3,4 l dohc engine swap info please (Page 2/2)
ltlfrari SEP 02, 11:43 AM
Looking at that motor, at a minimum you need to get it on an engine stand, pull the plugs and valve train covers and get some oil in there as well as in the crankcase. I think I'd avoid pulling the pan until I had to, at least initially, just overfill it to flood the crankcase then turn over by hand 'very' slowly.
If you are lucky that will be enough.

I an see one cam sprocket cover in the pics, and possibly an idler pulley on a bracket that 'might' be to replace the power steering pump pulley. Don't see the large plastic ribbed cover that covers the cam belts but you can easily make one from some a sheet of aluminum, it's nothing special from what I recall.

Looks like you've got some work ahead of you

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Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

donj SEP 02, 10:24 PM
ltlfrari:

I couldn't agree with you more!
Seller said that the motor was an older rebuild that he installed but never the motor. When he delivered the motor the story changes slightly, now its the "previous" owner had the motor rebuilt and never ran it.

I'm taking it to a re builder tomorrow and having him pull it down and Re do the whole motor, we will see if its rebuilt or not.

Couple of Question's to everyone...........SS swirled tulip valves? If I re cam it will I have a mess to deal with the computer (mild cam so I don't screw up the engine vacuum), and finally how well balanced are these motors from the factory? Every time I have a motor rebuilt I have it balanced, mostly because I have a heavy foot and like to wind them tight!

I found the other cam gear cover, but they are in fair condition so I will look for better ones (any one make parts for these motors yet?)

Thank everyone for the help and will post progress if anyone is interested

Donj
ltlfrari SEP 03, 08:29 AM
So far as I know there's pretty much nothing for these motors re tuning, at least over the shelf wise anyway.
There's a 13 degree cam timing change (At least I think it's 13 degrees, double check) but I never bothered with it, motor has plenty of umphh in stock form, especially in a light car like the Fiero.
DarthFiero (gmtuners?) might be able to do some stuff to the ECM re tuning.
I never touched mine, just put it in and ran it, seemed pretty smooth to me and I would rev it to the red line at times (gotta love that 9k redline).

In case you haven't seen it, this thread is useful http://www.fiero.nl/forum/Forum1/HTML/062728.html

And this one is interesting http://www.fiero.nl/forum/Forum2/HTML/143937.html although more about the car than the motor.
------------------
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 09-03-2020).]

FieroWannaBe SEP 03, 08:37 AM

quote
Originally posted by donj:

Couple of Question's to everyone...........SS swirled tulip valves? If I re cam it will I have a mess to deal with the computer (mild cam so I don't screw up the engine vacuum), and finally how well balanced are these motors from the factory? Every time I have a motor rebuilt I have it balanced, mostly because I have a heavy foot and like to wind them tight!


Donj



As far as I know after looking for some a few some years ago, any new valves have to be custom cut, no one makes them as standard product anymore.
Cams can be reground by Steve Long Racing. I had a set reground in 2014. There are lightweight lifters available, and higher rate springs as well from WOT-tech

[This message has been edited by FieroWannaBe (edited 09-03-2020).]

qwikgta SEP 12, 09:49 PM
Number one thing is to get the GM Service manual for the year of your motor. 91-93 were OBD1, 94-95 were OBD1.5 and 96-97 is OBD2. When I did mine, I had a 96 motor, but wired it up as a OBD1 (91) ECM and tune. I used the 91 service manual for a Buick. It has all the wire schematics, pin outs, harness connections and will help you make your wire harness. Plus all the info on how to make it run is within the service manuals.

Check out this site: http://www.dohcfiero.com/

also, use this search string in google: site:fiero.nl 3.4DOHC it will bring back only threads with DOHC info in it.


Good luck

[This message has been edited by qwikgta (edited 09-12-2020).]

Raydar SEP 13, 09:23 AM

quote
Originally posted by ltlfrari:
...
I never touched mine, just put it in and ran it, seemed pretty smooth to me and I would rev it to the red line at times (gotta love that 9k redline).



Wait... 9k?!
I was told 7200 by the guy that built my motor. (Essentially a stock spec build except everything is selected/balanced/assembled to support boost.)
Another guy I know is building his for more power, but is still only talking about ~8K.
ltlfrari SEP 13, 12:39 PM
Pretty sure the rev limit was 9k but it's been a while and as my tag line says 'What I say is worth what you paid for it'!

Edit. Seems I was wrong, 6500 redline. Oh well


------------------
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 09-13-2020).]

qwikgta SEP 13, 04:47 PM
Funny thing about this thread is that I thought I was done with the 60' V6 motors, and now i'm installing one (93 3.1L GenII) into a 87 GT i picked up a few months ago. I've found out the the wire harness for the 3.1 is the same as for my 91/96 DOHC motor. I'm back into my old notes and getting ready to start on the wire harness. Been reading all my old notes/threads and getting ready.

Rob
donj SEP 13, 11:16 PM
Well here's the progress report on the project.................

1)Motor is off to the engine builder's he will tear down the motor to see if it was actually a rebuilt. I have been looking on line for top end parts and found valves and light weight lifters, and heavy valve springs, all of which will go into the build, Including balancing

2) Have contacted the prez of a Fiero club in Milwaukee and will be picking up a engine cradle from him this week.

I am still in search of someone to make a wiring harness for me ( I am hoping that someone here will make a suggestion as to where to find one). there was someone who contacted me from Red River (on the bay in Door county WI) who was custom fabing wiring harness but I lost the link to his e-mail so unless someone here recognizes him it its a no go.

I have decided to leave the battery in the stock location and mount the puter in the stock location also. Any comments as to the problems I may incur with this would be appreciated.

So, that being said this is what I have gleaned looking through the archives.........

The push rod motors are "plug and play" I realize that the DOHC aspect of the motor complicates thing some.

1) mounts are the same as the 2.8
2) exhaust is the same (manifolds)
3) starter is in the same side as the 2.8
4) A dog bone mount will need to be fabricated ( among the "parts I received" was a aluminum strut and a mounting plate for a idler pulley)
5) I have the ecu (whether it is good or not I cannot say, but the price of these is not cost prohibitive)
6) fuel and coolant and exhaust will be custom

Is there anything that I have missed or misinterpreted that I should know about?

Thanks everyone for their help and expertise!!!

Donj

qwikgta SEP 14, 12:47 AM
Nothing about the motor being DOHC complicates the swap at all. Treat it as any 2.8, 3.1 iron block swap. Like I said in my last post, i'm working on a 3.1L swap from a 93 Buick and the wire harness is the exact same as the DOHC. All the sensors, are the exact same. You could use your 2.8L harness w/ a few extra wires. You can do your own harness, its very easy. Each wire goes from the sensor to the ECM, almost everything you need is here: http://www.dohcfiero.com/Factory%20ECU.htm

Good luck

Rob