Newb Question, How to tell if I have an LM7 or L59
07-29-2016, 04:36 PM
#1
Teching In
Thread Starter
Join Date: Jul 2016
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
Newb Question, How to tell if I have an LM7 or L59 I'm in the beginning stages of LS Swapping my '79 Chevy K5 Blazer 4x4 and have been searching the local Craigslist, Ebay and a few forums that I'm a member of for a cheap LS engine for the swap.
I found a 5.3 long block at a local performance shop for $200 (which seems like a good deal to me).
The owner of the shop who has the engine said it was removed and replaced due to oil consumption and oil foulding of #7 plug everytime the did an oil change which leads me to believe it is an L59 which had the DOD/AFM and had PCV issues.
I'm new to the LS world, all I know is Gen 1 SBC's and I'm just looking for some help on identifying the engine that I plan on buying.
If it is an L59 the first thing I plan on doing is buying and installing a DOD/AFM delete kit and a new non DOD/AFM cam from TSP or BTR to eliminate the PCV/Oil Consumption/Plug Fouling issues that L59's are known for.
Also, I plan on getting a stand alone harness/ecm from lsx4u.com and want to know if I need to tell them anything specific?
I found a 5.3 long block at a local performance shop for $200 (which seems like a good deal to me).
The owner of the shop who has the engine said it was removed and replaced due to oil consumption and oil foulding of #7 plug everytime the did an oil change which leads me to believe it is an L59 which had the DOD/AFM and had PCV issues.
I'm new to the LS world, all I know is Gen 1 SBC's and I'm just looking for some help on identifying the engine that I plan on buying.
If it is an L59 the first thing I plan on doing is buying and installing a DOD/AFM delete kit and a new non DOD/AFM cam from TSP or BTR to eliminate the PCV/Oil Consumption/Plug Fouling issues that L59's are known for.
Also, I plan on getting a stand alone harness/ecm from lsx4u.com and want to know if I need to tell them anything specific?
07-29-2016, 06:33 PM
#2
I am quite familiar with LM7 but not so much L59. As far as I can tell, L59 doesn't indicate DoD or AFM but indicate FFV(flex fuel). To me, this says you would see larger injectors on the FFV engine as it can run on high ethanol content fuel. Ethanol is less power-dense than gasoline so requires more fuel volume for the same power output..and larger injectors. True LM7s I have put my hands on had some pretty wimpy injectors from a mod-ability standpoint. So my vote is to check the numbers on the side of the fuel injectors.
I could be wrong about DoD/AFM above so please post up the info you based your assumption on?
I could be wrong about DoD/AFM above so please post up the info you based your assumption on?
07-29-2016, 09:06 PM
#3
Teching In
Thread Starter
Join Date: Jul 2016
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
The engine only consists on valve covers, heads, valley plate/cover, block, timing cover, crank pulley and oil pan (and all the internals. There is no intake, coils, injectors or anything else. They pulled this engine and swapped in a different one using all the stuff from this engine.
The reason I think it is a DOD/AFM engine is becasue of the oil consumption and plug fouling specifically plug #7. From what I've been reading these are tell tale signs of DOD/AFM. GM posted a bulletin on PCV provisions and parts with the correct baffling to correct these problems and they state the exact thing DOD/AFM engines suffer from oil consumption and the fouling of #7 spark plug.
All I really know about DOD/AFM is that it take the working cylinders from 8 down to 4 when certain criteria is met in order to conserve fuel.
I didn't know LM7's had DOD/AFM, I thought it was only the L59's.
I may pass on the engine due to having to source all of the other stuff and hold onto my money until a complete engine/ harness and PCM pop up for a reasonable price.
The reason I think it is a DOD/AFM engine is becasue of the oil consumption and plug fouling specifically plug #7. From what I've been reading these are tell tale signs of DOD/AFM. GM posted a bulletin on PCV provisions and parts with the correct baffling to correct these problems and they state the exact thing DOD/AFM engines suffer from oil consumption and the fouling of #7 spark plug.
All I really know about DOD/AFM is that it take the working cylinders from 8 down to 4 when certain criteria is met in order to conserve fuel.
I didn't know LM7's had DOD/AFM, I thought it was only the L59's.
I may pass on the engine due to having to source all of the other stuff and hold onto my money until a complete engine/ harness and PCM pop up for a reasonable price.
07-29-2016, 10:58 PM
#4
L59s are Gen 3 flex fuel 5.3L. LM7s are Gen 3 non flex fuel 5.3L. Any 5.3L with AFM/DOD will be a Gen 4. If it has the valley cover with knock sensors, it is a Gen 3. No Gen 3 had AFM/DOD. No way to tell if it was a LM7 or L59 as it will be the the items missing that make it one or the other