Builds My R2.8 Cummins FJ40 (RJ40) daily driver build (1 Viewer)

[Salem747]

AC Add on:

AC Add-on to Cooling Package
- AC Condenser
- AC Dryer
- AC Switch
- AC Hose from Cond to Dryer
- Mounting Hardware

 

[Salem747]

As I mentioned earlier, I think I will go with their motor mounts, they look like the best out there. $400 for the set.

 

[Salem747]

These are from Cummins' Gear calculator. I was thinking the Tremec was the winner (although they are $3600 plus shipping and shifter is $300) but the damn thing is 29" long!!! Probably would only work for a 4 door jeep (or maybe a 18" stretch TLC).

Other than that, really the AX15 or NV3550 have the best, most efficient sweep. Lots of Blue. 16.5, 16.7" respectively. Again though, the NV3550 is rated for 300lbft and the R2.8 is now stock at 310. but I guess it would be a whole lot stronger than the H42 or H55.

Now I just have to figure out how to adapt it into an FJ.

 

[Will Van]

As I mentioned earlier, I think I will go with their motor mounts, they look like the best out there. $400 for the set.

Great intel, thank you.

I wonder how much adjustability the Axis motor mounts allow? They’re designed around the H55F and the Axis bellhousing setup at a specific placement on the frame. I wonder if you can move them fore or aft depending on the transmission/bellhousing used?

 

[amico]

R2.8 -> QuickDraw -> H55F -> Split Case = Awesome!

Edit: Just realized y’all were talking about the Axis cooling package earlier in the thread. Oops!

FWIW, Axis Industries is developing R2.8 kits for the FJ40. If you have seen any of their work in the Jeep world, it's very nice. Great attention to detail and elegant design.

The full Axis kit will ultimately include a cooling package (radiator, intercooler, A/C condenser), intercooler piping, oil cooler mount, engine mounts, bell housing adapter kit, and trans crossmember for the H55F.

Unfortunately due to "packaging constraints" the Axis bell housing adapter is a two-piece unit that goes from R2.8 to an LS adapter plate, then an actual bellhousing from LS adapter plate to H55F trans (I think the TorFab setup below is similar/identical). This adds the extra length between the back of the R2.8 and the front of the H55F transmsmission to place the 5-speed shifter in the stock location, but also move the R2.8 away from the firewall. Axis said the dimension needed to be about 8", and a direct-fit bell housing was only 6". Anybody know the dimensions on the QuickDraw?

The Axis setup also requires a ring gear for the starter, and a spacer for the flywheel. That's how they setup all of their Jeep conversions. The reasoning behind the two-piece bell housing is that they want the shifters to come up in the stock location, but the R2.8 is so short that it would place the motor really close to the firewall. So they extend the bell housing length with the multiple adapter plates.

I still think the cleanest setup is the R2.8, QuickDraw Bellhousing, H55F trans, and Toyota Split Case.

NV4500 would be really cool because of the gearing and strength, but it looks like it requires some fab work on the trans cover. And driveline length may be an issue. Advance Adapters makes a kit to run an NV4500 to Toyota split case. And people have been swapping NV4500s for decades with 350 SBC/GM/LSX conversions, so you would think a lot of this has already been worked out.


@amico - Do you have your QuickDraw bell housing yet? I'm just down the road from you in Austin.

Will Van, yes I have my Quick Draw Adapter. I bought that and my Cummins Crate Engine thru Chad he sold it to me for cost with his machined flywheel that accepts standard Toyota clutch & pressure plate. Chad shipped both together. Cummins has a sell on these crate engines ($1500 off) I think thru June 30th, unless they have extended it. Got mine about a week ago and it appears everything is going to be close to the original transmission spot in the transmission cover. Hoping so anyways. Looking at the CAD drawing I like the way they moved the oil filter mounting up front under the radiator / intercooler location, that's a good idea didn't think of that.

 

[Salem747]

I think mine will be here today, super excited, although I can't actually DO anything with it for months probably. I can look at it!

Sorry for the mega hijack @ArthurFJ but I assume you would be interested in all these ramblings about powertrain.

 

[ArthurFJ]

My bad everyone! Here are some answers finally!

@Salem747 Yes that Axis stuff is a bit too pricey for me I think, but who knows, maybe I'll have no choice down the road. I'm still very early on in this build. For the transmission/tcase I'm still thinking of just using my NV4500 and getting a FJ60 tcase. It's alot of adapters but that's what Sheck44 did and his build looks damn good! The gear ratio and low RPM at high speed is just so appealing to me.

I just bought my radiator/fan a minute ago. Got it on eBay cause my billing/shipping addresses are different and SDPC won't let me buy from them. Got the same one as Sheck44. Still trying to decide what to do for the AC condenser. I think @amico is right about wanting to leave some radiator open to fresh air.

No worries about hijacking the forum! The more info the better!

@amico damn! The engine and adapter delivered at the same time.. wish I would've done that. I'll hopefully be shipping my flywheel to Chad this week...

Has anyone here done a gear conversion in their differentials? I think you can switch to a 3.70 ratio from the stock 4.11. How hard is that to do? If I can change that, maybe I'll just buy the H55 and sell my NV4500 online. That might compensate enough for the 5th gear 0.45 vs 0.73. At 70 mph, an H55 with the granny diff would run at 2373 RPM. An NV4500 with the stock diff would run 2277 RPM

Also, I bead blasted my driver door and it's in bad shape. Any know of anyone selling a driver door in good condition?

How about someone selling ambulance door hinges?

Thanks guys!

 

[Salem747]

So talking to Chad from Quick draw, there are very specific NV4500s that can be used with his adapter, I'm not sure the early one will work.

I did find some complaints about the early NV4500, that it struggles to get into 5th and that it is quite noisy, apparently this was fixed in later models. The issue with this is that the early one has the 6.34 low and the .73 OD vs 5.61 and .75 respectively.

I thought for sure I was going NV4500 yesterday, I can do it all, with a rebuilt trans and a tcase I own (including tcase rebuild kit) for $3146USD.

But then I found a guy in BC this morning who is selling complete H55F and split case for $1500 CAD used, and he has more than one! He will also take my old parts in trade (engine, electrical H42s, etc). Now I am back on the H55 train.

The NV4500 is guaranteed to be strong enough for anything you ever do to your R2.8 or your FJ, but it is a heavy truck tranny.

I feel like I am picking a wedding or prom dress for crying out loud!

Yes the NV4500 is a little lower RPM on the hwy but not a tonne. (especially the new one). The H55 handles the cummins quite well. It's in efficiency range well over 60mph. But it is definitely not as strong as the NV4500.

I thought the discussion about the drawbacks was on here:

The Novak Guide to the NV4500 Transmission but it isn't. If you search around you will find it.

 

[Will Van]

Just FYI, you can run overdrive Hi gears in the 60 series transfer case. 0.93:1 instead of 1:1 I believe.

Might save you some hassle of swapping the diff gears. Or impact your transmission decision.

 

[ArthurFJ]

@Salem747 my NV4500 is out of a 2000 HD2500 Chevy I believe (32 spline) so I think that makes it the newer model. That's a great price! Do you have his contact info?

@Will Van That's definitely good to hear! Anyone know what towing capacity a H55 has?

 

[Salem747]

I've tried to find a torque rating on the h55 but I haven't been able to.

I'm assuming that if I dont do anything too crazy to the engine it should be ok.

The 9.5" Toyota diffs are supposed to be tough.

Yes, I believe the old model nv4500 is like 93/94. But I think his adapter is only for dodge! What's your email? Will send you email thread with Chad.

 

[onemanarmy]

it's super easy to swap diff gears from 4.1 to 3.7

 

[ArthurFJ]

@onemanarmy can you suggest a supplier for the parts?

 

[Salem747]

Put lockers in there while you are at it!

 

[ArthurFJ]

Put lockers in there while you are at it!

Good call!

 

[Salem747]

So, I have ordered some axle parts and talking to the guy he said I likely have 4.11 gears in the '79 donor (factory front discs) and likely in my '75 too. I checked the '79 (it's on the lift) and it has 4.11! I was doing all my rpm stuff on 3.73. The way you can tell is there is a stamping on the edge of the ring gear that will say either 9x37 or 10x37. What that means is 9 tooth pinion and 37 tooth ring gear. What that really means is 37/9=4.11. What that really really means is:

This is for the H55 option. So not quite as nice on the highway but still reasonable. I picked 80mph just as a speed to pick for like REALLY going somewhere. 65mph is 2300 rpm.

 

[ArthurFJ]

@Salem747 Yeah that's pretty high RPM. I won't be using an H55 unless I swap my 4.11 to 3.70s AND find that overdrive HI gear for the split case. I don't think the R2.8 will be happy at 2830 RPM. I'm also planning on running 31 inch tires with the stock rims.

Again thanks for the info! I appreciate everything I can get.

@Will Van do you know where I can find anything on that overdrive HI gear? Is it built right into the case?

 

[Will Van]

@Will Van do you know where I can find anything on that overdrive HI gear? Is it built right into the case?

It’s a gear set installed into the split transfer case. Georg (@orangefj45) at Cruiser Brothers can help you out.

 

[amico]

I wish I had known about the overdrive Hi gears in the 60 split case when Georg had my transfer case out there. That reduces the rear end from 4.11 to like 3.81 I'm guessing. I would have sure had him do mine while it was there. Well Crap.

 

[ArthurFJ]

@amico if you wanna lower the diff ratio you can always switch to a 3.70. If I go with a H55 I'll do both the 3.70 diff AND the split case overdrive.