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2.5 Cylinder head questions (are all years the same?) by Kameirocco
Started on: 09-13-2025 07:46 PM
Replies: 10 (79 views)
Last post by: 82-T/A [At Work] on 09-15-2025 08:12 AM
Kameirocco
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Report this Post09-13-2025 07:46 PM Click Here to See the Profile for KameiroccoSend a Private Message to KameiroccoEdit/Delete MessageReply w/QuoteDirect Link to This Post
I had a 3500 i was going to swap in, but the version i pulled from a car was the later 3500 that was a destroked 3900 with VVT, and no one is willing to help me program the ECU easily lets just say, i can't afford that one.

So just to get my car running and driving reliably, i'm looking at doing a nice basic rebuild on my iron duke...
I'm looking at just getting a re-man prebuilt head, the only one i can find is for the 87-88 motor, and i have an 86...
Are there any differences between them as to where i couldn't use this?

https://www.summitracing.co.../pontiac/model/fiero

This looks to be a lot cheaper than getting my head rebuilt.
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Report this Post09-13-2025 09:26 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
The 87+ cyl heads are definitely different. If you have a 1986, then you can use a Fiero cyl head from 1984-1986, but not the later ones.


What's wrong with the one you have? Is it cracked?
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Report this Post09-13-2025 10:58 PM Click Here to See the Profile for KameiroccoSend a Private Message to KameiroccoEdit/Delete MessageReply w/QuoteDirect Link to This Post
As far as i know it's fine - the car however was sitting for 20 years and has almost 200k on it
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82-T/A [At Work]
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Report this Post09-14-2025 10:31 AM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Kameirocco:

As far as i know it's fine - the car however was sitting for 20 years and has almost 200k on it



Ok, in this case, you generally don't replace a cyl head. A cyl head is something that gets re-used, just like the engine itself.

Typically what you would do if you wanted to rebuild the top end is take the cyl head off, and then order new springs and valves, take it all to a machine shop, and they'll do all the machine work for you. That includes decking it to make sure it's still straight, doing a valve job, making sure the valve guides are still good, etc. And then you get it back from them and you re-install it. But at 200k miles, I don't know that I'd be putting any real effort into the top end, unless you were planning to also do the bottom end.

Does it smoke at all?

My daughter's engine had over 200k miles on it, but she ended up rebuilding the entire thing, and the motor runs really well. So, it's worth it, but if you want some real power, and still want the Fiero to feel like a Fiero, you can always go with an LNF Turbo 2.0 L4. We have one in our 2007 Pontiac Solstice GXP, and the thing is sick-fast.
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richard in nc
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Report this Post09-14-2025 12:37 PM Click Here to See the Profile for richard in ncSend a Private Message to richard in ncEdit/Delete MessageReply w/QuoteDirect Link to This Post
when my 2.5 head gasket blew a machine shop rebuilt the head for two hundred dollars.why not see if it will run first?
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Kameirocco
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Report this Post09-14-2025 06:42 PM Click Here to See the Profile for KameiroccoSend a Private Message to KameiroccoEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by richard in nc:

when my 2.5 head gasket blew a machine shop rebuilt the head for two hundred dollars.why not see if it will run first?


It does run, and runs decently. But while i'm going through everything, i'd rather have the head and block redone. i have about $1000 worth of parts sitting on a shelf waiting to go into the car. the internals of the engine are the last hoop

 
quote
Originally posted by 82-T/A [At Work]:
Ok, in this case, you generally don't replace a cyl head. A cyl head is something that gets re-used, just like the engine itself.

Typically what you would do if you wanted to rebuild the top end is take the cyl head off, and then order new springs and valves, take it all to a machine shop, and they'll do all the machine work for you. That includes decking it to make sure it's still straight, doing a valve job, making sure the valve guides are still good, etc. And then you get it back from them and you re-install it. But at 200k miles, I don't know that I'd be putting any real effort into the top end, unless you were planning to also do the bottom end.

Does it smoke at all?

My daughter's engine had over 200k miles on it, but she ended up rebuilding the entire thing, and the motor runs really well. So, it's worth it, but if you want some real power, and still want the Fiero to feel like a Fiero, you can always go with an LNF Turbo 2.0 L4. We have one in our 2007 Pontiac Solstice GXP, and the thing is sick-fast.



Oh i know all of that, this isn't my first rodeo with cars, come from a line of early watercooled volkswagens.
But it's cheaper while i'm looking at ones that are already rebuilt - and i'm already aware of what you're talking about (not being rude, promise!)
last time i got a quote on a cylinder head rebuild at 2 different shops around here, it was well over $400, that was just getting valve guides installed, cut, valve job and head decking.
I had a honda head rebuilt about 20 years ago at another machine shop and it was around the same price as well, and that was just a basic civic motor out of an 86.

i'm planning on doing the bottom end, but that's a different part of the project. i'm strictly looking at just the top end right now.

Not looking at getting a different engine at all right now. Plus i do not want a fast fiero, i just want a more modern one when i get to doing that, something that would keep up with traffic well, like a 3400 from a grand am, or a twin cam out of a late 90's Z24. I would like to keep it 4cyl whenever i go down that route though. the 3400 is just a maybe.
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Kameirocco
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Report this Post09-14-2025 06:57 PM Click Here to See the Profile for KameiroccoSend a Private Message to KameiroccoEdit/Delete MessageReply w/QuoteDirect Link to This Post

Kameirocco

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quote
Originally posted by 82-T/A [At Work]:
Ok, in this case, you generally don't replace a cyl head. A cyl head is something that gets re-used, just like the engine itself.

Typically what you would do if you wanted to rebuild the top end is take the cyl head off, and then order new springs and valves, take it all to a machine shop, and they'll do all the machine work for you. That includes decking it to make sure it's still straight, doing a valve job, making sure the valve guides are still good, etc. And then you get it back from them and you re-install it. But at 200k miles, I don't know that I'd be putting any real effort into the top end, unless you were planning to also do the bottom end.

Does it smoke at all?

My daughter's engine had over 200k miles on it, but she ended up rebuilding the entire thing, and the motor runs really well. So, it's worth it, but if you want some real power, and still want the Fiero to feel like a Fiero, you can always go with an LNF Turbo 2.0 L4. We have one in our 2007 Pontiac Solstice GXP, and the thing is sick-fast.


Also, if your daughter is the one doing GenZ garage, she's doing friggin fantastic. Between her and Ron, they're a godsend.
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Report this Post09-14-2025 07:44 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
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Originally posted by Kameirocco:
Oh i know all of that, this isn't my first rodeo with cars, come from a line of early watercooled volkswagens.
But it's cheaper while i'm looking at ones that are already rebuilt - and i'm already aware of what you're talking about (not being rude, promise!)
last time i got a quote on a cylinder head rebuild at 2 different shops around here, it was well over $400, that was just getting valve guides installed, cut, valve job and head decking.
I had a honda head rebuilt about 20 years ago at another machine shop and it was around the same price as well, and that was just a basic civic motor out of an 86.

i'm planning on doing the bottom end, but that's a different part of the project. i'm strictly looking at just the top end right now.

Not looking at getting a different engine at all right now. Plus i do not want a fast fiero, i just want a more modern one when i get to doing that, something that would keep up with traffic well, like a 3400 from a grand am, or a twin cam out of a late 90's Z24. I would like to keep it 4cyl whenever i go down that route though. the 3400 is just a maybe.


Ah ok... yeah, you never know. Sometimes people come on here and they're like... "I want to go 200 miles an hour. I have $500 dollars to spend, what do I do?" and then you just have to bring them back to Earth, haha.

The 3400 is kind of my "ideal engine" for a Fiero. I have an 87 Fiero SE / V6 in storage, and I'm doing a 3.4 rebuild with it. If I wasn't emotionally tied to the look and originality of my high school car, I'd want a 3400 in it too. Twin Cam is also awesome. I had one in a 97 Grand Am back in the day, they pull hard... love that LD9 Twin Cam.


 
quote
Originally posted by Kameirocco:

Also, if your daughter is the one doing GenZ garage, she's doing friggin fantastic. Between her and Ron, they're a godsend.


Yes, it is! Thanks for watching, I know she appreciates all the support she gets!
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Kameirocco
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Report this Post09-14-2025 08:21 PM Click Here to See the Profile for KameiroccoSend a Private Message to KameiroccoEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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Originally posted by 82-T/A [At Work]:

Ah ok... yeah, you never know. Sometimes people come on here and they're like... "I want to go 200 miles an hour. I have $500 dollars to spend, what do I do?" and then you just have to bring them back to Earth, haha.

The 3400 is kind of my "ideal engine" for a Fiero. I have an 87 Fiero SE / V6 in storage, and I'm doing a 3.4 rebuild with it. If I wasn't emotionally tied to the look and originality of my high school car, I'd want a 3400 in it too. Twin Cam is also awesome. I had one in a 97 Grand Am back in the day, they pull hard... love that LD9 Twin Cam.


Yes, it is! Thanks for watching, I know she appreciates all the support she gets!


Oh man, yeah, i know what you mean, the sort of equivalent motor in the VW community from early on was the ol trusty 1.8l 8v that was in EVERYTHING, came with around 90hp and 90?tq, people wanted to get 300hp by a few bolt ons... hahaha

and totally, the 3400 i feel like is the newer 2.8 that was in the fiero and somewhat modern fuel injection - i think if i got that, i'd be more than pleased and if that was your actual high school car, hats off to you! I had an 84.5 scirocco that i let go to the crusher.
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Report this Post09-14-2025 08:23 PM Click Here to See the Profile for KameiroccoSend a Private Message to KameiroccoEdit/Delete MessageReply w/QuoteDirect Link to This Post

Kameirocco

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OH and i did just go and do a compression test (not sure why i never did one)
Left to right
150-130-150-140 - so all in all, a motor with 180k that hasn't run in 20 years... i'll take it - drove it around the block once and to get it onto the trailer, but that was after a jump.
I think i'll pull the motor and re-gasket the whole thing (it's leaking like a shiv) replace the valve guide seals and run it until it dies... if i start seeing smoke or anything i'll probably take a look at pulling it at that point.

although... might wanna do the timing gear while i have the engine out, who knows!
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Report this Post09-15-2025 08:12 AM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Kameirocco:

Oh man, yeah, i know what you mean, the sort of equivalent motor in the VW community from early on was the ol trusty 1.8l 8v that was in EVERYTHING, came with around 90hp and 90?tq, people wanted to get 300hp by a few bolt ons... hahaha

and totally, the 3400 i feel like is the newer 2.8 that was in the fiero and somewhat modern fuel injection - i think if i got that, i'd be more than pleased and if that was your actual high school car, hats off to you! I had an 84.5 scirocco that i let go to the crusher.



Shortly after meeting my wife (then girlfriend), she had just bought a 2002 VW Jetta 1.8T Wolfsburg edition. It was pretty sweet. She ordered the really high-end version. The number grows every time I say it, but I think it was the 185hp version. They offered a Turbo version, and then they offered an improved version on top of that. That's the one she had. It's funny, because I don't even know why she ordered it. It was a stick shift, etc... but the only reason why she got it is because it had the interior options she liked.

If you would floor it at the light (not doing a burn-out, just accelerating normally and floor it). It would accelerate normally and then the turbo would spool up, and the tires would be peeling out by the time you got to the end of the intersection. It was pretty wild.


And yeah, I remember renting a Grand Am back in... I dunno... 2004 on a work trip? And it had the 3400 V6. I was so impressed with how it performed. It was just your run of the mill Grand Am sedan, not even a GT with the sportier transmission tune and RAM-AIR. The thing had a fantastic torque curve and really surprised me. I think that engine would be awesome in a Fiero.

And yeah, the 87 Fiero I have is my original high school car. It's been in storage for ~15 years... and the paint on the decklid is a little faded, but the car itself is in really good condition. You can see it when my daughter is going through the storage units, looking for parts in this video she made:




... you can also see my wife's 1973 VW Bus, which has also been in storage for 15 years.


 
quote
Originally posted by Kameirocco:
OH and i did just go and do a compression test (not sure why i never did one)
Left to right
150-130-150-140 - so all in all, a motor with 180k that hasn't run in 20 years... i'll take it - drove it around the block once and to get it onto the trailer, but that was after a jump.
I think i'll pull the motor and re-gasket the whole thing (it's leaking like a shiv) replace the valve guide seals and run it until it dies... if i start seeing smoke or anything i'll probably take a look at pulling it at that point.

although... might wanna do the timing gear while i have the engine out, who knows!



If you do the timing gear, a lot of people recommend the aluminum Cloyes timing gear. That's what my daughter went with. It's better than the fiber-based timing gears. A lot of people say the fiber timing gears fail, but I've had three 4-cyl Dukes, and never seen one fail. This engine that we disassembled had over 200k miles on it, and it was still in perfect shape... but I have seen failures in pictures, just never experienced it.
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