Anyone who the difference between a 3.1L and a 3.4L out of a 1994 Camaro

[Jerriko]

I pulled a motor out of a 94 Camaro to put in my 87 Firebird. The motor is supposed to be a 3.4L and the numbers matched the Camaro. I tore down the block the other day and noticed that the numbers on the crank say 3.1L as does the block. I measured the bore and it is 3.62" which is the bore for a 3.4L but I can't find any info on a 3.1L so I have nothing to compare with. Anyone have any input on this?
Any help would be appreciated.
Jim

[nova]

I think the stroke on the 3.4L and the 3.1L is the same, just the bore is different. If I remember correctly the 3.1L is a stroked 2.8L and the 3.4 is a bored and stroked 2.8L.

Of course I could just be talking out of my tail end so someone correct me if I'm wrong.

[Jerriko]

After looking in the technical database, I would the following info:
The stroke for the 3.1 and 3.4 are the same, 3.31

The bores are different: 3.1 is 3.5; 3.4 is 3.62

But still the question remains, why is the block I have labeled as a 3.1 when the bore size measures 3.62? I can understand why the crank is labeled a 3.1 since the stroke is the same on both.

[nova]

<blockquote>quote:</font><hr>Originally posted by Jerriko:
But still the question remains, why is the block I have labeled as a 3.1 when the bore size measures 3.62? I can understand why the crank is labeled a 3.1 since the stroke is the same on both.<hr></blockquote>

The block from the 3.4 and the 3.1 are probably identical just as the crank is. I've never looked at the numbers on my 3.4 block so I can't tell you if mine is the same way.

[Jerriko]

Would the blocks be different since they have different bores? Or would the 3.1 simply have thicker cylinder walls?
Regardless, I suppose this would be another of GM's ways of saving a buck, right.
I guess what I am still wondering is, is the only way to tell the difference between a 3.1 and a 3.4 to measure the bore? It just seems to cheap of GM to not change the numbers from block to block.
Thanks for your help.
Jim

[nova]

I think you're right on all counts. I think the 3.1L would just have thicker cylinder walls and I think it was just GM trying to save a little $$$ by not changing the numbers on the block.

[3.4 slow to go]

ah, someone else who knows the true value of a 94 camaro [img]tongue.gif[/img]

does your block have a big F cast into it onthe driverside? I can see mine when underneath working on the tranny & looking up. Up & to right of the oil filter adaptor.

[black34v6]

its GM. they do dumb stuff like that. the crank is stamped 3.31 i believe somewhere (mine was) - which is actually the stroke of the crank.. not sure what you mean by "crank numbers" and where you found out that number was related to the 3.1L motor.

also where on the block did you find a number that said it was a 3.1L. what was the number?

more info will help to figure out why gm did what it did.

and fyi:
the stroke of the 3.1/3.4L engine is 3.31
the stroke of the 2.8L engine is 2.77 i believe(i could be wrong)

the bore of the block is 3.623 for a 3.4
the bore of the block is 3.509 for a 2.8/3.1L

anyway. hope this helps.

-R

[Jerriko]

Yep, my has the big "F" on the side of the block.

'3.4 slow to go'
Also, the crank is stamped '3.1L' on the bottom of the first lobe of the crank.

'russell'
The block numbers can be found on the top of the block towards the very back where the transmission attachs. It would be located under the distributor had these motors been made with them. It appears as '31E3'. I found out through Alldata that this number tells you the size of the block and its manufacturing date.

[Jerriko]

Is there anyway to attach pics on this board? I have some for the above message. Or just email me at jamesmbeyer@netzero.net and I will send them to you.
Thanks,
Jim

[3.4 slow to go]

go to www.thenebula.com/carpics it's where I have my pics linked too. [img]graemlins/thumbsup.gif[/img]