Gen I 3.1L V6 POWER MODS

[90CamaroRS]

I want to do a complete rebuild from the ground up of the engine, and I want to make some considerable gains to the engine while I'm at it. I want to keep the original block, original intake, and it has to be normally aspirated. Everything else is up for change.

What I know:
-Increase compression ratio
-Increase air flow into engine through port and polish, K&N air filter, bigger throttle body
-Increase exhaust flow through cat back, headers
-Increase spark through Bosch Platinum +4 sparkplugs
-Increase fuel through increase in fuel injector rate
-Increase fuel pressure, penny trick anyone?
-Increase bore by increasing to 92mm from 90mm and using those pistons available from summit
-Decrease weight in rotating assembly, pulleys, and drivetrain
-Add cam
-Convert valvetrain to roller
-Decrease engine operating temperature with 160/180deg tstat
-Tuning ECM

Beyond that, I'm out of ideas, and do not know exactly what parts to get, like what cam would be good to provide more power but still keep mid range power that the 3.1L is so good at?

Will be tearing down the engine within a few weeks and will be sending it off to a machine shop to have the block and heads treated, and then the mass parts ordering will begin

Any help and ideas would be killer!! Thanks guys!

[bszopi]

Welcome to the site. With that said, is this the engine in a Camaro (as your name suggests)? If so, its a Gen 1 engine, not a Gen 2. Gotta know exactly what we are dealing with before we can make any suggestions. But, I will tell you that Bosch spark plugs (especially the +4s) do NOT work well in these engines, and usually cause more problems than good. Also, don't mess with the stat, as it has been proven that the lower stat temp really doesn't help out at all.

[mickaz]

with those mods you might get 170HP not bad but the top end will be your biggest restriction. you need more airflow witch btw 3.1 top end will not provide.

I suggest getting a 3100 topend the looks will be a little different BUT you will get 200HP out of those mods because of the added airflow that will make your Rev Higher!

oh and Btw the platinum +4 is Not a modification on those car. Stick to the try and tested OEM plugs

[stevalier]

im sure this might help but is its auto make it a 5spd

[Superdave]

If it's a gen1 3.1 ditch the heads. With the amount of money you'll spend trying to get decent flow out of them you could bolt on a stock 3100 or 3400 top end and come out ahead.


If you use the gen3 top end, use 3100 pistons and the gen3 headgaskets to end up at about 9.5:1 scr. The Comp 260H cam works well in this combination and you have headers available but you will need to slot the mounting holes a little.

decent info here: http://www.thirdgen.org/techboard/v6...eads-info.html

[90CamaroRS]

Alright so:

NO to different tstat
NO to Bosch Platinum +4 spark plugs

Correction:

Yes my bad, I got excited about posting and hit "I" one too many times to make it read GEN II instead of GEN I.

And:

Thanks for the site SuperDave, so I can or can't use the 3100 and 3400 heads on the 3.1L block directly as a bolt up? I;m trying to decipher what the site says for sure or not haha. And what about the 3.4L heads? Are they even an improvement and would they work with a distributor and the stock 3.1L plenums? I know that it will restrict the air flow, but I'm going to port and polish the plenums that come stock with the 3.1L so I should get some gains there, but I want to keep it looking stock so for me another plenum is a no go.

I wish I could find a T5, but a good V6 T5 is hard to come by around here...

And what about a different TB? I wish I could get a bigger TB, but I have to make sure that I do not interfere with the TV cable setup or I'll be getting a new transmission. So far I haven't heard of a larger TB that will work.

This car is a DD so its got to be driveable, its not a strip car by any means. I am hopefully getting another car to drive so I can take time off from the Camaro to take it all apart and work on it.

Has anyone ever overbored their engines just a bit? I saw 92mm pistons on summit but cant find them now for the 3.1 but I can get them for a 3.4 and do it that way. But that would just make it a 3.4L wouldn't it? haha Well except the stroke part of that...

And do I need to pay any attention to keeping the pistons dished or can I just put any piston in and not have to worry? Whats the operating difference between dished, dome and flat pistons? I assume dome is getting into Hemi territory...Aren't the ones in my engine now 8cc dished? And how is all this gonna affect my CR?

Oh boy, ok thats enough questions for now

[geoffinbc]

You can make your 3.1L into a 3.2L by doing a .040" overbore. But that is it. You cannot make it a 3.4L. Keep the stock style pistons so you can keep the daily drivability your after.

Yes the aluminum head stuff is great and flows a bunch more. But like you said your goal is to keep it looking stock. Your intake will only work with iron heads and that intake is required if your keeping the distributor. Plenty of people here are going to urge you to drop the cash and time on doing a full top end swap to Gen III aluminum stuff. But I have to keep reminding them that does not always fit budget and time constraints and sometimes emissions laws or personal skill and comfort levels. If you said your goal was to make your Camaro as fast as this engine family would allow then I would be on board with telling you to do a 3500 Turbo swap. But obviously that is not your goal.

You will be able to get this engine to a healthy 3.2L making nearly 200HP and over 200LBS of torque and even if you to a full tear down rebuild of the block and heads you will still be able to come in under 3500 bucks. I have a 3.2L build I did on my Trooper that I think you should take a look at http://members.shaw.ca/betterthanyou/isuzueng.htm I have a cost sheet near the bottom too.

[mickaz]

better then you did you dyno that engine? or did you tried it on a drag strip?

[geoffinbc]

Drag the Trooper? LOL no I haven't but I have drag raced the S-10 a few years ago and it ran a 15.9 on street tires.

[Superdave]

I'd just find a 3.4 from a 4th gen Camaro and throw that in with a set of headers, comp 260H cam, better valve springs and a set of 1.6 rockers. you might make 175 HP or so. Probably cheaper than having all that work done to the 3.1, start off with 20 HP more from the factory.

Down the road if you want to go faster you can use the 3500 top end at least.

[geoffinbc]

Yea that is true. But 3.4L's seem to be harder to find these days. But it is worth a look. It is also nice to be able to build the motor on a stand and still have your vehicle to drive while your wrenching on it.

[90CamaroRS]

I thought the 3.1 and 3.4L engines were the same except for the bore? So why it is that a 3.1 can only be made into a 3.2?

I've had people tell me to try and find a 3.4L engine that I could use but there are none around here to get, and the ones that I could get would easily eat half my budget.

betterthanyou, I noticed that you paid a shit ton for your machine work on your build sheet, I got everything that you got pretty much priced around half of what you paid, the guy told me only $50 per head to do what you had done. And you even spent a lot of money on other things that I probably wouldn't need like your clutch. Oh and thanks for the site, its great.

Pretty much I'm gonna need:

-From the machine shop
-Block blasted/hot tanked
-Cylinder walls bored
-Cylinder heads milled
-Rotating assembly rebalanced, machined with new main and rod bearings
-New cam machined with new cam bearings
-Heads ported/polished/ refinished
-Intake manifold ported/polished
-Plenums ported polished

-From the store/Summit
-Replacement pistons
-New cam
-Oil with filter
-Antifreeze/coolant
-All gaskets
-RTV sealer/Anti-seize
-Head bolts/any bolts that I end up breaking =p
-Rings
-New oil pump, no point in keeping the old one if its all coming apart
-Water pump depending on how mine is
-Replacement pushrods
-Replacement lifters
-Replacement rockers
-Sparkplugs/ wires/ ignition coil


After that I should have pretty much everything I need.

If I could keep the stock look of a 3.1L without switching to distributorless ignition and a different plenum and all the good stuff that comes with an engine swap like your saying SuperDave then I would look more into it, but in the end even if I could find a 3.4 for cheap, I'm sure that I'd still want to stick with the 3.1 anyways. I think its more fun to make what comes from the factory stock perform as best as it can than use something thats out of a different car, or even a different factory if were talking about a 3.4. The cheapest 3.4 I can find in reasonable distance from my house is $700 bucks, and the junkyard wants a core too, so for what I could get one for I could probably do up my 3.1L cheaper.

Something else that I was wondering about today at work....Has anyone ever stroked their V6 on here? If I'm going to bore I might as well stroke while I'm in that far, I mean if I could. I haven't looked to see if there are any different connecting rod lengths on Summit yet, but as far as I know I have the biggest stock stroke size for a 60* V6 engine, I don't think even the High Value engines have longer strokes.

But then I have a whole other set of problems to worry about changing the piston compression height and messing with the CR even more than what a cam would. Just a thought, If I could do it I would love to, it would still make it very driveable like it needs to be as my DD, but give me the extra power that I'm after.

As for a cam, SuperDave, would that 260H cam give me a good boost in power with a proper tune and still maintain pretty much the same powercurve? What I mean is not make the engine make all of its power in the higher RPM's, which would be a problem because of how well the engine breathes at anything over 4500RPM. I like how you can pretty much get around anywhere with this engine from about 2-3000RPM and would like to keep it somewhere close to that.

Thanks for the help so far guys! I know I'm asking a lot here...

[geoffinbc]

Well if you paying HALF of what I paid then I would be second guessing the machine shop. Unless he is a close friend and is only charging you for wear on his machine and the cost of electricity. Machine work is like most other things. You get what you pay for. If your getting the heads completely rebuilt for $50 and this is not your best friend then I would be questioning what, if anything, he is actually doing to the heads. I mean to MPI the heads for cracks, cut all the valve seats and grind all the valves and then install guides and machine them to proper clearance and also mill the head surface and do all that for $50 bucks then I would really question it. I would be willing to bet 50 bucks only covers milling the heads.

You cannot make a 3.1L into a 3.4L because the 3.1L is not cast with cylinder bores that will allow an overbore large enough to net you a 3.4L. A 3.4L is the same engine other than the block casting. It would be like trying to make a 305 into a 350. The stroke is the same but the 305 cylinders cannot be overbored to 4" to make a 350. Stroking can only be accomplished by offset grinding the crank. The next common rod journal with a TON of rod selection would be a 1.88" Honda journal or getting a 3500 crank with 2.25" journals and offset grinding them to stock 2" journals. Either method would require a new piston/rod combo. I am not sure if there is any off the shelf combo that would work so custom stuff may be the only route.

The COMP 260 cam will behave like stock but will make a ton more torque and will rev higher without falling on its face like the stock cam. Buying the K kit from COMP is a great deal because all the parts you need to make it work come in one box for a hell of a price.

[90CamaroRS]

Alright, that makes sense, just didn't know, you learn something new everyday! So if I bump it up from an 89mm bore to a 90mm bore then it will increase the displacement from 3.1L to 3.2L? Displacement isn't a big deal for me, just wondering about it. I figure if I'm going to pay money to get everything done to the block and get the cylinder walls refinished then I might as well bore it out a little bit.

I guess I'll have to look into the 260 cam then, that sounds awesome.

The thing now that I'm wondering about stroking is that if I increase the stroke a little bit, and get a 260 cam and 1.6 rockers, am I going to be in trouble? If a stroke is even something possible for this engine without custom work that is...

[Superdave]

Where are you located?

There are a few 3.4 Fbodies in the yards around here, i keep stealing parts off of them though.. lol


I think you are still too worried about displacement, the gains from a 3.1 to a 3.2 are going to be like 1 HP and 2 ft-lbs. increasing the stroke is going to require clearancing the block and custom pistons. Not really a cost-effective way to gain a few ponies.

Typically a shop will bore out the block just enough to clean up the cylinders, .020"-.030" is the normal range on a 100K+ mile engine. You'll just need have them order the correct pistons and rings once it's all done. Your rods will need to be reconditioned and swapped to the new pistons as well, that can get pricey. I had a set done this summer for around $200.


I don't know if it's been mentioned but talk to Forced Firebird about porting and cams, he's been able to get some pretty decent numbers out of the Iron heads and can also hook you up with a custom ground cam that will fit your needs better than an off the shelf grind.