L33 Vs L59 5.3l V8?

cujo8 · April 13, 2009

I recently discovered that my 2006 GMC extended cab pickup has a L33 HO 5.3L V8 in it and I was wondering what the design differences between the L33 and L59 engines, besides the aluminum vs. cast iron block and the 310HP vs. 295HP for the L33 and L59 respectively? Do these engines use roller cam and lifters or is it a hydraulic flat tappet setup? Do speed parts from the LS engines fit the L33/L59 engines? Thanks.

redvett · April 14, 2009

All engines GM has built since mid 90's are roller cams and LS engines include the 4.8,5.3,5.7 & 6.0 are all the same with exception of displacement and AFM.

cujo8 · April 14, 2009

All engines GM has built since mid 90's are roller cams and LS engines include the 4.8,5.3,5.7 & 6.0 are all the same with exception of displacement and AFM.

I was thinking that was the case, but I had not read it any where yet. Do you you know how they are getting the extra 15HP out of the L33 over the L59 engine? Different cam maybe? Thanks.

Jim

redvett · April 14, 2009

I know the compression is higher and possibly the cam is different. LM7 & L59 is 9.5:1 and the L33is 9.9:1

All engines GM has built since mid 90's are roller cams and LS engines include the 4.8,5.3,5.7 & 6.0 are all the same with exception of displacement and AFM.

I was thinking that was the case, but I had not read it any where yet. Do you you know how they are getting the extra 15HP out of the L33 over the L59 engine? Different cam maybe? Thanks.

Jim

cujo8 · April 14, 2009

I know the compression is higher and possibly the cam is different. LM7 & L59 is 9.5:1 and the L33is 9.9:1
All engines GM has built since mid 90's are roller cams and LS engines include the 4.8,5.3,5.7 & 6.0 are all the same with exception of displacement and AFM.

I was thinking that was the case, but I had not read it any where yet. Do you you know how they are getting the extra 15HP out of the L33 over the L59 engine? Different cam maybe? Thanks.

Jim

If that is the case then they both could not be a 5.3L engine, because with larger compression comes a larger displacement. Whether they used larger pistons or a longer stroke the displacement has to go up. If all they did is use a different cam or different ratio rocker arms then the displacement could still be the same, but those changes would not change the compression ratio though. ?????

66nova · April 14, 2009

I know the compression is higher and possibly the cam is different. LM7 & L59 is 9.5:1 and the L33is 9.9:1
All engines GM has built since mid 90's are roller cams and LS engines include the 4.8,5.3,5.7 & 6.0 are all the same with exception of displacement and AFM.

I was thinking that was the case, but I had not read it any where yet. Do you you know how they are getting the extra 15HP out of the L33 over the L59 engine? Different cam maybe? Thanks.

Jim

If that is the case then they both could not be a 5.3L engine, because with larger compression comes a larger displacement. Whether they used larger pistons or a longer stroke the displacement has to go up. If all they did is use a different cam or different ratio rocker arms then the displacement could still be the same, but those changes would not change the compression ratio though. ?????

Larger bore and longer stroke are not the only way to change compression ratio. Different pistons, thinner head gasket, different cylinder head chamber design all affect compression ratio. You can gain 0.4 extra compression by just using a thinner head gasket. If the older pistons have a dish or valve reliefs and the newer ones don't, smaller chamber in the cylinder heads. All of these can be changed and still have basically the same engine.

redvett · April 14, 2009

Compression is raised by doing two things. #1 a higher dome on the piston. #2 changing the cylinder head with less CC's in the dome. Stroke & bore changes only change displacement.

I know the compression is higher and possibly the cam is different. LM7 & L59 is 9.5:1 and the L33is 9.9:1
All engines GM has built since mid 90's are roller cams and LS engines include the 4.8,5.3,5.7 & 6.0 are all the same with exception of displacement and AFM.

I was thinking that was the case, but I had not read it any where yet. Do you you know how they are getting the extra 15HP out of the L33 over the L59 engine? Different cam maybe? Thanks.

Jim

If that is the case then they both could not be a 5.3L engine, because with larger compression comes a larger displacement. Whether they used larger pistons or a longer stroke the displacement has to go up. If all they did is use a different cam or different ratio rocker arms then the displacement could still be the same, but those changes would not change the compression ratio though. ?????

66nova · April 14, 2009

Actually you are both right and both wrong. Using the same cylinder heads and changing bore/stroke will change compression ratio, but cylinder head chamber size and piston dome/dish/valve relief size changes compression ratio. Along with as said earlier, head gasket thickness and block height. This changes the quench area.

redvett · April 14, 2009

Yes you are right, i just was trying to explain in simple terms where the compression difference comes from on a 5.3L. Most likely the L33 got a different cylinder head with less quench area to add 4/10 more compression.

Actually you are both right and both wrong. Using the same cylinder heads and changing bore/stroke will change compression ratio, but cylinder head chamber size and piston dome/dish/valve relief size changes compression ratio. Along with as said earlier, head gasket thickness and block height. This changes the quench area.

cujo8 · April 15, 2009

All the things that were mentioned, head chamber size, piston profile, stroke length, piston cylinder bore, & head gasket thickness changes will all change the displacement of the engine. Milling the heads, clearancing the deck height, using thinner head gasket, lengthening the stroke, or using domed pistons will all raise compression, but these will also change the total displacement, since all these things affect the effective cylinder volumes. The only way to increase compression that I can think of w/o changing displacement is with a cam profile change that increases the engine efficiency by allowing more of the air/fuel mixture into the cylinder before it is compressed by the piston.

66nova · April 15, 2009

All the things that were mentioned, head chamber size, piston profile, stroke length, piston cylinder bore, & head gasket thickness changes will all change the displacement of the engine. Milling the heads, clearancing the deck height, using thinner head gasket, lengthening the stroke, or using domed pistons will all raise compression, but these will also change the total displacement, since all these things affect the effective cylinder volumes. The only way to increase compression that I can think of w/o changing displacement is with a cam profile change that increases the engine efficiency by allowing more of the air/fuel mixture into the cylinder before it is compressed by the piston.

Sorry, don't want to start an argument, but you might want to do a little more research on this. Cylinder heads, head gaskets, deck height, have nothing to do with displacement.

Displacement is a volume measurement calculated from of bore, stroke and number of cylinders. The things mentioned above have nothing to do with these. You can buy a short block 5.3 without cylinder heads and then go buy an aftermarket cylinder head that would fit a 4.8, 5.3, 5.7, 6.0 and you would still have a 5.3l engine.

cujo8 · April 15, 2009

All the things that were mentioned, head chamber size, piston profile, stroke length, piston cylinder bore, & head gasket thickness changes will all change the displacement of the engine. Milling the heads, clearancing the deck height, using thinner head gasket, lengthening the stroke, or using domed pistons will all raise compression, but these will also change the total displacement, since all these things affect the effective cylinder volumes. The only way to increase compression that I can think of w/o changing displacement is with a cam profile change that increases the engine efficiency by allowing more of the air/fuel mixture into the cylinder before it is compressed by the piston.

Sorry, don't want to start an argument, but you might want to do a little more research on this. Cylinder heads, head gaskets, deck height, have nothing to do with displacement.

Displacement is a volume measurement calculated from of bore, stroke and number of cylinders. The things mentioned above have nothing to do with these. You can buy a short block 5.3 without cylinder heads and then go buy an aftermarket cylinder head that would fit a 4.8, 5.3, 5.7, 6.0 and you would still have a 5.3l engine.

I think I know why I'm confused about this displacement issue now, the automotive definition of displacement is as you stated "a volume measurement calculated from of bore, stroke and number of cylinders" and they are ignoring the other things we've been talking about that affect the actual volume of a cylinder. I work as an analytical chemist, so when I do volume measurements (displacement) I have to account for the total volume.

So engine displacement values for engines only accounts for the cylindrical volume that the pistons move in the cylinder bores. The compression ratio on the other hand does take into consideration the true volumes of the combustion chamber from TDC to BDC. OK then, I think we're all on the same page now.

So this means that the L33 and the L59 have the same cylinder bore & stroke, but the L33 has a slightly higher compression ratio than the L59. So what did GM change in the L33 engine to get this extra compression and HP over the L59? Different cylinder heads, piston profile, or something else? I am just curious about these type of things. I'm the type of guy who likes to know what I have and if there are things I can change/modify to make them even better . Thanks for setting me straight on engine displacement.

Jim

66nova · April 15, 2009

All the things that were mentioned, head chamber size, piston profile, stroke length, piston cylinder bore, & head gasket thickness changes will all change the displacement of the engine. Milling the heads, clearancing the deck height, using thinner head gasket, lengthening the stroke, or using domed pistons will all raise compression, but these will also change the total displacement, since all these things affect the effective cylinder volumes. The only way to increase compression that I can think of w/o changing displacement is with a cam profile change that increases the engine efficiency by allowing more of the air/fuel mixture into the cylinder before it is compressed by the piston.

Sorry, don't want to start an argument, but you might want to do a little more research on this. Cylinder heads, head gaskets, deck height, have nothing to do with displacement.

Displacement is a volume measurement calculated from of bore, stroke and number of cylinders. The things mentioned above have nothing to do with these. You can buy a short block 5.3 without cylinder heads and then go buy an aftermarket cylinder head that would fit a 4.8, 5.3, 5.7, 6.0 and you would still have a 5.3l engine.

I think I know why I'm confused about this displacement issue now, the automotive definition of displacement is as you stated "a volume measurement calculated from of bore, stroke and number of cylinders" and they are ignoring the other things we've been talking about that affect the actual volume of a cylinder. I work as an analytical chemist, so when I do volume measurements (displacement) I have to account for the total volume.

So engine displacement values for engines only accounts for the cylindrical volume that the pistons move in the cylinder bores. The compression ratio on the other hand does take into consideration the true volumes of the combustion chamber from TDC to BDC. OK then, I think we're all on the same page now.

So this means that the L33 and the L59 have the same cylinder bore & stroke, but the L33 has a slightly higher compression ratio than the L59. So what did GM change in the L33 engine to get this extra compression and HP over the L59? Different cylinder heads, piston profile, or something else? I am just curious about these type of things. I'm the type of guy who likes to know what I have and if there are things I can change/modify to make them even better . Thanks for setting me straight on engine displacement.

Jim

Hey, that's what we are here for. To have discussions and learn. Lord knows I have been set straight a time or two on here. Well, maybe just once. I'm not often wrong

As far as the 5.3's I'm not sure what GM did differently between these two motors. Sorry.

cujo8 · April 23, 2009

I know the compression is higher and possibly the cam is different. LM7 & L59 is 9.5:1 and the L33is 9.9:1

I bought a 2006 Sierra Truck brochure off eBay in hopes of finding out a little more about my 2006 Sierra truck. In the specification section of the brochure it shows that the 5.3L L59 (iron block) and the L33 (aluminum block) both have the same bore and stroke of 96.01mm and 92.00mm respectively. Other than the differences in block material the only other thing listed as being different is the HP ratings, 295HP @ 5200rpm for the L59/LM7 and 310HP @5200rpm for the the L33. They list the torque for both engines as equal @ 335 @ 4000. If this is true what I read in this brochure the only things I can think of for the HP differences are different (better flowing) heads and a cam upgrade. What do you folks think? The cylinder head casting # is 799 for my 2006 L33. It would help if someone with the L59 or LM7 engine check the cylinder head casting # and let us know. From my research apparently GM only installed the L33 in extended cab pickups from 2005 through 2007, so it would better if the folks reporting the head casting #'s do so for the same year range of 2005-2007. Thanks.

Jim