Heck, I live in the southeast and I might be in for that!!
New Build: GM 4.2L Atlas into '91 FJ80
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- #83
Rear sump pan
Yes, he's very active in the Inliners Group. There's a lot of wild stuff being done with the 3.7s and 4.2s... even a Bonneville race effort and a bunch of boosted (mostly turbo'd) projects. With that, there's been interest in a rear-sump pan.
We're still weighing off whether it's more cost-effective than the 'section-and-flip' approach.
Yes, he's very active in the Inliners Group. There's a lot of wild stuff being done with the 3.7s and 4.2s... even a Bonneville race effort and a bunch of boosted (mostly turbo'd) projects. With that, there's been interest in a rear-sump pan.
We're still weighing off whether it's more cost-effective than the 'section-and-flip' approach.
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- #84
Shop's in Boise, but with close family in Portland and Eugene is back-and-forth to Oregon a lot on projects.
This would be beautiful - the typical issue most of us have is either problems with access to fabrication or zero ability to deal with wiring. It's enough to keep you from pulling the trigger unless you have a wallet that doesn't dent easily.
I hope it's not just for the FJ80 though, to replace the 3FE, as the 1ZFE is an equally good candidate on the later model 80's.
Keep us posted!
Definitely, if you can offer a kit for the 1FZ, including a fresh modern motor, I would imagine that you would have people lining up to get the work done, myself included.
alia176
SILVER Star
I think a hardware and electrical kit would be great. I think most of us can source our own engines and drive train based on the guidance from this thread and the OP.
+1 on a kit like this! I've been looking into doing an engine swap, but it's a bit out of my range of work. To have someone put together an option like this would be great. I'd definitely go for it and I'm sure lots of others would as well!
but I would like to get everything - all bells and whistles. 
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- #89
Picture of the two motors
The primary issue with the 4.2L is the pan. Because the 4.2 (GM called it the LL8) only went into the Trailblazer and Envoys, they strictly used the through-the-pan-with-attached-differential scheme. The 3.7 (LLR) engine was (and is, still in production) used in the Colorado/Canyon/H3, all of which had traditional separate, frame-mounted differentials in the 4WD rigs, with the engine sump moved FAR to the rear to avoid interference issues. The net is that the LLR (240+ HP in current form) is sweet for the Cruisers, since they used rear-sump exclusively and the fit in an FJ80 or FZJ80 is great. Trailblazers had a front-sump pan, in order to provide mounting surface for the diff. This probably lowered the center of gravity a bit (wise, since the #1 competitor was the Explorer V.1 with all the rollovers), but makes it a pain for our applications.
Photo of I-5 (This is the L52, the earlier 3.5L version of the LLR currently 3.7L):
Left Side-- note the rear orientation of sump.
Picasa Web Albums - TL Care
Right Side of I-5 Atlas-- Ready to plumb the FJ80 Air Cleaner direct to throttle body.
Picasa Web Albums - TL Care
And, the LL8 version (note the front sump/diff mount and hole for shaft, that mounting area is behind the AC compressor on the left side of engine)
Picasa Web Albums - TL Care
They both fit, it's just the pan that's harder to modify (or replace with the after-market unit) on the I6... 242 HP version 270-290HP.
The primary issue with the 4.2L is the pan. Because the 4.2 (GM called it the LL8) only went into the Trailblazer and Envoys, they strictly used the through-the-pan-with-attached-differential scheme. The 3.7 (LLR) engine was (and is, still in production) used in the Colorado/Canyon/H3, all of which had traditional separate, frame-mounted differentials in the 4WD rigs, with the engine sump moved FAR to the rear to avoid interference issues. The net is that the LLR (240+ HP in current form) is sweet for the Cruisers, since they used rear-sump exclusively and the fit in an FJ80 or FZJ80 is great. Trailblazers had a front-sump pan, in order to provide mounting surface for the diff. This probably lowered the center of gravity a bit (wise, since the #1 competitor was the Explorer V.1 with all the rollovers), but makes it a pain for our applications.
Photo of I-5 (This is the L52, the earlier 3.5L version of the LLR currently 3.7L):
Left Side-- note the rear orientation of sump.
Picasa Web Albums - TL Care
Right Side of I-5 Atlas-- Ready to plumb the FJ80 Air Cleaner direct to throttle body.
Picasa Web Albums - TL Care
And, the LL8 version (note the front sump/diff mount and hole for shaft, that mounting area is behind the AC compressor on the left side of engine)
Picasa Web Albums - TL Care
They both fit, it's just the pan that's harder to modify (or replace with the after-market unit) on the I6... 242 HP version 270-290HP.
4200 performance
Hi guys thought I'd post in here - I've done a fair amount of parts development for the 4200 including the rear sump oil pan.
See mid body answer for info.
Hi guys thought I'd post in here - I've done a fair amount of parts development for the 4200 including the rear sump oil pan.
See mid body answer for info.
The "area under the curve" is certainly a lot better on the Atlas-6... it gets to 275-290HP by being able to rev to beyond 6000 RPM while maintaining basically full torque, so I find them more flexible engines (I can't fathom a 3FE spinning to 6000!) due to VVT and great head flow design.
I still need to post the torque curve for the stock unit-- it is amazingly flat.
The downside of all this optimization is that, in NA form, it's tough to bump it up too much without going FI. The guys over on Inliners and TrailVoy have looked at it a lot and most of the usual "tricks" are tougher on the Atlas...
COMPRESSION: it's pretty well optimized to run 85 Octane rot-gut Regular gas on a 10:1 ratio, so efficiency is very high, even running on regular. You might get an incremental bump by milling heads and running Premium. I do like buying cheap gas on mine, while still enjoying a pretty high SCR.
CAMS: GM never offered cam blanks to the after-market to build custom cams from. There is a group buy contemplated over on TrailVoy to get some made... Since it's not been done, no idea how much GM 'left on the table' with cam lift. As efficient as the heads are, this is probably the low-hanging fruit-- assuming cams can be procured-- It's got a very tame stock idle, much like the LQ/LM base engines, so if that's any guide there ought to be quite a bit of gain from swapping cams and valve springs. I'll cross-post if anything ever develops on the custom cam front.
EFIDIY >>>The stock cams are really tiny like 160* duration @ 0.050. Full lift is under 0.4". The cam follower geometry supports upto 0.5" lift before issue arise.
EFIDIY >>> I tried last year on Trailvoy to get a cam buy going- but at the end of the day no $$$ came in so the group buy died. I still have the cam blank designed and if some one else organized the group buy, took care of distribution etc. I'd consider it for another group buy. The magic number is 10 people (20 is better).
HEADS: As far as we know, there's no aftermarket head being offered (and GMPP doesn't even offer anything) and for good reason. Those stock heads are a wonder of CAD design, computer modeling and production engineering. They flow great out of the box and port-polish jobs haven't yielded much.
EFIDIY >>>On a reduced compression 10.1:1 to 8.3:1 engine (prepped for turbo) a combination of cams and head porting was good for 63 HP @ 6800 rpm. Bet it would have been more with stock compression. This was dyno'ed using a stock exhaust manifold. 3' of 2.75" head pipe going into 6' of 3" pipe - no muffler. There is power to be had with a better exhaust system. Some folks have split the stock exhaust manifold to get duals.
FI
On the PLUS side, the internals are REALLY strong (not quite 2JZ strong, but they are tough)... Some of the Inliners guys are running big boost levels (North of a Bar) and getting reliable 500-600 HP out of it.
If I was to bump one up I'd try the cams for 50+HP, for 150+ I'd do boost and methanol/ethanol injection.
Just our idle thoughts on it...
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- Thread starter
- #91
EFIDIY,
Thanks for the comments on the LL8. It's a pity the custom cam Group Buy didn't come together-- a more aggressive profile should bring a lot of power gain without much pain. Would love to get to 350HP in a street-able tune-- the cam'med 4.2L ought to get into that neighborhood-- And, at that level of power, the Atlas would be pretty compelling stacked up against the LS series of V8s-- better fit and better fuel economy.
For the FJ80/FZJ80s, the I-5 DOES fit a bit easier due to the pan clearance thing, so we've also toyed with the idea of the I-5 running 0.6-0.7 bar with a turbo on stock internals-- with intercooler and Methanol injection or maybe just running it on E85. The Inliners guys are using lots of boost and the engine clearly will take it. 8-10# seems do-able. Wouldn't sacrifice any fuel economy in daily driving, but with a 350HP reserve.
We still think these Atlas motors are a sweet answer for the Cruisers-- modern engine design that fits well in the FJ80s.
Thanks for the comments on the LL8. It's a pity the custom cam Group Buy didn't come together-- a more aggressive profile should bring a lot of power gain without much pain. Would love to get to 350HP in a street-able tune-- the cam'med 4.2L ought to get into that neighborhood-- And, at that level of power, the Atlas would be pretty compelling stacked up against the LS series of V8s-- better fit and better fuel economy.
For the FJ80/FZJ80s, the I-5 DOES fit a bit easier due to the pan clearance thing, so we've also toyed with the idea of the I-5 running 0.6-0.7 bar with a turbo on stock internals-- with intercooler and Methanol injection or maybe just running it on E85. The Inliners guys are using lots of boost and the engine clearly will take it. 8-10# seems do-able. Wouldn't sacrifice any fuel economy in daily driving, but with a 350HP reserve.
We still think these Atlas motors are a sweet answer for the Cruisers-- modern engine design that fits well in the FJ80s.
I would be very, very interesed in the wiring harness for this. I can source my own engine, tranny and put it in myself. All I would require is a plug and play wireing kit and motor mounts. This would be an almost 100% increase in power and an increase of mileage to boot. What mpg did you get with the LL8
Looks like the pan in both engines is cast? Is that the issue with it being a PITA to mod? Wonder if a fabbed or stamped pan would be the way to go instead? A stamped pan is probably a non-starter due to tooling costs, I'd imagine.
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- #94
Atlas Mileage
We're working to wrap up the LL8 right now. The LLR in the other truck, with the 3.7L version of the Colorado engine, is now nicely broken in and we're getting 20-21MPG on the highway (consistent with the Colorado or H3) on real 85 octane gas, slightly less with E10 gasohol. This is with the stock Cruiser gears, which I think are 4.10:1 or so. It would pull taller gears-- the easiest way to do that probably ends up being something larger than the 31.5" stock rubber on it.
Running 35s, the LL8 could actually be better-- the torque curve is really, really flat so it ought to cruise on the highway well. We'll post when we get it together and have some gas run through it.
On the LLR, I always phrase it that we are consistently getting an extra 100 miles out of every tank of gas-- this has been true whether commuting in-town (where I used to be lucky to get 10-10.5MPG) or on the highway.
We're working to wrap up the LL8 right now. The LLR in the other truck, with the 3.7L version of the Colorado engine, is now nicely broken in and we're getting 20-21MPG on the highway (consistent with the Colorado or H3) on real 85 octane gas, slightly less with E10 gasohol. This is with the stock Cruiser gears, which I think are 4.10:1 or so. It would pull taller gears-- the easiest way to do that probably ends up being something larger than the 31.5" stock rubber on it.
Running 35s, the LL8 could actually be better-- the torque curve is really, really flat so it ought to cruise on the highway well. We'll post when we get it together and have some gas run through it.
On the LLR, I always phrase it that we are consistently getting an extra 100 miles out of every tank of gas-- this has been true whether commuting in-town (where I used to be lucky to get 10-10.5MPG) or on the highway.
Thanks for the warm welcome. Like to see how your mounting the 4200 into the chassis (motor mounts). Any pix of the swap?
A stock block 4200 will put up with 7-8 psi boost - Providing the tune is good. The downside is the '02-05 (?) GM pcm's don't like boost. I'm not a GM PCM guy so this is 2nd hand from folks that are more in tune with the GM PCM electronics.
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- Thread starter
- #96
Cast Pan on Atlas
Yep, it's a pretty sturdy cast piece, consistent with what they did on the LS/LQ V8s. "theoretically" (and I'm a MSEE, not ME...) it's a 'structural element' and is key to reliability in holding tolerances even though the block is much, much lighter than previous GM sixes (think IRon Duke or the old 235). The fact that's it's structural makes me leery of stamped pans. EFI's done A LOT of work on his rear-pan design-- his CAD models are a marvel-- and they should be a good stand-in for the front sump design on the stock LL8.
I'll have to post pics of our 'sectioned-and-swapped' pan so you can see it. Just a LOT of welding, plus the extension of the pickup tube.
If GM had ONLY put the I6 in the Colorado (you CAN get the V8, oddly) we'd be in great shape!
Yep, it's a pretty sturdy cast piece, consistent with what they did on the LS/LQ V8s. "theoretically" (and I'm a MSEE, not ME...) it's a 'structural element' and is key to reliability in holding tolerances even though the block is much, much lighter than previous GM sixes (think IRon Duke or the old 235). The fact that's it's structural makes me leery of stamped pans. EFI's done A LOT of work on his rear-pan design-- his CAD models are a marvel-- and they should be a good stand-in for the front sump design on the stock LL8.
I'll have to post pics of our 'sectioned-and-swapped' pan so you can see it. Just a LOT of welding, plus the extension of the pickup tube.
If GM had ONLY put the I6 in the Colorado (you CAN get the V8, oddly) we'd be in great shape!
- Thread starter
- #97
I'll post the link to the project-- I think there are a couple in that album that show the mounts for the Atlas.
Boost controller isn't an issue for the shop. They've done lots of boosted projects, both "piggy backed" and full standalone with SDS. It's also possible to move to the E38 which will handle up to 2.5BAR.
The BEST solution would be your custom pan and a bigger cam. If we had those two pieces, it would easily trump the 5.3 V8 for the Cruisers.
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- #98
Sectioned and Swapped Pan
Here's a photo of the 'swapped' pan after the section-and-weld process
Here's a photo of the 'swapped' pan after the section-and-weld process
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- #99
Here is a photo of the motor mount for the Atlas
And the complete swap.
Picasa Web Albums - TL Care - Hummer H3 Dri...
As I say, we're actually really happy with the 240 HP and lighter weight... But are building the 4200 'cause, well, you always want more power, right?
