2.5 Iron Duke / Tech-4 - Rebuild Kit or Long Block? (Page 3/4)
82-T/A [At Work] APR 27, 09:50 AM
I think I know the answer to this... but would I have any issues if I took a 1990 Pontiac GrandAm 151 L4 and put it in my Fiero? Would everything from my daughter's 85 bolt up? Really want a roller block, and just looking at possible options (I may not even need it, but I'll know this weekend). If I remember, the oil pump and some other things were different, right? (88+?)


Thanks!
theogre APR 27, 12:37 PM
New E-man comes w/ stove for thermac. Just use that.

Some 4cyl have stoves on E-pipe farther down often does 2 jobs... Stove and heat shield.
Heat shield can protect the starter and solenoid. If you lose that for any reason then starter can cook.

later 4cyl heads won't work on 86 & older. That assume all are VIN R version. Other Duke cars use VIN U and can't use whole or parts of that.
87+ heads are made different on intake side only take intake man that's made for 700 TBI.
82-T/A [At Work] APR 27, 12:49 PM

quote
Originally posted by theogre:

New E-man comes w/ stove for thermac. Just use that.

Some 4cyl have stoves on E-pipe farther down often does 2 jobs... Stove and heat shield.
Heat shield can protect the starter and solenoid. If you lose that for any reason then starter can cook.

later 4cyl heads won't work on 86 & older. That assume all are VIN R version. Other Duke cars use VIN U and can't use whole or parts of that.
87+ heads are made different on intake side only take intake man that's made for 700 TBI.




Thanks Ogre, appreciate it. Sounds like that motor I'm looking at is not an option for me.

Will do on the thermac. Thanks!
sanderson231 APR 27, 09:26 PM

quote
Originally posted by 82-T/A [At Work]:

Hey guys, I'm looking at possibly rebuilding the 2.5 Iron Duke in my daughter's Pontiac Fiero. The motor is pretty solid right now, and runs fairly well, at least as much as I can tell. I



After many years of experience in industry and hobby, "if it ain't broke don't fix it"

------------------
formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged

82-T/A [At Work] APR 28, 07:35 AM

quote
Originally posted by sanderson231:

After many years of experience in industry and hobby, "if it ain't broke don't fix it"





Yeah, I agree, but in this case it's a learning experience for my daughter (she's rebuilding her first car)




So honestly... I think regardless of what I get, I plan to rebuild the engine with her. But if I'm going to pay the machine shop fees, I'd want to do it with a roller block.
82-T/A [At Work] MAY 24, 01:05 PM
Hey guys... I'm resurrecting this thread because I'm quickly getting to the point where this will become something I want to address sooner.

So, my daughter ran a compression test on the engine last weekend, and essentially, from drivers side to passenger side, the compression was as such:

160 / 60 / 110 / 90


Cyl 1 (whatever it actually is... #4 I think?) had FANTASTIC compression. Second cyl was just attrocious, third was barely adequate, and the last one was also quite bad.

So it's clear that I will need to rebuild it.


I've started collecting parts, and I just bought a Felpro head gasket set... basically, everything from head-gasket up. So that's great.

But now I'm needing to figure out how / what I want to do rebuilding the engine. Truth is, I've never rebuilt an engine before. I assumed everything was a standard size (or maybe), so I could just order basic replacement parts, but I'm realizing that's not the case.

At the end of the day, I recognize that the Iron Duke is very much NOT a performance motor (this one at least isn't), and the operating range probably doesn't even exceed 5,500 rpms... probably doesn't even produce much additional power above 4,800. All of this is to say that I don't need a super specialized machine shop to rebuild this engine ... so, I want my daughter and I to do this together. I've always told myself that if someone else can do it, then I can do it too. I won't go through the list of all the things I can do, but suffice it to say, this isn't above my ability or intelligence. I've just never done it before.

I'd want to do a BASIC rebuild... but looking for some advice on not only what tools I need, but in what order I need to do these things. I assume I need a micrometer, a feeler gauge, and that thing that attaches to my power drill with the stones so I can hone the cyls. I know that I'm also supposed to be using an oil for when I do that... what kind of oil do I use? Also... how do I know what bearings I use? Do I measure the old ones and just order whatever matches up? How do I prep the crank to go back into the block? Do I use some kind of sand paper or leather strap to "polish" the journals? What about the pin that allows me to connect the connecting rod into the piston? What kind of piston does the Duke have... is it one of those ones that go in super easy and it uses a circlip to keep it in, or is it one of those ones that I have to press in. And if it's one of the ones that I press in... how do I make it so the pin goes into the connecting rod and the piston properly... as in, equally spaced? No bearings on that pin, so no idea what I do there.

Is there a step-by-step book (my service manual?) or are there good videos? I have no clue...


Bonus (for me) question... I seem to really have a hard time with cyl heads and torque wrenches. I had a "clicking" torque wrench, that didn't do **** . Both times I used it, it never clicked, and I busted the threads on two engines when I was re-installing a cyl head. In one case, I had to ask a shop to helicoil my motor and re-install the heads for me, and in another... I just said F-it and tightened the other bolts (another Iron Duke I had) and drove it like that (with no leaks.... haha). But I'm not 19 anymore, and want to do it right. What the hell was I doing wrong? Why did it not click? I stopped using one of those and now only use the needle ones, which suck. Any advice?


Really appreciate the help...
Patrick MAY 24, 05:00 PM

quote
Originally posted by 82-T/A [At Work]:

So, my daughter ran a compression test on the engine last weekend, and essentially, from drivers side to passenger side, the compression was as such:

160 / 60 / 110 / 90

Cyl 1 (whatever it actually is... #4 I think?) had FANTASTIC compression. Second cyl was just attrocious, third was barely adequate, and the last one was also quite bad.

So it's clear that I will need to rebuild it.



It's clear to me that the valves need attention. Unless the engine is burning oil (worn rings), or the rods are knocking (worn bearings), I wouldn't bother rebuilding it.

Having said that, if you pull the head and discover (using a cylinder bore gauge) that the cylinders are badly worn, then you might consider the effort and expense of a total engine rebuild.
theogre MAY 24, 05:48 PM

quote
Originally posted by 82-T/A [At Work]:

160 / 60 / 110 / 90


Cyl 1 (whatever it actually is... #4 I think?) had FANTASTIC compression. Second cyl was just attrocious, third was barely adequate, and the last one was also quite bad.

So it's clear that I will need to rebuild it.

#1 is Battery end. #4 next to trans.

Is likely test is wrong for many reason because likely won't start, burning a lot oil, and other problems to get those very low numbers.

Let's assume you did the test right and is a Dry test....
Still May not = to rebuild.

More so if car has been parked for months or years.

Rings and Valves get "stuck" in crap and can leak until have run @ highway speeds for an hour or more.
More so if fools don't change the oil.

1. Get a bore scope and look into the spark plug hole w/ piston at bottom. Look for damage cyl walls. If true, you need a machine shop or get another engine. look in 1 4 then 2 3. If #4 piston is clean(er) then likely bad intake gasket sucking coolant.
2. If parked, Run the engine then wait to cool/cold and test again. Valve Lifters and more need to run to get oil flowing and if not screw up the meter reading.
3. Then Do a Wet pressure test. Wet test helps tell you if the rings are bad/stuck even if cyl walls look good.
4. try a leak down test too. loaner/rental tools may have that tool.
pmbrunelle MAY 24, 06:56 PM
I don't think you can know in advance the exhaustive list of what will be needed for a given rebuild.

At a minimum, everything is taken apart for cleaning/inspection.

Then, depending on your observations/measurements, you can decide what needs replacing/machining. We can't say at this time what preparation the crankshaft (or other parts) needs.

If you're lucky, and almost nothing needs changing, then you have gained peace of mind by having evaluated the state of everything.

More importantly, the value in a complete teardown is that your daughter can handle a crankshaft and other key components; I wouldn't do just a top-end rebuild in this case.
82-T/A [At Work] MAY 25, 08:32 AM

quote
Originally posted by Patrick:

It's clear to me that the valves need attention. Unless the engine is burning oil (worn rings), or the rods are knocking (worn bearings), I wouldn't bother rebuilding it.

Having said that, if you pull the head and discover (using a cylinder bore gauge) that the cylinders are badly worn, then you might consider the effort and expense of a total engine rebuild.




Thanks Patrick, that was kind of my thought as well... that the issue is with the valves. You've probably seen the video that I've posted before, the car runs and drives just fine, so the engine does run. There's no smoke coming out at any point... though I've not bothered to floor it. I actually have a valve that I took from a top-end rebuild I did many years ago on an 84 Fiero that I had... it had... don't really know how to explain it, not a crack, but a fissure that developed along the side of one of the exhaust valves where I can only assume it was losing compression. I kept it after I rebuilt the engine (and it sits on my desk) just because I thought to myself at the time how crazy it is that the engine ran like this.

If this was a car that I owned for myself and was just going to putz around in, I'd probably just have the cyl head rebuilt. But for me, I want it to be a learning experience for my daughter, so I intend to rebuild it regardless so she'll have that experience. But like you said... my opinion is that it's the valves, and not the block itself. But I will buy a cyl bore gauge.



quote
Originally posted by theogre:

Is likely test is wrong for many reason because likely won't start, burning a lot oil, and other problems to get those very low numbers.

Let's assume you did the test right and is a Dry test....
Still May not = to rebuild.

More so if car has been parked for months or years.

Rings and Valves get "stuck" in crap and can leak until have run @ highway speeds for an hour or more.
More so if fools don't change the oil.

1. Get a bore scope and look into the spark plug hole w/ piston at bottom. Look for damage cyl walls. If true, you need a machine shop or get another engine. look in 1 4 then 2 3. If #4 piston is clean(er) then likely bad intake gasket sucking coolant.
2. If parked, Run the engine then wait to cool/cold and test again. Valve Lifters and more need to run to get oil flowing and if not screw up the meter reading.
3. Then Do a Wet pressure test. Wet test helps tell you if the rings are bad/stuck even if cyl walls look good.
4. try a leak down test too. loaner/rental tools may have that tool.



Thanks Ogre, the test was done with the car sitting (having not started) for 2 weeks. Before that though, the car ran and drove fine. This is the video I posted earlier that shows me driving it around the block: https://www.youtube.com/watch?v=1lrNs5OyhXA

It had been warmed up for about 5 minutes before this, and drove maybe less than a mile. Before we bought it, it had been driven regularly and the owner never mentioned any issues. When I pulled the spark plugs, they looked to be fairly new (as though they had been changed within the past year), and weren't dirty or covered in soot either. They all looked the same.

I used a normal compression testing gauge that screws into the spark plug hole. The car had been sitting for two weeks, and with a charged battery, we cranked it about 6 times for each spark plug. Cyl 4 was the best. I have a bore scope (or really, something like it that will fit in there from Harbor Freight), maybe I'll do that and see if I can tell what condition the combustion chambers are in. I plan to pull the engine in the next weekend or two.



quote
Originally posted by pmbrunelle:

I don't think you can know in advance the exhaustive list of what will be needed for a given rebuild.

At a minimum, everything is taken apart for cleaning/inspection.

Then, depending on your observations/measurements, you can decide what needs replacing/machining. We can't say at this time what preparation the crankshaft (or other parts) needs.

If you're lucky, and almost nothing needs changing, then you have gained peace of mind by having evaluated the state of everything.

More importantly, the value in a complete teardown is that your daughter can handle a crankshaft and other key components; I wouldn't do just a top-end rebuild in this case.




Yeah, that's the biggest thing for me... my daughter gaining this experience, otherwise I'd just put something else in there.