Needed: DOHC vs Pushrod Advice

[DomestikDemon]

Ok everybody you havent failed me yet. In the time Ive been a member at this stie, Ive learned lots about my car that I otherwise wouldnt know. So here's another thing I've been pondering and can't decide upon just yet.

As my topic states this is about wether or not I should go with a DOHC 3.4 or build the shit out of my factory motor. Here's one thing about me you all should know; for the most part, I generally dont like the whole "sport compact" segment of the market our cars fall into. However, the idea of a really light car with lots of power is what the designers of sports cars throughout history have been aiming for, e.g.- Ferrari. The Grand Am is a far cry from a Ferrari obviously, but as far as I'm concerned, I love the damn thing. (Coupe, lol, I read that)

As I understand the 3.4 "twin dual-cam" is a rare motor to come by, but where there's a will, there's a way. I happen to be a fan of the good ol GM pushrod motor, but since Ill soon be buying this 4-banger cavalier my friend is selling me, the GA will become my toy.

The DOHC motors are signifigantly more powerfull than the 3400. As I have found though, there are reliability issues involved with the DOHC. Not exactly sure what they are yet, Im not done researching this topic. Asking other members for opinions is part of my research. As far as I know, there squat for performance parts in the way of the dual cam, but with any 4-valve per cylinder motor, it's gonna perform.

Someday, and do mean someday, I will have boost. Most likely this will be in the form of a supercharger. I already have found the tranny (5-speed, re-man, from a 3.1 berreta) that I need for emense power.

As I said, the 4-valve per cylinder performs. Not only that but with a supercharger forcing air into prolly around or a little over 75% of the cylinders circumference, a lot more of that boost pressure can be utlilized. Camshafts are gonna be pricey for this thing, but most of the major camshaft companies (crane, crower, edelbrock, etc) will do custom grinds.

Some of you may already know that I am in need of a motor. Long story really, but here's a brief- between LIM and t-stat getting stuck, it over heated real bad (the worst Ive ever seen an engine overheat), leaving me with a cracked block. More people with mechanical knowledge than just me have comfirmed tha my block is cracked, tust me I already tried new heads.

Since the GA is gonna be my toy, WTF? Lets soup it up.:)

I was discussing this with, umm, slowbird, yea. Anyway I wanted to get Wiseco's 9.5 compresssion pistons and rebuild the engine with those and prolly a cam to help out the pistons once I found a suitable block. Without further ado, I want to know just a few things, and here they are;

- Does the 3.4 DOHC have the same bore as the 3400?

- Im pretty sure it will since it's a 60* motor, but I have to ask if the DOHC block bolts to a 3.1 baretta tranny?

- What car can I find an OBD-II equipped 3.4 DOHC from?

- (stupid one) Do Milzy's 3400 headers work on the DOHC?

- When running boost, Im gonna use copper head gaskets for reliability reasons, but will this affect the timing belt and its reliability? (less tension on belt, I know for 3400 something will have to be done about the lifters when milling heads)

- The high output oil pump, available on the A.R.I. stroker motor site, will it work on the DOHC? should I think...


Yea quite a bit I know, but there's people on this board who know a whole lot more than I do. Please help me out here, Im sure I aint the only one here whos tryin to build a hot rod at the age of almost 19...

Heres what I had in mind for the two motors, different plans for each. Oh, and without boost for now...

3400

9.5 compression pistons
stage 2 cam
LS1 springs
Chromoly pushrods
mms stage 2 PCM
underdrive crank pulley
3500 heads and manifold
civic intake
68mm throttle body
S&S or Milzy Headers
2.5" exhuast
remove screen from MAF
--my estimate is prolly 260 HP and 275 TQ?

------------------------------------------------------------------------------
3.4 DOHC

custom grind cams
wiseco 9.5 pistons
high output oil pump
underdrive crank pulley
ac compressor delete
EGR delete
cold air intake
2 3/4" exhuast
custom headers
68mm throttle body
remove screen from MAF
ported ehads/manifold
larger injectors (not sure on specs yet)
wabro fuel pump
adjustable FPR
theres valve springs from a ford motor that fit these, gotta find out what they are, cuz theyre a lot stiffer apparently (60degree site)


For those that know more than me, enlighten me on wat to do. Any postive or informative response on this will be appreciated. Thanks all...

Cheers

[loud2kse]

the dohc 3.4 will be more work than it's worth. if you want a motor swap, swap in a 2.4 LD9 or an eco and boost it. It'll be easier, lighter, and you'll have a lot more aftermarket parts available to use.

[DomestikDemon]

I hate 4-cyl. Sry man aint goin that way....I was thinkin about boostin an ecotec, but naw ill keep my V-6.

[loud2kse]

Originally posted by DomestikDemon
ill keep my V-6.

so you just answered your own question.
Cuz you're not gonna swap in a dohc 3.4 I welcome you to prove me wrong, but i'm 99.999% sure it'll never happen. The engines are way too different, so to get the computer and everything to work, it'll be more of a project than you prolly think. And that's if the engine will actually physically fit.
so either get a new 3400 block and build it (just realize it's the same motor, prone to the same problems you've had). Or go with one of the other engines offered in the 99+ GA (all of which are 4 cylinders).

[DomestikDemon]

what i mean by ill keep my v-6 is that im not goin to a 4-cyl.

th DOHC block shouldnt be any larger than the other motors, its still a 60*block with a different top end......

[MantaGreen97]

The LQ1 is almost entirely different than the other 60 degree V6s with pretty much no shared parts. Due to the fact that it was adapted from the 60 degree pushrod V6 engines, however, the 3.4L TDC has a higher than normal deck height. So it is in fact a bit larger than the other 60 deg. V6 motors.

As I said to someone before recently (could have been you actually, lol), putting an LQ1 into an N-body is not going to be fun at all--definitely not easy. The fact that I don't think anyone has done it tells that story pretty well. I'm not saying it's impossible--I'm sure it is possible with enogh time and money--just that it's in no way going to be an easy swap.

If you want to stick with the V6s and still have lots of power, think about turbocharging a 3400 instead. It'll be easier than trying to get an LQ1 in there I think, especially considering there's a lot of people with turbo 3400s out there that you can get help/advice from.

[bballr4567]

I think your estimate on the 3400 engine you built up there is a little off. If you go to the Milzy site and check out the customer cars you will see one that has some of the similar parts and makes about 230 HP.

Im with Manta too because the swap is going to be unrealistic unless you really really just want to build a ton of custom parts. Just keep the 3400 in it and get a SC or a turbo set up. IIRC there is a company that is making kits for our cam right now but they are holding off for a little bit so that they can redesign some parts of the system.

The ECOTEC is a great engine if you are wanting to boost it. Some people have got upwards of 300 HP with it. If you are taking it out of the equation of a new motor just because its a 4 CYL then you are being blind. It has a ton of potential and people have proven it as does the 3400. Look at this http://www.grandamgt.com/forum/showthread.php?t=65071 and you will see why quads have a huge potential.

The DOHC will use a complete different PCM and all other computer parts. To me it just seems like a ton of work to switch a motor into a car that already has a motor with the same potential.

[Colin]

Originally posted by DomestikDemon
I hate 4-cyl. Sry man aint goin that way....I was thinkin about boostin an ecotec, but naw ill keep my V-6. The fastest GA on here is a 4 cylinder . ;)

[pontiac3100]

oh man that civic did'nt sound to nice.
to be honest i would'nt mind owning a quad 4.....it's just that they blow h/g's and rods..like nothing

[randizzle]

Originally posted by pontiac3100
oh man that civic did'nt sound to nice.
to be honest i would'nt mind owning a quad 4.....it's just that they blow h/g's and rods..like nothing
Again the bad reputation because of poorly designed SOHC heads. The vin D's, vin A's and later vin T's are just as reliable and MUCH quicker stock for stock than a 3.1 or 3100.

[loud2kse]

dohc quad ftw

[VanishingImage]

those twin cammed 3.4's were mostly junk,GM even gave up on them. Thats the ONLY v6 I hate. I haven't even owned one and still have expirenced all the problems they have had. Its either a 99+ 3400 SFI motor or the 3800 motor. Those are really the only 2 that would be an easier and more enjoyable swap. Theres someone here that swapped a 3400 into their pre 99 Grand am here somewhere.

From all the information on this site and on the other GM 60degree forums,your going to find that the 3.4 TC motor is junk and that your just going to be giving yourself nothing but hassle and problem after problem. The 3400 and the 3800 are pretty much tried and true swaps right now.

BUT the fastest car on the forums and that I know of is a Quad4 so don't rule them out,they can spank some v6's,hell even some v8's

[VanishingImage]

Originally posted by loud2kse
dohc quad ftw

ahmen

[DomestikDemon]

Ok thats what I thought too, that the DOHC might be a PITA. With more money and custom crap than I'm willing to spend though, the swap could result in an over 600 horse turbo DOHC. I ask again though, what exactly are the problems the DOHC has that makes everyone stay away? Certain things I can fix and dont mind fixing, but as long as its not stuff thats gonna leave me sit somewhere...or something thats gonna kill a weekend for a $13 part, lol, that would suck.

BTW, please stop trying to convince me that a 4-cyl is the way to go. Yes some are pretty powerful, but I hate the damn things, enough said. No offense to anyone of corse, I just hate them.:nono:

anyway, my mods are only good for around 230 horses heh? Good enough for now I guess, until I sit down and design a turbo setup. The 5-speed is gonna make it a lot quicker......

I know what can be done with a 3400 and the potential they have, but I still want specifics as to why the DOHC is so bad....

Thanks though, opinions are apreciated.
Cheers

[DomestikDemon]

BTW, when I bought my GA, I was gonna get a red 2001 SE coupe that was 5-speed and only half the miles that were on mine when I got it, and for only about $1,200 more. Know why i didnt get it? The salesman said 4-banger. I promptly told him I didnt want that one. damn thing was loaded too....every option mine has plus chrome wheels and the steering wheel radio controls. woulda been nice.....looking back I shoulda got it and swappedin a V6 right away....oh well Im happy with my GT. IMO they look better anyway

edit:
come to think of it, it was prolly atleast an SE1, maybe an SE2

[pontiac3100]

well for one they use a t-belt system.
so you would have to change the t-belt 60k miles.
if the alternator goes out...your gonna have LOADS of fun removing it.

i heard it consumes oil but don't quote me on that.
these 2 guys came into my job and was hating on the 3.4...then other shopper's(mechanics) kinda came in the conversation about how bad the 3.4dohc is to work on.


it's a nice engine.
has an impressive high redline.

but i feel the 3400 has some power.
i've driven many 3400 gt's...and man i love how they get up.

does the badly desing of the quad 4 applies to the auto ho quad 4?

[MantaGreen97]

Originally posted by VanishingImage
those twin cammed 3.4's were mostly junk,GM even gave up on them. Thats the ONLY v6 I hate. I haven't even owned one and still have expirenced all the problems they have had. Its either a 99+ 3400 SFI motor or the 3800 motor. Those are really the only 2 that would be an easier and more enjoyable swap. Theres someone here that swapped a 3400 into their pre 99 Grand am here somewhere.
Maybe only one has done it here, but there are lots of people that have swapped 3400s in to Grand Ams as well as older J-bodies, and Berettas...

Also, I would not call the 3.4L TDC junk...

Originally posted by VanishingImage
From all the information on this site and on the other GM 60degree forums,your going to find that the 3.4 TC motor is junk...
If you go over to 60degreeV6.com I don't think you would find many people referring to the LQ1 as junk there either ;) In fact you're going to find quite the opposite.

Anyway that doesn't make it any easier of a swap, and I've already said what I could about swapping an LQ1 into a GA...

[eric99gt]

There's just no point. The way you're talking about building this engine you're better off sticking with what you have. You dump enough money in to either motor and you can get huge horsepower numbers. With that being said the power in the 3400 will come easier so stick with that.

[bballr4567]

Originally posted by eric99gt
There's just no point. The way you're talking about building this engine you're better off sticking with what you have. You dump enough money in to either motor and you can get huge horsepower numbers. With that being said the power in the 3400 will come easier so stick with that. Thats so true. I was just about to say that. Say you dump 4k into the DOHC and the 3400 chances are you will end up with exactly the same power with out having to change the engines. Sure itll be fun to do a swap but it just isnt needed.

[slowbird]

Yea...forget the DOHC.

[Matt95GT]

Lets not turn this into a 4-cyl vs 6-cyl debate.

:penny: Stick with the 3400 you have... the DOHC 3.4 is more trouble than it's worth, and the pushrod engines have much more aftermarket support.

[DomestikDemon]

Oh no, i was hoping it woudlnt get to that. I just dont like 4 cylinders- my opinion. Your cars prolly a shitload faster than mine anyway......but I still like bigger engines. There's no replacement for displacement, they say.....

As for the DOHC though, I kinda want to do it, but at the same time, I dont want to fabricate too many parts, if it'll bolt in that would be great. If not, I dont wanna screw with it too much...

With similar modifications, the LQ1 would way overpower the 3400, thats where Im coming from. General consensus is that I shouldnt bother, I havent even seen one of these motors in real life though. I want to see it (out of vehicle if possible) and look at where hoses, lines, wires, etc are located and what would have to be done to put it in my car. BTW, Ive done t-belts before, theyre not that bad, besides I enjoy difficult tasks, to a certain degree of course.

If it bolts in and the hood closes, I have a why not attitude toward things, I just want to know what the hell it is about this swap that make everyone veer away? If it really is that horrible of course im gonna keep a 3400 in it, but I know the 3.4 dual-cam is capable of much more power in the end, all becuase of two extra vavles in each cylinder.

Pontiac3100
What exactly is the redline?

[pontiac3100]

where's the redline...try 7,000rpms buddy.
other than that i've driven the 3.4 and the gt 3400...i dunno the gt3400 seems to have more balls...but that 3.4 whould have more balls in the higher rpm's.

[DomestikDemon]

ok cool i was thinkin aybe 6500 or so...i heard somewhere that supposedly the factory 3400 cranks are only good to 7500 rpm. thanks

if im not mistaken, i think all the 60*s have the same crank starting with 3.1 and larger

[RocketFast321]

A little video of 3 Gens. of 3.4 twin duel cams
http://www.youtube.com/watch?v=yAud7CjwRYE
http://www.youtube.com/watch?v=sGgldDEfcBE

[DomestikDemon]

nice

I want one even more, got an even beefier sound than the 3400 too IMO, I really liked the black lumina

[bballr4567]

The sound can totally be changed.

Dont be fooled by TWO cars. There is very very little aftermarket for the DOHC not to mention the tooling that would be required to get the motor in the car.

However its your money and TIME. Its just crazy to me that you are thinking about switching the two motors considering that they are so close to each other and with one having more potential (3400).

These two are turbo'd 3400's. Look at the time the bottom one runs!!! lol
http://www.youtube.com/watch?v=7ibU1k8UZoo
http://videos.streetfire.net/search/3400+Turbo/0/70b49dcd-4742-4000-a814-adec1a94162e.htm

The next one is two 3400 SC Aleros.
http://www.youtube.com/watch?v=GiPn3aVx8IY

Just go look at streetfire.net for a ton more vids on the 3400.

[Matt95GT]

^Agreed. The swap will only get you a slightly broader powerband with higher red line. But boost on the 3400 could be had for the same or less and will run circles around it.

[DomestikDemon]

Ok, well this might make you all happy. Im stickin with a 3400. I found one for sale not far from me and for a good deal too. As soon as I get the money ($250 for the block) it's mine. prolly by next week when i get paid......

I kinda wanted the DOHC, but Ive been looking and theyre impossible to find. Thanks everyone who posted though.

The mods I listed for the 3400 are ones I actually plan on doing, theonly thing is how much them pistons and the cam are gonna cost. the rest is easy stuff. also, the 5-speed tranny is only 175 used, tested and it works, 3 month guarantee

cheers

[Pte Socks]

Heres an idea, buy a 3.6L DOHC and the new 6speed and you will have a fast car. The problem with all cars out there now, like the G6 and saturn aura is they all weigh in at 35-3600 lbs! And even with that weight, the aura runs in at 14.9's. Combine the same engine and tranny ( or just engine ) in a 3100 lb GA and you have a mid to low 14's car right there. It seems to be im the only one seeing all this potential in the new 3.6L and what it could do to this car. Sure it would be a PITA to do right, but hey, so are most engine swaps in a car that is built in the late 90's and 2000's.

[TA^Guy]

The DOHC 3.4 Liter motor has greater peak factory hp numbers, but the motor was notorious for problems.

Not to mention DOHC motors are significantly wider than pushrod 3.4 liter motors due to needing wider heads to accompany the dual cams. I would bet that you would have some firewall clearence issues with a DOHC 3.4. BTW, IMO pushrod motors are more reliable than DOHC engines.

[VanishingImage]

my only input would be stick with has been known to work. If your going to be putting in a lot of $$$ to get the 3.4 DHOC thing to work,might as well buy the 3400 and dump a little into that and have a much better motor. The 3400 has been known to produce some good numbers.

Also,how many people have actually stuck with the 3.4 and got some great numbers out of them? How many actually went the extra mile to do any machining to them to make them stronger etc.... Basically I just don't want to see someone pour a lot of money into an engine that in the end wasn't what they thought.

[DomestikDemon]

Ive though about this as well, was kinda wonderin too...I know a couple site for a racing shop in minnesota or somewhere that has racing strength rods and a crank, but theyre still at factory sizes

as for rods theres always the option f shimming an an SBC rod.....