Replacing a 3.4 '92 DOHC with a crate '96 DOHC engine UPDATE

[Scott205]

I bought a brand new 3.4 DOHC in the crate off ebay and have pulled my 92 motor out. I have either a bad gasket or head, the white smoke coming from the tail pipe saddened me greatly. I am re-using my intake, plenum and everything else from the orginal engine (the crate is just the block, heads and a few sensors and an oil filter installed).

Anyone know any modifications I will have to do? I see the vent tube on the front bank has moved location and their is none in the back. There is an extra NOC sensor on the front of the engine that i can remove and put the ICM and coils on, and I have thought about remounting the coils. I would love to hear how hard or easy that one is.

Appreciate any help!

Scott205

[pepsi_coke]

http://www.60degreev6.com/modules.php?op=modload&name=News&file=article&sid=12

A guide is already written up for this

You can thank Bobby (dohcfiend)

Hope it helps, and there is alot of info pertaining to this swap written up, try using the Search button.

Good luck,
Jay

[Anonymous]

http://www.60degreev6.com/modules.php?op=modload&name=News&file=article&sid= 12

A guide is already written up for this

You can thank Bobby (dohcfiend)

Hope it helps, and there is alot of info pertaining to this swap written up, try using the Search button.

Good luck,
Jay

While that guide is good and helpful, it doesn't really help him.

Here is what you need to do to use it. I had to put a 95 crate motor in my 92 Lumina, same concept. Reuse your onld parts, with new gaskets. Gaskets should be for a 91-93 engine, except for the exhaust manifold gaskets, which need to be 96-97. Concerning the camshaft position sensor, extra oil pan sensor, and the extra crank sensor: Leave these all unplugged. 91-93 OBDI uses less sensors for its management, and these are not used. So just leave them as they are now.

The hardest part of the swap is the alternator. You must buy a 96-97 alternator, and get the alternator mounting brackets. These can be gotten from a junk yard, or the dealership. Then to wire the alternator, the 96-97 use a different plug, it is a 4-wire plugin, but a different style. Get the new plugin from the junkyard as well, or get it from the dealer. Then splice this plugin into your 91-93 harness. I forgot off hand which wires go where.

You will also need to get the 96-97 exhaust manifolds. This is going to be tricky. You need to find the front and rear manifolds, and the crossover. They might bolt up to your factory exhaust, but may not, I do not honestly know. Then buy 2 brass plugs from an auto parts store, and plug off the AIR injection holes (1 per manifold) on the 96 manifolds. The EGR pipe may need to be retrofittied to fit the 96 manifolds, but it may line up, I am not sure.

Our 91-93 air conditioning mounted up to the new engine just fine, but I'm not sure if it will the 96-97. Power steering should also mount up just fine. Use your old intake manifolds, fuel rail, etc with 91-93 gaskets.

I hope this helps, you would have been better off getting a 94-95 crate motor, but too late now. So feel free to ask if you have any other questions.

[Scott205]

thanks for the info, keep it coming

Thanks Pepsi-Coke. But your hurting me if your serious about the Altenator. Do you know how much I paid for that thing? and it has a lifetime install and exchange from GM paid for twice! And I must have finally gotten a good one since this one has lasted more than 2 years.

Exhaust manifolds.. i was wondering about that one after searching for performance ones.. anyone actually make one???

Definitely need an EGR tube for a 96, comes off the front head in a different spot, none on the rear.

Looks like the top will fit just fine, just the different sensors and outlets that will be fun.


I bought it off ebay.. it was cheaper than a rebuilt, and it wasn't until the last day a 91-95 came availble from Hawaii. would have taken over a month to gotten here. Then last week i see a 91-95 for $750 go unbought. I figure I will rebuilt the original and maybe buy a convertible 96/97 to stick this in 100k miles more I would love to have everything updated to OBDII but nice having it "stock" in 25 or so years..

The Fiero on the other hand, anyone ever stuck a 383 Ram Jet in one......

[Anonymous]

Re: thanks for the info, keep it coming

But your hurting me if your serious about the Altenator. Do you know how much I paid for that thing? and it has a lifetime install and exchange from GM paid for twice! And I must have finally gotten a good one since this one has lasted more than 2 years.

I am serious. I guess you could try to make your's work by fabbing up your own brackets though...

Exhaust manifolds.. i was wondering about that one after searching for performance ones.. anyone actually make one???

No one makes them, you need stock units unless you wish to make them yourself.

Definitely need an EGR tube for a 96, comes off the front head in a different spot, none on the rear.

That is the breather line, the EGR is a tube that comes off of your exhaust manifold right after the crossover Y-s with the rear manifold.

Looks like the top will fit just fine, just the different sensors and outlets that will be fun.

Use your old top parts. They will bolt on directly, using all the same sensors. You will need nothing from the 96 up top, excluding the EGR line.

The Fiero on the other hand, anyone ever stuck a 383 Ram Jet in one......

Search over at www.fiero.nl, there are a lot of people with small block Chevy's in them. It is a bad swap though, really difficult, expensive, and time consuming. As a Fiero owner myself, I am doing a 3.4 DOHC swap, which is pretty easy, and will drop an otherwise stock Fiero into the flat 14s.

[Scott205]

Thanks 91gtp

sorry about that Gerbil Bait, I meant to thank you for all the great info.

Engine is out, top looks pretty easy, manifold and accessories look to be a lot of work.

What is the call on MSD Ignition Coils, what chip to use, and any good catback systems?


Hmm, maybe a 3.8SC would be an easier swap for the Fiero but i really wanted 300HP in a reliable motor.. man they stuff that V8 in there.. don't like the water pump issue.. if i did it I would get an electric w/p. But i was thinking I could build a 350HP V8 cheaper than rebuilding a 3.4 DOHC

Thanks

[Anonymous]

Re: Thanks 91gtp

sorry about that Gerbil Bait, I meant to thank you for all the great info.

You mean 91gtp? It's ok, I figured I was the one you were thanking.

Engine is out, top looks pretty easy, manifold and accessories look to be a lot of work.

I make it sound a lot harder than it is. The entire top end bolts right on with no issues. The exhaust won't be a pain, so long as you get the right parts. Accessories follow suit.

What is the call on MSD Ignition Coils, what chip to use, and any good catback systems?

The MSD coilds made for the L67, 3800SC, will work on our motors, but I have no diea on if they will add any power, but I doubt they would if you are near stock. Maybe if you were boosted, or high compression though.

Hmm, maybe a 3.8SC would be an easier swap for the Fiero but i really wanted 300HP in a reliable motor.. man they stuff that V8 in there.. don't like the water pump issue.. if i did it I would get an electric w/p. But i was thinking I could build a 350HP V8 cheaper than rebuilding a 3.4 DOHC

The 3.8SC is not a good swap for the Fiero IMHO. I rode in one the other day. For the amount of stuff that has to be gjhetto-rigged together, it isn't worth it. It was quick, but the motor didn't suit the Fiero, and the swap was a big pain in the ass so the guy says. I'd do a 3.4 DOHC if I were you. They can be found for pretty cheap, the swap is really easy, and it will put a Fiero into the flat 14s. Coming from flat 16s, that's a HUGE difference. And from what everyone who has done it says, its high end personality fits the sports car like personality of the Fiero extremely well. The hardest part is wiring, but even that is much easier than the 3800. You use the stock engine mounts, stock tranny, etc.

Also, 300hp is easily attained from the DOHC. TimG put down 263whp (310hp) with nothing but a turbocharger, intercooler, and exhaust. And two 3.4s now have hit 220whp (265hp) all normally aspirated, with no bottem end or headwork, and both have much more left in them.

[dohcfiend]

RE: Re: Thanks 91gtp

appreciate the referral pepsi coke.

this particular adaptation sounds like a cakewalk. if u did not read my guide, well shame on you

i only read about 1/2 of it. sorry my attention span is short today. if you really want your original alt to fit you can switch the timing chain cover. otherwise you are stuck with having to get a 94-97 alt. i know from experience a 94 alt will fit a 96 bracket, so that will widen your interchange years. if u haven't done so already, you will need to straighten up your heater system. on your 96-97 there is a plug where your heater hose used to plug into on the side.

simply stick a 3/8 extension in there and replace it with the port off of your old motor. put some thread sealent on it and you will be good to go.

lastly, there is the egr. if u do not have an egr tube with your 96-97 manifolds if u got them yet it will be hard. but simply cut your old egr tube in 1/2 as well as the 96-97 tube. keep the top 1/2 of the 92 and the bottom 1/2 of the 96-97, take them to a machine shop and have them brazed together. as far as i know that should be it. all of your old parts will switch over.

p.s. if your mani do not have the egr tube, i cna ssell you one i had made when i did an egr conversion, mine was using the old style solenoid with the 96 intake but i am pretty sure it is long enough to fit an older intake and work just fine with your stock gaskets. i paid alot to have everything made so if you want it, it will be 35 bux plus shipping. lata

[Scott205]

Re: RE: Re: Thanks 91gtp

lastly, there is the egr. if u do not have an egr tube with your 96-97 manifolds if u got them yet it will be hard. but simply cut your old egr tube in 1/2 as well as the 96-97 tube.

I am reusing my 92 Intake and plenum. So I don't think I have to worry about that issue with the ERG, but the PVC hose routing will be the thing since the heads are different.

Hopefully I will get a 100k out of it then put the rebuilt orginal back in it since it should be around 18-20 yo and quickly becoming a classic. Then drop this new one into a Fiero or maybe a convertible Cutlass with a 96/97 Plenum, wires and OBDII.

[dohcfiend]

RE: Re: RE: Re: Thanks 91gtp

pcv is no sweat. that one port on the front valve cover(assuming 96 valvecover) goes to your intake tube and whatever port on the tb of your 92 plenum simply goes to the dist block as it did be4.

unless you are plugging your egr hole and using a chip you will need to adapt your egr setup like i said be4. you 92 egr tube will not connect to a 96 exhaust manifold, that is why i said u get both tubes cut them and braze them. that piece i was suggesting was for your application of a 96 manifold with a 91-94 egr valve setup.

[your_I.D.]

Re: thanks for the info, keep it coming

Fiero on the other hand, anyone ever stuck a 383 Ram Jet in one......

How about an LT1 http://www.fierolt1.com/

http://www.fierolt1.com/fotolog_1.htm

[Anonymous]

I'd rather have a L67 Fiero than a LT1. Fuck I'd rather have a 2.8 Fiero, at least it'd still handle.

[dohcfiend]

bs, 2.8 fiero's can't handle either. only exeption may be an 88 model since i have never driven one. but i have driven a 87gt and that thing had the worst front end push i have ever experienced. the car felt lik eit had no balance. people put bigger motors into fieros for one reason, to go fast.

as far as engines into fiero's what haven't they put into them is more like it . i have seen a 455 big block with my own 2 eyes(that was a thing of beauty), heard of porsche motors, heard of a ferarri motor. sbc into a fiero is nothing new, hell they even have kits made for them. surprisingly, i do not think the fiero has a strong l67 following.

[Anonymous]

bs, 2.8 fiero's can't handle either. only exeption may be an 88 model since i have never driven one. but i have driven a 87gt and that thing had the worst front end push i have ever experienced. the car felt lik eit had no balance. people put bigger motors into fieros for one reason, to go fast.

as far as engines into fiero's what haven't they put into them is more like it . i have seen a 455 big block with my own 2 eyes(that was a thing of beauty), heard of porsche motors, heard of a ferarri motor. sbc into a fiero is nothing new, hell they even have kits made for them. surprisingly, i do not think the fiero has a strong l67 following.

My 88 handles exceptionally well IMHO, and after driving a 86, it was noticably worse, but not that bad still.

The Fiero has a huge L67 following, it is probably one of the most popular swap besides the 4.9.

[Fierobsessed]

people put bigger motors into fieros for one reason, to go fast.

I put in a smaller 4 cyl in one of my Fiero's... What does that mean?