331ci 86GT - Just for fun. (Page 3/8)
fishsticks MAY 07, 03:16 PM

quote
Originally posted by La fiera:

That's a bummer!! Did you put silicon seal on the head bolt threads?



Yeah, all wet threads got sealer. The motor held for a year. We'll see what I find when the heads come off.
fieroguru MAY 07, 08:12 PM
Looks like a fun SBC swap.
fishsticks MAY 08, 02:09 PM
ALL RIGHT LETS BREAK SOME STUFF!

I took the afternoon off and decided to start taking stuff apart yesterday. Only had an hour and a half to spend on it, but got some answers.

First things first... Do you hate coolant messes? I do. So we need to get the coolant out of this thing. Draining the coolant sucks. You know what works awesome though?



Ye Olde Home Depot 6hp shop vac will happily empty your cooling system for you. Just put it to the fill port and let er rip. After a minute or so, go up front and crack the radiator cap. No mess!






I'm sure many here know this already, but it's always worth saying: Plan your wire and hose routing ahead of time! Smartly laid out routing makes the difference in being able to take things apart in 15 minutes or 2 hours.

EFI Off:



Intake manifold Off:



We can see #8 intake is carboned up from reversion since the exhaust valve wasn't closing.



We'll just leave those down there for now.



Head stud nuts off. Let's make sure we're dry inside.



Hmm, no obvious signs of gasket failure from this side. #8 doesn't look great though.



Let's look closer...

Aaaaaaaaand...

Oof.




I guess this is going to turn into a REBUILD thread now.


I made a couple calls and have a few options in front of me:

  1. Send the block to a machine shop. Have them check it and install a sleeve into #8. In the interest of thoroughness, I'd likely have them go through the rotating assembly as well. I'd also take this opportunity to bump compression with different pistons.
  2. I have a buddy who's a truck mechanic. He has a professionally rebuilt L31 4 bolt main long block that's sitting in plastic. He bought it for a customer and the sale fell through. He paid too much for it though ($2400), and I don't want to kick his butt on price. Plus I only need a shortblock.
  3. Buy a forged 383 ATK shortblock from Jegs, or similar. ($2500ish)
  4. We have a 2008 Denali with a 6.2L L92. These motors have rec port heads, 403hp factory and are a cam swap away from 500hp (My 2011 6.2L truck has a few goodies and moves for a 5000lb pig). It's got 330K miles, but runs great. The trans is sketchy though, and we've considered replacing it with a new car. Yanking the trans out of that was supposed to be my next project.


LS swapping is tempting, and there's big power available, but at this point it means discarding a lot of what I've already done and starting over. I kinda want to drive this car again soon. Plus I'd need to freshen the engine.

Buying another shortblock is a quick option to get the car running again, but requires I machine a late gen1 flywheel to accept the Fiero clutch. I'd also gain some displacement and compression (with the 383). The downside of course is cost.

If I can get a quick turnaround from the machine shop, I can get this block back in service with a little more compression as well. The problem here is this block is 55 years old, and I can't figure out what caused the cylinder crack other than metal fatigue. I'm concerned this one has just lived its life.


Guess I have some thinking to do.
Raydar MAY 08, 09:46 PM
I'll just drop this here. Not that it's practical, but it may give you some ideas.
https://www.fiero.nl/forum/Forum2/HTML/144310.html

When I posted this, lots of people brought up very valid points regarding SBC vs LS swaps (among other things.)
I won't attempt to argue with those, but since you're about hip-deep in SBC hardware, and not averse to "flying in the face of convention", I'll go ahead and post it anyway.

[This message has been edited by Raydar (edited 05-08-2021).]

fishsticks MAY 08, 11:53 PM

quote
Originally posted by Raydar:

I'll just drop this here. Not that it's practical, but it may give you some ideas.
https://www.fiero.nl/forum/Forum2/HTML/144310.html

When I posted this, lots of people brought up very valid points regarding SBC vs LS swaps (among other things.)
I won't attempt to argue with those, but since you're about hip-deep in SBC hardware, and not averse to "flying in the face of convention", I'll go ahead and post it anyway.




I like the thinking in that thread. I'm a former 4th gen F-body guy, so I've built a couple LT1s and thought in the past about doing an aluminum head swap L99. If I wasn't knee deep in nearly new SBC parts (like you mentioned) it might be a fun change of course.

One of the traps I see a lot of people fall into (especially in the "what-if" scenarios) is sky-high RPM. Yes, you can do it. Yes, valvetrain stability is a challenge that can be managed. The thing a lot of people forget is the use case though - does anyone really want to wind a motor to 8K+ on the street? I don't. I think 7K is the upper limit for a V8 street car personally, and probably less. I was pretty happy shifting at 6500 on the 327, and I wish I'd have had time to get to the dyno and compare results to what the simulations I ran said.

The nice thing about this car relates to the "Just for fun" tag I put in the title. I's not a drag car and it's not an AutoX or road race car. It's just a toy. If I was building a car for any competitive motorsport, I'd want to compete. IMO the Fiero just isn't suited to... well any of those. I'm not 19 anymore, so I'm certainly not daily driving a Fiero and dealing with all the compromises of reliability. I just built a car that I can jump in when I want to, have fun driving and hurt feelings on the interstate with.

I've had a BIG problem with scope creep on some past projects. So for this one I'm highly focused - on not making the car specialized for anything in particular.

The way I'm leaning right now is to buy a forged 383 shortblock at around 11:1 compression, bolt my current heads on, and overcam it to soften the low RPM torque. It should make gobs of power under 7000 even with the "wrong" cam, and the bottom end will stand up to being bottle fed should I get a wild hair. It's not the cheapest option, but it would me driving the car again reasonably quickly. Or maybe I'll cheap out and grab a junkyard 9:1 Vortec and do the same.

Someone please tell me why this is a bad idea.
fieroguru MAY 09, 09:42 AM
With all you needing is a short block, the quickest path to more fun is getting another short block of the same vintage to maximize the usage of your current parts. Going with a 86+ block or going down the stroker route just means you will have more parts to buy and some parts become more complicated (stroker balancing issue). Nothing that can't be solved, but solving them will cost more $$ or require other custom parts.

Once you start looking beyond a simple short block swap that includes changing a lot of parts, then you might want to take a step back and really consider your options.

I defected from the SBC camp back in 2009 and focused my efforts and $$$ on the LS4/F40 swap when I was faced with replacing the SBC in my Fiero (pulled it to fix my DD truck). I totaled up the $$$ I was planning to spend to upgrade my SBC swap and factored in the $$$ I could get from selling off my SBC parts (got 75 cents on the dollar) and got within striking distance between the cost of the two. The main issue was the time... as there was no starter, flywheel or clutch solution at that time and it took me 3 years to get the car back on the road.

I am very happy I made the switch, but it definitely isn't for everyone.
La fiera MAY 09, 09:55 AM
Get the junkyard motor half fill it with Hard Block then get the stroker kit .060 over. Block doesnt need cooling, the heads do.
fishsticks MAY 09, 12:19 PM

quote
Originally posted by fieroguru:

With all you needing is a short block, the quickest path to more fun is getting another short block of the same vintage to maximize the usage of your current parts. Going with a 86+ block or going down the stroker route just means you will have more parts to buy and some parts become more complicated (stroker balancing issue). Nothing that can't be solved, but solving them will cost more $$ or require other custom parts.

Once you start looking beyond a simple short block swap that includes changing a lot of parts, then you might want to take a step back and really consider your options.

I defected from the SBC camp back in 2009 and focused my efforts and $$$ on the LS4/F40 swap when I was faced with replacing the SBC in my Fiero (pulled it to fix my DD truck). I totaled up the $$$ I was planning to spend to upgrade my SBC swap and factored in the $$$ I could get from selling off my SBC parts (got 75 cents on the dollar) and got within striking distance between the cost of the two. The main issue was the time... as there was no starter, flywheel or clutch solution at that time and it took me 3 years to get the car back on the road.

I am very happy I made the switch, but it definitely isn't for everyone.



Thanks for taking the time to explain your journey. Before I bought this car, I did some lurking here to see what the current trends were. I've checked in on a lot of your threads and watched your progress. You've definitely brought some incredible engineering and products to the Fiero community. And (since I notice these things) you've been free in sharing your knowledge, rather than trying to cover it as some sort of trade secret. As a guy who struck out on his own trying to push the envelope on another platform (GMT360), I get the time investment that's required.

Obviously I'm not the first to go down the SBC Fiero path, nor will I be the last. But it's good to learn from those who've already been there.


quote
Originally posted by La fiera:

Get the junkyard motor half fill it with Hard Block then get the stroker kit .060 over. Block doesnt need cooling, the heads do.



You think like I do, lol. 388 FTW.


Here's where I'm at after a day or so of research:

  • Local machine shops with any sort of automotive reputation are all over 1-2 months out.
  • "Rebuilder" machine shops within 100 miles don't offer anything other than stockish parts, even on their "performance" offerings.
  • CL is filled with the usual "rebuilt/race motor but I lost the receipts" for $4000+, rusty "ran great when pulled" motors that have sat in the rain for 20 years etc.
  • Early SBC stuff is gold plated. Silly people asking $600/ea for camel hump heads, $300 for 993s etc. I have this weird feeling I could sell this cracked 327 block...
  • Junkyards want $1000ish for high mile SBCs and won't sell a shortblock.
  • TLDR: I live on the Left Coast. Everything is expensive, including LS stuff.


Also:
  • I am at the point in life where the money-time paradox has shifted from lacking money to lacking time.
  • This isn't an unlimited budget project, but I have cash to throw at it.
  • Time is at a premium right now. I own a small business and we've had our two best quarters ever back to back.
  • I have traditionally been the guy who needs the have his hands in every part of a project. But learning to be a good manager has taught me that sometimes you have to delegate.


So, I've delegated my engine build and bought this:
https://www.jegs.com/i/ATK-...es/059/SP52/10002/-1

It should be overkill for the power/RPM level I want. Not top shelf parts per se but I've had good luck with Scat in the past. My understanding is ATK builds their performance line in house (they farm out the cheaper rebuilds to Mexico) and they seem to review well.

I'm going to need:
  • A new flywheel - the OEM one I use currently is available in one-piece RMS flavor. I should be able to handle redrilling it here on the press.
  • A new oil pan - I've been wanting to try a baffled circle track pan, and I believe there's axle clearance.
  • A new cam - Would need to happen anyway. My retrofit lifters are tall and SHOULD clear the late model bores. But not a big deal if not.
  • There are a couple other "Wish I would have..."s that I will address.

[This message has been edited by fishsticks (edited 05-09-2021).]

La fiera MAY 09, 02:00 PM
Is it internally or externally balanced? The description is not clear.
fishsticks MAY 09, 02:50 PM

quote
Originally posted by La fiera:

Is it internally or externally balanced? The description is not clear.



All SBC's are -technically- internally balanced. However, the post 86 blocks and roller blocks (1 piece RMS) moved the rear crank weight to the flywheel to make room for the rear main seal adapter. A lot of people consider that to now be externally balanced.

The one I bought is a later roller block, so it will be 1 piece RMS and need the weighted flywheel. If you look in the description, they refer to the block as a "Seasoned OE 4 bolt main 1pc seal 1996-2000 roller block". That means it will be an L31 block.

[This message has been edited by fishsticks (edited 05-09-2021).]