My Magnum heads are "cracked".

[JoeDust451]

took them in today, he didn't even have to Mag them to see the crack in the one head, but he mag'd them to show me & sure enough, cracked in-between the valves on both heads, are any of you running the RHS heads from Hughes engnes, they are out of the "magnum rams".

 

[Mad Dart]

took them in today, he didn't even have to Mag them to see the crack in the one head, but he mag'd them to show me & sure enough, cracked in-between the valves on both heads, are any of you running the RHS heads from Hughes engnes, they are out of the "magnum rams".

I bought the Indy/RHS heads from Hughes and sent them to Bobby at BJR RACING who is a member here. I bought them RAW and Bobby set them all up for me.

Check out the thread here.

http://www.forabodiesonly.com/mopar/showthread.php?t=73132

 

[fishy68]

Stock magnum heads are bad about that. I've read post after post on different boards about them being cracked. The RHS heads are brand new heavy duty castings. Much better than stock magnum heads plus they flow alot better.

 

[ramcharger]

I wonder if the stock used magnums do this because the engines are tuned to run "hot and lean" from the factory due to emissions regulations? Just a thought.

 

[dodgetkboy78]

I don't know, actually, I think the best way to pass emissions is to keep exhaust temps down.

 

[ramcharger]

I don't know, actually, I think the best way to pass emissions is to keep exhaust temps down.

Well, not from what I've been taught and experienced. The higher the combustion and exaust temps, the less unburned hydocarbons can escape to the atmosphere from what I know. Also, the higher the coolant temps are, the less emissions are produced. Please expound on you idea? I'm not trashing what you said at all, I just need enlightenment.

 

[JoeDust451]

To pass emissions, you need a higher exhaust temp, & leaner burning engines.

I was told that the factory magnum heads had issues with not having enough meat in the seat area between the 2 valves, now the machinest told me that most all of them crack on the end chambers, so this could have also been a cooling issue.

 

[1wild&crazyguy]

Besides the running on the clean side with lean & temp, the magnum heads were mopars answer to chevys fast burn series of heads that were thin casting [cheap] just like magnums and crack just as much.jmo

It was a cost thing.

 

[fishy68]

I used to do alot of emissions work on forklifts in some of the local factories and I always had to run them pretty hot to keep the emissions down. Lean but not way too lean also. Seemed like when I got them over 17 to 1 ratio the emissions went back up. I was never schooled in it. Just what I learned that worked.

 

[moper]

The heads dont have a lot of meat there. Replacements now do. But, have them pressure tested... Many heads that have cracks between the seats do not have any issues running or mixing fluids. On a milder engine I know several that are running fine that way. Most factory ones have them too.

 

[JoeDust451]

The heads dont have a lot of meat there. Replacements now do. But, have them pressure tested... Many heads that have cracks between the seats do not have any issues running or mixing fluids. On a milder engine I know several that are running fine that way. Most factory ones have them too.

I asked him about this, he said its a 50/50 change you take, he did a VJ on a set for a customer, about 3 weeks later, it started useing coolant, so i opted not to take the chance, so i ordered a set of the RHS Magnums today, i can run a .500 lift cam, & have a healthy magnum with some grunt.

 

[dodgetkboy78]

Well, not from what I've been taught and experienced. The higher the combustion and exaust temps, the less unburned hydocarbons can escape to the atmosphere from what I know. Also, the higher the coolant temps are, the less emissions are produced. Please expound on you idea? I'm not trashing what you said at all, I just need enlightenment.

Not sure, but from what I have seen, magnums run in the 14-15-1 area. A wise guy once told me, the best way to pass emissions, was to have flame coming out of the exhaust port, or fuel left, to burn in the cat. This actually takes a richer mixture, to a point. Yes, lean will make the headers glow, but no flame until it starts to miss.
The flame was why the first air injection systems were in the port, injecting extra air to complete the combustion in the manifold. If it were too lean, that wouldn't happen.

I may be wrong.

I think Magnums were the first of the "throw away" LA series, but you just cant screw up a chrysler SB.

OOTH, you can also run the cracked heads forever.