Some insight into the 3.4L OHV RWD motor

[Mad Max]

Re: Some insight into the 3.4L OHV RWD motor

Thanks for the welcome. I am actually going to tune the injection before I change to carbs. My real plan is to install a dual quad cam 3.4 in a RWD chassis and set it up with stand alone mega squirt and tune it to max performance fuel mapping. They have 215 HP stock, I think 225 would not be unrealistic. Maybe with headers and exhaust, 235. It would definately be different. Or.... I have 3 Olds diesel 4.3 V6s. A tubo diesel 4.3 with a 5 speed? And funny gas? A 14 second diesel? Uh huh.:burn:

[louie138]

street legal

just want to be sure but what makes this 3400 swap illegal? is it the fact that rk sport headers arent street legal?

[Bandit127]

Re: Some insight into the 3.4L OHV RWD motor

Ok, I've been reading this thread a few times, but I just want to have a direct answer for a few questions.

Heres what I am working with: 3.4 (obviously) and I want to put the heads and intake off of a 2000 Malibu 3.1. Its the intake where the heads are split in half and the lower intake manifold make up the other half. Just giving more info, more the merrier eh?


1.- Will this bolt straight on? Or will I need to change my pistons? I remember reading something about running up to 12.1 compression ratio if I didnt, but I think that was on the 3500's.
1.5- Are the stock pistons in the 3.4 flat tops or dished? Everywhere I look for piston I find dished, I havent taken the heads off before so I dont know yet.

2. What is the 3.4 stock crank able to handle safely with the longest life possible? My goal is 250 rwhp, not alot but plenty to move you when needed, and I think its easily achievable if I put my money in the right places. (I work at a shop so labor is free AND my boss builds racing engines for dirt circle tracks, but wants me to do research on my own, which is fair.) I'm not going to drop the money for a company to make me one, so if 250 is still to high then I'd like to know now before I start investing in cams and such.

3. Obviously I'll need to use the 3.1's pushrods, since the heads are taller, but is there anything else I need to carry over?

I'll need new fuel injectors, probably will get 24lb/hr injectors, and my fuel pump is putting out only 38 psi at the fuel rail so that'll need replaced. Anyone who has done this before, is there any thing else I need to move too?

The throttle body cables will still be in the same relative location, so cables wont be an issue. I already have a cold air intake and pacesetter headers installed, and we have a chassis dyno, so I will put accurate hard data up with what changes this head change will bring, my primary goal at this moment is not get the car stranded for a week or more because of a planning oversight.

Thanks in advance!

[Forced_Firebird]

Re: Some insight into the 3.4L OHV RWD motor

Ok, I've been reading this thread a few times, but I just want to have a direct answer for a few questions.

Heres what I am working with: 3.4 (obviously) and I want to put the heads and intake off of a 2000 Malibu 3.1. Its the intake where the heads are split in half and the lower intake manifold make up the other half. Just giving more info, more the merrier eh?


1.- Will this bolt straight on? Or will I need to change my pistons? I remember reading something about running up to 12.1 compression ratio if I didnt, but I think that was on the 3500's.

More than 12:1. 3500 heads and RWD pistons will net about 11.5:1.

1.5- Are the stock pistons in the 3.4 flat tops or dished? Everywhere I look for piston I find dished, I havent taken the heads off before so I dont know yet.

Dished. 8cc's

2. What is the 3.4 stock crank able to handle safely with the longest life possible? My goal is 250 rwhp, not alot but plenty to move you when needed, and I think its easily achievable if I put my money in the right places. (I work at a shop so labor is free AND my boss builds racing engines for dirt circle tracks, but wants me to do research on my own, which is fair.) I'm not going to drop the money for a company to make me one, so if 250 is still to high then I'd like to know now before I start investing in cams and such.

Crank is nodular iron and will easily hold 250hp. The gen 1 block starts getting weak at about 450-500whp since the mains will start stretching, and the only block I have known to fail was a local making 340hp N/A (highly modified) in his 14:1 SCR Midget car. It split along the lifter valley.

3. Obviously I'll need to use the 3.1's pushrods, since the heads are taller, but is there anything else I need to carry over?

No, the Gen 3 pushrods are too long. You MIGHT be able to get away with the Gen 2 pushrods (think Cavalier 3.1 from the 90's) MIGHT work depending on your cam manufacturer. Best thing to do is get an intake and exhaust pushrod after the long block is assembled and check the pre-load. If they are too short/long then obviously custom ones are in order. You will need about 1-1.54 turns of the rocker mounting bolt from zero lash.

I'll need new fuel injectors, probably will get 24lb/hr injectors, and my fuel pump is putting out only 38 psi at the fuel rail so that'll need replaced. Anyone who has done this before, is there any thing else I need to move too?

24# injectors won't go well with your stock tune, are you planning on swapping out the ECM to something tunable? The 93-95 ECM/PCM's have zero support. If you DO plan on swapping the ECM for an OBDII, OBDI, or MegaSquirt, I suggest you go ahead and leave the stock shortblock and use the higher compression the 3500 heads will give you. It will run on pump gas ;)

The throttle body cables will still be in the same relative location, so cables wont be an issue. I already have a cold air intake and pacesetter headers installed, and we have a chassis dyno, so I will put accurate hard data up with what changes this head change will bring, my primary goal at this moment is not get the car stranded for a week or more because of a planning oversight.

Not really the same location. The FWD TB's pull from the front and therefore will require a longer cable.

Thanks in advance!

Your Welcome, and welcome to my 60 degree v6 world :p

[A fireman]

Re: Some insight into the 3.4L OHV RWD motor

If I have an entire 3100 block from a mid 90's pontiac will I have all the parts there that i need excluding the tuenable PCM and headers? I have located a junked car ( i belive its a grand AM) and there is no damage to the car around the engine bay. The owner of the yard thats keeping it said i can pull what ever i wanted/need from it so here is what i think i will need

UIM/LIM
heads,
valves
rockers
pushrods
valve covers
fuel rail

should be everything ill need to pull right?
other things
megasquirt
pacesetter headers

will i need to buy a new head gaskit and if so for which engine the 3.4 or the 3100?
thanks everyone

[Forced_Firebird]

Re: Some insight into the 3.4L OHV RWD motor

Head gaskets need to match the pistons. The FWD pistons are .020" proud of the bore, the iron head 3.4 pistons are .010" in the bore.

[A fireman]

Re: Some insight into the 3.4L OHV RWD motor

so by keeping my L32 pistons use a L32 gasket. This is going to sound stupid but, can i just reuse the one on my engine if its not damaged taking the heads off?

[Forced_Firebird]

Re: Some insight into the 3.4L OHV RWD motor

Absolutely not. Once a head gasket is compressed, they are no good when removed.

You also should buy new head and LIM bolts as well.

[mdenz3]

Re: Some insight into the 3.4L OHV RWD motor

If I do the 3400 heads, with the 3400 pistons on 3.4L shortblock, will it run untuned? At least enough to hold me over a few months until I am ready to goto megasquirt.

[Forced_Firebird]

Re: Some insight into the 3.4L OHV RWD motor

hold you over, yes it will buck and kick...

[mdenz3]

Re: Some insight into the 3.4L OHV RWD motor

Stupid untunable PCM...

Some one really needs to crack them, seems like it shouldn't be much different than the LT1 PCMs.

[Guest]

Re: Some insight into the 3.4L OHV RWD motor

I am looking for a solid lift full racm for a 2.8/3.1/3.4 chevy engine could someone out there tell what cam would be right .

[A fireman]

Re: Some insight into the 3.4L OHV RWD motor

wrong thread this isnt a cam thread. but check compcams they may have one for you.

[Forced_Firebird]

Re: Some insight into the 3.4L OHV RWD motor

If you have a 93or a 94-95 manual car, there is a tuning option for you - swap over to the GM OBD1 1227727 ECM.

[Forced_Firebird]

Re: Some insight into the 3.4L OHV RWD motor

All out race cams should not be bought on the shelf, ask Max.