What is the difference between the 3.1 and 3100 engines?

[Navybass]

My car has the 3100 in it and was wondering what the difference between it and the 3.1 was?

 

Also, which engine is better? What should I watch out for?

[GnatGoSplat]

Yours is better.

The 3100 is the 3rd gen design, 3.1L is the 1st gen. Block, heads, intake, all completely redesigned with the 3100. HP increased by 20. It's still similar to the 3.1L and some parts can interchange, but everything was slightly redesigned and improved.

 

Intake manifold gaskets are what I would be most concerned about where cost is concerned. I don't know what year your car is, but you can also eventually expect the normal wear items like starter, alternator, water pump, p/s pump, etc. to need replacing sometime between 100,000-200,000 miles (some cars earlier).

[Justin]

Depends on if you want performance or durability. I'd take a 3.1 over a 3100 any day, the 3.1 has a better intake gasket design, doesn't suffer from horrible piston slap as much, and seems to last longer than the 3100, in my opinion.

[manitcor]

Depends on if you want performance or durability. I'd take a 3.1 over a 3100 any day, the 3.1 has a better intake gasket design, doesn't suffer from horrible piston slap as much, and seems to last longer than the 3100, in my opinion.

 

all that depends on what year 3100 you have, 94 and 95 3100s suffered from piston slap. 96s and higher get progressivly better.

 

as for the LIM gasket, yeah its a PITA, but at least there is a revised desgin for that gasket out (been avail since '02). Once you swich to the new gasket there is really nothing bad maintance wise for the 3100.

[Supreme Cutlass]

could you put the top end from a 3100 on a 3.1?

[94CutlassSLCoupe]

could you put the top end from a 3100 on a 3.1?

 

yep

[Navybass]

What is piston slap? What causes it?

 

I have a 94 GP.

[TeeJay3800]

Yours is better.

The 3100 is the 3rd gen design, 3.1L is the 1st gen. Block, heads, intake, all completely redesigned with the 3100. HP increased by 20. It's still similar to the 3.1L and some parts can interchange, but everything was slightly redesigned and improved.

The 3.1 is a SECOND generation Chevy 60° V6. I do not consider it fair to say the 3100 is better either. The 3100 seems to have more maintenance issues. Also, the 20 HP advantage held by the 3100 comes at the expense of low end torque. Having owned both, I would rather have the 3.1 any day. Just my 2 cents.

[jeremy]

I've owned both: 89 GP LE with the 3.1 and a '97 Cutty Supreme with the 3100.

 

That being said, both are about the same as reliability and maintenance in my eyes and I would prefer the 3100.

 

Like mentioned the intake gaskets on the 3100 should be replaced, but it is fairly easy to do.

 

FWIW: My 3100 NEVER had the "piston slap"

[94CutlassSLCoupe]

I don't have piston slap either...and mine is a 1994...

 

Intake gaskets go on 3100's when they are the orignal...

 

It seems like i see more electrical problems on the MPFI engines (ICM's)

 

The power curve is flatter on a 3100...i'll take it over a MPFI

[GnatGoSplat]

Yours is better.

The 3100 is the 3rd gen design, 3.1L is the 1st gen. Block, heads, intake, all completely redesigned with the 3100. HP increased by 20. It's still similar to the 3.1L and some parts can interchange, but everything was slightly redesigned and improved.

The 3.1 is a SECOND generation Chevy 60° V6. I do not consider it fair to say the 3100 is better either. The 3100 seems to have more maintenance issues. Also, the 20 HP advantage held by the 3100 comes at the expense of low end torque. Having owned both, I would rather have the 3.1 any day. Just my 2 cents.

 

Oops, I knew that, I don't know why I typed 1st (cuz the 1st is the iron headed 2.8L).

 

Well, the 3100 has many improvements, but none that really added to reliability. For instance, the block is stiffer, they had roller lifters, some had roller tipped rockers, and the coil and ignition module are placed in a more accessible location. For a daily commuter, the 3.1 very well could be better.

[TeeJay3800]

That's a good point and something worth mentioning. The 3100 can be easier to work on for routine maintenance issues such as spark plugs and wires. They are MUCH easier to do on the 3100 because of how easily accessible the rear plugs are.

[Navybass]

No one answered this.......What is piston slap????

[jeremy]

No one answered this.......What is piston slap????

 

http://www.pistonslap.com/whatisit.htm

[GnatGoSplat]

It's a noise poorly fitted pistons make when their skirts hit the piston walls.

[Pabz]

Looks like you beat me jeremy.

[Navybass]

Thank you. Now, how do I know if I have piston slap?

[GnatGoSplat]

From the audio clips I've heard, it sounds like knocking that varies with RPMs. It's pretty loud, you can't miss it.

[94CutlassSLCoupe]

you could also have a simlar noise that some people call piston slap that is really just front pump cavatation on the transmission...that goes away if you drive the car a block though

[digitaloutsider]

The 3100 also has the provisions for the flux capacitor.

[jeremy]

The 3100 also has the provisions for the flux capacitor.

 

I can't believe that no one mentioned the most important feature of the 3100 until now....thanks Shaun

[Crazy K]

What else do you have to do?

Assuming either you replace all the upper engine stuff to put 3100 parts on a 3.1 block, or...

 

Drop a 3100 motor in whole...

 

What else must be done? does the 3.1 computer run the 3100? (BTW, I assume that swaping the upper parts or the whole motor would have the same result, please let me know if that is incorrect)

I once read that all you have to do is extend any short wires...., but on another you must use the 3100's computer AND an electronic transmission that matches.)

Curious..... -ken