Jeep 5.2 V8 motors

[Grandman]

Heres a little heads up im just ran into . I own a 94 Grand 5.2 , do to miles i tore down an extra motor i had to rebuild out of a 95 grand .

Well the heads up is the heads . Seems there very prone to cracking . This motor ran fine as does my current motor but once its tore down you find there is stress cracks between the valves . Given it is a design flaw its near impossible to find good used ones and the best price iv found on bare heads is $ 275.00 each .

Also these are roller cam engines , there the Magnum design and a rebuld kit will run you near $600.00 With out machine shop work or labor you looking at $1200.00 dollars in parts .

The good news is , the one i tore down still ran good and had 240,000 miles on it . They do last well .

[GerkTJ]

so even with the cracks they are not leaking antifreeze into cylinders?

[GreaseMonkey]

Check out www.manciniracing.com for any Mopar motor parts you might need. I've gotten quite a few stuff from them for the 440 BB I'm rebuilding.

[Grandman]

Originally Posted by GerkTJ

so even with the cracks they are not leaking antifreeze into cylinders?

Nope no leaks , but its like a time bomb so im not putting them on a new motor . My whole point is to reagain reliability .

Its not uncommon to have heads that dont leak but magnuflux them and find cracks .

[PavementPounder]

Does the 360 from the 98 Limited use a different head? Might want to see if they are compatible.

[h8pvmnt]

Originally Posted by PavementPounder

Does the 360 from the 98 Limited use a different head? Might want to see if they are compatible.

Naw magnum heads are magnum heads from what I understand. You can get heavy duty replacement style heads or the magnum r/t mopar performance heads, with hardened inserts instead of induction hardened seats, which prevents the cracking. A good site for small block stuff is :

www.hughesengines.com

They have a nice 420 c.i. small block for the 5.9's

[Grandman]

The thinkg that is causing the cracks is the new shape of the combustion chamber . The heart shape is causing a hot spot . Yes 5.2 or 5.9 either one is having the same issues .

Again there is options , theres just no cheap option on it .

[5.9zj]

Originally Posted by PavementPounder

Does the 360 from the 98 Limited use a different head? Might want to see if they are compatible.

nope same head as all 360. Even the dakota rt's have the same heads, even though some of those guys think they have the R/T heads. There are some expensive alternatives, mopar R/T heads and edelbrock aluminum heads.

[84Scrambler]

Yep, all 5.2 and 5.9 magnums have the same heads. I had the same cracks on my '96 5.2 heads. Both were cracked between the inner most cylinders. It is all too common with these motors. I have a set of 2.02 Mopar Magnum R/T heads sitting in the garage, but those are a little more than $275 a piece. ;)