Project “Tomahawk”

[ghetdjc320]

So the 5th gear update difference is in the gear hub design. The new style uses different keys and springs for the synchro hub. Looks like a better design to hold it in gear better. The gear itself looks identical.

 

 

[ghetdjc320]

Transmission internals are all finished and the upgrades are in place. Very satisfying project. Really came to appreciate the way this thing is engineered.

 

 

[Eagle_SX4]

2 hours ago, ghetdjc320 said:

So the 5th gear update difference is in the gear hub design. The new style uses different keys and springs for the synchro hub. Looks like a better design to hold it in gear better. The gear itself looks identical.

 

 

Awesome thanks for the pics. Upgrades maybe in my future, next time I open up my transmission. 

[ghetdjc320]

Just finished up the re assembly. It shift so smoothly. Really happy with how it turned out. It’s worth noting that the synchros that come in a rebuild kit will typically give you the wrong rings for 3/4 gears. The part you need that has the “house” shaped teeth is the same as the 5th gear synchro. One could just order up a couple more 5th gears synchros to compete the kit. I ended up re-using my 3/4 synchros as they were if like new shape with almost zero wear. Evidence of the relatively low mileage on this Comanche (90k). First and second synchros were a bit more worn but everything is new now. One particular aspect to pay attention to on a transmission rebuild are the springs and keys that are inside the synchro hubs. They play a crucial role in shift performance and keeping you in gear. They aren’t difficult to assemble but are a bit finicky. Still need to finish prepping and painting the case.
 

On to complete the engine work tomorrow. 

[ghetdjc320]

[Comanche SS]

Looking good! Decide on any engine upgrades?

[ghetdjc320]

2 hours ago, Comanche SS said:

Looking good! Decide on any engine upgrades?

No real mods planned. I just wanted to do all the reliability upgrades that have been developed in the last 20 years. The trunions, new lifter trays and lifters, ls2 water pump etc. I was considering running 243 heads and the ls6 cam but ultimately decided against it as the power band would have moved a bit out of my ideal range. Surprisingly, the 241 heads have considerably better exhaust flow than the 243’s and the C5 cam was made specifically for these heads.
I’m trying to balance this build from an engineering perspective. Between the engine, tranny, t case, axles, brakes and steering, just trying to get everything on the same level if that makes sense. Something along the lines of what could have been a factory style build if that makes sense. 

[ghetdjc320]

Ordered up some odds and ends. Crossmember with skid from stinkyfab offroad along with their upper control arm mount and track bar bracket. I wasn’t too pleased with the Barnes 4wd parts that i installed.

[Comanche SS]

19 hours ago, ghetdjc320 said:

No real mods planned. I just wanted to do all the reliability upgrades that have been developed in the last 20 years. The trunions, new lifter trays and lifters, ls2 water pump etc. I was considering running 243 heads and the ls6 cam but ultimately decided against it as the power band would have moved a bit out of my ideal range. Surprisingly, the 241 heads have considerably better exhaust flow than the 243’s and the C5 cam was made specifically for these heads.
I’m trying to balance this build from an engineering perspective. Between the engine, tranny, t case, axles, brakes and steering, just trying to get everything on the same level if that makes sense. Something along the lines of what could have been a factory style build if that makes sense. 

Totally makes sense....I admittedly went a little on the large side with my LS3 (stage 3 cam) in the comanche, it doesnt have much go below 3K RPM, but above 3K it is like having two engines lol

The LS1 in my GTO has a stage 2 cam, and its great for a car, not that I would want it in a jeep.

My Denali, has a Stage 1 cammed LS3 build, and it is great for daily driving...if I do anymore off road LS builds, itll be a stage 1 LS3 build. 

Maybe I missed it, are ya doing all the engine oil upgrades? New pump, o-ring, barbell, etc...?

[ghetdjc320]

17 minutes ago, Comanche SS said:

Totally makes sense....I admittedly went a little on the large side with my LS3 (stage 3 cam) in the comanche, it doesnt have much go below 3K RPM, but above 3K it is like having two engines lol

The LS1 in my GTO has a stage 2 cam, and its great for a car, not that I would want it in a jeep.

My Denali, has a Stage 1 cammed LS3 build, and it is great for daily driving...if I do anymore off road LS builds, itll be a stage 1 LS3 build. 

Maybe I missed it, are ya doing all the engine oil upgrades? New pump, o-ring, barbell, etc...?

I had installed new o rings when I did the new pan. I am still considering doing and engine oil cooler though. Just can’t find a good place to mount the cooler. Also installed a new rear cover and gasket while I was back there but didn’t do the barbel. 

[Comanche SS]

1 hour ago, ghetdjc320 said:

I had installed new o rings when I did the new pan. I am still considering doing and engine oil cooler though. Just can’t find a good place to mount the cooler. Also installed a new rear cover and gasket while I was back there but didn’t do the barbel. 

This was my plan...only until I figured out the headers I have leave absolutely no room for the Oil line adapter. That, and the fact I read that oil needs be hit 212* on occasion at least to burn off any water, or other potential contaminants and it was hard to do with a big oil cooler like the one pictured. Also heard rumors about it lowering oil pressure...ended up just abandoning the idea as most LS vehicles didnt come with an oil cooler from GM to begin with...

[TurboedMJ]

14 hours ago, Comanche SS said:

This was my plan...only until I figured out the headers I have leave absolutely no room for the Oil line adapter. That, and the fact I read that oil needs be hit 212* on occasion at least to burn off any water, or other potential contaminants and it was hard to do with a big oil cooler like the one pictured. Also heard rumors about it lowering oil pressure...ended up just abandoning the idea as most LS vehicles didnt come with an oil cooler from GM to begin with...

I watched a video from engine masters about a 300 i6 I think, they gained 20 HP by making the oil as hot as possible and the coolant as cold as possible. Not sure I will run an oil cooler on anything I build after watching that. (Unless it has a high pressure oil system or something like that). 

[A-man930]

There is a reason that the OEMs submerge engine and transmission oil coolers in the radiator side tanks...

[ghetdjc320]

Never seen an engine oil cooler in the radiator on a gas engine 

 

Many L series (LM/LQ/LR etc. Don’t know of any actual “LS” model engines that came in trucks) truck applications came with oil coolers from factory. A correctly installed oil cooler is not a problem and is a sound add on for heavy engine loads such as towing.
 

As with so much of the aftermarket crap, poor design, copy cat, imitation, bargain bin products and poor installation ruin the reputation of many sound concepts 

 

if there are contaminants in your oil, you need to change your oil (and possibly find the cause of your contamination). Used to see gas in oil on many supercharged Kawasaki engines. Ultimately, you had to just change the oil more frequently as gio tends to be a side effect of forged internals combined with high cylinder pressures. 
 

But many performance engines come with an engine oil cooler 

 

[ghetdjc320]

[Comanche SS]

2 hours ago, ghetdjc320 said:

Never seen an engine oil cooler in the radiator on a gas engine 

 

Many L series (LM/LQ/LR etc. Don’t know of any actual “LS” model engines that came in trucks) truck applications came with oil coolers from factory. A correctly installed oil cooler is not a problem and is a sound add on for heavy engine loads such as towing.
 

As with so much of the aftermarket crap, poor design, copy cat, imitation, bargain bin products and poor installation ruin the reputation of many sound concepts 

 

if there are contaminants in your oil, you need to change your oil (and possibly find the cause of your contamination). Used to see gas in oil on many supercharged Kawasaki engines. Ultimately, you had to just change the oil more frequently as gio tends to be a side effect of forged internals combined with high cylinder pressures. 
 

But many performance engines come with an engine oil cooler 

 

My Denali Sierra has an engine oil cooler in the factory coolant radiator. (L9H engine, would assume other similair NNBS trucks and SUV's come this way as it was a factory option for all of them)

Has a separate trans cooler, separate steering cooler.

[ghetdjc320]

I’d want to shed some btu’s and get the engine oil on its own cooler perhaps with a thermostat. The stock cooling system has a hard enough time handling a 4.0.

Not sure if I’ll do this or not though. Would need to find a good location and the right sized cooler thats actually designed for engine oil. 

[A-man930]

Just replaced an engine in a 2017 Yukon over the summer that had a factory oil cooler in the radiator. Tow packages often times add an external cooler in series prior to the submerged cooler.  It's quite common. The goal is temperature regulation, either up or down.

I agree with the sentiment that the mj/xj cooling system is already basically maxed out from the factory, but employing a cooler setup as described above would, ideally, not burden the cooling system. It actually might help, if the external cooler brought temps too low.