1967gtx]

not sure if its me or not first time using this cam.seems to run crappy i have
about 8 hg of vaccum real hard to tune extremly lumpy looks like the engine wants to jump out of the car any one from south jersey hear thats using this
cam so i can hear it run

 

[1badgtx]

I,m runnin the 509 purple shaft in my 440..I ave the same problem with low vacum also..Had to put in an extra canister for my power brakes...You got to find the happy medium for carb and timing...
Petty Blue 67 gTx

 

[lewtot184]

in my opinion, big hydraulic cams are a pain in the ***. you'll have to do a lot of ignition and carb work to find the "sweet spot". mechanical cams are easier to tune and more forgiving.

 

[Belvedere]

Sounds normal for that cam. Just make sure you have lots of initial timing; around 20 degrees. Should even out....a little.

 

[lewtot184]

Sounds normal for that cam. Just make sure you have lots of initial timing; around 20 degrees. Should even out....a little.

those cams need a bunch of compression to work right. good heads, good intake and exhaust also.

 

[Sweet5ltr]

What size power valve and jets are you running, and what type/size carburetor?

 

[TheGodfather]

Rhodes Lifters

those cams need a bunch of compression to work right. good heads, good intake and exhaust also.

This is my opinion only; I'm not a real big fan of those purple shafts due to the notorious low vacuum and associated rough idle plus they're not keeping up with cam technologies. Real old school stuff. An easy fix is a new set of Rhodes hydralic lifters which will boost the compression by keeping valves closed a little longer while still giving you good mid range and top end. Other than that; try a new Comp cam instead.

 

[Sweet5ltr]

My personal opinion is the fact that the camshaft is a great performing cam, when/if the carburetor, compression, gearing, and converter is set up to perform with it. You cannot place a "box stock" VS carburetor, 8.5:1 compression big block with 3.23 gears and expect it to actually do anything but burn gas.. It is all about combination, and part matching for drive-ability.

 

[Cranky]

My personal opinion is the fact that the camshaft is a great performing cam, when/if the carburetor, compression, gearing, and converter is set up to perform with it. You cannot place a "box stock" VS carburetor, 8.5:1 compression big block with 3.23 gears and expect it to actually do anything but burn gas.. It is all about combination, and part matching for drive-ability.

Amen! Also, it's important to degree in the cam too. If you just aligned the dots, you have no idea where it's set at. I've seen people bend all 8 intake valves because the key ways in the sprockets were not in the right place or the dots were wrong or both. Even the cam could have been ground off some. Machining tolerances can stak up against you so using a degree wheel is the only way to set a cam in. Also, depending on the combination, I usually advance the cam a few degrees with the purple cams. It helps smooth them up a bit plus it brings the power band into a lower rpm range.

 

[rumblefish360]

I do not think I have seen a better group of replies that are not only honest but dead bulls eye on target about the MP Purple cams. While there not to bad for a basic street strip ride when certain things are not a worry, like power brakes with low vacuum isues being, .... what did that say above? I love this line!

notorious low vacuum and associated rough idle

Considering there a single pattern cam, they will work fine if the heads are ported out well. (IE a good balance in flow) Have headers, etc.... for a good street strip effort. These cams do love Compression and advance in timing.

 

[WileE]

It's been a LONG time since I've used a PS cam in my, or others, cars. The newer cams, are much better, as long as the combination is matched.

 

[1badstroker]

I have a 500 incher with the 590 lift MP cam with everything else matched up and it is not bad. Vacuum, there is none, have manual brakes and manual steering, 5500 stall, 12.50 compression, 456 gear and a 29 in. tall tire. It is all older tech, so is the car. Nothing will run right if you put the wrong parts with the wrong application and that equals sh*t the way it will run. Big cams and a highway gear are not a match most of the time.

The 509 cam will run great with the right parts behind it. vacuum is another thing. Get a vacuum tank or a pump and then you can run anything that requires vacuum. good luck with your build.

 

[MoparBill]

My personal opinion is the fact that the camshaft is a great performing cam, when/if the carburetor, compression, gearing, and converter is set up to perform with it. You cannot place a "box stock" VS carburetor, 8.5:1 compression big block with 3.23 gears and expect it to actually do anything but burn gas.. It is all about combination, and part matching for drive-ability.

Ma Mopar actually wrote a book on this, the Mopar engines book. It gave combinations for a complete engine build with all the mopar part #s. I followed one of the builds for the 440 in my last RoadRunner with the purpleshaft 484 cam and I was pretty happy once I tweaked the carb a bit.
As said above, the magic is having all the parts work together.

 

[67 B-body]

My 69 RR had the 509 cam and it ran 12's. I had a Weiand tunnel ram with two holley's. The more carb I gave it, the higher the MPH was in the 1/4 mile. I too have the .590 solid MP cam in my current engine.1.6:1 ratio rockers, Lots of compression 13.5:1, large valves, 2" primary headers, aluminum heads... The combination makes it all work.