Rebuilt Motor - Failure. Hypothesize (2 Viewers)

[concretejungle]

We also haven't talked about what your break-in looked like for the new rings/old walls. if those new rings didn't seat right on the cylinder walls you can expect some of these issues.

well it's been a little over 10 years but I remember using a specific oil for the break-in. I recall having to run it at certain RPM's for a certain time and then changing the oil. But I don't recall exactly what that process was.

 

[Marvelicious]

Your previous go around wasn't a rebuild, more like a minor refresh, the valves looked ok so they were left alone. Rings were put into a honed cylinder instead of bore and new pistons and rings. When I did mine it was a 'partial rebuild' which included line bore, rod resizing, new +1 sized pistons, new rings, all new bearings, new oil pump bushing, a 'full valve job', timing chaing components, injector service, cometic gasket, arp head bolts, all new hoses, etc...

On mine the machine shop hosed up the 'full valve job' which caused the engine to burn oil and after only 50K miles, a premature failure. They did so by not bothering to check spring pressure. They also didn't mention that the exhaust valve guides were worn. The worn out valve springs didn't provide sufficient seat pressure for valve cooling which caused the valve faces to erode and loss of compression. So I had to do a head job after only about 50K. This required all new OEM valves, all new OEM valve springs, and new OEM exhaust valve guides. The proper head job cost over $2K on it's own, plus I had to replace the cometic head gasket.

So my point is, that if you want OEM original, like new reliability, you have to go all in. If you do it half-way your results may vary.

I'm with you. Doing a refresh is a roll of the dice. @concretejungle I hate to say it, but it looks like you rolled the dice and lost. You may have other issues that caused it, or it may be that something you didn't replace is the source of the failure, but you got ten years out of it (even though you didn't put many miles on it).

A motor swap doesn't tend to come with any warranties either.

 

[mudgudgeon]

I understand that, however I'm trying to figure out the path forward. I'm a little hesitant to "tear down and rebuild" and go back with what I had if this happens again. Also considering just sending the truck off and having someone else fix it and if I do that I need to know what the plan is. Do I put the supercharger back on without figuring out what happened? Do I sell the SC and try a turbo? Do I swap a V8 in?

You tear it down, do you have the experience to do a full and thorough analysis and trouble shoot?

If you pass it off to someone else, are they going to put in the effort? Or just go ahead, business as usual?

You may never know for sure what the root cause is.

Ignoring blackened plugs repeatedly is kinda telling.
Shouldn't ignore the spidey senses.
If something looks odd, smells odd, sounds odd etc, investigate.
BTDT waaaay too many times!

 

[mudgudgeon]

I'm with you. Doing a refresh is a roll of the dice. @concretejungle I hate to say it, but it looks like you rolled the dice and lost. You may have other issues that caused it, or it may be that something you didn't replace is the source of the failure, but you got ten years out of it (even though you didn't put many miles on it).

A motor swap doesn't tend to come with any warranties either.

I agree with this. Refresh is not the same as rebuild.
Refresh, we tend to go "Ehhhh, . . . it'll do!" And cut a lot of corners.
Its a roll of the dice for sure

 

[Trollhole]

Put a borescope in it and look at everything. I can't ever remember just putting a new set of rings on a motor without honing the block. Also carbon buildup can cause all kinds of issues.

 

[concretejungle]

he did hone the block on the surface for the HG replacement but felt the cylinder walls didn't need it.