New Hesco heads
- Thread starter Darky
- Start date
XJZ
NAXJA Forum User
- Location
- SF Bay Area
Bloose said:
Gotcha.
REDXJ4FUN
NAXJA Forum User
- Location
- fredericksburg VA
Well one simple thing that can be changed is your ignition timing. with an alum head you can run more advance there for more power(to a point) with ou detonation since the combustion chamer will be cooler.
2001XJeep
NAXJA Forum User
- Location
- Helena, AL
I believe there is some confusion here regarding the aluminum vs iron debate. The difference is heat transfer. The more heat that is transferred into the coolant, the less efficient the combustion process is, period. Iron doesn't transfer heat as well as aluminum and is therefore a more efficient material for reducing heat transfer. Engines with aluminum heads require more compression to offset this energy loss. Heat that goes into the cooling system is wasted energy. Keeping as much heat in the combustion chamber as possible is more efficient, pure and simple. As was mentioned previously, heat reflective coatings on the piston crown, combustion chamber and valve faces are good solutions. Getting the heat transfer qualities of iron with the weight savings of aluminum is the best way to go.
explorer
NAXJA Forum User
- Location
- rosemount,mn
I'm with ya now Bloose. The arguments for more compression and advanced timing were what I've seen before. But I completely understand how the slower heat transfer makes the effieciency higher. Now, about that HP/ weight ratio thing.....
Darky
NAXJA Forum User
- Location
- 29 Palms, CA
These are up to $1995 now on their website. Why, oh why, did I not have $1000 to spend on them 4 yrs ago?!
Boostwerks.com
NAXJA Forum User
- Location
- Colorado
For that amount of $, I'd rather get an entire SB 350 crate motor. $2,000 is a little rediculous for an aluminum head.
yossarian19
NAXJA Forum User
- Location
- Grass Valley, CA
Especially when you have to deck the block to raise compression for the full 30 HP gained...
For Jeepspeed rigs built to go fast in competition... sure.
For my rig... 258 crank / rods + mid grade gas & call it done.
For Jeepspeed rigs built to go fast in competition... sure.
For my rig... 258 crank / rods + mid grade gas & call it done.
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
..and add the Hesco RVOB cam, '99+ intake, injectors, and Unichip with dyno tune. It ends up being a hugely expensive 30hp gain.
$7k for an aluminium block and aluminium head in a Jeep that's worth less than $3000? I don't think so.
Last edited:
yossarian19
NAXJA Forum User
- Location
- Grass Valley, CA
By the time you get done with Hesco's all-aluminum 4.x or 5.0 (whatever) stroker, you're making 300-350 horse with a 7.5K build cost in round numbers... The AW4 probably wouldn't last too long behind that sort of power. I wonder what it would take to get an LS series chebby in there?
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
It might last about 5 minutes.
A lot less than $7.5k that's for sure.
POLAR_JEEP_04
NAXJA Forum User
- Location
- Ohio
doesn't aluminum not take to heat too well? I know on hot days on the trail when im really working my poor jeep the temp really gets up there if I don't pay attention. I would be afraid to warp a 2k head
5-90
NAXJA Forum User
- Location
- Hammerspace
Aluminum is more efficient at heat transfer than iron (note the discussion above on CR under iron vice aluminum.) If you've got an "all-aluminum" engine, the block and head will expand at the same rate.
The MLS composite head gaskets came about because people were trying to seal aluminum heads against iron blocks, and the head gaskets were "scrubbing out" with head (aluminum expands twice as much as iron, for a given temperature and size.) Single-layer head gaskets were losing seals because they were literally being scrubbed away over time. Thus, the MLS gaskets.
Sealing aluminum/aluminum or iron/iron isn't much of a problem - since everything around the gasket expands at the same rate, the gasket simply gets stretched and released - no scrubbing. The MLS gaskets are still better (the outside sealing layers stretch and release, slipping around the steel core,) but they're not as necessary as they are when sealing aluminum/iron.
This is why the Buick 215ci V8 worked so well for Land Rover for so very long (LR bought the tooling for the Buick 215ci all-aluminum V8 engine in the late 1960's, and used it in the Defender "series" models - mainly the D90 and D110 - ever since. These engines crossed the Sahara without mishap, so you know they're at least reasonably good...)
dakineJ
NAXJA Forum User
- Location
- central OR.
You could go with something like the Level10 trans, www.levelten.com ,but then you add another 3k+ to price tag.
REDXJ4FUN
NAXJA Forum User
- Location
- fredericksburg VA
the aw4 is a hell of a lot tough than you think stock and then built its the same trans that turbo supras are using and pushing 900hp. wasn't some one here using a aw4 behind thier 401 powered drag mj.
- Location
- Thornton, CO
A stock AW4 yeah, not a good idea. But like Red said, the Supras run this same setup. A 
member actually has a "hyrbid" AW4. Basically took the internals out of a Lexus AW4 and rebuilt his. Its been so long since I've researched it, but pretty sure the LS 400 (V8) has the AW4.
member actually has a "hyrbid" AW4. Basically took the internals out of a Lexus AW4 and rebuilt his. Its been so long since I've researched it, but pretty sure the LS 400 (V8) has the AW4.
