I would like to conduct a poll about magnum heads and what folks here on the board have to say and what experiences have occured. I have heard some real stories about magnum heads cracking. Claims that the heads came from the factory already cracked and etc. I kind of wonder if the problem isn't the result of improper installation procedures? for instance, it is known that the "kegger" intake manifold can create problems by leaking, and when folks go to fix the problem they do not pay attention to torque on bolts, bolt tightening sequence etc resulting in cracked heads. overheating seems to be another issue from detonation, seems that the engine can develop a ping that is not noticeable to the average driver until head gaskets come apart and then there is the one service bulletin regarding the "kegger" intake and gasket issues with heat coefficients between intake and head mounting that cause problems. The reason I am curious about this particular bit of urban legend is that I have 4 mangnum engines of different sizes and in various conditions from running to stored parts and I do not recall having any issues with cracked heads. Of course, I understand that there is the possibility that I will eventually come across this situation, but really, how common is it among the literally thousands of magnum engines out there, IF the engine has not been mistreated, improperly serviced or repaired by an inexperienced weekend mechanic with no service manual or other proper tools to do the job? Just for the record a 5.9 magnum engine that had its "beer keg" intake changed out with an M1 early in its life still has no issues with blown head gaskets, oil consumption or cracked heads and it was maintained as required by the factory service manual. So, what is the view point out there? Am I going to have a problem with a 4.7 in a 03 4x4 dodge ram 1500 with 37,000 miles on it in the future or is it pretty much what I figure, maintenance and proper tools/techniques?

AND I will state again for the record, my expertise is in the B and RB engines from way back and A/LA engines are a recent affliction.

By the way, I seem to notice a lot of old B/RB heads that have cracks, might be my age, huh?

Thanks for the view points.

regards,

doc

They crack when the breeze blows,whats the point in a poll? You have 4 magnum engines that have at least 1 cracked head,that doesn't mean you'll be stranded on the side of the road,many don't end up with a leak,just a crack. 308's are the same story,I've got many prs of both and the odds are 7out of 10 show cracks,maybe more. They came off running engines with no problems.Your poll should be toward folks that rebuild them daily to be accurate,not the internet.I daily drive a 2001 Dakota 5.9 in good health for 118,000miles,but I bet the heads are cracked,so what? I don't worry much about it,I wouldn't spend time porting magnum heads like I did 12-15years ago.Lots of theories as to why,but weigh them compared to early heads or say a magnum R/T and you'll see,they are very light.The magnum cooling system is fine,the typical tune is way rich,the timing is way retarded,the heads are a problem.

I've replaced several sets of magnum heads for cracking between valves, causing a difficult to feel mis-fire, that turns on the CEL. I don't think they would crack in that location by improper intake torque. Nor do i think they came that way from the factory. Seems to be limited to a few model years and takes 100k or so miles for the problem to occur. I would think a rash of poor castings Most of the ones i did were on 5.9's

4 sets, 5.9 ddifferent years, all had cracks. probably how they did the heat treatment on the heads make them crack.

is this problem time period specific, or a batch of serial numbers or is this a problem with every magnum head from 91 to 03(every single head)?

Interesting info so far. Questions that I would ask:

On the 5.9 that has gone thru 4 sets of heads?
were these new heads or purchased from a recycler or private party who took them off to upgrade or maybe had cracks?

Other question would be, does the problem seem to occur with high mileage?

And were the engines run for awhile with MIL light for say vacuum leaks or misfiring cylinders?

Some of the statements seem to indicate my earlier opinion that engines may have been run with the engine having preliminary problems.

Appreciate the info and would still like specifics on what engine size, year and what the history of the engine is; did you have it since new etc? have a great weekend.

doc

Don't see many responding to this thread, its old news, there are new thicker & better castings out there for reasonable prices, a no brainer really.

But good luck anyways

Yup...cracks and more cracks...3 crate motor stockers,all 3 had cracks between 1 pair of valves. None ever leaked though,so it was no big deal. I'm still running on a cracked passengers head now and never give it a second thought

I'm 99% sure the cracking comes from the induction hardening of the valve seats, I had a set of brand new bare castings that were already cracked- as in brand new meaning they just came out of the box, never had valves/springs etc in them.

these were 4 different 100k+ engines but the ones i had on my truck i never knew they were cracked, ran great passed smog. another set came off a running truck no problems with it, and another i got from a junk yard.

I just wanted the blocks as i am building another 5.9 for my truck, yes i am hard on them

mine came off an unknown mileage 5.2 with a spun rod bearing. no cracks when I had them checked....they're '671 castings.