Top End Rebuild

Getting close to the 200k miles...figure time for the top end rebuild...squeeze some more life out of her...any recommendations for kits or just piece it as required???

Unless there is a problem I wouldn't bother with it and just save for a full rebuild or replacement at 250 ish or whenever it quits.

Traxx said:

Unless there is a problem I wouldn't bother with it and just save for a full rebuild or replacement at 250 ish or whenever it quits.

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I agree. Im not a fan of fixing things that arent broken.

Is it making any noise?

It's running rough...I've changed out cops....plugs...air filter. .cleaned throttle body and maf sensor...even battery terminals are clean cel is on for misfire/lean bank....eats a little oil...no leaks..it's only rough till 25mph...then smooth...

no problem moving cross country last year...

Any codes?

Odimus said:

..it's only rough till 25mph...then smooth...

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Haha! It's a 5 cylinder. It's like trying to run with a leg missing. You'd run rough too! :giggle:

For misfire and I think lean bank.....will have to get it checked again

That's sort of the thing you lead with lol. At 200k personally I would just pull it and drop it off at a machine shop for rebuild. Unless you enjoy taking it all apart again in 30-50k anyway.

Odimus said:

For misfire and I think lean bank.....will have to get it checked again

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Odimus said:

For misfire and I think lean bank.....will have to get it checked again

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Check your intake manifold bolts. Mine had loosened up at one point and caused those two codes. Just like yours, it was only an issue at idle and very low speed.

I'll take a look...is it a pain to tighten? A lot of things to remove to get to the bolts? Limited to the wrenching I'm allowed to do due to health..

Took it out for a couple hours...after first hour idle was smooth but acceleration was still rough through 30ish...will take a look at the manifold bolts in the morning

I've had spotty luck cleaning MAF's in the past (using the correct cleaner/proceedure). A lot of times it helps, not always, and that seems to be a pretty consistent message I've read by others on various forms over the years. Do you have the ability to read the voltage on a scanner? (or backprobe to a multimeter). On a Jetta I had the MAF was at the outside edge of spec (as read through a scanner), but still just within spec after cleaning. I was reluctant to fork out $60 for a new one. After I ultimately replaced it, it brought the voltage readings closer to 'ideal' and corrected the engine missing issues. So, I'm not saying that's *is* the problem, but something to keep in mind as you cross off the rest of your troubleshooting items. Also have you put a vacuum gauge on it and check vacuum readings? Another possibility is a bad coil pack or even a cracked spark plug (cracked underneath or internally). EGR?

It might be helpful to run a compression test on your engine too. And maybe a leakdown test, and a vacuum test BEFORE starting or planning potential engine "refreshing" work. A compression test can tell a few things which could guide whatever it is you need to do. You should cock open the butterfly first (may have to remove a wire), remove all the plugs, engine warm. Record carefully what you see. Using only 4 'puffs' per cylinder:

Normal: Compression builds up quickly and evenly to specified compression on each cylinder
Piston Rings: Compression low on first stroke, tends to build up on following strokes but does not reach normal. Improves considerably with the addition of oil.
Valves: Low on first stroke, does not tend to build up on following strokes. Does not improve much with the addition of oil
(You may want to read the specific H3 process out of a H3 manual, above is general GM process)

https://www.ebay.com/itm/Fuel-Pump-...-Carburetor-Pressure-Diagnostics/142006103841

I would almost suggest, if you're going to take it apart to re-do the head, you may as well consider taking out the rest and redo the block ....considering 200k. But look at the block cylinder wear after you get the head off and see what sort of ridge you see. Some blocks like older Toyota blocks were high nickle content iron and even after 120-150k you could still see the original crosshatches with virtually no ring worn the top of the cylinder. I've seen it myself on two engines I took apart. Kind of amazing. A lot also depends on maintenance and driving conditions.

What is the reputation of these blocks for wear? Anybody know?

I remember a few years ago reading about a Colorado guy doing a rebuild and looking into how they remove the cylinder sleeves for when he was doing a rebuild I guess they were fine and he just honed them and moved on.

Don’t waist your time on top end, 5 cyl life expectancy ~125/140 mil

5 cylinder is not produced anymore

Rebuilt whole thing and be done with it
Longer u wait more ware will be there and more $ to rebuild
I rebuilt one this summer ~2.5 k and 2.5 labor.
Ended up with ~6 k due to spun bearing and more internal damage ~125k on truck


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The I5 routinely goes 250k+ if proper maintenance is kept.

I would never pay 6k to have an I5 motor rebuilt, plenty of low mile engines on ebay to have shipped in or I would just buy another H3.

Traxx said:

The I5 routinely goes 250k+ if proper maintenance is kept.

I would never pay 6k to have an I5 motor rebuilt, plenty of low mile engines on ebay to have shipped in or I would just buy another H3.

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Depending on my life situation when my I-5 croaks, I may spring for a v-8 swap. Almost 2/3 of the way there at 6k.

I’ll probably rip an I-5 out of a Colorado, if they’re still abundant by the time I need one.

There are varying degrees of "rebuildness" depending on how far a guy wants to go. Nobody can say until it's taken apart and inspected. Could be cylinders look great and perhaps a good honing is all they need. Clean the pistons and other parts. Or even new pistons if need be. Measure the crank and cam. It's entirely possible the crank is serviceable, cam's probably not, but who knows? Let's say new cams, moderate head work, valve job, etc, a guy could be into it for significantly less. Depends if yer doing it for fun or paying a rebuilder too. Maybe at that point it's not 100% 'new', but maybe 90% at half the cost. Things could go the other way too if most of the parts are too worn.

But then you have to look at the rest of the vehicle and at that point how much wear is the rest of the drivetrain going to have ...would it go another 200k miles w/o major and costly upkeep? It's a good question. Hard to say. Possibly. Maybe now is the time to stock up on another 120k mile rig while you can still find one!!! Ha ha..

Like others say, a used engine is a definite idea too.

Thanks for all the info...due to health restrictions right now I'll have the guys down the road check for any vacuum leaksand go from there...I'll keep an eye out for some possible engine swaps if it comes to it...its a great rig...never failed me...wife got it for me when I retired from the military...

Odimus said:

Thanks for all the info...due to health restrictions right now I'll have the guys down the road check for any vacuum leaksand go from there...I'll keep an eye out for some possible engine swaps if it comes to it...its a great rig...never failed me...wife got it for me when I retired from the military...

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I've got an F150 that can haul *** and a lot of ****, but I still love taking the H3 out, especially in late spring through summer when I can throw the tube doors on. When the I5 goes belly up, I'm hoping funds and life allows me to put in an LS3 and SAS/OD Dana44 (wink), that would make this rig perfect!