3100 3400 BLOCK differences.....1993 Cavalier.

[iceman31061]

I'm new so be easy on me if this is on here somewhere and I can't find it.......

I recently purchased a 93 Cavalier Z24 to bracket race. The car had run hot and I had to have the heads cut. Once I got it back together the bottom end had a "rattle". With 210K on the bottom end I'm thinking about going to a 3400 block and keeping the rest of my 3.1....now the question....


What are the differences between the blocks? Motor mount bosses and things like that? What are my year limitations? Will the 3.1 heads work with a roller block? Typical questions.

Like I said, be easy on me.....if it's already on here direct me to it.

Thanks in advance

Bill Mitchell
Milledgeville, Georgia

[bszopi]

Just for clarification for other posters, the original engine is NOT a 3100, but a 3.1L MPFI.

There are some mounting differences between the 2 blocks. Take a look at the following guide : http://domesticcrew.com/installguide.htm It is for installing a complete 3400 into a J-body, but it should cover any questions you have. Any reason not to go with the entire 3400 and not just the block? Since you mention bracket racing, I'm assuming it might be something to do with the class you are running.

Welcome to the site!

[iceman31061]

No special reason not to go with the complete 3400 other than I have already done the heads and didn't want to change a bunch of crap.

Bill

[Superdave]

The Cavalier 3400 swap is pretty easy, i've done several and the power increase is great. Stock 3400 5 speed jbodies are putting down around 190 WHP, that's 90 more than stock. Typically they run mid 14's with an average driver on street tires, with a good driver and slicks low 14's wouldn't be a problem.

I'm assuming that yours is an auto trans since you are bracket racing, make sure to put a big trans cooler on that 125c. Those can be built to take some serious abuse but in stock form they don't last long.


To address your original questions, yes you can put Gen2 heads on a 3400 but you are really going to lose power potential that way. It will make some nice torque though.


Check out www.v6z24.com, lots of engine swaps and builds going on there.

[iceman31061]

I was really looking for a bolt in bottom end with low miles. I wanted a newer block that I could bolt right in with no mods. I don't even want to build motor mounts. The Z24 Cavaliers have a history of being bracket monsters. They are consistant as heck and go round after round. I was looking for an easy way out since all I can find are 3.1's with 100k+ miles on them.

Bill

[Superdave]

your best bet is going to be to rebuild the one you have then, the only 2 engines that bolt right in are gen2 2.8's and 3.1's. gen3 engines need a different front mount, the rear and trans mount are still the same though.



There is a guy on v6z24.com that is selling the front mount needed to put a 3400 in, http://www.v6z24.com/jbodyforum/3400...s-t109634.html

[iceman31061]

Thanks for all the help. I would have been fighting this for weeks. But heck if it's only the front mount would the roller bottom end be basically bolt in? It would just be a "bored out" 3.1.....wouldn't it???

Bill

[Superdave]

the 3400 block has quite a few improvements over the 3.1 but yes, same exact crank just a bigger bore to get 3.4L.

http://domesticcrew.com/installguide.htm is an old guide but it's got great info.

Are you planning on any suspension work for your z24? it took me a while to get my '91 Z24 set up well enough to be consistent. I never bracket raced it though, just T&T.

[iceman31061]

Most people that bracket race them do very little to the car. This past Saturday at Silver Dollar Raceway, in my first time even down the track in the car, I won three rounds and got eliminated at seven cars. Just to add to the story....I've just bought the car and it had been run hot...the heads were warped and needed .024 taken off to true them up. I finished the car friday night and drove it for the first time saturday just before putting in on the trailer.....I did install a manual fan switch. I trailered it to SDR and right off the trailer it ran a 16.55 quarter, then 16.61 in the second time run....first round of eliminations I dialed 16.61 and the car ran 16.612. my .046 RT and my opponents .045 coupled with that close run forced him to a 12.005 on his 12.05 dial, so I won by breakout. The car stayed there the rest of the day. If I hadn't gone red I might have made the final.

I plan on changing out the engine mounts, redo the shocks and other minor things but I want to drive this thing to the track and I live 70 miles away. If it didn't have the rattle on the bottom end I'd drive it there now.

You really need to have and automatic to bracket race. It takes the mistakes the humans make out of the equation.

I'm assuming if I do the swap my only block choice is the 1LA. Am I correct?

Billy

[Superdave]

The LA1 is the 3400, you can also use a 3100 which is basically the same just has a smaller bore. Both are gen 3 roller engines.

One big failure point on these cars is the motor mounts. I ended up welding the rear passenger side one solid, filling the front one with polyurethane and making a custom trans mount with poly sleeves. That really helped my launches and pretty much got rid of wheel hop. I don't know if you've looked but search youtube for "3500z". That's my 91 Z24.

[iceman31061]

In all my rambling on the internet your pic kept coming up in posts that I was interested in so I was hoping you'd post on my question....so thanks.

I had a camaro almost identical to yours that I lost in a shop fire last year. it was black with gray "prongs" and the 4" cowl hood. It was a V8 though.

Heck send me some pics of what you did. iceman31061@yahoo.com

I was looking for the poly mounts....of course I didn't find any. I'm not really planning on going that fast though. Just want to remain consistant.

Bill Mitchell