Magnum 5.9 Magnum Rebuild: What can You get away with?

-
Wow, thanks for the heads up magnum heads, mainly the part about the valve guide cutting. In the last day since i posted this I've been scoping RHS heads. Over at summit you can get a set for $650 bear of course. Is there any qualms to using magnum valves in them? cam shaft brand/spec recommendations?
 
PoisonDart74 said:
Wow, thanks for the heads up magnum heads, mainly the part about the valve guide cutting. In the last day since i posted this I've been scoping RHS heads. Over at summit you can get a set for $650 bear of course. Is there any qualms to using magnum valves in them? cam shaft brand/spec recommendations?
Click to expand...

I got mine at hughes engines complete for 875.00.
 
I think I would call RHS to make sure they are machined for 8mm valves of the same length as the magnums and not assume they will work.

People refer to 8mm and 5/16" when it comes to valve diameters interchangelby but an 8mm is .315" and a 5/16 is .312".
 
I was the same as you dgc33, I didn't see how what Hughes told me was going to work. I asked Hughes specifically how they were able to do this with their retainers. I was told as you said that the relative position of the locks were the same but that mopar had engineered extra material on the underside of the retainer that was unecessary and that their retainers were reengineeered to do away with that extra material. They had redesigned the retainers to allow for an extra .125 of lift from the camshaft and that they were running camshafts in excess of .600 with these retainers. The second time I called and spoke to a different guy I was told that there was no clearance issue on the magnums in terms of putting a camshaft in there with lift over .525!!! . I just went out and measured the set up. I gutted a hydraulic lifter and used an adjustable push rod and set every thing up. With the 512 lift cam I still have almost .040 from the point of highest lift to the retainer hitting the top of the valve guide seal. I have stock thickness head gaskets on it and the heads were milled just enough to clean them up(a few thousandths). So in my situation I feel very safe at .512. At this point I'm not sure what to believe but I'm glad for this thread because I now know for sure that I don't have any clearance problems.
 
PoisonDart74 said:
If you buy me a 24 pack I'll go mopar parts...... That's a little steep for a stock piston in a junkyard dog.

Thanks for everyone's input, greatly appreciated! :cheers:
Click to expand...

HOLY SNICKIEZZZZZ!!!!!!!!!

I just called the dodge garage.......... 144$ for a freaking piston........

All I could say was, "are you kidding me"??????

LOL, used one it is!
 
dodgetkboy78 said:
HOLY SNICKIEZZZZZ!!!!!!!!!

I just called the dodge garage.......... 144$ for a freaking piston........

All I could say was, "are you kidding me"??????

LOL, used one it is!
Click to expand...


[/RANT START]

Although I can appreciate supporting the Mopar Corporation, we gear heads walk a fine line on what material goods go into our cars. Advice is a powerful thing, a less savy person might not benifit from tomfoolery, as some folks can't afford costly mistakes. Especially now a days.

May the spirit of the iron horse fulfill you. :toothy10:

[/RANT STOP]
 
You can order stock replacement pistons from Rock Auto for about $50 each.
 
dustoff440 said:
I was the same as you dgc33, I didn't see how what Hughes told me was going to work. I asked Hughes specifically how they were able to do this with their retainers. I was told as you said that the relative position of the locks were the same but that mopar had engineered extra material on the underside of the retainer that was unecessary and that their retainers were reengineeered to do away with that extra material. They had redesigned the retainers to allow for an extra .125 of lift from the camshaft and that they were running camshafts in excess of .600 with these retainers. The second time I called and spoke to a different guy I was told that there was no clearance issue on the magnums in terms of putting a camshaft in there with lift over .525!!! . I just went out and measured the set up. I gutted a hydraulic lifter and used an adjustable push rod and set every thing up. With the 512 lift cam I still have almost .040 from the point of highest lift to the retainer hitting the top of the valve guide seal. I have stock thickness head gaskets on it and the heads were milled just enough to clean them up(a few thousandths). So in my situation I feel very safe at .512. At this point I'm not sure what to believe but I'm glad for this thread because I now know for sure that I don't have any clearance problems.
Click to expand...

That's cool! :)

When I put magnum heads on my 360 the only spring choices at that time were two from Mopar Performance and Comp told me to use the "R/T" spring for the cam I was choosing. I used mopar 2.2 4cyl motor retainers (was told they were the same as the ones in the MP catalog). Anyway, I have .509/.512 lift and have about 0.020-0.030" of clearance between the bottom of the retainer and the top of the seal. The engine has been running strong now for 45,000 miles and is still pumping 195 +/-5 psi on a compression test.
 
I'm running the Hughes retainers on my 5.2 with 1.72 roller rockers that put me at .538 lift. I have about 10k miles on the engine with stock rods and pistons. I shift it at 6200 quite often. The rods and pistons have over 100k on them without any I issues. I know the 5.9 will be different because its a longer stroke engine. I needed the offset retainers to get the installed height correct for the springs. I had to have my valve guides cut down for enough clearance for a .550 lift that I was expecting from the 1.72 rockers. Hope this info helps.
 
You must log in or register to reply here.
-

Back
Top