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| 3,4 l dohc engine swap info please (Page 1/2) |
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donj
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AUG 27, 06:50 PM
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I have a chance to pick up a 3.4 dohc motor, is there anyone willing to help me w/ info on what I will need for the swap. Individual says he has cut up wiring harness and puter,pulleys and cut motor mount.
I would like to put this motor in my 87 GT.
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Rickady88GT
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AUG 27, 07:43 PM
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| quote | Originally posted by donj:
I have a chance to pick up a 3.4 dohc motor, is there anyone willing to help me w/ info on what I will need for the swap. Individual says he has cut up wiring harness and puter,pulleys and cut motor mount.
I would like to put this motor in my 87 GT. |
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I love how that engine sounds. It really is a great engine and should have been a stock option for the Fiero.
My opinion is that you should get everything you can. It will pay off down the road.
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sspeedstreet
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AUG 27, 08:56 PM
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Couple of things you need to know:
1. Year of the motor (1991-1995 or 1996-1997). The later motors have additional sensors on the valve train.
2. Did it run before being pulled? If unknown, pull the spark plugs out and try to rotate the crank. My first purchase was frozen due to the pan bottoming out a curb impact. If the pan bottom is dented in, it blocks the oil pickup and the engine seizes.
3. Make sure you get all the wiring connectors and they're not cracked or broken. I replaced all of the wires from the chassis to the motor with new. Until you have all of the components (coils, ECU, EVAP canister etc.) mounted in their final locations' you will have no idea of wire lengths. I started with making the harness as a first step. If I did it again, it would be one of the last steps.
4. I found locating the coil pack a challenge. Look at photos of other peoples swaps. The stock 1991-1995 location is mounted on the of the block all the way down at the pan rail. In front engine installations that's fine; right out front by the radiator. But on the Fiero it's right where the down-pipe drops.
I did mine 6 or 7 years ago, so random things pop to mind about the swap. I finally bought a new GM long block and used the brackets, manifolds and accessories from the junk motor on it.
I have a fair amount of wiring docs I can email you. Other than that, just ask as the questions come up. I'll try to help.
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Rickady88GT
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AUG 27, 10:52 PM
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That is a great swap and good info sspeedstreet. It is a VERY clean piece of art.
Another thing to consider is, do you plan on keeping it emissions legal. That could complicate the swap some what.
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donj
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AUG 28, 12:01 AM
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speedstreet:
I don't know the year of the motor presently, but it was rebuilt and installed but never run. I am a fair mechanic but without knowing what is needed for the swap I'm at a loss.
Here are a list of questions I have.............
1) Can I use the 87 engine frame or do I need to use an 88?
2) What parts (non motor) will I need to mount the motor in the car?
3) what exhaust ?
4) Is the induction going to be the same or does it need to come from the 3.4 ?
5) Any specialty parts needed (hard enough to get stock parts now)
This is what the seller is advertising............
3.4 dohc lq1 engine Rebuilt many years ago but never installed have boxes of misc fiero conversion parts ecu and boxes of cut up wiring harness has a never used 6 puck style I forget what stage,
I asked if the motor was free and was assured that it was in good condition and turns freely.
My biggest concern is that this will turn into a project that is either beyond my capacity and monetary constraints
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ltlfrari
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AUG 28, 09:04 AM
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Any year cradle.
I used stock gearbox mounting position (so no custom axles) but had to fab a front engine mount.
I deleted the power steering pump and replaced with an idler. Had to make a custom mount for that to go in the ps pump location.
Made my own exhaust. I got another front manifold and replaced the big honking std one with that so that you end up with something more akin to the stock Fiero exhaust layout. Had to weld in an O2 bung and make/weld in a saddle for the EGR pipe. That exhaust was he first time I'd ever done any welding and it turned out ok (eventually!).
I used some exhaust pipe to make up an intake pipe and fitted a filter to it. Worked ok but f you can connect to stock intake plumbing, then probbly better. Stock is 'cold' air. Anything that has an under hood filter right above the exhaust is gonna be a 'hot air intake'.
Mine was mated to a 5 speed isuzu box from the 4 speed fiero (85). Had to get an 88 flywheel as has to be nutral balanace but you could probably rebalance a non 88 one. I replaced the clutch etc while in there with a WCF clutch and 9 11/16-inch organic/organic friction plate. Didn't have any problems with West Coast Fiero at the time re delivery but seems to have gotten much worse since then (are they even still in business?).
Worked fine. 5 speed Suzy bix is prob too low first gear but it stood up to the motor fine although I didn't dump the clutch on it either. Gotta love the high gearing in 5th. 2200 rpm at 70 on the freeway, put your foot down and it just goes!
You'll need to change the oil dipstick. The 3.4's is too short to reach when the engine is in the Fiero because it's up under the firewall. A Fiero v6 one (tube and stick) can be made to fit with a bit of bending.
I made a new dogbone mount that bolted to the engine/gearbox bolts. I then had to make a mount that went onto the trunk tub wall and a short adjustable connector to go between the two.
I had to mess around with the water pump plumbing some, using AN connectors.
I installed a Walbro 340M fuel pump (255 LPH) in the tank. I also put an in line pressure gauge in the fuel line just so I could see what was going on. Not really needed but did help with some problems later on (that turned out to be nothing to do with the fuel!).
If you have a 4 speed now, the tach will be way off. You an replac with a v6 one or get a conversion box to change the signal but I just lived with it.
You'll probably need to make up a new throttle cable and cruise cable. The worst part of that is installing it onto the accel pedel in the car. I lost some skin doing that!
I replaced the Fiero evap canister and plumbing with a generic one from Napa. Depends if you need emissions stuff or not where you are if you do that but I figured why not.
ECM. you will need a new ECM and prom. I used an ECM from a 91-93 manual Olds Cutlass. Had the prom programmed by DarthFiero. Never had a problem. Wiring is fun (no it's not). I built my own harness from scratch and mated it up to the Fiero connectors. Lets just say it took a while!
All this is on my web site but it is down right now. It's a long ead but may help you understand what's involved.
I'll see if I can get it back up in the next few days (jut need a ups for the pc)
I should add. If you do it, it's an awesome engine in this car, even though there is little (ok nothing) to be had re tuning. Should have been what was in the Fiero from the get go.
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Anything I might say is probably worth what you paid for it, so treat it accordingly!
Dave
www.ltlfrari.com[This message has been edited by ltlfrari (edited 08-28-2020).]
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fierosound
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AUG 28, 10:49 AM
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FieroWannaBe
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AUG 28, 12:46 PM
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For my DOHC swap I bought a 1996 Lumina LQ1, and put it in my 86 GT.
I had to buy a ECU and wiring harness and a fabricated Power steering delete pulley, I bought an AC delete pulley from the NAPA as well.
I used the Fiero V6 front mount bracket that I trimmed a little to fit behind the timing cover. I used Rodney Dickman Polyurethane engine and transmission mounts, and Spec stage II clutch/Pressure Plate with a Fidanza flywheel.
It was 4 speed car, so I used that transmission, and fabricated a new crossover by cutting up the DOHC piece, and welding in parts from a 2.25" J-bend from summit, routing it around the whole transmission. The exhaust was a simple piece from the a factory LQ1 down pipe, to a Y I welded up into two "spiral-flow" mufflers, keeping the factory trunk. I mounted the ECU in the battery tray, and relocated the battery up front using Norms battery tray.
I mounted the coilpack on top of the intake, where the engine cover piece would normally sit.
That car was taken apart a couple of years ago and the engine was rebuilt, but its not in a car at the moment.
Edit to add:
I didn't use a dog bone mount like the Fiero V6. I used a piece of Hex aluminum radius rod and two rod ends where the factory driveline damper was mounted on the 2.8L. Transmitted the vibrations a little more than I would have liked.[This message has been edited by FieroWannaBe (edited 08-28-2020).]
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Dennis LaGrua
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AUG 28, 04:36 PM
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Coming from a friend that did that swap.
That engine will give good top end power and it can bolt in using the Fiero mounts. I'd favor using it for a stick application. The only drawback would be the engine weight and the tight fit in the engine compartment. It is one of the heaviest V6 swaps coming it at around 496 lbs (w all accessories) but many owners like it. If you add just a little bit of boost the power comes up in a hurry------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "
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donj
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SEP 01, 09:24 PM
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Well the motor and "parts" showed up! Here's pics of what I got.
I have the fuel induction system also just forgot to take a pic.............
Seller says the motor is a 1995. I don't know how this will affect the build, I remember someone saying that the earlier motors had less wiring problems?
I am looking for a engine cradle out of a v6 car so I can work on this without pulling my car apart ans scattering it all over the garage.
Then i guess the wiring harness has to be addressed (would consider a custom harness if anyone knows where to buy one) given that what I have for puters will work.
I can see some long hrs in my future!
Thanks guys!
I love this forum
Donj
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