Do you see significant value in a modification such as this one?

http://www.flashoffroad.com/Diesel/RearheadCooling/rearHeadCooling.htm

:D Funny,

I was considering modifing the blockoff plates in a similiar manner but to serve as a source of hot engine coolant for my WVO fuel heater. At $300 I'd gladly tap it myself. Those fittings are right out of jegs or summit' catalog. I guess I was on to something in looking to utilize the hot rear coolant passages that arn't there.

I think that is a popular upgrade for the 6.5 hummers out there. I was also curious why we don't hear much about this upgrade.

There are three styles on the front crossover, the '92-'94 w/ single horizonatal thermastat housing, the '95-'96 single verticle therastat housing and the dual HO set up.

I wonder if you could add the '92-' 94 front crossover w/ single horizontal housing or the '95-'96 verticle to the rear passages and plumb the extra heater hose outlet into the heater core with the other?

QM,

Actually, I think someone was talking about it over at that other forum. It sounds like an interesting idea, and, I kept my old style cross-over from my 94 Blazer. It would make a really cool base for a WVO or SVO fuel heater, if you use something like a cannister and mount it to the top with a heating element to get the process started. Not sure how it would alter the coolant flow in the heads.

It could'nt hurt the system to have that crossover back there. It would balance the coolant between the #8 and #7 cylinders and I can see how it would drop the head temps near that water passage due to radiational cooling in the new crossover. If you plumb it right and get it to flow back into the system like the kit attempts by the use of the coolant T, it should take even more heat out of the head.

This requires some real numbers from a heat probe in block off plate and then the new crossover to quantify these changes.


The WVO heater would take even more heat out of the crossover.

I'm a member at that other site http://GM-diesel.com (http://gm-diesel.com/). I'm QM over there, I'd like to do some posting but I've read some unanswered one's I'm waiting till my account is ok'd again to answer.

this subject is why I quit paying attention to anything said at the other place. We run coolant out of the back of the heads on every race car we have and people have for years. This is such standard practice that the intake manifold we are required to use in our craftsman truck has two separate peices of the intake, the lower being the water transfer passage from rear to front. At that point, when none of the diesel wizzards could tell me why it works on our $42K 700 hp engines, yet isnt' good enough for our diesels that GM obviously did so much homework with, I quit listening and started building my own junk. I guess GM really got it right considering everyone who has ever owned one of these engineering marvels gets to hear about cracked heads.


P.S. I asked that question on the other board about 2 1/2 years before those whatever guys they are, started selling that peice of crap with AN 4 lines.......which are brake line size for most vehicles.

So.. you're for the rear crossover then?:ro) I get the feelin' you mean the diesel page when you say the other site. :o

I just checked my spare parts collection and I think I tossed the crossover housing along with the old water pump. The funny thing is I kept those parts for a just in case scenario for 6 years. Got tired of tripping over them in my space constrained garage.

i would think that bigger hoses would work better than those #4's ? Whatcha think?

I don't know guys......gm is really good at engineering:rolleyes: ......just like the first 3 years of the SB2 head in which it was recomended to run a quart of sodium silicate with each radiator fill in Nascar applictions. Now we have the new and improved SB2.2, yeah for rule changes.

I don't know guys......gm is really good at engineering:rolleyes: ......just like the first 3 years of the SB2 head in which it was recomended to run a quart of sodium silicate with each radiator fill in Nascar applictions. Now we have the new and improved SB2.2, yeah for rule changes.
You changed the rules again? whats next ? LOL :D

I think the '94 takes up too much space to put it in the back passage without making some space for it.

I havn't been able to upload my image yet.

I have been running a system similar to this on my 94 for a couple of years with good results. I have the high capacity cooling upgrade with the dual t-stat housing. I used plates from the early 6.2 where the glow controller was mounted to the drivers side rear of the head and was threaded for 1/2" pipe. I believe that I used 10AN lines and ran them directly to the top of the engine side of the t-stat housing. Jegs has a Y- block available now that would plumb 2 10AN lines to a 12AN line, requiring only one connection at the t-stat. The whole system can be made for less than the one at the beginning of this thread and has bigger hose. With my engine running hard up hills in 90* weather I would get the truck gauge up to 215* and a gauge mounted to the rear passenger side head up to 235* due to the higher temps in the rear of the engine. After adding the extra lines the difference was 210* truck gauge and 220* for the add on one. I had several people on the diesel page tell me how foolish I was and that I would destroy my heads in no time. So far I have seen only positive results and if I were to have another 6.5 I would do the same mod again with the Y-block and maybe 8AN lines instead of 10. The fitting that goes from 1/2" pipe to the AN fitting only has a hole slightly more than 3/8" anyway. :)

I have access to fittings and the hoses so all I need to find is the plates for the head. Do you have the Jegs part number for that y-fitting so I can look at it too. Also do you have any pictures of your setup toyboxrv?

Sounds like an excellent article idea!

What were some of the reasons they gave as to why it was a foolish mod?

the way the head gasket is made, when you turn it up the correct way, the front passage is blocked more than the rear. So the thinking is that water won't go forward through the head, instead just bypassing the front of the head and out...........easy solution.......file the head gaskets and make the openings match front to rear. On our race engines we don't even put the cold water in the front of the block anymore......instead, all of our(the guys you see on sat, and sun.) waterpumps are cheated up and actually have no hole cast towards the front of the engine. Instead they have an AN12 port cast into them facing outwards and a line connects to where the center freeze plug would be, keeps things much more even.

Member's Area - 6.5 Head repair article - 6.5l head cross-section, sectioned vertically thru pre-cup

Word to the wise, vis-a-vis flow............

Member's Area - 6.5 Head repair article - 6.5l head cross-section, sectioned vertically thru pre-cup

Word to the wise, vis-a-vis flow............
what did he say

BTW, grape - I put nascar and nastruck racing in the same classification as wimmin's mud wrasslin' - they're the only two sports I'll watch ;)

Any hints as to who to look for, from your neck of the woods?

Bowtie the Y-fittings are by MagnaFuel and are 665-MP-6208 or 6220 in Jegs. I also used the aluminum weld bungs for the fittings on the crossover at the t-stat housing. Part # for that is 555-15264, or if you use one AN12 line, then 555-15265. No pictures at the moment, but could get some to you if need be.

pictures would be great too if you get some but I think I have a picture in my head as to what it will look like. Now it I can just find it up there somewhere