Was looking and found that the 2.8 only has 8.5:1 compression ratio Is there anyway to jack it up to around 10.0:1. I heard you could stroke it with a 3.1 crank, was wondering what would that bring me to. Also would a 3.4 crank work or is that a 90* engine??

 

3.1 and 3.4 have the same stroke. you cannot throw just that crank in there with 2.8 pistons. but, you can do 3.1 pistons and crank...get the extra cubic inches but you'll still only have about 9:1 CR

 

If I did the pistons wouldnt that be more bore?? What if I used the crank and rods from the 3.4, still 9.0:1?? If so is there any company that makes say dometop HC pistons??

 

2.8s and 3.1s have the same bore. crank, again is the same between the 3.1s and 3.4s. the rods are the same in any 2.8, 3.1, or 3.4. i don't know of any company that has over the counter dome pistons for our motors. you could get some custom made but that's not cheap.

 

So in other words theres basically no way to get the compression up to 10:1

 

mill the heads, dome pistons, or do a 3X00 conversion

 

go to the 3.1 rotating assembly, mill the heads and run the thinnest gaskets you can find. thats about the best you're going to do unless you get custom pistons. i have 10.75:1 compression on my 3.1 but that's with custom pistons. the heads have not been milled or anything, either.

 

If the heads were milled wouldnt tht make the combustion chamber bigger resulting in less compression??

 

no, it makes the chambers smaller

 

Im not understanding how it would be smaller. Your removing metal from the heads right?

 

Whats a 3X00 conversion??

 

yes you are removing material from the heads but not to make the combustion chambers larger

watch my cheapo text drawings here


you have a stock combustion chamber shaped lets say like this


__
| |
| |
| |


so you mill the heads what it does to that combustion chamber is now make it like this
__
| |
| |

again this is cheap text drawing so know it doesn't look like the combustion chamber but still should convay the same idea.

your removing material from the bottom of the head not out of the combustion chamber itself
so sinec your cutting off the bottom part of the combustion chamber there is less area in the combustion chamber

 

3100
3400
3800
it refers to the displacement of the motor
3100 = 3.1L
3400= 3.4L
3800= 3.8L
though I'm not sure how well a 3.8 would fit. haven't heard anyone talk about it as I can recall maybe someone else can shed some light though

 

Got it! Completely understand now. Should i find some heads to practice on first?? Would it be better to mill the heads or fly-cut them?? I took a machining course for 3 years and in my opinion the fly cutting would be better but since their cast heads Im not all that sure. Should I have them surface ground after for a smoother finish? How much should I take off, thinking maybe .050 - .075. Never seen how small the chambers are on these heads or how close the valves come to the piston. Im gonna be buying an aggressive cam sometime soon and most likely 1.6 rockers. The drawing helped for how simple it was, thanks.

 

you will not be milling the heads yourself unless you have access to and experience using a resurfacing machine. that is all we are talking about...resurfacing them. if i remember correctly, the chambers are 52cc, stock.

no, you cannot use anything from the 3800/3.8s. that's a 90* V6 instead of our 60*. even with the 3100/3400, i think they still only run about 9:1 CR. you have to change over to those pistons if you're going to run the aluminum heads off of one of those motors.

 

^^

yes, 3X00 would = 3100/3400 conversion. For some reason I didn't even think of the 3800 ( ) only concertrating on the 60* engines

 

I have used several machines including surface grinders numerous times. How much should I take off tho? What gains if any can I expect? What would the CR be raised to by taking off a certain amount?

 

I think the rule of thumb is .030 before the intake needs to be machined to maintain the correct angle between it & the heads. also, look into custom legnth pushrods, as you will be decreasing the legnth between the lifters and the rockers (keep that valve geometry good)

 

If I left the pushrods alone would the valves open more, seeing as how the rods would theoretically be .030 longer?

 

maybe, depends on how much clearance the slots in teh rockers have from teh studs keeping them in place. One solution is a product called "long slot" rockers, to allow more lift by letting the rockers have more movement upward.

Are you going for a powerful n/a motor? why the quest for high compression?

 

Ive attempted to "boost" my car already. Was gonna do a M90 and custom intake manifold but my blueprints were caught in a fire. Cant find the right turbo and dont wanna try to make headers again. I got a new plenum to replace the upper and middle thats almost done, so I figured why not N/A the hell outta it? Got lots of plans All I need ios alil more money to finish my intake and then after that I can do the heads, prolly get them ported and polished while their out, new valves,springs,rocker,racing cam and timing chain. Pace setter headers minus the Y-pipe, no cat, duel pipes into Dynomax super flow mufflers, MSD coil and 6AL box, accel 8mm wires, Denzo Irridium plugs. I got a couple questions for my fuel system tho. Venom makes a pump but it says its for 88 and up, is there a differance? They also make a performance modual Venom 400 also for 88 and up. Would those parts work? What do yall think about my plans?

 

milling the heads (having standard length pushrods) will NOT give you any more lift. lift is only differenciated by lobes on the cam or rocker ratio. you almost have to run the pacesetter y-pipe with their headers because the driver's side header actually points back towards the front a little bit so that the y-pipe runs in stock location under the oil pan. if you try to run a custom pipe off of it...you will have more than a 90* bend at that point which will be very restrictive. which cam are you planning to run with this setup?

 

Lets say I get my heads milled to the maximum amount they can be milled to. What will be my compression ratio after this on a 8:5:1 3.1L?

 

Intake duration 292
Exhaust duration 302
Intake @ .050 258
Exhaust @ .050 262
Intake lift .510
Exhaust lift .510
Lobe seperation .106
Valve lash .020

What else would I need to run this cam? They have a kit with lifters and such to go along with it so Im thinking I should get it.

 

Its a solid cam. I could get a solid roller with more lift but its more than twice the price of the one mention in my last post.

 

i don't want this to come out the wrong way but if you don't know how to do things (such as "mill the heads") or you don't know what else you need to do when you change the cam...I might reccomend not going with a cam that extreme. when you get into running things like that, often times you will require a lot more maintanance on your motor and often times it will call for someone with experience to work on things. solid cams will require more, regular, attention to the motor. also, a cam that size, you're probably going to want a lot more than 10:1 compression but then you get into other problems (such as not being able to run the motor on pump gas). these blocks are not setup for roller cams so, if you wanted the solid roller cam, you'd need even more work done to the block in preperation for the parts to be installed. just food for thought.

 

i love smart people

 

I know a good amount about engines just when it comes to valvetrain and fuel injection I get kinda lost. Ive never heard of milling the heads before, didnt know you could do such a thing. I wanna get this engine to 175Hp and over 200 ft lbs but theres just no aftermarket. If it was for say my Charger I got it over 425ft lbs just by adding longtube headers and a differant intake manifold and carb. But since thers nothing to really choose from with these cars you have to do everything yourself and its a PITA to me. Seeing as how I got a V8 I think its would be sweet to get a Naturally Aspirated V6 to some high performance level, I mean when a 2.5L Ford Probe has 210hp and my 2.8L has 135 it flat out pisses me off. I dont want it to run 9's but I do want it to make it down the track before I fall asleep. When I ran it on my ghetto strip my time was a high 16. I want it to run high 14's when Im done or atleast be able to beat a civic. Ive heard plenty of people say I dont know **** about cars and that I shouldnt be doning what I have planned. Honestly I dont care. I wanna do it and thats all that matters to me. If something blows up, oh well its my fault and I dont blame anyone except me. Im asking opinions and trying to get information. Instead of telling me I dont know anything about engines maybe you should explain it to me so that I do for future referance? I grew up with my mom and figured out everything by myself just by tearing lawnmowers and such apart to see what everthing inside did. I moved up to cars when I bought my first one and that just happens to be this Camaro. I tore that engine apart atleast 4 times all the way down to the block. But theres just some things I cant learn by myslef and that is why I ask people on here. You can either help me out or not its your choice. If not Ill just try and find someone else to explain it.

 

sorry, like i said, i didn't want that to sound rude. i'm just trying to save you some trouble down the road. i'm simply recommending that you make sure you do all your research and know what all you're going to be dealing with. i understand what you mean about trying to make one of these motors powerful and not having the best variety of parts available. i've been there...still dealing with it. i'm willing to help people out and share some knowledge, though.

 

First off, to dispel a myth or rather give another approach...

If you were to swap to a pair of aluminium heads, you could run the stock iron head pistons and get around 11:1 static CR, slightly more with the longer 3.1L stroke. 2.99" for the 2.8 and 3.31" for the 3.1 (and 3.4).

There's quite a bit involved in doing that swap though, but IMO worth ever blood drop, sweat drip and tear.

Now staying iron head, because it's easy.....

You want 160 HP and 200 ft/lbs of torque, Ubber easy. Get a 3.4L from a 4th gen F-body '94 to '96 model years, they made those exact numbers (a little more torque IIRC).

If you want more, which I know you will, get some headers, port the intake/heads, cam swap (MANY to choose from), better valves, better valve springs, oiling tricks, lighter rotating/reciprocating assembly, under drive pulleys, etc.

I wouldn't say there is no aftermarket for these engine, you just have to learn to adapt other parts.

 

2.8 = 8.9:1 compression
3.1 = 8.5:1 compression

 

Depends on the year some of the earlier 2.8s were 8.5:1. I've never heard the 3.1 being said to have 8.5:1 though, most cases it's listed as 8.8 or 8.9:1

 

Dont have the time for an engine swap. If I did it would be done already. Dont have an engine crane either.

 

Then you don't have time to get the power you want.

The 3.4L engine swap will be much quicker to perform than any internal engine work. espescially to get the same numbers.

Even a head swap will probably take longer, especially anything other than swapping on other iron heads. Add in cam swap, rocker swap and set-up, etc, and you're at the same time or longer than a complete long block swap.

The 3.4 swap can be completed in a weekend, and takes minimal tools, can be done with mostly hand tools.

Engine cranes can be borrowed or rented.

To swap any pistons or crank, etc, you'd have to pull the engine anyway.

 

Cant find any places that rent them out, only sell. If I could find someone to sell the car to I would and just take the money and dump it into suspension on my Charger. But nooone up here wants one thats a V6. Well Im in the process of replacing my stareter at the monment so got get to that.

 

I'm not sure where you are, but places like "Rent-all" and others also rent engine cranes.

Look for places that rent augers, back hoes, cement mixers, chainsaws, scaffolding stuff like that, they usually have engine cranes as well.

 

For that matter, if you can't find an appropriate large tree limb to hang a come a long from, $50-$75 bucks worth of landscaping 4X4's, a post hole digger and some 3" sixteen penny nails will whack together a suitable overhead from which you can push the car under and attatch a come along for the purpose of pulling that engine.

As far as that giant solid lifter cam? Waaaay too much for the engine to handle, I'm sure the heads would need valve guide mods to handle the extreme lift, and the ECU would have a fit with it. Never get any idle vaccum for the brakes either.

To get what you want the most cost effective bang for the buck is going to be a shot of nitrous. Do a search on the username of "Drew" on this V6 board.

 

not to mention the 4,000 stall convertor that would be neccessary to make it even remotely streetable.

 

yes and no.
He will actually get a totally minute more lift, as the heads are closer to the block, and the camshaft. So the push rods would be a tad too long for the new demensions...

Will it equate to anything measureable at the valve? hell no. But technically yes, the push rods, with a shaved head, will grant more lift just doing math...

 

Well if that cam is too much like you say(taking yall's word for it). Can you find me one that is ment for mid and upper ranger torque/horsepower? I got a nitrous bottle what else would I need besides a jet and solenoid? My intake still isnt ready so I can have a hole drilled for it Im guessing or should I buy the plate design that comes in the kit? Why is the head swap so difficult? Do they need machining to clear the intake and such? What engine do they come off of? I got a junk 3.1 Lumina at a friends house that might have them cause the texture of metal definately looks differant. Whats a good weight reduction, already removed A/C.

 

Charger,

As far as a cam goes I'd look for something in the .400-.450" lift range with no more than 215-220* duration @ .050" lift on a 112-114* lobe center. The Melling MTC-5, or some of the Crane grinds come to mind. Just be sure to use the valvesprings they recomend.

As far as going with spray, you don't need to drill a hole in the intake unless you are talking about the boot ahead of the throttle body, you can place the nozzle there.

The front wheel drive versions of the 3.1 did use aluminum heads, however, there are several reasons it's not quite a bolt on. The heads will from what I understand physically bolt to the Camaro's block, but they require a completely different intake manifold, the front wheel drive manifold has no hole for your distributor to go through as they used distributorless ignition.

Problem #2 is the front wheel drive heads have much smaller combustion chambers and require the use of the front wheel drive engine's pistons......not exactly a weekend top end type job.

There is nothing wrong with doing a different intake on your existing setup if you have the fab skills. Just plan that to get maximum results from your intake you need to open up the exhaust with some headers as well.

Good luck and keep us posted!

A couple nitrous threads!https://www.thirdgen.org/techbb2/sho...hreadid=254304

 

again, you will not get more lift because of milling the heads...i don't care what pushrods you use. the only way you will get more lift because of this is if you don't adjust the rockers correctly (you set them too tight)... you will get more lift but the valves won't close all the way. that will utterly distroy any hopes of making any horsepower. if you run a short pushrod...your rockers will look like this (exaggerated):
|\ (vertical line being the valve stem)
if you run a longer pushrod...your rockers will look like this (again, exaggerated):
/
| (the roker above, and the valve stem on this line)
see what i'm saying? you have to set the valve lash properly regardless of what length pushrod you run. that means that your valve lift will always be cam lobe lift times rocker arm ratio.

eric, you're right, the aluminum heads will bolt directly to the rwd block. the problem with the intake is that the distributor (base under cap) hits the rear most runner. these motors, the dist. doesn't go through the intake manifold like on small blocks and stuff.

 

AM91.. good drawings lol. They do help. Is there anyway to explain the problem with the heads/intake/distibutor any better. Im having trouble understanding it. I was making a base manifold before but couldnt figure out how to keep injectors in the manifold and the rails securly to not have gas spray over everything and destroy my car. Actually I think you (AM91) said that if I didnt know how to do that I shouldnt be making an intake. Again if you explain it Ill understand, if you dont wanna take the time to its cool, Im sure its a PITA to explain. I dont mean anything against you by what Im saying cause I appreciate all the info given so far. Ill have my blueprint for my intake up tommorow so that all V6ers can use it if desired. It will replace the upper and middle plenum. There is slight modification needed tho. In order to make it less weight and smaller angles its needed to make custom fuel lines. I really hope this intake works better cause Im dumping paycheck after paycheck into it lol.

 

which problem with the heads/intake/dist.? the fwd heads and fwd intake with the dist. hitting the intake? before i try to explain....please specify which problem. lol. i don't think i said anything about not making an intake manifold...did i?? the base is/will be quite a bit harder to build than an upper or even the mid section. there are more (and more critical) surfaces that have to be aligned properly and be flat. that is part of the reason i haven't messed with anything other than an upper, so far. i might be building a base but it will be very time consuming and could be a little more pricey, also.

 

The aluminium top end/distributer issue, is a big one. The rear most runner needs to be almost completly cut out to clear the distributer, if I had pics scanned I'd show you. I already have a stock 3400 LIM that is clearanced for the distributer, just to see how much it would take.
I was hoping that I could get away with a mild clerancing, which is no where near the case.

More info as I get it.

 

Mainly with the distributor. If my intake is shorter maybe it could work out? What base manifold would I use and would I have to change anything else?

 

...not if he adjusts the rockers for the proper preload so the valves don't hang open...

 

that's why I said yes and no.
the less distance will put more load on the rod, meaning the rockers would need to be adjusted, but also increase side-side movement, as the rockers would be sitting higher, and more on the bare shaft and not on any sort of guide. Granted yes, I am exagerating everything, as it would be mere hundereths of an inch. But it still holds true.

 

valve stem is still only 1.5 or 1.6 times the distance from the pivot point (aka rocker stud) than the distance to the pushrod. it is a ratio....not a variable. it will ONLY open as far as the rocker ratio will allow it (times the cam lift). "mere hundereths of an inch"....so...are you telling me that if i mill my heads, i could get .500 lift on the intake side rather than .484?? that's what you're saying but it is not true regardless of the angle of the rocker arm. too much angle on the rocker will only cause you problems (if its enough) it will never help you with anything (including lift numbers).

if you build a base intake manifold (69charger), and build it with the distributor in place...you can make it work fine. the upper section is not where the problem is, though. actually, if its lower (closer to the base), it might cause more problems...depending on how its built. you need a base manifold from a FWD car/van. that, or a custom built one. you have to change the pistons (i'm not sure if you're including that in anything else or not.

 

sorry, I meant that the valve would have more of a preload, and be open farther than it should be at any point.