Questions on 5.3L engines

[srobertsfsj]

I found a possible good deal on a 2000 5.3L LM7 drivetrain from a K1500 and I was wondering if the LM7 is a good candidate for the swap? I am not familiar with the difference between the different engine codes other than HP and torque. I know some are electronic gas pedal vs cable, etc. The Wikipedia site doesnt have much about the difference but if I am reading the site right this is a cast iron block instead of alumimum. Should I hold out and find a L33 or LM4? Or should I look for a Gen IV 5.3?

Also, would this have an 4L60E behind it?

P.S. I should also mention it has 127k on it.

[j20owner]

LM7 is a truck 5.3 with an iron block. Nothing inherently wrong with it. I've got one in my Wag, came out of an 02 2wd. If it has an auto behind it, it is the 4l60e. Mine supposedly had ~130k on it when I tore it apart, still had cross-hatch in the cylinders. LM7 engines can be had much cheaper than L33. LM4 sounds like it'd be hard to find, also.

Your vintage of LM7 will have dished pistons, not flat-tops. Will have aluminum heads, probably not the best ones, either, but they'll work. I've got 806 heads on mine(I think that's the casting number, it's the one with the small intake valves). I doubt you'd notice a difference with a stock cam and tune between the small valve and a big valve.

[JeepinPete]

That is roughly a 285hp engine. They love to rev, not a grunt engine. 127k would not scare me at all, but I wouldn't spend much more than $750 complete on it either. Since you already have a TBI conversion on the 360, I wonder if it would be worth it. But I don't know the reliability and mpg of your conversion either.

[srobertsfsj]

I have a couple more questions for folks who have done the swap.

1. For those of you who have used the chevy TC (np241c i believe) How did you deal with connecting the speedo to the stock cluster? The NP241c is an electronic vss, correct?
2. How about connecting the temp sensor from chevy block to the stock cluster?
3. do the stock exhaust manifolds fit or does the heater box need to be trimmed?
4. Has anyone tried to connect the GM A/C compressor to the FSJ system? Is this possible?

I have a line on a low mileage 2007 5.3L drivetrain for $900, does not include harness tho

I am still trying to figure out which engine code it is since in 2007 it could have been 6 different codes, heck in 2007 it could have been a gen 3 or gen 4. Is the engine code stamped on the engine somewhere or to I figure it out by the VIN?

[Stuka]

I would stay far away from 2007+ 5.3L's. I know three people all with 07's that had had to have new pistons put in, and two had MDS failures. Not sure if these were gen 3 or 4. They were in Tahoe and Suburbans in these cases.

Do a google search for 5.3L oil consumption.

[srobertsfsj]

Thanks for the info Stuka, a quick search shows it was due to the AFM when it shuts down cylinders it uses excessive oil. Good to know!

[Stuka]

Ah interesting, I had not heard a cause yet. I know on my co-workers '07 Suburban they had to replace all the rings and pistons. It was using a quart of oil every 900 miles.

[Jeffsj]

I have a couple more questions for folks who have done the swap.

1. For those of you who have used the chevy TC (np241c i believe) How did you deal with connecting the speedo to the stock cluster? The NP241c is an electronic vss, correct?
2. How about connecting the temp sensor from chevy block to the stock cluster?
3. do the stock exhaust manifolds fit or does the heater box need to be trimmed?
4. Has anyone tried to connect the GM A/C compressor to the FSJ system? Is this possible?

I have a line on a low mileage 2007 5.3L drivetrain for $900, does not include harness tho

I am still trying to figure out which engine code it is since in 2007 it could have been 6 different codes, heck in 2007 it could have been a gen 3 or gen 4. Is the engine code stamped on the engine somewhere or to I figure it out by the VIN?

Sorry, I can't help you with the stock gauge questions, because I went with the Dakota Digital dash and it made it all VERY simple. The stock exhaust manifolds fit just fine on mine. It was from a 2003 GMC Yukon. As far as the A.C. goes, I am still planning to hook mine up. I was told by a local auto a.c. guy, that all he needs is the stock a.c. manifolds from the 5.3 and he will modify the hoses to work with the system. He said it will run about $500 to get it up and running.

[ProTouring442]

1. For those of you who have used the chevy TC (np241c i believe) How did you deal with connecting the speedo to the stock cluster? The NP241c is an electronic vss, correct?

The ECM will be looking for a signal from the transmission, not the transfer case. If you use the transfer case output, the TCM will not tell the transmission to shift when you are in 4-low.

2. How about connecting the temp sensor from chevy block to the stock cluster?

To use the stock temp gauge, you will end up using two temp sending units. One will give the info to the ECM, the other will be the stock Jeep item.

3. do the stock exhaust manifolds fit or does the heater box need to be trimmed?

I cannot say on this, but I would think they should fit with little problem.

4. Has anyone tried to connect the GM A/C compressor to the FSJ system? Is this possible?

Shouldn't be an issue, you'll just have to have to new lines made up with the correct fittings for the GM compressor.

I have a line on a low mileage 2007 5.3L drivetrain for $900, does not include harness tho

PSI (www.psiconversion.com) charges about as much for a completely new harness as you will spend having your old harness modified. They can also supply the ECM and TCM. Their customer service was excellent, and the harness seems to be of very high quality.

I am still trying to figure out which engine code it is since in 2007 it could have been 6 different codes, heck in 2007 it could have been a gen 3 or gen 4. Is the engine code stamped on the engine somewhere or to I figure it out by the VIN?

You should be able to find out exactly which engine you have by the eighth digit of the donor vehicle's serial number (VIN).

Hope that helps!

[srobertsfsj]

That was EXTREMELY helpful. Thank you very much!! Excepecially the link for the harness. Now I am just questioning if I should go with the 2007 or look for something older. I also read that 2002+ went to electronic gas pedal. Not sure I like fly by wire in my offroader.

[ProTouring442]

That was EXTREMELY helpful. Thank you very much!! Excepecially the link for the harness. Now I am just questioning if I should go with the 2007 or look for something older. I also read that 2002+ went to electronic gas pedal. Not sure I like fly by wire in my offroader.

Talk to PSI, but I think you can convert a FBY to cable operation by replacing the throttle body.

[Jeffsj]

I am curious as to why you are concerned with the fly by wire for an off roader? I have it in my Jeep and a 2003 Silverado. I also have a 2000 GMC Yukon with the cable operated throttle and I honestly can't tell the difference between the operation of them and I've never had any issues. It did take some extra fab work in the Jeep, but I am very happy with it. The thing I really like about it is the ease with which I can hook up cruise control. The wires are right there, ready to go. I use mine for trails AND daily driving, so this might be of more importance for me than you though.

[j20owner]

1. For those of you who have used the chevy TC (np241c i believe) How did you deal with connecting the speedo to the stock cluster? The NP241c is an electronic vss, correct?

The ECM will be looking for a signal from the transmission, not the transfer case. If you use the transfer case output, the TCM will not tell the transmission to shift when you are in 4-low.

Not 100% true. If you use a 4wd tune and have the 4lo signal hooked up to the ECM when in 4lo, you won't have any problems, especially when using a 2.72:1 low range. You can get the vss from either the trans(with an add on speed sensor between the trans and tcase) or from the transfer case. If using a transfer case vss, just make sure you have the 4lo signal hooked up properly and it will shift just fine in 2wd or 4wd.

As for the speedo, if you have a vss transfer case, I really have no idea how to drive the speedo. Not all nP241c have the vss. Some had the old style gear drive.

Thanks for the info Stuka, a quick search shows it was due to the AFM when it shuts down cylinders it uses excessive oil. Good to know!

On that issue, it's not that the engine uses excessive oil when the AFM is activated. It has more to do with the oil being used a lot harder than in non AFM engines, getting hotter, staying vaporized longer, getting sucked into the PCV system and then being burnt. We've done several piston/ring swaps at work. It's really not a fix, just a 'get it to stop eating oil for a while' repair. It will do it again. The oil runs hotter than it should, and there's not enough oil to keep it cool enough to let it return to liquid form. That's one reason the new engines coming out in '14 have an 8.5qt capacity.

[ChiefBigB]

I have a 2004 Yukon SLT that was totaled. It has the 5.3 and auto trans. What specific engine (alum?), trans, and transfer case would this model have?

[srobertsfsj]

On that issue, it's not that the engine uses excessive oil when the AFM is activated. It has more to do with the oil being used a lot harder than in non AFM engines, getting hotter, staying vaporized longer, getting sucked into the PCV system and then being burnt. We've done several piston/ring swaps at work. It's really not a fix, just a 'get it to stop eating oil for a while' repair. It will do it again. The oil runs hotter than it should, and there's not enough oil to keep it cool enough to let it return to liquid form. That's one reason the new engines coming out in '14 have an 8.5qt capacity.

Thank you for the clarification, I just did a quick search and wasn't really paying attention to the details. I think I should probably stay away from the AFM engines.

[JeepinPete]

Not all exhaust manifolds will work. At least driver's side manifolds. I had a '99 5.3L in my old Cherokee, and the outlet dumped right into the frame rail. I ended up using a F-body manifold from a LS1. Apparently newer year manifolds will work, but I couldn't tell you which applications are a sure bet.

[nester]

Seems like if it's a function of the AFM, that disabling that in the tune would help a lot..

[nester]

I have a 2004 Yukon SLT that was totaled. It has the 5.3 and auto trans. What specific engine (alum?), trans, and transfer case would this model have?

Should be a LM7 with a 4L60. Not sure on the transfer case.

[srobertsfsj]

I have a 2004 Yukon SLT that was totaled. It has the 5.3 and auto trans. What specific engine (alum?), trans, and transfer case would this model have?

I have been using this wiki page.

http://en.wikipedia.org/wiki/GM_Vortec_engine#5300

[Stuka]

Seems like if it's a function of the AFM, that disabling that in the tune would help a lot..

Oil still passes into the AFM manifold. The solinoids just aren't moving if its disabled.