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Discussion Starter · #1 ·
So here is the story. Bought my 99 1500 4x4 5 speed with a smoked motor 5.2 magnum. Did a full rebuild. Also put in a comp cams small RV cam and heavier valve springs. Everything of inportants was replaced or gone through.

The problem I'm having is it seems slow and definately a dog between shifts. Anybody have any idea what this might be? Solid vaccum pressure. Timing is solid.
 

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So here is the story. Bought my 99 1500 4x4 5 speed with a smoked motor 5.2 magnum. Did a full rebuild. Also put in a comp cams small RV cam and heavier valve springs. Everything of inportants was replaced or gone through.

The problem I'm having is it seems slow and definately a dog between shifts. Anybody have any idea what this might be? Solid vaccum pressure. Timing is solid.
The first thing I recommend is that you do a fuel pressure test, make sure it's at 43.5 PSI, 40 MIN.

The next thing I'm going to ask is what Cam did you get, the timing might be right, but the engine might not be producing enough torque at low RPM's. Also did you make sure to match the torque converter to the cam application, on comp cams site they have a camselect thing that will give you theoretical dyno results will also give you an indication of a properly selected torque converter.

This is what I can think of for right now. I noticed the comp cams have grinds that are advanced 4 degrees if installed dot to dot where the stock cam has a grind which is retarded 3 degrees when installed dot to dot.
 

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Discussion Starter · #3 ·
Fuel pressure is good. It's a 5 spd manual. So it doesnt come back alive when I shift. We could only get the cam to degree in at 106* and its a 108* cam. Not a problem normally. By the way no one makes cam keys for magnum motors. Had to custom make one. Im almost thinking of just sticking the stock key back in it and see what it does.
 

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Fuel pressure is good. It's a 5 spd manual. So it doesnt come back alive when I shift. We could only get the cam to degree in at 106* and its a 108* cam. Not a problem normally. By the way no one makes cam keys for magnum motors. Had to custom make one. Im almost thinking of just sticking the stock key back in it and see what it does.
Yea I know, Comp' intake center lines are almost always 108 for the magnum motors, I hate that because since the grind is advanced 4 degrees in order to get the center lines to match well atleast get the timing events to match the cam would have to be retarded 7 whole degrees and that would be NUTS! I'm going through the same garbage as you did.

I think it's timing related, the cam is matched to the dam ECM. The people we usually talk to at comp are just idiots not the engineers, the engineers are busy doing the real work.
 

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Discussion Starter · #5 ·
I'm just going to stick the stock cam key in it and see what I come up with. If that doesnt work im going to checking to see if that rockers need to be shimed because the guy who helped me said that maybe that the valves arent sealing. By the way im not a big motor guy. Kind of learning as i go.
 

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I'm just going to stick the stock cam key in it and see what I come up with. If that doesnt work im going to checking to see if that rockers need to be shimed because the guy who helped me said that maybe that the valves arent sealing. By the way im not a big motor guy. Kind of learning as i go.
Well tell me how it works out, hopefully you've got it!
I'm not to big of a motor person, I'm more transmission then motor but I do know a bit.
 

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Discussion Starter · #7 ·
I hope it works too because I'm not looking forward to shimming the rockers. Probably be paying omeone to do that. Im more of the axle and suspension guy. dont have all that trouble shooting experience with motors like some do.
 

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I hope it works too because I'm not looking forward to shimming the rockers. Probably be paying omeone to do that. Im more of the axle and suspension guy. dont have all that trouble shooting experience with motors like some do.
I hate doing axle and suspension work, specifically axles. I wouldn't mind rebuilding a rear end if it was removed from the vehicle but then it costs more money, for me atleast.

Well hopefully you won't have to space the rockers!

Tell me how it works out though.
 

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Discussion Starter · #10 ·
Well talk to the people over at comp cams and you were right. Not much for help. Going to try the guys at hughes engines and see what they think.
 

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Well talk to the people over at comp cams and you were right. Not much for help. Going to try the guys at hughes engines and see what they think.
Hughes will probably have some recommendation. The issue will selecting a cam for these magnum engines is that a majority of the cam manufactures who made cams for the engine never really tested it in an actual magnum engine with the stock ECM. Even to stock replacement at comp for the 5.2L part number 20-608-9, Comp cannot even promise that it will work properly with the 5.2L engine because of the ECM. The ECM is a big issue atleast with stock because the stock ECM cannot be programmed easily if not at all. Another issue is that chrysler experimented with cams on the magnum engines during their lifetime. So the cams in the 5.2L are different in a 93 then a 95 then a 97 then a 03. So it's such a pain in the rear to get dead on balls with a cam, it's really boiling down to trial error.
Great engines, but modifications aren't always easy. Thing I hate the most of all is that their are more mods avail for chevy engine then anything else.
 

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Discussion Starter · #12 ·
The recommendation was re-degree in the cam to 109*. Also to clean up the ecm with a custom tunes with a SCT tuner.
 

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The recommendation was re-degree in the cam to 109*. Also to clean up the ecm with a custom tunes with a SCT tuner.
Try 110 intake, it might be different for your year but from the calculator I made it shoots out 110. I hate how chrysler used so many different cams on the same engine. But the ECM's were different from OBD1, OBD2, and engine OBD3. The magnum covered all 3 amazing...

Anyway's I made a Cam Calculator for excell/openoffice if you want it I'm happy to give it out. Simply you enter in the valve events and it tells you the ICL ECL LSA OVERLAP Durations and how many degrees the cam ground is advanced or retarded when installed dot to dot, in my calculator it allows you to enter in the degree you want and it will tell you the new valve events the new ECL ICL LSA etc... Very fun little calculator
 

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Discussion Starter · #14 ·
You definately know your stuff! Haha. I'll pass that on to the motor guy thats helping me. I just hate that i have to take the motor back down.
 

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This is very true!
Hey do you want to try the calculator I made? I added some other things to it, now it will allow you to enter in data to figure the vehicles potential speed and it graphs it also, it also will display the torque throughout the entire drivetrain at each gear and graph it also. I really would like someone else to try it then me because I make them so I get bored of them... It works in excell and open office spreadsheet.
 
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