Seriously considering a 5.3.. tell me why not.

[Slammed68]

I know a 5.3L vortec motor is iron block and heads..

 

Will a LS1 intake fit on one without too many mods? Will a T56 bolt right? I already have the JTR headers for an LS1 but will they fit a 5.3?

 

Tell me why I should and shouldn't get a 5.3L for like a quarter of the price of a LS1.

[Pop N Wood]

The 5.3's don't flow as well due to the smaller bore. And if it's a truck motor you will need to replace the intake, oil pan and all the accesory drives (including water pump and crank pulley) with F body units.

 

So my recommendation is you need to source the needed accesories and intake before you will know what the motor actually costs.

[milesz]

Thats not all together true. I am currently placing the 5.3 into my 240z. I agree you have to replace the oil pan and cut and put a hood scoop on the hood. On the plus side, it is a cheaper engine and tranny combo. On the less side the intake is much higher. Its rated at 285 hp in the truck but my car is much ligther with a 3.7 diff and running stright pipe, no converters, I should get over 300 hp.

[JMortensen]

The L33 is an all aluminum 5.3, rated at 300 hp 330 tq stock. My 2006 GMC 1500 has one in it. I was thinking of going with this motor because of the weight/displacement rules for X Prepared class in autox. I'd love to see someone else pave the way...

[zgeezer]

The L33 is an all aluminum 5.3, rated at 300 hp 330 tq stock. My 2006 GMC 1500 has one in it. I was thinking of going with this motor because of the weight/displacement rules for X Prepared class in autox. I'd love to see someone else pave the way...

 

Actually, I think someone on this forum has already done this swap. I remember that the truck manifold actually cleared the hood, but not by much. The truck intake, according to one published article, flows very well indeed up to 5500 rpm.

 

There are differences in the location of the accessory drive and, for some reason, the truck drive is spaced forward one half inch or so. At least, the folks at Street and Performance told me this when I inquired about swapping the truck manifold for an LS1.

 

G

[Pop N Wood]

Yes, guess I should say to clear the stock hood you will need to replace the intake and mount the alternator differently.

 

Mounting the alternator down low in the F body position works well with a Z. But to do that you will need to replace the water pump and crank pully cause the F bodies run the belt closer to the block than the truck motors.

 

I think we can also add to get the engine back close to the firewall without having to move the hood latch will require a different intake.

 

And my guess is you will need to fab your own mounts cause JCI mounts probably won't work with a truck intake. I am just guessing on that.

 

But if you going through that much trouble, get a 6.0L truck motor instead of the 5.3. Same amount of work to install, will need to deal with the oil pan and intake either way. But the big difference is throw in little more than the correct cam and you can get 500 HP out of the bigger motor.

 

http://www.carcraft.com/projectbuild/116_0704_lq4_short_block/index.html

 

Plus the 6.0 motor has the option of using L92 heads incase you want to get closer to 600 HP.

 

And Milesz is the guy to talk to about the 5.3 swap cause he is the only member I have seen post details of his swap

 

http://forums.hybridz.org/showthread.php?t=124821

 

Those pictures don't look too promising in terms of hood clearance.

 

There was a member, I think Lason, who always advocated the truck motors. He was supposedly doing a truck motor swap, but I don't know if he ever posted the finished product. He was going to replace the truck intake with a carb.

[zgeezer]

I know a 5.3L vortec motor is iron block and heads..

 

Will a LS1 intake fit on one without too many mods? Will a T56 bolt right? I already have the JTR headers for an LS1 but will they fit a 5.3?

 

Tell me why I should and shouldn't get a 5.3L for like a quarter of the price of a LS1.

 

There is a long thread on this subject, along with pictures of actual swaps. Search on 5.3 truck and you will see.

 

Here is a turbo charged 5.3 into a 240Z http://forums.hybridz.org/forumdisplay.php?f=58

 

g

[JMortensen]

Actually, I think someone on this forum has already done this swap. I remember that the truck manifold actually cleared the hood, but not by much. The truck intake, according to one published article, flows very well indeed up to 5500 rpm.

I haven't seen the all aluminum 5.3 swap. Maybe I missed it, as I don't follow the V8 forum as closely as some of the others. I guess it's probably going to be exactly the same procedure when you really get down to what is involved though...

[mobythevan]

I run the 5.3 in my rx7. As mentioned I swapped the following parts from my broken LS1: oil pan, windage tray, pickup tube, harmonic dampner, intake, steam pipe, water pump, valve cover with shorter oil fill tube and placed the alternator in the lower mounting position. I think that was all, its been a few months since I did it. I think it works out to be a better replacement when your LS1 gets destroyed and your budget is low.

 

In the RX7 hood clearance and oil pan clearance was incedibly tight, so maybe you can get away without swapping all those parts.

 

Here is a turbo charged 5.3 into a 240Z http://forums.hybridz.org/forumdisplay.php?f=58

 

That link didn't seem to work

[mobythevan]

I remembered one more thing. When you put the alternator in the lower position on the 5.3 iron block you have to drill and tap for one of the bolt holes there. It might work without that bolt, but it was easy enough to tap the block for it.

[silicone boy]

I remembered one more thing. When you put the alternator in the lower position on the 5.3 iron block you have to drill and tap for one of the bolt holes there. It might work without that bolt, but it was easy enough to tap the block for it.

 

 

Good to see that you got it running, especially since I sold you a defective motor! Good job!

[mobythevan]

Good to see that you got it running, especially since I sold you a defective motor! Good job!

 

You refunded my money, it was just another bad luck event this summer. I hate to see the run of bad luck you had with both of your cars. The 5.3 engines are a great option when you end up with a cracked up LS1. And a 76mm turbo will make up for anything it is lacking.

[silicone boy]

You refunded my money, it was just another bad luck event this summer. I hate to see the run of bad luck you had with both of your cars. The 5.3 engines are a great option when you end up with a cracked up LS1. And a 76mm turbo will make up for anything it is lacking.

 

 

 

OMG! I didn't see the turbo until just now. That thing must be a beast!

[LS1 240Z]

you can get LQ4 6.0s for 1000-2500... its a much better motor than the LS1 even

[Pete84]

In the GenIII blocks, is there any internal differences that make certain years better? Heard that there was some issue with crankcase pressure building up on some of the engines years, and oil being sucked into the intake on others.

[jonus079]

So you want to know about the 5.3l gen III v8 huh? *(crack knuckles). Well here is what I can tell you.

 

Background:

 

The lm7 (5.3l) Gen III sbc engine shares the exact dimension with the ls1 meaning you can use and motor mount kit for the ls1, and it will fit the same way. The similarities don’t end there. The engine shares the same crankshaft and rods as the ls1. The only differences with the internal parts are the pistons. Obviously the pistons in the lm7 engine have a smaller diameter to make it 5.3l rather than 5.7 (ls1). The block however can be bored to ls1 displacement. If you choose to do this, you will find an endless amount of possibilities for aftermarket internal parts. The ls1 heads are very similar to the lm7 ones as well. The only difference is the intake valve is like .05 (or something like that, I cant remember the exact number) bigger. They are so similar that a popular upgrades for the ls1’s are to swap out the head for the lm7 version to up the compression ratio of the engine.

 

The other obvious differences in the two long blocks are block material. So how much of a difference do you think iron makes over the aluminum block? 300lbs? 200lbs? Well actually if you look at the illustration below, the difference is only 118 lbs.

 

 

Intake:

 

The ls1 and lm7 (5.3l) engines uses difference intake manifold but because the engine dimensions are the same they can easily be swapped. When I first got my engine I planed on keeping the truck intake manifold. As the following picture shows, it will fit under the hood however it’s extremely tight and the engine is put far back in the engine bay.

 

 

 

My bet is it wont work with jr mounts meaning you will probably have to custom make you engine mounts if you don’t want to cut your hood. You will also have to move the hood latch as it interferes with the manifold.

 

The alternative to using the truck intake is to use the ls1 intake. They are very cheap (I got mine for $35 buy it now off eBay) and bolts line up exactly but you will have to move around a few things to make it all work (explained further down). The throttle body is also a direct fit but only if its NOT a drive by wire setup. As you can see from the picture bellow, the fit between the coolant hose and the throttle body is close but its clears. To increase the clearance you can heat the water pump up with any old torch (I used a propane torch) and turn the pipe.

 

 

 

Oil pans:

 

There are a few things you can do here. All ls1 oil pans will work with the lm7 or any gen III sbc engine. In my case I am using the corvette oil pan with allows me to mount the engine extremely low in the chassis but I am custom making my motor mounts. The simplest alternative is to get an f-body oil pan, pickup tube, dip stick tube and dipstick. It’s a direct bolt on solution. This will alow you to use jr's ls1 mounts without any problems.

 

Transmissions:

 

Since the two engines share all the same dimensions and crankshaft, the t56 and clutch/flywheel are direct bolt ups. No modification needed. Pretty much, any transmission you can use on an ls1, you can also use on an lm7 or any Gen III sbc engine.

Headers:

Since the engine has the same dimensions, any heads you can use on the ls1, you can also on the lm7.

 

The biggest problem:

 

The only major problem I ran into is the alternator. Because its mounted so high it actually hits the hood. To fix this problem I modified the lm7 alternator bracket to swing it further out. This solution works well and only takes a spacer and cut off wheel to pull off. Unfortunately I don’t have any pictures of the modified bracket and but once I go home for thanksgiving break (im away at college) ill try and get some good pictures to give you an idea of what needs to be done. Here is a picture of my serpentine belt system.

 

 

 

There are a lot of other ways to deal with the problem other than the one I listed above including swapping all the pulley (including the water pump) to the ones used on the ls1.

 

I think the lm7 is a great engine an I am currently using it in my 1972 240z. There are people over at performancetruck.net with turbo charged lm7’s putting close to 700rwhp on stock internals! The cost for the engine itself is also significantly lower. I found my engine for about $400 with 49k miles (they even let me check the odometer on the SUV before they took the engine out). Of coarse all the modifications I’ve listed about adds up. Still, for the intake, oil pan, and all the other parts I needed to make the engine work, you still save a lot over an ls1, especially if you get an ls1 from a corvette. Cost vs reliability and performance makes it a hard engine to ignore in the V8 category.

 

So really, I cant think of a reason not to choose the lm7 although Im not saying its any better or worse than the ls1.

[mobythevan]

To fix this problem I modified the lm7 alternator bracket to swing it further out.

 

I like that. I have mine in the lower camaro position, but that is not going to work with my turbo hot side piping. I'll have to try that position and see if it will clear in the RX7.

[Pop N Wood]

That motor must be sitting a good ways forward. When I looked into mounting the alternator there it hit the strut tower. Yours looks to have the entire alternator in front of the tower.

 

The corvette accessories run the belt 3/4 of an inch closer to the block than the F body. The truck accessories run the belt farther out than the F body. But still, that motor comes forward a good bit. I wonder where the shifter would be with a T56 installation.

 

And as for oil pans, the new pan of choice is the LS2 pan. Cost the same as an F body unit but gives and inch better ground clearance and has better internal baffling to better handle hard turns. Do a search, part numbers have been listed.

 

I still think by the time you buy everything needed to fit it in a Z the 5.3 could be a false economy. Depends upon your goals, resourcefulness, and whether you want an automatic transmission.

[jonus079]

the engine is mounted rouughly in the same position as where the ready made mounts put it (oil filler cap lines up with the pas. side strut tower). i havent created the mounts yet but i can move the engine back further and it will still clear the shock tower because of how low it is. heres what my costs came out to so far.

 

engine: $400

oil pan: $75

oil pickup/dipstick tube/dipstick: $42

intake manifold: $35

aeromotive fuel rails: $200

8-42lbs injectors: $398

 

total: $1080

 

i planned on going witht aeromotive ls1 rails and upgrading the injectors for the turbo which as you can see are some of the most expensive parts on the engine. i supose you could save a about $400 if you use factory rails and injectors. there are people practially giving them away on ebay.

 

btw my goal is 450hp+ @ 6 psi (with a t56 transmission) and 25+ mpg (highway of course)

[sstallings]

If you really want to go 5.3L and replace the truck parts, look for an '05 or newer Impala SS to scavenge parts from. The SS runs the 5.3L without the complications of taller manifold, pan, etc. and it would be legal in case you need to deal with the smog police like we do in CA.