3.1 block swap into 96 Monte Carlo?

[TRayford]

Guys,
This is my first post here as I've had no major mtr problems until now. I have low oil pressure and metal in my oil in my 3100 96 Monte Carlo. I have a 3.1 from an old lumina with a blown head gasket but a good bottom half in the garage. Can I use the old 3.1 block and bolt on my 3100 heads, intake and 96 accessories to make this swap? I'm pretty sure I'll need to use my cam out of the 96 to use all the 96 roller valvetrain. Is this swap a simple changeout? I don't want to buy a new mtr or rebuild right now if I can keep from it. Any help with this is appreciated, thanks.

[TRayford]

A little more info,
I've been searching for more info, and ran across a chart showing the 3.1 pistons make a compression ratio of 8.9 to 1. On a 3100, c.r. is 9.6 to 1. If there is a cam change, will that much difference in compression be noticeable, in regards to the cam profiles? I'm a good "shade tree" mechanic but most of my work is on muscle car v-8's, mostly Poncho's and Olds. This problem is on my wife's car, thanks.

[Guest]

No that will not be a simple swap out, due to one major hurdle, that being the cam position sensor. This sensor gets mounted in the block, just beind teh front cover (passenger side of vehicle), the genII engine is not drilled or machined for the sensor.

The genII block also will not support the roller cam from the genIII (your 3100), due to the oiling system and lack of bosses to retain the lifter anit-rotation bars.

The passenger side front mount might be an issue, even with it being the high mounted dogbone. the block where the lower part of the dog-bone bracket attches does not share the same mount bosses between the generations.

Your best, cheapest and easiest bet is to use a genIII engine, if you want a bit of an upgrade a 3400 will drop in almost as easy as a 3100 replacment.

[TheProfessor]

you could put the gen 3 top end on the 3.1 if you use the 3.1 OBD1 computer and wiring harness
you will still need the PCM in the monte to run the tranny though
and a question for the raven............cant you just switch mounts if necessary

[Guest]

you could put the gen 3 top end on the 3.1 if you use the 3.1 OBD1 computer and wiring harness
you will still need the PCM in the monte to run the tranny though
and a question for the raven............cant you just switch mounts if necessary

No, the bosses on the block do not exist, therefore no where to attach the mount.... Now I suppose you could get a mount bracket from an older W-body that used the 3.1, and it should line up, but I have no real way of verifying this without trying it, or doing a lot of measuring.

I suppose you could use the older ECM and go back to an MPFI system, but I still feel a genIII engine would be cheaper in the long run.

[TRayford]

Thanks, exactly what I needed...

Ya'll are great,
Didn't know what route to take but that clears it up. My father-in-law's a mechanic for a wrecking yard owner so I get a good hookup on everything. I found a couple of 3100's out there but they had water in them. Could have been heads or gaskets, didn't check, but I will now. I've replaced a few 2.8's and 3.1's but never swapped anything. I guess I'll be looking for parts Monday, thanks guys.

[imported_germ]

check out....

https://www.3400swap.com

https://www.mymonte.com

http://members.cardomain.com/germsws