New LS1 Owners - Newbie Tech - 5.3 build, what am I missing??
03-23-2012, 07:04 PM
Ok so I've done some searching and scanning over build threads and I just want to see if I'm missing anything to be able to go together with my engine and have it running.
Here's what I have so far:
241 heads with ls6 valve springs
7.425 push rods
Ls1 master gasket kit
Ls2 timing chain kit
Ls1 intake/fuel rail/injectors
Fbody cable throttle body
Need to get:
Fbody PCM and wiring harness (or will truck harness and PCM work?)
Cts v front accessory drive kit
Ls1 coil packs (or will truck coils work?)
All this is going in my 240sx, so the height clearance of the motor is optimum, thus the ls1 top end stuff. My question is: am I missing anything other than what I've posted to get everything running correctly? I've been trying to find a specific breakdown on everything needed for the 5.3lsx hybrid conversion, but It either doesn't exist or I'm searching for the wrong things.
Any help and suggestion would be much appreciated. Thanks!!
03-23-2012, 08:43 PM
The truck coils will work for you, not sure about the PCM. Did the engine come out of a auto or standard transmission truck? Do you have all the covers? Sensors? Does your master gasket set come with head bolts, and crank pully bolt? Are you going to disassemble the bottom end?
Things for your list...
Mass air flow
03-23-2012, 11:45 PM
It came out of an auto, the only reason I suggested possibly using the truck PCM and harness is ease of sourcing and less $$$. All sensors that are block/head/intake related are there, I know I'll need O2's but other than that should I replace the other sensors as well? The bottom end is staying together, forgot to mention I have the lifters, block only had around 35k on it when it was pulled for a 6.0l swap.
Needless to say I didn't even think about the MAFS, that completely slipped my mind. The crank bolt and head bolts are going to be ARP. The gasket kit comes with head bolts, but I like to be doubly sure about strength and longevity. All the covers are on the motor as well.
I planned on the flywheel/clutch/slave when I picked up a t56, guess I should have mentioned that.
Thanks for clearing up that I can use the truck coils, I really wasn't sure about that one.
So other than the stuff I listed and now you (Conan) listed, I should be all good to go together without issue?
Any further advice and suggestion ALWAYS appreciated, I'm really new to LS motors, so I'm trying to cover all my bases before I even start assembly.
03-24-2012, 01:04 PM
Sounds good to me. If you have all the sensors that came with the 5.3L I would run all of them unless you get a ses light for one of them after the install is running.
Also, does you 5.3L have flat top pistons or dished ? Are you going to have the heads milled ?
03-24-2012, 02:45 PM
They have a raised ring on the outer most part of the piston face, but they seem to be flat (as opposed to what I'm assuming you mean concaved)
I wasn't planning on mulling the heads to regain stock compression, hence using a longer push rod, I'm just driving it daily so I'm not going for crazy performance just something fun. Do you think that's a bad idea? I've seen a lot of posts doing the same cam/head/push rod setup I'm talking about, but if it's a bad idea I'll change my plans
03-24-2012, 06:17 PM
Do you have the original heads from the motor? Do you know what the casting # is?
Does your pistons look like this one...
03-25-2012, 08:47 AM
You won't have to change the harness or PCM. You will have to change the injector clips to the EV1 still as the LM7 has the EV6 clips.
I would recommend doing this to your harness, but it is not intended for those who aren't good with wiring. Do lots of prep work, and when you pull it apart, YOU MUST USE electrical tape in each place as necessary to hold the harness together. Buy 3 rolls, wrap each spot, if you need a wire out, cut the electrical tape off, then re-wrap right after.
I learned this that hard way.
03-25-2012, 10:11 AM
send your ECM to frost for a tune.consider a TSP cam kit for more power,maybe 224r cam.
03-25-2012, 09:11 PM
Conan, yes my piston does look like that, as far as I know It had the original bottom end parts as its a super low mileage block. I'm not around the motor do I'm not sure what the casting number is.
Lm7mustang, thanks for the advice on the harness, I'm glad to know all I really need to do is swap injector clips. The electrical tape idea is great, wiring is a PITA, so any tricks to keep things clean and easier is ALWAYS helpful.
Garygnu, as far as the tune, I talked to poconojoe, and I think I might go his direction with the tune, but I'll def talk to frost and see what my options are as well. I'm gonna stick with the ls6 cam for now because I already have everything for it, but I may get a hunger for a bit more power later on and use a bit more aggressive cam.
Thank you guys again for your input
03-26-2012, 12:26 AM
The ls6 cam will do fine in the 5.3L, but I would do a compression ratio calculator with the 241 heads. The combustion chamber in the 706 head common to the 5.3L, is smaller than the 241 heads. That with a dished piston made around 9.5:1 compression, so you stick a bigger CC head on and you might be down in the 9.0:1 range. I would shoot for high 9, low 10 compression.
Give this a look through...http://ls1tech.com/forums/1740922-post41.html
03-26-2012, 01:18 PM
I've read about milling the heads Down a Specific amount to bring the compression back closer to stock AND be able to use the stock 7.400 length push rods. The issue is, I don't know how much to get milled off, and I'm ASSUMING it's not as easy as just knocking off .025" but I may be just thinking its more complicated than it is. Any suggestion on how to figure how much I should get milled off the head?
03-26-2012, 08:48 PM
If you have any reputable machine shops in your area give them a call and tell them what you have (heads, block, pistons, push rods) They should be able to tell you what compression your compression would be and how much to mill.
Did the engine come with heads or just the block?
03-27-2012, 10:27 AM
Go with some milled 5.3 heads to get your compression back up, and if you have the funds get a better cam matched to those heads.
03-28-2012, 03:35 AM
Sorry to butt in, but I've been thinking of swapping out my Blown LS1 for a 5.3 since I can't afford another LS1.
My question is, it the 5.3 a strait drop in for my 98 Trans Am / Auto? Will my parts off my LS1 (intake, injectors, water pump, oil pan, ECU & Harness, etc) If not, what would I need? I am trying to shoot for a dressed 5.3, but just in case I was wanting to know if my parts would work.
Also, what is the best 5.3 and best year - if there is a "BEST" ;)
Thanks guys and again sorry for jacking the thread :cheers: