4.8 or 5.3 external ID?

[Ray G.]

[Duke W.]

Re: 4.8 or 5.3 external ID?

Are you talking about 283s, 327s, and 350s?

283s with advertised CRs of 9.5 have flattop pistons with valve relieve notches. The only 283s with domed pistons were the FI engines rated at 10.5 or 11:1.

250 and 300 HP 327s also have flattop pistons with valve relief notches. All SHP/FI 327s have domed pistons.

I'm not sure about base 350 pistons, but SHP 350s up through '70 have domes, but smaller volume than 327 domed pistons.

Things get more complicated beginning in '71 with all engines having lower compression ratios to operate on 91 RON fuel, so I won't go there.

You are correct in pointing out that if stroke is increased, total combustion chamber volume must be increased to maintain CR either with smaller chamber heads or less dome volume, or a "dish" volume in the piston.

A flexible tube borescope can be used through the spark plug hole to observe crown configuration and check out the cylinder walls for damage such as scoring. On a good engine you can usually still see the cross hatch marks from proper honing except at the very top where there might be some wear on a high mileage engine.

Duke

[Joe L.]

Re: 4.8 or 5.3 external ID?

Hello;
Searched the TDB and the web as technically able.
Have read websites claiming buy pulling a spark plug a 4.8 has flat top pistons and 5.3 have dished pistons to compensate for
the longer stroke in a 5.3…. But, some 5.3s have flat top pistons.

Are there other external IDs for 4.8, 5.3, and 6.0 ?

Thank you.
Ray

Ray------


I assume you're referring to Gen III and later small blocks. My distinct recollection is that the size in liters is cast on the block, usually in the area of the bellhousing flange (i.e. behind the cylinder heads).

[Ray G.]

Re: 4.8 or 5.3 external ID?

Thanks Gentlemen. Gen III, 99 up is correct. Should made the question more clear.
I will look at the bell housing flange .
Thank You.
Ray

[Joe L.]

Re: 4.8 or 5.3 external ID?

Thanks Gentlemen. Gen III, 99 up is correct. Should made the question more clear.
I will look at the bell housing flange .
Thank You.
Ray

Ray------


If it's not on the bellhousing flange, look elsewhere on the block. I think it should be there somewhere.

[Richard M.]

Re: 4.8 or 5.3 external ID?

Ray, I have a 2006 Silverado with the 5.3L Vortec. I could take a few pics of particular areas if needed. What exactly are you trying to get?


I went to the NAPA website, http://www.napaonline.com/ and did a search for pistons for the 3 various engines based on my '06 truck data. You can also enter just the vin# and the engine data character should specify what engine as shipped, that is, if you have a vehicle and not a engine separated from one.

5.3L is dished Sealed Power SEP 1127CT

4.8L is flat top Sealed Power SEP 1132CT

6.0L is flat top Sealed Power SEP 1129CT

I just remembered I had this.(see attached "vincard06.pdf"). The 8th character is the engine type.

Rich

p.s. Duke, you got the right church but the wrong pew because the caretaker wasn't explicit with the question......(just kidding Ray)
......but, I very much enjoyed reading your information for furthering my SB engine education.

[Ray G.]

Re: 4.8 or 5.3 external ID?

Gentlemen;
Just received this article. Sounds like an easy ID is not available on these engines.
Maybe there is more current info since this was written some years ago.
Thank You

During our research of the General Motors Gen III engine family we continued to run up against a stumbling block of exterior identification between the 4.8L and 5.3L engines. It seemed that no matter who we spoke with, be it core suppliers, wrecking yards, engineers or rebuilders, when asked how they differentiated between the 4.8L or 5.3L engine from the exterior, no one had a solid answer. As a matter of fact no one had any answer.
So we thought we would look at the internal component differences between these two engines and perhaps come to some solution of external identification.


These engines came on the scene in 1999 in General Motors truck applications and were the upcoming replacement for the original design small block engines (GenIE). They were a spinoff of the LS1, 5.7L passenger applications used in the Corvette, Camaro and Firebird two years prior. Just so we have all the ducks in a row, both of these engines are OHV, pushrod V8 engines with cast iron blocks and aluminum cylinder heads.
Because both engines use the same block (c/n 12551358), GM seemed to play what may be described as a cruel, twisted joke on us since it cast "4.8/5.3" right on the block both in the front and in the rear in large numbers. The only problem is that you never really know which engine that you have from the exterior. The standard cylinder bore for both engine applications is 96mm (3.779˝) however the stroke for the 4.8L is 83mm (3.268˝) and has a crankshaft casting number of 12553482 while the stroke for the 53L is 92mm (3.622˝) and that crankshaft casting number is 12552216. Looking at the two crankshafts just standing next to each other they do not have what you would consider an obvious difference in appearance.
The connecting rods for the two engines do provide us some visual identifiable differences. The 4.8L connecting rod is longer in length and has the casting number 121 with an additional boss on the thrust face. The 5.3L connecting rod is shorter with casting number 143 and no additional boss on the thrust face. Both connecting rods are PM (powder metal) with a "crack" parting face.
There is also a difference between the pistons of these two engines, the 4.8L has a flat dome and the 5.3L has a cup dome. Another thing that we noticed is that the 4.8L pistons from OE had a pink ink mark in the pin area and the 5.3L had a green mark.


The cylinder head for both engines is aluminum with a casting number of 862, however on the deck face area in a small cavity there is a 4.8 cast onto the cylinder head. Do not be confused by this cast number for the cylinder head is for both 4.8L and 5.3L engines.

That leaves us with one option, pull a single or multiple spark plug(s) and look down the hole. Optimally, if you have a bend-a-light that will go into the spark plug hole you will have a better view. If you see a flat top piston, it is a 4.8L.


If you have a cup top piston you have a 5.3L. That is the best we were able to find as a quick identifier. But it works and it is relatively easy. Best of all, it is definitive. So if you have someone who is trying to sell you a 5.3L you might want to pull a plug and make certain that it has a cup top piston, otherwise ...well, I guess it could always be an honest mistake.
SourcePERA casting identification research continues to be the best available information for the engine remanufacturing industry. Also be on the lookout for the new 2004 PERA Engine Application and Identification Catalog. For more information go to www.pera.org and contact Roy Berndt via email link.

[Duke W.]

Re: 4.8 or 5.3 external ID?

Ray, I have a 2006 Silverado with the 5.3L Vortec. I could take a few pics of particular areas if needed. What exactly are you trying to get?



p.s. Duke, you got the right church but the wrong pew because the caretaker wasn't explicit with the question......(just kidding Ray)
......but, I very much enjoyed reading your information for furthering my SB engine education.

Oops! I did make one mistake. The following statement is incorrect:

You are correct in pointing out that if stroke is increased, total combustion chamber volume must be increased to maintain CR either with smaller chamber heads or less dome volume, or a "dish" volume in the piston.

It should be:

You are correct in pointing out that if stroke is increased, total combustion chamber volume must be increased to maintain CR either with larger chamber heads or less dome volume or a "dish" volume in the piston.

Duke

[Joe L.]

Re: 4.8 or 5.3 external ID?

Gentlemen;
Just received this article. Sounds like an easy ID is not available on these engines.
Maybe there is more current info since this was written some years ago.
Thank You

During our research of the General Motors Gen III engine family we continued to run up against a stumbling block of exterior identification between the 4.8L and 5.3L engines. It seemed that no matter who we spoke with, be it core suppliers, wrecking yards, engineers or rebuilders, when asked how they differentiated between the 4.8L or 5.3L engine from the exterior, no one had a solid answer. As a matter of fact no one had any answer.
So we thought we would look at the internal component differences between these two engines and perhaps come to some solution of external identification.


These engines came on the scene in 1999 in General Motors truck applications and were the upcoming replacement for the original design small block engines (GenIE). They were a spinoff of the LS1, 5.7L passenger applications used in the Corvette, Camaro and Firebird two years prior. Just so we have all the ducks in a row, both of these engines are OHV, pushrod V8 engines with cast iron blocks and aluminum cylinder heads.
Because both engines use the same block (c/n 12551358), GM seemed to play what may be described as a cruel, twisted joke on us since it cast "4.8/5.3" right on the block both in the front and in the rear in large numbers. The only problem is that you never really know which engine that you have from the exterior. The standard cylinder bore for both engine applications is 96mm (3.779˝) however the stroke for the 4.8L is 83mm (3.268˝) and has a crankshaft casting number of 12553482 while the stroke for the 53L is 92mm (3.622˝) and that crankshaft casting number is 12552216. Looking at the two crankshafts just standing next to each other they do not have what you would consider an obvious difference in appearance.
The connecting rods for the two engines do provide us some visual identifiable differences. The 4.8L connecting rod is longer in length and has the casting number 121 with an additional boss on the thrust face. The 5.3L connecting rod is shorter with casting number 143 and no additional boss on the thrust face. Both connecting rods are PM (powder metal) with a "crack" parting face.
There is also a difference between the pistons of these two engines, the 4.8L has a flat dome and the 5.3L has a cup dome. Another thing that we noticed is that the 4.8L pistons from OE had a pink ink mark in the pin area and the 5.3L had a green mark.


The cylinder head for both engines is aluminum with a casting number of 862, however on the deck face area in a small cavity there is a 4.8 cast onto the cylinder head. Do not be confused by this cast number for the cylinder head is for both 4.8L and 5.3L engines.
So how does any of this help with our ability to discern between these two engines from the exterior? If the oil pan is off, you could look at the crankshaft casting number, only every time you want to do that your odds are about as good as an open face peanut butter and jelly bread hitting the floor face up. But you can look at the connecting rods and see if that additional boss is there, you have eight chances to do that! But do you really want to pull the oil pan if you don’t have to?
That leaves us with one option, pull a single or multiple spark plug(s) and look down the hole. Optimally, if you have a bend-a-light that will go into the spark plug hole you will have a better view. If you see a flat top piston, it is a 4.8L.


If you have a cup top piston you have a 5.3L. That is the best we were able to find as a quick identifier. But it works and it is relatively easy. Best of all, it is definitive. So if you have someone who is trying to sell you a 5.3L you might want to pull a plug and make certain that it has a cup top piston, otherwise ...well, I guess it could always be an honest mistake.
SourcePERA casting identification research continues to be the best available information for the engine remanufacturing industry. Also be on the lookout for the new 2004 PERA Engine Application and Identification Catalog. For more information go to www.pera.org and contact Roy Berndt via email link.

Ray-------


I'd forgotten that the 4.8 and 5.3 shared the same bore, so the block would be the same. However, there's another angle for identification. The block should have an engine code stamped somewhere on it. I don't know where it's at for these Gen III and later engines (I think I knew once but I've forgotten it). That code should identify the engine without the need for any disassembly to check internal parts.

[Richard M.]

Re: 4.8 or 5.3 external ID?

Hmmm, Now I'm curious, so I went to the gmheritage center, and guess what.... They have the AMA specs for these engines. Duke turned me onto these docs years ago and I decided to check.

https://gmheritagecenter.com/gm-heritage-archive/vehicle-information-kits.html

I chose 2006(my truck year) and here is the 390 page document.

https://gmheritagecenter.com/docs/gm-heritage-archive/vehicle-information-kits/Silverado/2006-Chevrolet-Silverado.pdf

Go to page PDF page 109 (page 93 printed doc page). There are all of the specs for these engines.

Go to page PDF page 136 (page 120 printed doc page). There are all of the RPO codes for these engines.

I suspect there may be a ID Label of some sort on the engine, if still visible.

4.8L RPO LR4 VIN V

5.3L RPO LM7 VIN T or L33 VIN B (I think for Std or E85)

6.0L RPO LQ4 VIN U or LQ9 VIN N (I think for Std or E85)

There may be more info in the document to identify assembly code stamp, etc.

Rich
p.s. I looked at the engine on my 5.3L Silverado and saw no label or ID, Only the 5.3L Id on the Emissions Label.

[Ray G.]

Re: 4.8 or 5.3 external ID?

Hello Gentlemen;
Checked a 4.8 today and found light green paint marks on the front of the engine on the intake plane and on the corner of each head gasket protruding from the front lower corner of the cylinder head. I think the marks are assembly proof by the person torquing the bolts.

Also looked at a 6.0 and it has NO paint marks in those locations.

Both vehicles are low milage 2003 and 2006 and the VIN verified the engine sizes.
Ray