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| 331ci 86GT - Just for fun. (Page 1/8) |
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fishsticks
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MAY 04, 09:51 AM
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****To skip to the 355 rebuild click here.****
**WARNING - I write novella length posts**
Hey all,
I think I was on this forum 20 years or so ago, or I at least lurked here. Thought I'd pop in and show what I've been working on for the past year or so.
A little background:
This is my 4th Fiero. I took a 15+ year break to play with F-bodies, rock crawlers, Rotrex'd Tacomas, LS trucks etc. I still have some of those, but through all those years there was still a Fiero shaped hole in me. A couple years ago I bought some property with a proper shop on it, and it didn't take me long to start looking after that. My lovely bride-to-be is more than just patient with my hobbies, she encourages them. All systems were go.
I, like many others, was thinking about a 3800 swap car. I've purchased other people's projects before, and really thought I'd want a blown up 2.8 car to start fresh with. Also, I like autos for trucks and drag cars, but all my Fieros were sticks, and this one was going to be the same. This wasn't going to be a resto and it wasn't going to be a drag car. I wanted a weekend warrior that might do an occasional club day at the track.
I spent a few months looking around. I found:
- a bunch of autos
- a bunch of horrible fiberglass mods
- soooo many cars without titles
- clean stock cars that guys were still in love with and wanted way too much for
- a couple V8 swaps (4.9s)
Eventually, I ended up with this:
I actually skipped over this car twice while looking. It was listed as a "V8 Fiero with bad motor" and the pictures kind of sucked. I messaged the guy and got additional (better) pics, discovered he'd painted the car recently and it was mostly complete with a good trunk and a TITLE. I drove 3.5 hours to go look at it and bought it. The guy actually had a lot of other cool cars (not junk) at his shop. The Fiero "needs a new owner" though. He'd done some work but was over it.
The car BARELY ran and the ring gear on the flywheel was toast. We half drove, have ran the starter half pushed it onto the trailer.
I also bought one of these.
The car is an early 86GT with a 4 speed. Don't let the 88 wheels fool you. The swap was done with an Archie plate but most everything else looks like it was homebrew. The guy I bought it from did not do the swap (I actually bumped into the original owner on Youtube recently).
The original plan was simple:
- Toss the SBC
- Buy a 4.8L LS truck flywheel. They are thick enough to bridge the .400 gap between SBC and LS crank setback.
- Install LS4 to Archie plate with starter mounted to plate.
- Buy Terminator-X
- Profit
First though, I figured I'd see what was up with this SBC. Maybe I could get it going and have a motor to sell. The PO had tried to build it and put some cheap speed parts on it, including a set of heads and a FiTech. I respected that, because back when I was last into Fieros, people thought pulling a smog 305 out of a run-down truck and putting it into a Fiero somehow made a fast car.
Pulled casting numbers off the block - Wait just a second here. 1966 327-300.
Camel hump heads weren't there, obviously. Those are junk anyway, despite what your dad said. 30-30 cams suck too. It's 2021 people.
Check the front deck pad - This block's been decked. Hmmm. OK, let's pull this thing and see what we got.
Oh. Two bent valves. Tore up rocker studs. Guide plates and self-aligning rockers. There's why it runs like crap.
.030 over flat top pistons. Block was decked on both sides. About .035 deck clearance on the piston.... and the PO put .049 head gaskets on it. Reason two why this thing sucked. It was sporting like 8.5:1 compression and .085 quench.
Spin the motor over and pull the pan.
This rotating assembly is CLEAN, the forged components are still there, and it's had work done. I measured out the bores, and checked clearance on a couple bearings. This thing is fresh!
Let's look at the heads...
These are Assault Racing SBC heads. They are Chinese Dart Pro-1 knockoffs with 200cc runners and 64cc chambers. Multiple sources have flowed them at 250cfm as cast. They're notorious for having terrible hardware on them though.
But.... they're true and the seats aren't chewed up. Nor are the guides bad.
I hadn't built an SBC in a hot minute. But golly, this was starting to look like I could have some fun with it. The PO had stuck a way-too-big Thumpr cam in it with flat tappet lifters (bleh). Maybe I can bring a little 21st century tech to this thing?
That's enough for now. I'll pick this up later.
You've made it this far. Here's one last teaser picture.
 [This message has been edited by fishsticks (edited 06-16-2021).]
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Will
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MAY 04, 11:08 AM
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So it's a 0.030 over 327? Interdasting.
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fishsticks
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MAY 04, 12:40 PM
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| quote | Originally posted by Will:
So it's a 0.030 over 327? Interdasting. |
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That it is.
I doubt there will be much groundbreaking tech wise in this thread. I know the 3800 is the darling currently and a lot of guys are testing the limits of various V6/Ecotec swaps now.
I'm also aware SBC swaps get some hate in various corners of the internet. Maybe some of it is warranted.
Power is power though, we're all trying to make some.
The weight thing is meh to me, as an aluminum head/intake SBC really doesn't weigh much more than the 2.8L package and when you strip out all the extras (A/C, emissions junk) the weights get even closer. If I get really stuck on weight savings at some point, I'll just go on a diet.
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Raydar
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MAY 04, 01:02 PM
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This looks interesting.
The thing that most people bag on SBCs about is the low-down torque that tends to shatter Fiero manual trannies, and perceived lack of top end.
This looks to be more of a "revver". Maybe it'll make some good power without blowing differential gears all over the ground.
(I can't talk. I've got a manual 4.9, so I get it. Haven't broken any transaxles, yet, but have broken a motor mount off of the block.  )------------------
Raydar
88 Formula IMSA Fastback. 4.9, NVG T550
Praise the Lowered!
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fishsticks
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MAY 04, 01:33 PM
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| quote | Originally posted by Raydar:
This looks interesting.
The thing that most people bag on SBCs about is the low-down torque that tends to shatter Fiero manual trannies, and perceived lack of top end.
This looks to be more of a "revver". Maybe it'll make some good power without blowing differential gears all over the ground.
(I can't talk. I've got a manual 4.9, so I get it. Haven't broken any transaxles, yet, but have broken a motor mount off of the block. )
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My understanding is Archie's flywheel is also pretty heavy (>30lbs) which doesn't help with shock loading. I am using a redrilled early Corvette flywheel that weighs in at around 15lbs.
I considered overcamming the motor to shift the power curve even further up, but ultimately didn't.
Spoiler: The car actually works well. I've been driving it for several months. I am pretty easy on launches though. I don't foresee any 1.5sec 60fts in this thing's future.
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fishsticks
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MAY 04, 04:32 PM
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So, I guess we're building a 327 now. Cool.
327s are famous for liking to wind out (though really, any SBC will). That's desirable for a small sporty car.
They also came factory with solid lifter cams. That might be cool for a retro thing and would definitely give us RPMs. But accessing the forward valve cover requires one to tip the cradle down in back. Not exactly conducive to adjusting valve lash regularly. OK, hydraulic it is.
But flat tappet hydraulics all have lazy ramps and low lift. These heads flow best around .550 valve lift. Here is the cam that came in the car.
12-601-4 Comp Cams Mutha Thumpr Hyd Flat Tappet Cam
235/249 @ .050 .489/.476 107 LSA
Good grief. This thing is designed to do one thing - idle poorly.
So, Engine Analyzer Pro is a neat program. The calculated power results aren't a substitute for real dyno time. But they usually get close if you give the program the correct values (including accounting for an actual exhaust). More importantly, the plotted curves let you compare how different components will react in a motor. For SBCs, head flow numbers, cam and intake profiles are prolific and included with the program.
Here is a plot of the two cams I narrowed my choice down to.
Blue/Green is the Comp Cams XE503 Hyd Roller 224/230 .503/.510 112LSA
Red/Cyan is the Lunati Voodoo 20120711 Hyd Roller 219/227 .515/.530 112LSA
Both are run on 1.6 rockers in this simulation. We get a touch more valve lift and the valves stay in the higher lifts (where our heads breathe the best) a bit longer.
I had great luck with the XE503 in an LT1 F-Body I had (bolt ons, cleaned up stock heads). That car dynod 363rwhp at around 6000rpm. So it was on my short list from the get go.
The Voodoo is the cam I actually ended up going with for this motor, even though the 503 made more peak HP. The Voodoo beats it all the way until around 5500RPM. While I shift this car at 6500, I don't live above 5500 for long periods of time.
So anyway, I stripped the heads and put new valves and hardware into them. Then started putting the motor back together. I used a .015 steel shim head gasket to get quench to .050. SCR came out to 9.66:1, DCR is 7.90:1.
[Cue video montage of engine assembly, cut with dramatic music and overlays of tigers roaring]
Ignore the goofy T-bars. They were floating around the shop.
That exhaust system is a war crime, but I was anxious to get the car back together so it stayed for the moment.
On Nov 24th, 2019 I drug this car home. On Jan 8th it fired for the first time. By Jan 14th I had it running pretty well.
https://youtu.be/gxey9jTzsFc
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Will
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MAY 04, 05:46 PM
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Still working with the tilted carb... 
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fishsticks
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MAY 04, 05:57 PM
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| quote | Originally posted by Will:
Still working with the tilted carb... |
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That's a FiTech "600hp" EFI setup in ugly carb gold. I even stuck a triangle of death on it for awhile. 
It's gone now. 
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fishsticks
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MAY 04, 06:36 PM
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Here's a random picture of the old clutch.
It has a Spec Stage 3+ now. The flywheel is from an early Corvette (15lb) redrilled for a Fiero clutch. It was in good shape beside the ring gear, so I bought a new ring gear. Weed burners are good for heating up ring gears for easy removal/installation. The Powermax starter needed a new clutch/drive assembly as well. Apparently I wasn't feeling like a photographer that day.
I started working on some interior things. Because OF COURSE the heater core leaked (it wasn't hooked up when I got the car). Also, someone who had no business touching electrical had touched electrical. So I had to fix that.
Dew wipes? Yeah, those too.
Found this in the CD player.
Dash wasn't terrible, but had a couple questionable spots. Vinyl wrap does a pretty good job with that.
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fishsticks
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MAY 04, 06:57 PM
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