Crate 3.4L vs 95 Lumina LS

[Tofuball]

Parts interchange questions for you all!

I have a GMPP 3.4L with iron heads on my . . . "vehicle," and I was wondering if it would be reasonable to put the heads on from a 95 Lumina LS (3.1L Aluminum heads)? Would that make the C/R change signifigantly? What pushrods should I use, or parts should I retain?

I plan to use ARP head studs if I do the head swap, what torque spec should I use?



Also, does anyone know offhand if I could swap the front cover on?


Sorry to ask so many questions, and thanks much in advance!

[geoffinbc]

Everything will swap that is not a problem. But not everything will work together.

The aluminum heads will casue the compression to go sky high. It would be drivable on high octane gas the right cam and a good tune. But it is not recommended. Plus the heads will not work with any iron head intake you may currently be using. The aluminum heads have no options for a carb intake. You have to go with port injection.

Depending on what you are doing with the motor you can go any way you like because all 660 engines have almost 100% interchangability which is really nice.

[Tofuball]

Thanks for your reply!

Well, I'm using the fuel injection intake off a Fiero right now, but I have the entire Lumina, so I would be using the Lumina intake\fuel rail\etc.

I'm using a MegaSquirt, so don't worry about the fuel injection side of things, I can handle that :P

Any idea what the compression would go to? And does anyone offer a "thicker" metal head gasket that could offset that?

I've got a towing cam in there right now, and I don't want to run high octane gas. :P

[ForcedFirebird]

Just use the FWD pistons from the donor engine and you will be ok .
Have you checked out the CR calculator on the side bar of this site? It comes in handy with parts interchange...

http://60degreev6.com/test.php?do=start

[Tofuball]

Sweet! Thanks!

[Tofuball]

The 3.4 in the calculator has a 9.5:1 C/R

According to GMPP, my engine has a 9:1 C/R

http://www.gmperformanceparts.com/EngineShowcase/tech_specs.jsp?engId=HT34V6&engine=HT%203.4%20V6&sku=12363230&engCat=rpo

[sharkey]

the 3.4l in the calculator is a gen 3 3400 engine. what causes the high compression when swapping aluminum heads to an ironhead motor is the combustion chamber design. gen 1 3.4l motors (and the 3.4ht) use a 48cc combustion chamber and 8cc dished pistons. a 3x00 uses 28cc dished pistons and 26cc combustion chambers. compression will end up around 12.5:1.

the fix for this is simple, get a set of 3400 pistons. they will drop rightinot your motor and drop the compression down to factory 3400 specs (9.5:1).

keep in mind with this top end swap, you will need to change the intakes, accessories, possibly timing cover.

[ForcedFirebird]

Sharkey, the iron head 3.4 (Camaro) is in fact listed at 9.54:1 in the CR Calculator with 48cc chambers and 8cc dish. The 3400 is also listed as 9.54:1 with 26.4cc chambers and 27cc pistons.

Mistake maybe?

[sharkey]

i guess im wrong there, i had heard the 3.4 ironhead was 9.0:1. i have no firsthand experiance with one of those beasts.

either way, when i calculate a 3.4 ironhead short block with 27cc aluminum heads, it comes out at 13.73 compression. IMHO, thats to high for any street car to run on pumped gas. with that high compression, i would be running race gas (112 octane) or alcohol.

[ForcedFirebird]

i guess im wrong there, i had heard the 3.4 ironhead was 9.0:1. i have no firsthand experiance with one of those beasts.

either way, when i calculate a 3.4 ironhead short block with 27cc aluminum heads, it comes out at 13.73 compression. IMHO, thats to high for any street car to run on pumped gas. with that high compression, i would be running race gas (112 octane) or alcohol.

That's what tofuball is trying to say, that the 9:1 3.4 is showing as 9.54:1 on the calculator.

Yeah, I also calculated the 3.4 with 3400 heads because I found a 3.4 to go in place of my 3.1 to make the top end swap easier (mainly because of DIS). The difference is the 3.4 went down to an 8cc piston vs. 12cc in the 3.1.

If you read post #4, I suggested he will need to use the FWD pistons from the donor engine.

[bszopi]

As far as the calculator being wrong, there is a possibility. When I created it and entered the values into the database, I went off of numbers that I found via searches on the site. If someone can look at the numbers and figure out what I have wrong, please let me know and I will get it updated.

[Tofuball]

I gotta figure out what the C/R is going to be before I bother pulling everything apart to do the swap, but this is all a good starting point, thanks for everyone's input :P

[ForcedFirebird]

I gotta figure out what the C/R is going to be before I bother pulling everything apart to do the swap, but this is all a good starting point, thanks for everyone's input :P

As long as you use the coorect pistons with the heads, you will yield a "stock" CR for that engine. You said you had a donor motor for parts?

[ForcedFirebird]

As far as the calculator being wrong, there is a possibility. When I created it and entered the values into the database, I went off of numbers that I found via searches on the site. If someone can look at the numbers and figure out what I have wrong, please let me know and I will get it updated.

The calculator states the Camaro 3.4 pistons are 8cc, the family tree states 7cc. I can't verify which is correct, but if this deal goes through I will be getting a 3.4 soon and can measure the dish.

[Superdave]

As far as the calculator being wrong, there is a possibility. When I created it and entered the values into the database, I went off of numbers that I found via searches on the site. If someone can look at the numbers and figure out what I have wrong, please let me know and I will get it updated.

you should bug Ben about CC'ing a 3500 piston for me..