Long time fiero nut here looking at possibly rebuilding an 87 2.5, I have done multiple engine swaps in the past and now I am more interested in having a fully stock restored fiero. I originally was going to put my Northstar engine in, but to be honest, I would fully satisfied with a good running stock fiero and I think the Northstar will sit in the garage a bit longer.
So with that said, I'm not looking for an overpowered car with 80s suspension, I just tore down my motor today to find that two of the connecting rod bearings are trashed and spun destroying the crank and connecting rod bearing surfaces. At this point I want to do a full rebuild with pistons, rods, and cam. Keeping in mind this is the 87 2.5 with DIS, can anyone recommend a cam for this? The stock cam is a roller and before I go with stock I was curious if going with a performance non roller is worth it. Also anyone have any other recommendations for pistons and or connecting rods?
I believe there is a oil galley problem (trying to change from a roller to a Non Roller) WHY would you WANT to ? (I would for sure stick with the roller cam you could" port match" blueprint, balance,( you have to replace the rods and pistons,Crank, might as well balance the assembly)... a Duke was not designed for High Rpm so I don't know how much you could "reliably" get out of it. just use QUALITY parts.
If the crankshaft isn't scored too badly, you could have it reground, and get bearings to match. I also agree you should keep the roller cam. Maybe a custom cam shop could regrind it, or grind out something a little more aggressive. If the pistons and rods aren't damaged, you can keep them. But you should have the block honed, with new rings to match.
For the cylinder head, there are two options. You could have your existing head reconditioned, or you could swap on a head from a Chevy S10. There's a thread about that in the archives. ---> https://www.fiero.nl/forum/A...130314-2-116541.html
Since your taking the engine apart anyway I would also put in the adjustable rockers like Ventura did on his duke. I plan on doing mine to make it quiet. Good luck with it, I have an 85 GT that I like but my 85 duke 5 speed is fun to drive too.
Thanks for the input. I spent the evening looking for new connecting rods and not having much luck. The Fiero Store sells "reconditioned" ones, but I was hoping to find new. Rock auto has 3 in stock with a notice about the manufacturer no longer providing them. Three out of the four connecting rod bearings spun and the journals look very bad on two of them on the crank. It's hard to justify cost to rebuild a 100 Hp engine when in the past I was able to install a 4.9 engine for less money. I'm trying to stay on track and resist cutting this nice car up for a bigger engine. I have never had a stock running fiero and would like to enjoy owning one for a change and just enjoy driving it as a classic. It's so hard for me to stay on track and stick with keeping it stock when I have a 4.6 Northstar, Getrag, and flywheel setting next to the car.
If anyone knows of a source for new connecting rods, I'm interested.
Get a better motor to start with. DIS VIN R engine was common 87-92. Late years adds more HP.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Originally posted by Eric_PA: I'm trying to stay on track and resist cutting this nice car up for a bigger engine. I have never had a stock running fiero and would like to enjoy owning one for a change and just enjoy driving it as a classic.
Unless you're committed to rebuilding just for the fun of it, what about the option of sourcing an '87 2.5L? That's what I did for my '86 that had a death rattle. I used & sold more parts from the donor car than it cost before I got around to the swap. Basically the engine was free...
Unless you're committed to rebuilding just for the fun of it, what about the option of sourcing an '87 2.5L? That's what I did for my '86 that had a death rattle. I used & sold more parts from the donor car than it cost before I got around to the swap. Basically the engine was free...
I guess I was kind of thinking to keep the car 100% original including the engine, but maybe that's just not a realistic idea. I was also thinking of a full rebuild so I know exactly what I have as far as the engine goes. I figure a quality rebuild would be just as good, if not better than factory. You may be right about sourcing another 2.5. I think back to over ten years ago when I decided to do a performance rebuild on a 1990 3800 engine for my fiero. I spent $3000 on the engine for a high 13 second car when I could have just put in a SC 3800 engine. Sometimes I'm a bit stubborn.
For the cylinder head, there are two options. You could have your existing head reconditioned, or you could swap on a head from a Chevy S10. There's a thread about that in the archives. ---> https://www.fiero.nl/forum/A...130314-2-116541.html
That's all I can think of for now.
Thanks for that link blacktree! And your not cheap OP. Your just budget orientated. lol
I had the same "CHOICE" to make (my 85 Has a very Low mile 4 cyl), I ended up getting a 87 GT body to put my 3800SC into, the 85 remains bone stock ( in too good a cond to alter)
Eric, I am doing the same with mine. I race vintage two strokes which are faster than any Fiero I can build. So I too decided to go all stock, port match etc. I just want good fuel economy and handling, so I am refreshing all components to new/better than stock. Sometimes it's nice to have something as the engineer intended, especially if you've built custom in the past,
I'm subscribing to your thread, look forward to your build.
[This message has been edited by mckaymotoworks (edited 04-01-2014).]
Buy new head bolts Buy the ARP rod bolts Have whatever rods you choose to use re-sized.
I wouldn't go with a hotter non-roller cam, when you can get a reground roller. That said, I don't know that you'll have any/many valvespring options, and a hot cam with stock springs is useless. You'll probably have to get on the phone with Comp Cams due to the short installed height of the springs.
I would go for the best valve job you can reasonably afford, under about .200" lift valves limit flow more than the port itself.
The exhaust manifold is pretty terrible, specifically in/near the collector.
There has been some really good input here from you all. It has been a tough decision to make as far as what direction I want to go with this car. I bought it over the summer knowing the engine was bad, so I just parked it for the winter in my garage until I could get my other projects out of the way. At this point, I just want to drive it cause it's been about four years since I sold my last 4.9 Fiero.
I'm going through withdraw...
Anyway I had to do one more reality check before I commit to rebuilding a 90 HP 4 cylinder. I have to say, it's hard to look this direction with a 300 Hp engine setting in the garage. But the reality is It would take me over a year to find time to cut up the Fiero to wedge the northstar in it.
I spent the afternoon looking at the costs one more time, and realized that I would need to spend an additional $3500 to get the northstar in since I would need to convert the trans over along with shift cables , slave cylinder, and clutch plus misc items. I already have a spec flywheel, but that may become a paper weight in the garage for an eternity. To rebuild the 2.5 and fix the exhaust, I'm looking at about $1400 (doing things right) and that would get me back to driving a Fiero by summer.
So another wards my mind is made up on this project and would like to proceed using as good of components as I can find for the Iron Duke. My first step will be a visit to the local machine shop to see if the crank is reusable. I also will need to get a new head and need to sift through all of the info online to figure out what works and what doesn't. The 88 S10 head idea looks promising. I am being realistic about this and want to state I will not be building a performance engine. The word performance and Iron Duke do not go together. I just want to build a better than new engine to keep this thing on the road and enjoy for some time. If I want to go fast, I have other toys at my disposal.
It has been a long time since I have posted on this forum, so I will need to look into how to post pictures again. I remember way back I used a tool called image poster. I promise when I get things moving, I will post pictures and progress on the rebuild and will create a link in this thread to point to it.
