OT. Diesel Engine rebuild?

Hobby Shop · Oct 19, 2020

I bought a low hour engine from a salvaged tractor. Its been sitting outside under a tarp for years when I bought it. I pulled the injectors, spun the engine and #1 exhaust valve is sticking. There’s not a scratch or imperfection the length of the bores and I can still see all the crosshatching. I checked with telescope gauges and it showed .0005” of being perfect. I’ll check again with a bore gauge when the pistons come out.

It looks like some water got in there because there’s a little bit of rust at the top of #1 cylinder. All 3 cylinders look smooth or somewhat glazed. I also had to smack the 1/2” ratchet with my hand to get it to initially rotate but it didn’t take much to turn over.

Unless someone tells me differently, the plan is to put the block on the radial drill, run the Sunnen AN-100 hone through it with a 180-220 grit stone, clean everything up, put all new rings and reassemble. The engine is a 66hp turbo diesel with 4.400” bore.

Any and all help is always appreciated, I’ve rebuilt plenty of dirt bike engines over the years but this is is my first go at a diesel engine overhaul and I’d like to get it right.

Andy

Bill D · Oct 19, 2020

A injector pump rebuild is basically identical in parts and cost to the engine it fits. If the engine has rust the pump may need a rebuild as well.
Bill D

PackardV8 · Oct 19, 2020

We're an engine shop and don't usually discourage folk from wanting to rebuild, but those engines routinely sit outdoors for months and years, are cranked up and run against the governor until that job is done and then parked outdoors for months and years.

Look it over and ask yourself what you're risking by cranking it before tearing into it.

jack vines

GregSY · Oct 19, 2020

The question I have is just what exactly is 'a little rust'? That bears further explanation....

Garwood · Oct 19, 2020

Doesn't sound broke to me.

I have an old 12 valve Cummins that must have been ran without an air filter or really bad injectors for a long time. It was pulled from a wrecked truck and sat outside in the rain for 10 years before I bought it. I pulled the head, scraped the rust out with a razor blade and berry honed it enough to get it to turn over. Hell of a ridge.

I bought it as a core to rebuild, but decided not to and just put it in the old truck that will rarely get driven. It runs fine with new injectors. You'd never know it has .020" wear and rust pits in the cylinder walls.

dkmc · Oct 19, 2020

So it's within .0005.......with a telescope gauge...
Near perfect how? Round? Taper? What are you intending to do with the hone? How much are you taking out? Sounds like a quick pass with a glaze breaker is all that's needed. But if it's a good as you say, then why take it apart without running it and checking it's performance, save a lot of time and expense.

john.k · Oct 19, 2020

Agreed ,scrape rust away with a razor blade,just to stop it getting in the oil eventually,oil the bores,free the valves with a splosh of kerosine ,refit the head,pout oil over the valves,rockers etc,and see if the pump is pumping fuel in spurts .......spray test the injectors .....if you dont have a tester ,hook them to the fuel lines outside the engine...if the fuel is spraying evenly,the engine will run.......Ive rebuilt countless diesels over 60 years,plenty of salvage motors got running again,to give good service.

edwin dirnbeck · Oct 20, 2020

You should have pulled the head FIRST,and oiled all the cylinders.Mice will carry stuf up the exhaust pipe past the valve and into the cylinder.If a cylinder is rusted ,oil it up and try to rotate the engine so that the piston goes down. The most rust is usually above the piston because that is where water and debris collect.Why would you try to rotate a stuck engine? Edwin Dirnbeck

Mark Rand · Oct 20, 2020

You've got one sticking echause valve and no other problems. Take that valve out and clean it and its valve guite. Then put the engine back together and run it in. There's no reason why yhou shoud do anything else unles you think some of the rings are gummed up. on an injector isn't workiing. Those wil be obvious once you run it.

DDoug · Oct 20, 2020

Garwood said:
I bought it as a core to rebuild, but decided not to and just put it in the old truck that will rarely get driven. It runs fine with new injectors. You'd never know it has .020" wear and rust pits in the cylinder walls.

Yabutt the people driving behind you doo.....:d

texasgeartrain · Oct 20, 2020

Hobby Shop said:
. . .#1 exhaust valve is sticking.

It looks like some water got in there because there’s a little bit of rust at the top of #1 cylinder.

I can still see all the crosshatching.

. All 3 cylinders look smooth or somewhat glazed.

With #1 exhaust valve stuck, and rust at top of #1. . . That tells me rain water came down the exhaust. You may be able to save the valve if you pop it out and clean it, but replacing with a new valve is cheap anyway. Might need a little wire brush from a gun cleaning kit or something to scrub valve guide hole a bit.

Glazed would be an expression that crosshatch is not there. But you said all 3 had crosshatch. If it indeed has all the crosshatch you do not need to hone. I'd probably pull #1 piston to ensure rings are not stuck in piston grooves though, from the water sitting on that cylinder for unknown time. Might consider rings for that one cylinder.

With it cleaned and freed up you could run it without issue, even with a little water marking the top of the one cylinder.

Hobby Shop · Oct 20, 2020

Thanks for all the replies.

Using a bore gauge, Cyl. 2 & 3 has a .001” taper but are perfectly round so they’re good to go. They look exactly the same and cleaned up really nice. I can move the pistons around in the bore a little bit and checked with feeler gauges, both pistons are perfectly centered.

Here’s a couple pictures of the cylinder in question.....
Cyl. #1 has a .0015” taper but it’s rusted, scratched up and pitted a couple inches from the top. It won’t wiggle in the bore and is off center to one side. Maybe a rusted up ring? Hopefully the picture will show it.

I did pour some oil in the injector holes before trying to turn it over. I’m not trying to create work but the head was coming off to fix the stuck valve so this is where I’m at.

Garwood · Oct 20, 2020

digger doug said:
Yabutt the people driving behind you doo.....:d

Higher RPM's I can tell it's not a go-getter. Doesn't smell like burning oil at all. Blowby isn't bad.

I think a stock Powerstroke is worse.

texasgeartrain · Oct 20, 2020

Hobby Shop said:
Cyl. #1 has a .0015” taper but it’s rusted, scratched up and pitted a couple inches from the top. It won’t wiggle in the bore and is off center to one side. Maybe a rusted up ring? Hopefully the picture will show it.

The rings for #1 you want to address, be it cleaning them and piston grooves, or replacing the rings for that piston.

The cylinder liner wall, while ugly, will run all day long without smoke or power loss.

Being on the gulf coast with hurricanes, massive heavy rain. . . I see engines flooded with water fairly often. We clear the flooded cylinder and send it on its way. A caveat would be if you hit the start button with water on cylinder, which could bend a rod.

Based on your story and picks I doubt that here, with stuck valve and all. You barred it by hand etc. But a quick check on a bent rod, roll the engine over by hand and watch the peak of each piston in cylinder. If one piston was noticeably lower at the peak, like 1/8" to 1/4", that rod would be bent.

kustomizingkid · Oct 21, 2020

Thats rust aint nothing... I pulled apart a running 6.0 Powerstroke that had was more rust in the cylinders from water+blown head gaskets. Unless this is a critical engine that is getting run 8+ hours a day I would do nothing.

Garwood · Oct 25, 2020

kustomizingkid said:
Thats rust aint nothing... I pulled apart a running 6.0 Powerstroke that had was more rust in the cylinders from water+blown head gaskets. Unless this is a critical engine that is getting run 8+ hours a day I would do nothing.

I make parts for 6.0's. When I was first developing stuff for them I bought a 2005 F-350 that was a good runner. Upon teardown I found one of the passenger bank cylinders had an area of heavy pitting an inch down in the hole you could loose a quarter in. Metal gone, corroded away. The rings just skipped right over it.

kustomizingkid · Oct 25, 2020

Garwood said:
I make parts for 6.0's. When I was first developing stuff for them I bought a 2005 F-350 that was a good runner. Upon teardown I found one of the passenger bank cylinders had an area of heavy pitting an inch down in the hole you could loose a quarter in. Metal gone, corroded away. The rings just skipped right over it.

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