buying junkyard engine tomorrow.advice???

71 chevy · 10-16-2009, 02:45 PM

I'm picking up a 5.3 from the junkyyard tomorrow and want to know what pitfalls I should be aware of

Are there any identifying marks that tell a newer year from an older year?

Are there certain numbers less desireable?

Any advice is welcome.thanks

cash · 10-16-2009, 02:54 PM

If your are going to use a blower or turbo get the 5.3.

If you want a N/A or big cam nitrous motor, start with a 6.0

kj598bbc · 10-16-2009, 04:05 PM

Newer years would definitely have dbw throttle body, and if you intend to stay with the dbw make sure you get the pedal assembly. Not sure, some of our more knowledgeable members can be more specific, but i think the older 5.3's have iron heads.

FastKat · 10-16-2009, 05:16 PM

That is good advice. If it's DBW (drive by wire) also get the TAC module as well. It's' a black plastic box, a little smaller than the computer, that has a couple plugs on it. One plug will go to the wiring harness, the other will go through the firewall to the pedal. I believe they were used on trucks through 2007, and then the function was integrated into the PCM.

If you are doing DBW and get the throttle body, TAC module and pedal assembly out of the same vehicle, things will be easier and cheaper for you. Also, when you're taking the TAC and pedal out, get as much of the wiring and connectors that you can!

Quote:

Originally Posted by kj598bbc

Newer years would definitely have dbw throttle body, and if you intend to stay with the dbw make sure you get the pedal assembly. Not sure, some of our more knowledgeable members can be more specific, but i think the older 5.3's have iron heads.

71 chevy · 10-16-2009, 05:45 PM

thanks for the great info guys. I'll look for a dbw one. I am using a vic jr intake with a 4bbl tb so I dont need the dbw stuff, but maybe I can recoup a little bit of my cost with it.

please keep the information coming

kj598bbc · 10-16-2009, 08:23 PM

Quote:

Originally Posted by 71 chevy

thanks for the great info guys. I'll look for a dbw one. I am using a vic jr intake with a 4bbl tb so I dont need the dbw stuff, but maybe I can recoup a little bit of my cost with it.

please keep the information coming

Victor jr. is a single plane, you must plan on h/c and higher rpm usage ?

busta9876 · 10-16-2009, 09:51 PM

99-02=Cable throttle body, 03=Drive By Wire
99-03=Duel Fuel Line Connections, 04+=Single Fuel Line Connection
Rectangle-ish inj connectors=LM7 regular fuel, Square-ish inj connectors=L59 Flex Fuel

Injector Part# (on flat side of injector, 8 digit, faces intake, may have to turn inj to read it)
1999 and SOME 2000 part# 25317669
MOST 2000 part# 25323974 and 25320288
2001+ part# 25317628

Don't have any real advice to tell a 4.8/5.3 apart. I've heard only looking at pistons will tell you. Flat Top=4.8, Slight Dish=5.3

dec010974 · 10-16-2009, 10:17 PM

the other ls1tech members gave you some useful advice. follow it. and if the motor is already pulled out with the brackets for alt and power steering off the motor, it will be stamped 5.3. also you can run the casting numbers. that will tell you what year motor you have. DBW and a single feed line on the fuel rail came about 03-04. you R carb guy so many tings will B simplified. google/bing casting #s and you will find the info you need. also remember that information found on the net or any where is only as good as it source.

50adrod · 10-17-2009, 12:02 AM

Quote:

Originally Posted by cash

If your are going to use a blower or turbo get the 5.3.

If you want a N/A or big cam nitrous motor, start with a 6.0

why is that?

Paul57 · 10-17-2009, 12:27 AM

There is an aluminum block 5.3, if that interests you...L33. 8th digit on the VIN is a B.

71 chevy · 10-17-2009, 12:58 AM

thanks guys. I'll have this page up on my phone tomorrow when I go so I can get the newest(and hopefully) best engine.

its for a mild turbo application and Ive gathered everything else except the engine. I want to try and get it in the car tomorrow by just changing the stock oil pan to the champs pan and adding the conversion mounts.

can I use the existing oil pan gasket? if not, what gasket to I need?

busta9876 · 10-17-2009, 02:12 AM

a few other year identifiers.

EGR was only the truck's up to 2001.

GM started using MLS head gaskets in 2002. You can look at the corner of the block, right where the head & block come together, and there will be a small rivit holding the 3 lays of the head gasket together. Sure sign of MLS head gaskets, will be better for boost.

The block will say 4.8/5.3. Both engines used the same block, and are stamped both numbers. Crank shaft was a different stroke, and rods different length. head casting on both engines IS the same.

good luck.

kevin99hoss · 10-17-2009, 08:25 AM

one more tip, make sure you can freely spin the balancer, i had a junkyard motor sent to my house and it was frooze up, the intake was cracked when the truck was in a accident which allowed water to get into the cylinders

Pop N Wood · 10-17-2009, 01:13 PM

If you can crank it over bring a compression guage. Should tell you a lot about the wear.

71 chevy · 10-17-2009, 10:22 PM

hi guys. quick update. went to the junkyard. they had about 6 or 7 5.3, mostly from 2000-2001 vehicles. they were cable throttle and no rivet on the gasket. I found ONE that was from a 2003 that had just come in maybe 4 weeks ago.

it had drive by wire, the rivet in the gasket, and the casting number was 12567393 which I pulled up and it said 03 tahoe or suburban.

it had been in a small wreck(evidenced by cracked alt bracket, and pass side coil mount closest to firewall was also bent up) but my friend and I dont think the engine was touched, so we ended up getting it. Im hoping that there is no internal damage of any kind

71 chevy · 10-17-2009, 10:30 PM

one quick question. all the lsx blocks at the jy had only one dowel pin to locate the trans to the block .

is this normal??? or do I need another pin. and where can I get one?

gofastwclass · 10-17-2009, 10:40 PM

Quote:

Originally Posted by 71 chevy

hi guys. quick update. went to the junkyard. they had about 6 or 7 5.3, mostly from 2000-2001 vehicles. they were cable throttle and no rivet on the gasket. I found ONE that was from a 2003 that had just come in maybe 4 weeks ago.

it had drive by wire, the rivet in the gasket, and the casting number was 12567393 which I pulled up and it said 03 tahoe or suburban.

it had been in a small wreck(evidenced by cracked alt bracket, and pass side coil mount closest to firewall was also bent up) but my friend and I dont think the engine was touched, so we ended up getting it. Im hoping that there is no internal damage of any kind

I can tell by your pics if you are using any transmission older than 1998 or a 4L80E of any year you will need the flexplate spacer and appropriate bolts.

Looks like a good find.

Last few I picked up still had the accessory belts on them, looks like yours did too. I'd rather have all that stuff now and not use it than need to score it later.

gofastwclass · 10-17-2009, 10:43 PM

Quote:

Originally Posted by 71 chevy

one quick question. all the lsx blocks at the jy had only one dowel pin to locate the trans to the block .

is this normal??? or do I need another pin. and where can I get one?

No, you should have two. The other must have come out with the trans. You can steal one off another engine, however they really aren't absolutely necessary, they only make life easier.

71 chevy · 10-17-2009, 11:39 PM

Quote:

Originally Posted by gofastwclass

I can tell by your pics if you are using any transmission older than 1998 or a 4L80E of any year you will need the flexplate spacer and appropriate bolts.

Looks like a good find.

Last few I picked up still had the accessory belts on them, looks like yours did too. I'd rather have all that stuff now and not use it than need to score it later.

I asked this question and didnt get an answer. here is the question: I had my converter mfg do a th350 back and an ls1 front- which I think is just a slightly longer snout - do I still need the longer bolts?

Quote:

Originally Posted by gofastwclass

No, you should have two. The other must have come out with the trans. You can steal one off another engine, however they really aren't absolutely necessary, they only make life easier.

thanks for the info. I really would like and get the second one. maybe I'll go back to the junkyard and ask for it. do you know if places like autozone etc sell this piece?

G-Body · 10-18-2009, 12:43 AM

Since your th350 convertor has the longer LS1 style nose you will not need longer bolts.

I don`t think that any of the chains will have a dowel pin. I picked mine up from the dealer when I bought my motor (only had 1 in it just like yours, they stick in the trans all the time). IIRC it was less than $10.