94 F350 White smoke low compression

TheRagnarok · Jan 20, 2020

White smoke came back after advancing the injection pump.
It would start clean, and then start smoking after 5 seconds.
After considering new injectors, I got off my ass and did a compression test....

--Back--
200-|-400
350-|-380
380-|-420
418-|-380
-Front-

Is it worth even going any further at this point?
If I were to guess, its either a whole in the piston, head gasket, burnt valves, bent/bad rockers, or a bent/bad push rod.

I just bought some seats from a 97 power-stroke last Sunday and I asked the guy what he wanted for the motor, ECU, harness, dash...... $1000 with only 250k on the motor.
That is another option.

IDIBRONCO · Jan 20, 2020

I could be wrong, but I don't think you could get 200PSI compression with a hole in the piston. It's your truck, your money and your time, but I say keep going. It may be time to pull the engine out or at least start by pulling the valve covers. Then go deeper. You'll figure this out eventually.

riphip · Jan 20, 2020

I'm betting on a bent rod on #7 if engine has no turbo. Any knocking noise?

TheRagnarok · Jan 21, 2020

Ya, I'm going to pull the valve covers this weekend and check the valve train.

This is a non turbo IDI with 330K, And I couldn't hear any noticeable knock.

DaytonaBill · Jan 21, 2020

Can you hear a whistling or chuffing sound at the exhaust or air cleaner?

TheRagnarok · Jan 21, 2020

Yes, definitely a chuffing sound from the exhaust.
I posted on here not to long ago and fixed the smoke by advancing the injection pump.
Truck has probably been driven less that 10 miles after that and sat for a week.
Started smoking again which led to the compression test.
Here is a video of the exaust.

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Philip1 · Jan 21, 2020

Cuffing out the exhaust usually indicates a bent exhaust valve or some other issue bleeding compression out the exhaust

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riphip · Jan 21, 2020

You may get lucky and it will only be a broken exhaust valve spring & not allowing the valve to seal thus low compression.

IDIBRONCO · Jan 21, 2020

The chuffing out of the exhaust is usually a bad exhaust valve guide. It lets the valve tip slightly so that it doesn't seat completely. Not seating completely would sure explain the low compression on that cylinder. When you pull the valve cover, if there's black, sooty looking stuff on the bottom side of the valve cover, on the valve spring, or anywhere around the exhaust valve (on the cylinder with low compression) that's a sure sign. Then you know that it's time to do some valve work. If you do one, you should do all of them. All of the valves have 330,000 miles. Hopefully it's just a broken valve spring like riphip said, but it may not be.

TheRagnarok · Jan 27, 2020

So I did the compression test on cylinders 5 and 7 with charged batteries.
Cyl 5 went from 350 to 420 and cyl 7 went from 200 to 250.
Used a little oil in cyl 7 to check the rings and the psi stayed at 250.
I did notice that one of the valve springs seemed to slightly "wiggle" when turning over the motor.
Now I'm leaning towards valve guides as some of you have mentioned. And that last springs looks poopy.

So A local shopped quoted me $300 per head for an repair and by the time I get gaskets I will be up to $700 total.
I couldn't see myself just rebuilding the top end, so think a full tear down/rebuild is better.

And old boy with the power stroke wont return my text or call, hahaaa.

I did find a 7.3 IDI with a supposedly 65k miles for only $1000 in Atlanta. I may jump on that and you bet ima bring a starter and batteries to do a comp test!

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IDIBRONCO · Jan 27, 2020

It does appear that the guide may be bad in that last picture. The whole rebuild or the other engine may not be a bad way to go at this point. That sludge will probably be all through the rest of your engine too.

Macrobb · Jan 27, 2020

IDIBRONCO said:
That sludge will probably be all through the rest of your engine too.

I will say that a couple of short oil change intervals and perhaps some MMO will clean up that sort of sludge real quickly. It's not the end of the world.

TheRagnarok · Feb 2, 2020

All cylinders on the passenger side still had a visible crosshatch, and the lifter valley looked clean.
I took off both of the Cylinder#8 valve springs and the intake valve had significant moment.
The exhaust valve barely had any play in it and the exhaust valve stem seal crumbled apart.
There is a good bit of carbon buildup on the suspect cylinder.

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94 F350 White smoke low compression

TheRagnarok

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IDIBRONCO

IDIBRONCO

riphip

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TheRagnarok

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DaytonaBill

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TheRagnarok

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Philip1

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riphip

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IDIBRONCO

IDIBRONCO

TheRagnarok

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IDIBRONCO

IDIBRONCO

Macrobb

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TheRagnarok

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